Sound Practices Mailing List Files - Volume 2
=========================================================================
From: "Rice, Doug" <RICEDA@phibred.com>
Subject: [JN] Baby-O
Date: Thu, 16 Mar 2000 09:30:33 -0600
Source: Sound Digest Archive v02.n485
Could someone copy Gordon's Baby-O article from SP#9 for me? I can't get a
back issue from Joe.
A gift of appreciation will be sent.
Or, if anyone has a spare issue 9, I would love to buy it!
Thanks in advance,
Doug Rice
=========================================================================
From: rcjones1@mmm.com
Subject: [JN] Baby on the way
Date: Tue, 18 Sep 2001 13:50:32 -0500
Source: Sound Digest Archive v02.n977
All,
As an "infrequent regular" on the list I want to let everyone know that my
wife and I are expecting our first child early next year.
Oh and my 76->71a->6B4G amp sounds great!
Richard&Joyce
=========================================================================
From: Steven S <steven@403forbidden.net>
Subject: Re: [JN] Baby on the way
Date: Tue, 18 Sep 2001 17:16:46 -0400 (EDT)
Source: Sound Digest Archive v02.n977
congrats,
I'm not the daddy type so I work too much, brew beer and build too much
crap (amps, speakers, hot rods) for my own good but.. all my friends are
doing it! Just dont go naming him/her blackie or joe!
On Tue, 18 Sep 2001 rcjones1@mmm.com wrote:
> All,
>
> As an "infrequent regular" on the list I want to let everyone know that my
> wife and I are expecting our first child early next year.
>
> Oh and my 76->71a->6B4G amp sounds great!
>
> Richard&Joyce
>
=========================================================================
From: "Phil Sieg" <triodelover@home.com>
Subject: Re: [JN] Baby on the way
Date: Tue, 18 Sep 2001 17:37:07 -0400
Source: Sound Digest Archive v02.n977
Congrats to both of you. Here's wishing your wife a complication-free
pregnancy, an easy delivery, and both of you a healthy, joyful offspring.
Best,
Phil
- ----- Original Message -----
From: <rcjones1@mmm.com>
To: <sound@lists.io.com>
Sent: Tuesday, 18 September, 2001 14.50
Subject: [JN] Baby on the way
> All,
>
> As an "infrequent regular" on the list I want to let everyone know that my
> wife and I are expecting our first child early next year.
>
> Oh and my 76->71a->6B4G amp sounds great!
>
> Richard&Joyce
>
>
=========================================================================
From: "Phil Sieg" <triodelover@home.com>
Subject: Re: [JN] Baby on the way
Date: Tue, 18 Sep 2001 17:59:17 -0400
Source: Sound Digest Archive v02.n977
Howsa 'bout David Harold Thomas Jones. Or Deborah Hillary Theresa Jones.
Either way, the kid would be DHT Jones ;-).
Phil
- ----- Original Message -----
From: <rcjones1@mmm.com>
To: "Phil Sieg" <triodelover@home.com>
Sent: Tuesday, 18 September, 2001 17.38
Subject: Re: [JN] Baby on the way
>
> Thank you for your best wishes! I hope it goes well. How about "triode"
> as a name?
>
> :)
>
> Richard
>
>
>
>
>
> "Phil Sieg"
> <triodelover@ho To: Richard - BIE C.
Jones/US-Corporate/3M/US@3M-Corporate
> me.com> sound@lists.io.com
> cc:
> 09/18/01 04:37 Subject: Re: [JN] Baby on the
way
> PM
>
>
>
>
>
>
>
> Congrats to both of you. Here's wishing your wife a complication-free
> pregnancy, an easy delivery, and both of you a healthy, joyful offspring.
>
> Best,
>
> Phil
> ----- Original Message -----
> From: <rcjones1@mmm.com>
> To: <sound@lists.io.com>
> Sent: Tuesday, 18 September, 2001 14.50
> Subject: [JN] Baby on the way
>
>
> > All,
> >
> > As an "infrequent regular" on the list I want to let everyone know that
> my
> > wife and I are expecting our first child early next year.
> >
> > Oh and my 76->71a->6B4G amp sounds great!
> >
> > Richard&Joyce
> >
> >
>
>
>
>
>
>
=========================================================================
From: Nicholas McKinney <nick@lambdacoustics.com>
Subject: [JN] Baby Photos
Date: Thu, 11 Nov 1999 18:58:28 -0500
Source: Sound Digest Archive v02.n330
Hi guys, I took my baby to the photo shop to get a few pictures taken, hope
you like.
http://www.lambdacoustics.com/products/tubedrivers.html
cya
Nick
Nicholas McKinney
Lambda Acoustics Inc.
www.lambdacoustics.com
=========================================================================
From: Bjorn Kolbrek <bjornk@studpors.hit.no>
Subject: [JN] Back again
Date: Wed, 22 Aug 2001 14:45:37 +0200
Source: Sound Digest Archive v02.n953
Hello folks!
I'm back on the list again. To all I met at the ATF: Thanks for a great time
and many inspiring ideas. Not much done yet, but I work on it. I also hope
to update my homepage soon with pictures and shematics.
Regards,
Bjørn
- -------------------------------------------------
__/\__
/ ____ \ Bjørn Kolbrek
| | || | |
| | || | | bjornk@studpors.hit.no
| | || | | http://www.geocities.com/la1zka
| | || | |
| |____| |
| /||||\ |
--------
| | | |
- -------------------------------------------------
=========================================================================
From: Steven <stevensl@mindspring.net>
Subject: [JN] Back issue of speaker builder anyone?
Date: Tue, 14 Mar 2000 18:59:54 -0500 (EST)
Source: Sound Digest Archive v02.n483
Looking for a copy of Speaker Builder 97 & 98
on the snail horn and snail II horns..
hate to spend $64 bucks for 2 articles...
;-)
steven
=========================================================================
From: "Bert Doppenberg" <lowther@wxs.nl>
Subject: [JN] Backloading Lowther
Date: Thu, 27 May 1999 10:11:27 +0200
Source: Sound Digest Archive v02.n153
Hi Johari, all,
>Well, I'm not sure what this 250Hz frequency "dip" sounds like but I sure
>would appreciate any fellow Lowther fan on this list, who have had
>experience with the MAU IVs, to show me how to look out for this "dip".
>Anyway, I did noticed that kickdrums on the MAU IVs do sounded a wee bit
>"recessed" and "mused". Is this the frequency "dip" we're talking about?
I have the Mauhorn driven by the DX4's. The low-mids are a bit shy compared to the hights
and low frequencies. Classical music does sound not bad at all. I like the Mauhorn most
(except for the Carfrae horns!) for single driver horns I've heard. The Medallion does do
a better job (more colouration though) in the low-mids but lacks a bit in bass extension.
It's always a compromise using a backloaded horn with Lowther...
>I'm also curious to know how the DX3/DX4 driver sounds in the MAU IVs. Will
>the 150Hz front horn "except" the DX4 driver in this application? I was
>told that the PM4A is the best option.
The DX4 is a very good candidate for the 150 front horn approch. I should try the front
horn on the Mau horns if i can find the time...
Regards,
Bert,
- ------
E-mail:
Business : BD-Design@lowther.nl
Private : BD@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Tel./Fax: (0341) 254500 Mobile: (06) 51242990
=========================================================================
From: "johari yip" <hfyip@pacific.net.sg>
Subject: [JN] Re: Backloading Lowther
Date: Thu, 27 May 1999 22:32:54 +0800
Source: Sound Digest Archive v02.n153
- ----- Original Message -----
From: Bert Doppenberg <lowther@wxs.nl>
To: Johari Yip <hfyip@pacific.net.sg>; <sound@lists.io.com>
Sent: Thursday, May 27, 1999 4:11 PM
Subject: Backloading Lowther
>
Bert, everyone
>
> I have the Mauhorn driven by the DX4's. The low-mids are a bit shy
compared to the hights
> and low frequencies.
The same conclusion as mine proving that it's not the cause of a specific
driver but rather the horn design shortcoming.
Classical music does sound not bad at all. I like the Mauhorn most
> (except for the Carfrae horns!) for single driver horns I've heard. The
Medallion does do
> a better job (more colouration though) in the low-mids but lacks a bit in
bass extension.
> It's always a compromise using a backloaded horn with Lowther...
I have been listening to the Acousta 115 with the 7A previously and found
the MAU IVs with the same drivers sounded thinner in the lower mid and mid
as compared to the Acousta. Colouration of the Acousta enclosure maybe?
>
>
> The DX4 is a very good candidate for the 150 front horn approch. I should
try the front
> horn on the Mau horns if i can find the time...
Great. Keep me in the loop, Bert. Should be interesting
Johari
=========================================================================
From: "Robert Lamarre" <rlamarre@rlacoustique.com>
Subject: RE: [JN] Backloading Lowther
Date: Thu, 27 May 1999 19:28:26 -0000
Source: Sound Digest Archive v02.n154
Bert,
I agree with you on all accounts about the shiness in the low mids on the
Mau IV and "Extra" low mids in the Medaillons.
But as you put it, it is really coloration ( from the box, I might add)
How are your impressions on the sound of the Carfrae. They look real nice,
thats for sure.
Cheers,
- -------- Robert Lamarre --------
- ----- RL Acoustique, Canada ----
- ------ Ph/Fx: 450-653-3461 -----
- --- rlamarre@rlacoustique.com --
- ----- www.rlacoustique.com -----
- -----Original Message-----
From: owner-sound@lists.io.com [mailto:owner-sound@lists.io.com]On
Behalf Of Bert Doppenberg
Sent: Thursday, May 27, 1999 8:11 AM
To: Johari Yip; sound@lists.io.com
Subject: [JN] Backloading Lowther
Hi Johari, all,
>Well, I'm not sure what this 250Hz frequency "dip" sounds like but I sure
>would appreciate any fellow Lowther fan on this list, who have had
>experience with the MAU IVs, to show me how to look out for this "dip".
>Anyway, I did noticed that kickdrums on the MAU IVs do sounded a wee bit
>"recessed" and "mused". Is this the frequency "dip" we're talking about?
I have the Mauhorn driven by the DX4's. The low-mids are a bit shy compared
to the hights
and low frequencies. Classical music does sound not bad at all. I like the
Mauhorn most
(except for the Carfrae horns!) for single driver horns I've heard. The
Medallion does do
a better job (more colouration though) in the low-mids but lacks a bit in
bass extension.
It's always a compromise using a backloaded horn with Lowther...
>I'm also curious to know how the DX3/DX4 driver sounds in the MAU IVs. Will
>the 150Hz front horn "except" the DX4 driver in this application? I was
>told that the PM4A is the best option.
The DX4 is a very good candidate for the 150 front horn approch. I should
try the front
horn on the Mau horns if i can find the time...
Regards,
Bert,
- ------
E-mail:
Business : BD-Design@lowther.nl
Private : BD@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Tel./Fax: (0341) 254500 Mobile: (06) 51242990
=========================================================================
From: "Johari Yip" <hfyip@pacific.net.sg>
Subject: Re: [JN] Backloading Lowther
Date: Fri, 28 May 1999 09:14:34 +0800
Source: Sound Digest Archive v02.n154
- ----------
> From: Robert Lamarre <rlamarre@rlacoustique.com>
> To: Bert Doppenberg <BD@lowther.nl>; Johari Yip <hfyip@pacific.net.sg>;
sound@lists.io.com
> Subject: RE: [JN] Backloading Lowther
> Date: Friday, May 28, 1999 3:28 AM
>
Robert, Bert and all in Joeland,
>
> I agree with you on all accounts about the shiness in the low mids on the
> Mau IV and "Extra" low mids in the Medaillons.
> But as you put it, it is really coloration ( from the box, I might add)
Bob, I remembered sometimes back during our short email exchanges where you
give some hints on how to further improve on the MAU IV shy lower mid
region and one of they is to enlarge the chamber behind the driver by
cutting holes into the bottom reflector separating a void space from the
chamber. Now my question is, will placing an appropriate "spacer" between
the driver and the enclosure effectively enlarge the chamber as well? If
so, how thick such this spacer be? I have thought of using a piece of 1"
plywood as "spacer". Appreciate your feedback.
Johari
>
> How are your impressions on the sound of the Carfrae. They look real
nice,
> thats for sure.
Yes, I'm interested to know as well.
Johari
=========================================================================
From: "Bert Doppenberg" <lowther@wxs.nl>
Subject: Re: [JN] Backloading Lowther
Date: Sat, 29 May 1999 11:48:21 +0200
Source: Sound Digest Archive v02.n157
Hi Robert,
>I agree with you on all accounts about the shiness in the low mids on the
>Mau IV and "Extra" low mids in the Medaillons.
>But as you put it, it is really coloration ( from the box, I might add)
>
>How are your impressions on the sound of the Carfrae. They look real nice,
>thats for sure.
These are great! due the cornere loading, the common low-mid dip is almost gone but the
length of the horn is a bit too long. If you don't listen to the music but to technical
aspects of the system, then the low and low-mids are coming a bit too late in time. For
example, the 'kickdrum" mentioned earlyer doesn't give the "kick" compared to my Oris with
Onken-like subs do.
Bert,
- ------
E-mail:
Business : BD-Design@lowther.nl
Private : BD@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Tel./Fax: (0341) 254500 Mobile: (06) 51242990
=========================================================================
From: "Larry D. Moore" <l-moore@onu.edu>
Subject: [JN] Back on Line!
Date: Sun, 17 Oct 1999 18:00:39 -0400
Source: Sound Digest Archive v02.n304
Just got my new modem up and working here at home. What a bitch! These
things get tuffer every time.
L.D. Mooore
=========================================================================
From: "Thomas Sylvester" <TRS@carlsmith.com>
Subject: [JN] Back on line
Date: Wed, 19 Apr 2000 17:02:31 -1000
Source: Sound Digest Archive v02.n525
I've been off-line since 4/11 (a whale swam over the cable between Hawaii and LA). Can anyone tryin
g to correspond on the OPT headphone amp design please resend?
Thanks, Tom Sylvester trs@carlsmith.com
=========================================================================
From: "Epstein, Jeremy" <JEpstein@ndbcap.com>
Subject: [JN] RE: backwards amp
Date: Fri, 12 Jan 2001 14:37:39 -0500
Source: Sound Digest Archive v02.n783
Conrad says:
>>>>>I cannot believe that someone hasn't suggested it yet, but why
not
+__ spkr___+
) |
) |
+----------+--- *GND*
) |
auto ) |
former ) |
| ----- DC
PLATE --- SUPPLY
+--GRID | #3
| CATH |
| | |
| +----------+ Note *negative* wrt GND
| |
<<<<<
Cool!
>>>Which does take some extra wire:
If we've got 4k:4ohm step down that's sqrt(1000) turns or about
30:1
So the "overhead" of getting the DC out of the spkr is about 3%.<<<<
I'm not sure what this part means. Are you talking about the difference in
ratio between having the secondary contained between the ends of the total
winding vs. having it hang off of one end? Trying to keep up here.
Would this output arrangement invert phase?
>>>>But, the real question is: if we have to wire the "speaker" part
of the "auto"former with a separate gauge to the "plate" part,
how is this different to a conventional transformer?<<<
Well, you would not need an insulation (dielectric) rated for the difference
between the plate voltage and ground, just the AC swing of the output is
all, I guess. And I'm assuming that the coupling between two pieces of one
winding will be closer than between two seperate windings, but as I think
about your challenging question I find I have no basis for that assumption.
One thing: having the speaker section grounded and suppose we wind it
outermost, then we have a built in shield, don't we? But that's no different
either, is it?
- -j
=========================================
Jeremy Epstein........jepstein@ndbcap.com
=========================================
=========================================================================
From: Conrad Drake <conrad@directwest.iinet.net.au>
Subject: [JN] Re: backwards amp
Date: Sat, 13 Jan 2001 14:14:18 +0800
Source: Sound Digest Archive v02.n783
"Epstein, Jeremy" wrote:
> Conrad says:
> +__ spkr___+
> ) |
> ) |
> +----------+--- *GND*
> ) |
> auto ) |
> former ) |
> | ----- DC
> PLATE --- SUPPLY
> >>>Which does take some extra wire:
> >>If we've got 4k:4ohm step down that's sqrt(1000)
> >> turns or about 30:1 So the "overhead" of getting
> >> the DC out of the spkr is about 3%.<<<<
>
> I'm not sure what this part means. Are you talking about the difference in
> ratio between having the secondary contained between the ends of the total
> winding vs. having it hang off of one end? Trying to keep up here.
Correct:
the 30:1 autotransformer needs 29 x N turns of thin wire and one
x N of thick.
the "extended" autotransformer now needs 30 x N turns of thin.
Interestingly, in theory, (from the viewpoint of fixed, if
relative, DCR) the one x N of thick wire "needs" the same cross
sectional area as the 30 x N turns of thin wire.
The impression that I get is that, relatively speaking, the HT
winding is over-provisioned: that is the ratio of gauges used
does not match the turns ratio.
Eg: our 30:1 transformer might use 60ga for the HT, and 2 ga for
the LT. Both of which are outside the "normal" range one sees.
Can anyone who actually winds transformers comment on whether
this reflects (commercial) reality? Or point out the massive
hole in my (zero reference to the manual) theory?
> Would this output arrangement invert phase?
Yes.
> >>>>But, the real question is: if we have to wire
> >>>>the "speaker" part of the "auto"former with a
> >>>>separate gauge to the "plate" part, how is
> >>>>this different to a conventional transformer?<<<
>
> Well, you would not need an insulation (dielectric) rated for the difference
> between the plate voltage and ground, just the AC swing of the output is
> all, I guess. And I'm assuming that the coupling between two pieces of one
> winding will be closer than between two seperate windings, but as I think
> about your challenging question I find I have no basis for that assumption.
It's funny - but my knee jerk reaction would be to wind the
speaker coil first (innermost) and then the HT around the
outside.
I'm afraid I'm not very good at visualising nearfield magnetic
coupling: I'm used to dealing with either far field or capactive
coupling.
Yours,
Conrad Drake
=========================================================================
From: Douglas Purl <dcp@selway.umt.edu>
Subject: [JN] RE: backwards amp
Date: Sat, 13 Jan 2001 14:19:51 -0700 (MST)
Source: Sound Digest Archive v02.n783
I can't recall who now, but one of the late and legendary electroluminati
used to take delight in drawing up circuits in a manner that confused his
colleagues. Maybe we need a competition here.
Doug Purl
=========================================================================
From: "Dave Slagle" <dslagle@earthlink.net>
Subject: Re: [JN] Re: backwards amp
Date: Sat, 13 Jan 2001 17:14:15 -0500
Source: Sound Digest Archive v02.n783
i think martin nailed it... the extended autoformer is nothing different
than a conventional transformer, and the PS makes it look like something
else... look at an input trannie with one side of each winding grounded...
same animal.. (except for the inverting)
> Interestingly, in theory, (from the viewpoint of fixed, if
> relative, DCR) the one x N of thick wire "needs" the same cross
> sectional area as the 30 x N turns of thin wire.
>
> The impression that I get is that, relatively speaking, the HT
> winding is over-provisioned: that is the ratio of gauges used
> does not match the turns ratio.
this goes to the whole thing martin brought up a while ago... the idea of
cheating one or the other, but when it comes down to it, the AC signal is
what dictates losses, and requires by "rule" the primary and secondary have
the same X-sectional area (neglecting losses) this holds try for power
trannies, but when we do bring into consideration the se primary also
carries DC and its associated losses... the ideas of cheating come into
play.
> Eg: our 30:1 transformer might use 60ga for the HT, and 2 ga for
> the LT. Both of which are outside the "normal" range one sees.
it seems this would be an output, or power transformer, at which point i
would think the 50/50 rule should hold...i guess the arguemnet could be made
for cheating either way, but in the case of an IT that delivers voltage...
maybe a little beefier primary would cut losses on one side, without much
penalty on the other?
i guess a bifilar IT would be the test bed... use say #34 on each side for a
matched one, and then #33 and #35 for the other... you could then reverse
the cheating from primary to seconadary... and see what happens.
hell wind it trifilary and this will allow you the option of trying some
current cancellation with the third winding, just terminate it with some CC
diodes, or an active source... or you could parallel the odd winding with
one side or the other.
dave
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] RE: backwards amp
Date: Mon, 15 Jan 2001 10:04:10 -0500
Source: Sound Digest Archive v02.n783
like i said, it's just a matter of where you put the grounds...:)
good one conrad!
and i guess this is not much different from a standard
transformer (assuming you would normally ground the secondary
- - i generally do not...).
so i guess i'm also not sure what the benefit of an autoformer
output stage is (although i do so enjoy these thought experiments).
however, there may be some distinct differences with respect to
voltage gradients, and capacitances, depending upon how you wind and connect
the autoformer...
> ----------
> From: Epstein, Jeremy[SMTP:JEpstein@ndbcap.com]
> Sent: Friday, January 12, 2001 2:37 PM
> To: 'conrad@directwest.iinet.net.au'; Joenet (E-mail)
> Subject: [JN] RE: backwards amp
>
> Conrad says:
>
> >>>>>I cannot believe that someone hasn't suggested it yet, but why
> not
>
> +__ spkr___+
> ) |
> ) |
> +----------+--- *GND*
> ) |
> auto ) |
> former ) |
> | ----- DC
> PLATE --- SUPPLY
> +--GRID | #3
> | CATH |
> | | |
> | +----------+ Note *negative* wrt GND
> | |
>
>
> <<<<<
>
>
> Cool!
>
>
> >>>Which does take some extra wire:
> If we've got 4k:4ohm step down that's sqrt(1000) turns or about
> 30:1
> So the "overhead" of getting the DC out of the spkr is about 3%.<<<<
>
> I'm not sure what this part means. Are you talking about the difference in
> ratio between having the secondary contained between the ends of the total
> winding vs. having it hang off of one end? Trying to keep up here.
>
> Would this output arrangement invert phase?
>
> >>>>But, the real question is: if we have to wire the "speaker" part
> of the "auto"former with a separate gauge to the "plate" part,
> how is this different to a conventional transformer?<<<
>
> Well, you would not need an insulation (dielectric) rated for the difference
> between the plate voltage and ground, just the AC swing of the output is
> all, I guess. And I'm assuming that the coupling between two pieces of one
> winding will be closer than between two seperate windings, but as I think
> about your challenging question I find I have no basis for that assumption.
>
> One thing: having the speaker section grounded and suppose we wind it
> outermost, then we have a built in shield, don't we? But that's no different
> either, is it?
>
> -j
> =========================================
> Jeremy Epstein........jepstein@ndbcap.com
> =========================================
>
=========================================================================
From: "Epstein, Jeremy" <JEpstein@ndbcap.com>
Subject: [JN] RE: backwards amp
Date: Wed, 17 Jan 2001 08:52:54 -0500
Source: Sound Digest Archive v02.n785
Thanks, Conrad. I guess Purl is right - we just have a wacky way to draw a
transformer coupled circuit - I don't really see where the benefit would be
in the negative supply at this point, do you?
- -j
=========================================
Jeremy Epstein........jepstein@ndbcap.com
=========================================
> -----Original Message-----
> From: Conrad Drake [mailto:conrad@directwest.iinet.net.au]
> Sent: Saturday, January 13, 2001 1:14 AM
> To: Epstein, Jeremy
> Cc: Joenet (E-mail)
> Subject: Re: backwards amp
>
>
>
>
> "Epstein, Jeremy" wrote:
> > Conrad says:
> > +__ spkr___+
> > ) |
> > ) |
> > +----------+--- *GND*
> > ) |
> > auto ) |
> > former ) |
> > | ----- DC
> > PLATE --- SUPPLY
>
> > >>>Which does take some extra wire:
> > >>If we've got 4k:4ohm step down that's sqrt(1000)
> > >> turns or about 30:1 So the "overhead" of getting
> > >> the DC out of the spkr is about 3%.<<<<
> >
> > I'm not sure what this part means. Are you talking about
> the difference in
> > ratio between having the secondary contained between the
> ends of the total
> > winding vs. having it hang off of one end? Trying to keep up here.
>
> Correct:
> the 30:1 autotransformer needs 29 x N turns of thin wire and one
> x N of thick.
> the "extended" autotransformer now needs 30 x N turns of thin.
>
> Interestingly, in theory, (from the viewpoint of fixed, if
> relative, DCR) the one x N of thick wire "needs" the same cross
> sectional area as the 30 x N turns of thin wire.
>
> The impression that I get is that, relatively speaking, the HT
> winding is over-provisioned: that is the ratio of gauges used
> does not match the turns ratio.
>
> Eg: our 30:1 transformer might use 60ga for the HT, and 2 ga for
> the LT. Both of which are outside the "normal" range one sees.
>
> Can anyone who actually winds transformers comment on whether
> this reflects (commercial) reality? Or point out the massive
> hole in my (zero reference to the manual) theory?
>
> > Would this output arrangement invert phase?
> Yes.
>
> > >>>>But, the real question is: if we have to wire
> > >>>>the "speaker" part of the "auto"former with a
> > >>>>separate gauge to the "plate" part, how is
> > >>>>this different to a conventional transformer?<<<
> >
> > Well, you would not need an insulation (dielectric) rated
> for the difference
> > between the plate voltage and ground, just the AC swing of
> the output is
> > all, I guess. And I'm assuming that the coupling between
> two pieces of one
> > winding will be closer than between two seperate windings,
> but as I think
> > about your challenging question I find I have no basis for
> that assumption.
>
> It's funny - but my knee jerk reaction would be to wind the
> speaker coil first (innermost) and then the HT around the
> outside.
>
> I'm afraid I'm not very good at visualising nearfield magnetic
> coupling: I'm used to dealing with either far field or capactive
> coupling.
>
> Yours,
> Conrad Drake
>
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: backwards amp... wuz [JN] What power supply
Date: Tue, 9 Jan 2001 11:31:25 -0500
Source: Sound Digest Archive v02.n779
oops... suppose i should have retitled this..
>Dave, you mention autoformer coupling, presumably for conventional speaker
>and dc offset issues, but assuming the current is accurately balanced
>between each half, then you've got no dc if you're output taps are
>symmetrical about CT? Of course, if one tube goes kaputt, then you may have
>a problem, then again, maybe not too much to worry about depending on the
>resistance of the "secondary".
i was referring to SE usage... i should have made that clear
reposted under new header
for the longest time i have been wanting to build a
backwards amp... i have the design, just haven't come up with all the iron
and figured out all the rubs yet
using the idea that the worst place for a transformer is on the output of
an amp, why not flip the whole thing around. all the transformer does is
impedance match and isolate, we could use an autoformer and ground the
output and use negative supplies, hell you could even direct couple all the
way back and using negative supplies... then your only problem becomes
isolating the grid of your input tube a cap or a trannie would do nicely
here... given the choice would you rather have your means of isolation deal
with 1V or 300V?
if you look at the whle picture here... you esentially built the entire amp
backwards.
the only problem i run into with the above idea is if the autoformer is a
tapped plate choke carrying DC... the speaker coil will not like the DC...
so some isolation is still needed... its always something.
dave (again)
=========================================================================
From: "Dave Slagle" <dslagle@earthlink.net>
Subject: Re: backwards amp... wuz [JN] What power supply
Date: Tue, 09 Jan 2001 21:28:33 -0500
Source: Sound Digest Archive v02.n779
> This discussion goes completely over my head.
> I don't get the circuit description.
> What are you saying Dave?
take a three stage all dc gain structure with a grid choke on the input and
a transformer on the output with positive supplies on the plates across the
board.
reverse i all... move the grid choke to the output and tap it for your
impedance match and ground it... stack negative supplies in the cathodes of
each previous stage, and then you need an input trannie on the first stage
to block
dc... hell take it back two stages dc (direct coupled) and IT couple your
first stage and you are back at ground potential.
the problems are
dc will flow through the speaker coil (makes me think field coil speaker?)
i have yet to wind an tapped choke for impedance matching that impresses me
that will carry dc... (don't even mention caps here)
its basically a good idea that won't work as i see it, but there may be a
creative way around it... so i figure i would toss it out there...
dave
=========================================================================
From: "Sellek, Grant (TSA)" <Grant.Sellek@transport.sa.gov.au>
Subject: RE: backwards amp... wuz [JN] What power supply
Date: Wed, 10 Jan 2001 10:51:48 +1030
Source: Sound Digest Archive v02.n779
This discussion goes completely over my head.
I don't get the circuit description.
What are you saying Dave?
Grant Sellek, Adelaide, Australia
>-----Original Message-----
>From: dslagle@earthlink.net [mailto:dslagle@earthlink.net]
>Sent: Wednesday, 10 January 2001 3:01 AM
>To: sound@deliverator.io.com
>Subject: backwards amp... wuz [JN] What power supply
>
>
>oops... suppose i should have retitled this..
>
>>Dave, you mention autoformer coupling, presumably for
>conventional speaker
>>and dc offset issues, but assuming the current is accurately balanced
>>between each half, then you've got no dc if you're output taps are
>>symmetrical about CT? Of course, if one tube goes kaputt,
>then you may have
>>a problem, then again, maybe not too much to worry about
>depending on the
>>resistance of the "secondary".
>
>i was referring to SE usage... i should have made that clear
>
>reposted under new header
>
>for the longest time i have been wanting to build a
>backwards amp... i have the design, just haven't come up with
>all the iron
>and figured out all the rubs yet
>
>using the idea that the worst place for a transformer is on
>the output of
>an amp, why not flip the whole thing around. all the
>transformer does is
>impedance match and isolate, we could use an autoformer and ground the
>output and use negative supplies, hell you could even direct
>couple all the
>way back and using negative supplies... then your only problem becomes
>isolating the grid of your input tube a cap or a trannie would
>do nicely
>here... given the choice would you rather have your means of
>isolation deal
>with 1V or 300V?
>
>if you look at the whle picture here... you esentially built
>the entire amp
>backwards.
>
>the only problem i run into with the above idea is if the
>autoformer is a
>tapped plate choke carrying DC... the speaker coil will not
>like the DC...
>so some isolation is still needed... its always something.
>
>dave (again)
>
>
>
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: backwards amp... wuz [JN] What power supply
Date: Wed, 10 Jan 2001 11:18:33 -0500
Source: Sound Digest Archive v02.n780
a picture's worth a thousand words.
let me see if i got you right.
> take a three stage all dc gain structure with a grid choke on the input and
> a transformer on the output with positive supplies on the plates across the
> board.
>
>
> reverse i all...
>
LOL
> move the grid choke to the output and tap it for your
> impedance match and ground it... stack negative supplies in the cathodes of
> each previous stage, and then you need an input trannie on the first stage
> to block
> dc...
>
oooooooh. *negative* supplies. how do you make those?!?
doncha need them reverse rectifiers or sumthin' ? ;)
actually, it's just a matter of where you put the *ground*
see below:
+----------+--- *GND*
| |
)__ spkr |
auto ) |
former ) |
) |
| ----- DC
PLATE --- SUPPLY
+--GRID | #3
| CATH |
| | |
| +----------+
| |
| +----------+
| | |
| ) |
| ) |
| ) |
| ) |
+----| ----- DC
PLATE --- SUPPLY
+--GRID | #2
| CATH |
| | |
| +----------+
| |
| +----------+
| | |
| ) |
| ) |
| ) |
| ) |
+----| ----- DC
PLATE --- SUPPLY
INo-+ +-GRID | #1
| | CATH |
)|( | |
IT )|( --- bias |
)|( - batt |
| | | |
| +---+----------+
|
GND
> hell take it back two stages dc (direct coupled) and IT couple your
> first stage and you are back at ground potential.
>
>
there's an interesting topology.
i'd call it "full-circle".
since your positive reference for the output stage is GND
and your negative reference for input stage is GND.
sorta blows the grid/plate bias for the 2nd stage, though.
hmmm... how would we do it?
+----------+--- *GND*
| |
)__ spkr |
auto ) |
former ) |
) |
| ----- DC
PLATE --- SUPPLY
+--GRID | #3
| CATH |
| | |
| +----------+ Note *negative* wrt GND
| |
| +----------+
| | |
| ) |
| ) |
| ) |
| ) |
+----| ----- DC
PLATE --- SUPPLY
+---GRID | #2
| CATH |
| | |
| +--+-----------+ Note *negative* wrt GND
| |
|--- bias
| -
| | +----------+ Note *positive* wrt GND
| | | |
| )||( |
| )||( |
| )||( |
|__)||( |
| ----- DC
PLATE --- SUPPLY
INo---+-GRID | #1
| CATH |
( | |
( --- bias |
( - batt |
| | |
+---+----------+
|
GND
if i drew this out on paper, i could do it in a circle,
and have the bottom connect to the top....
cool!
> the problems are
>
> dc will flow through the speaker coil
>
right.
big problem, i think.
fwiw, the DC voltage drop across the choke should not be very high, though. and even less at the out
put tap point.
> (makes me think field coil speaker?)
>
as far as i know, field coil speaker use a separate dc source
to excite the field magnet.
the voice coil gets the ac.
i'd imagine that any audio modulation on the field would show
up in the speaker output.
but i don't know what the sensitivity would be thru the field
winding.
i use some old field-coil speakers in guitar amps that i built.
the field coil is used as a filter choke in the power supply.
i'd imagine that there is a fair amount of ripple current
thru the field, yet i don't hear it.
that's why i doubt the field sensitivity is very high...
> i have yet to wind an tapped choke for impedance matching that impresses me
> that will carry dc...
>
hmmm...
> (don't even mention caps here)
>
ok. i'll do it a little bit further down the page... ;)
> its basically a good idea that won't work as i see it, but there may be a
> creative way around it... so i figure i would toss it out there...
>
i assume you feel it's a good idea because you avoid the
primary-secondary coupling, and the compromises involved with
leakage inductances/capacitances, etc.
i still wonder why the parafeeder haven't latched onto this approach.
with parafeed you get rid of dc, so why would you bother to provide
galvanic isolation to the secondary.
an autoformer would do just as well, if not better.
who knows, it might make a parafeeder out of you, dave...
it's a big compromise, but you're probably the only one set up to
build an autoformer output.
what are you trading. a "selectable" capacitor for the parasitics
that you are "stuck-with" in the OPT...
gotta get back to work, now...
bob.d.
=========================================================================
From: "Spence Barton" <ence-ack@rio.com>
Subject: Re: backwards amp... wuz [JN] What power supply
Date: Wed, 10 Jan 2001 12:48:46 -0800
Source: Sound Digest Archive v02.n780
>>
>> i use some old field-coil speakers in guitar amps that i built.
>> the field coil is used as a filter choke in the power supply.
>>
>> i'd imagine that there is a fair amount of ripple current
>> thru the field, yet i don't hear it.
>>
>> that's why i doubt the field sensitivity is very high...
Heres my theory...
When there is ripple on the supply to the field coil it is not heard at all
in the absence of signal because the voice coil has no current through it
save what is induced by the field coil and so is not magnetized and feels no
force from the ripple in the field. When there is a signal though voice
coil, the ripple does affect cone movement and is heard because it now has a
magnetized voice coil to work on. So not only is there hum but it amplitude
modulates the audio signal. Ick. ( Could be worse, I guess, if it were FM.)
Therefore, I think you have to have a very pure field current supply. This
is a somewhat pesky problem - because there is no audible hum with no signal
one might think everything was totally fine. I would guess if you had a
ripple equal to 2% of the DC voltage on the field coil it would be same as
having a ripple component equal to 2% of the signal to the voice coil in
terms of sensitivity but in the latter case you don't get the AM so it
probably would be easier to listen to. Plus it would be there all the time
and therefore be easier for the brain to ignore than the ripple plus a bunch
of side bands that come and go with the signal envelope.
Some of this comes from an e-mail exchange with the awesome Finn Hammer who
built the giant field coil woofer - field coil, voice coil, cone and wooden
frame all in his home shop. No longer on the list. At the time he said he
was being distracted from audio by the deep inner need to build big Tesla
coils.
spence
=========================================================================
From: "Paul Croft" <pcroft@iximd.com>
Subject: RE: backwards amp... wuz [JN] What power supply
Date: Wed, 10 Jan 2001 13:22:10 -0500
Source: Sound Digest Archive v02.n780
OHhhhh, Bob,
When you talk like this, the earth moves for us!!!!
Cheers,
Paul
> -----Original Message-----
> From: owner-sound@lists.io.com [mailto:owner-sound@lists.io.com]On
> Behalf Of Danielak, Robert M
> Sent: Wednesday, January 10, 2001 11:19 AM
> To: 'sound@deliverator.io.com'
> Subject: RE: backwards amp... wuz [JN] What power supply
>
>
> a picture's worth a thousand words.
> let me see if i got you right.
>
> > take a three stage all dc gain structure with a grid choke on
> the input and
> > a transformer on the output with positive supplies on the
> plates across the
> > board.
> >
> >
> > reverse i all...
> >
> LOL
>
> > move the grid choke to the output and tap it for your
> > impedance match and ground it... stack negative supplies in the
> cathodes of
> > each previous stage, and then you need an input trannie on the
> first stage
> > to block
> > dc...
> >
> oooooooh. *negative* supplies. how do you make those?!?
> doncha need them reverse rectifiers or sumthin' ? ;)
>
> actually, it's just a matter of where you put the *ground*
>
> see below:
>
>
>
> +----------+--- *GND*
> | |
> )__ spkr |
> auto ) |
> former ) |
> ) |
> | ----- DC
> PLATE --- SUPPLY
> +--GRID | #3
> | CATH |
> | | |
> | +----------+
> | |
> | +----------+
> | | |
> | ) |
> | ) |
> | ) |
> | ) |
> +----| ----- DC
> PLATE --- SUPPLY
> +--GRID | #2
> | CATH |
> | | |
> | +----------+
> | |
> | +----------+
> | | |
> | ) |
> | ) |
> | ) |
> | ) |
> +----| ----- DC
> PLATE --- SUPPLY
> INo-+ +-GRID | #1
> | | CATH |
> )|( | |
> IT )|( --- bias |
> )|( - batt |
> | | | |
> | +---+----------+
> |
> GND
>
>
> > hell take it back two stages dc (direct coupled) and IT couple your
> > first stage and you are back at ground potential.
> >
> >
> there's an interesting topology.
> i'd call it "full-circle".
> since your positive reference for the output stage is GND
> and your negative reference for input stage is GND.
>
> sorta blows the grid/plate bias for the 2nd stage, though.
>
> hmmm... how would we do it?
>
> +----------+--- *GND*
> | |
> )__ spkr |
> auto ) |
> former ) |
> ) |
> | ----- DC
> PLATE --- SUPPLY
> +--GRID | #3
> | CATH |
> | | |
> | +----------+ Note *negative* wrt GND
> | |
> | +----------+
> | | |
> | ) |
> | ) |
> | ) |
> | ) |
> +----| ----- DC
> PLATE --- SUPPLY
> +---GRID | #2
> | CATH |
> | | |
> | +--+-----------+ Note *negative* wrt GND
> | |
> |--- bias
> | -
> | | +----------+ Note *positive* wrt GND
> | | | |
> | )||( |
> | )||( |
> | )||( |
> |__)||( |
> | ----- DC
> PLATE --- SUPPLY
> INo---+-GRID | #1
> | CATH |
> ( | |
> ( --- bias |
> ( - batt |
> | | |
> +---+----------+
> |
> GND
>
>
> if i drew this out on paper, i could do it in a circle,
> and have the bottom connect to the top....
>
> cool!
>
> > the problems are
> >
> > dc will flow through the speaker coil
> >
> right.
>
> big problem, i think.
>
> fwiw, the DC voltage drop across the choke should not be very
> high, though. and even less at the output tap point.
>
> > (makes me think field coil speaker?)
> >
> as far as i know, field coil speaker use a separate dc source
> to excite the field magnet.
>
> the voice coil gets the ac.
>
> i'd imagine that any audio modulation on the field would show
> up in the speaker output.
>
> but i don't know what the sensitivity would be thru the field
> winding.
>
> i use some old field-coil speakers in guitar amps that i built.
> the field coil is used as a filter choke in the power supply.
>
> i'd imagine that there is a fair amount of ripple current
> thru the field, yet i don't hear it.
>
> that's why i doubt the field sensitivity is very high...
>
> > i have yet to wind an tapped choke for impedance matching that
> impresses me
> > that will carry dc...
> >
> hmmm...
>
> > (don't even mention caps here)
> >
> ok. i'll do it a little bit further down the page... ;)
>
> > its basically a good idea that won't work as i see it, but
> there may be a
> > creative way around it... so i figure i would toss it out there...
> >
> i assume you feel it's a good idea because you avoid the
> primary-secondary coupling, and the compromises involved with
> leakage inductances/capacitances, etc.
>
> i still wonder why the parafeeder haven't latched onto this approach.
>
> with parafeed you get rid of dc, so why would you bother to provide
> galvanic isolation to the secondary.
>
> an autoformer would do just as well, if not better.
>
> who knows, it might make a parafeeder out of you, dave...
>
> it's a big compromise, but you're probably the only one set up to
> build an autoformer output.
>
> what are you trading. a "selectable" capacitor for the parasitics
> that you are "stuck-with" in the OPT...
>
> gotta get back to work, now...
>
> bob.d.
>
>
>
>
=========================================================================
From: Dan Marshall <mdaniel7@uswest.net>
Subject: Re: backwards amp... wuz [JN] What power supply
Date: Wed, 10 Jan 2001 14:55:24 +0000
Source: Sound Digest Archive v02.n780
Hi All,
Spence Barton wrote:
>
> >>
> >> i use some old field-coil speakers in guitar amps that i built.
> >> the field coil is used as a filter choke in the power supply.
> >>
> >> i'd imagine that there is a fair amount of ripple current
> >> thru the field, yet i don't hear it.
> >>
> >> that's why i doubt the field sensitivity is very high...
>
> Heres my theory...
>
> When there is ripple on the supply to the field coil it is not heard at all
> in the absence of signal because the voice coil has no current through it
> save what is induced by the field coil and so is not magnetized and feels no
> force from the ripple in the field.
Not so. Audible hum is not a function of whether the VC has current
through it. It is a direct relationship between the field-induced hum
voltage vs the VC circuit resistance, including the amp output Z. If
ripple current exists in the field coil, it will induce a voltage into
the VC by transformer action. When the VC is connected to an amp, which
is roughly equivalent to shorting the VC terminals (or if the terminals
are shorted together), the induced voltage will result in a hum current
flowing through the voice coil, which will be translated to cone
movement, or audible hum.
> When there is a signal though voice
> coil, the ripple does affect cone movement and is heard because it now has a
> magnetized voice coil to work on. So not only is there hum but it amplitude
> modulates the audio signal. Ick. ( Could be worse, I guess, if it were FM.)
The induced hum would be the same (to a first-order approximation)
whether a VC signal is present or not, assuming the hum component in the
field is constant vs signal level. The important factor being that the
ripple component in the field current will induce a voltage into the
voice coil, which will cause a VC current as a result of the near short
circuit presented by the amplifier output. As above, this is a function
of the field-induced VC voltage and the total VC circuit resistance.
Also of importance, the field, being an inductor, will tend to result in
a relatively constant current, even in the presence of some ripple
voltage from the first filter cap. At least the hum current is very
considerably less than the ripple voltage across the field. This in
itself will tend to minimize the field-induced hum.
Many speaker, such as the Jensen A-12, have hum-bucking coils built into
the field structure. This is a small coil which is connected in series
with the VC. With the proper number of turns, an equivalent value of
hum voltage will be induced into the hum-bucking coil as into the VC.
Properly phased and connected in series with the VC, this voltage will
effectively cancel (or buck) the hum induced into the VC by ripple
current in the field. The A-12 also has a rather heavy copper shorted
turn built into the pole piece which acts to short the ripple magnetism
from the field, as well as to negate the demagnetizing effects from the
VC current. BTW, these old speakers are quite amazing.
> Therefore, I think you have to have a very pure field current supply. This
> is a somewhat pesky problem - because there is no audible hum with no signal
> one might think everything was totally fine. I would guess if you had a
> ripple equal to 2% of the DC voltage on the field coil it would be same as
> having a ripple component equal to 2% of the signal to the voice coil in
> terms of sensitivity but in the latter case you don't get the AM so it
> probably would be easier to listen to. Plus it would be there all the time
> and therefore be easier for the brain to ignore than the ripple plus a bunch
> of side bands that come and go with the signal envelope.
From above, I would tend to think that either you have hum, or you
don't, irrespective of the signal level. Also, if you have 2% ripple
voltage across the field coil, the ripple current would be much less, as
the field coil is an inductor, which, as we know, attempts to keep
current constant. Of course, if the PS ripple voltage increases at high
level signals, then you have a somewhat different situation. This is
assuming no hum-bucking coil is provided. If one is provided, then the
ripple cancellation of the HB coil would tend to track these increases.
If B+ current increases at high signal levels, as with, say, an AB2
amplifier, this may cause some modulation, perhaps acting somewhat as a
volume expander on loud passages, assuming the time constants don't
cause too much delay. If the field is sufficiently strong to saturate
the front plate, then these effects would be minimized. With high power
(AB2) amplifiers it would be better to provide a separate field supply.
Also, I would think that a series field/filter coil would be inviting
problems with a SE amp, esp at very low frequencies where ripple values
reflected from the load are of a greater magnitude than the rectified
line ripple.
Dan Marshall
> Some of this comes from an e-mail exchange with the awesome Finn Hammer who
> built the giant field coil woofer - field coil, voice coil, cone and wooden
> frame all in his home shop. No longer on the list. At the time he said he
> was being distracted from audio by the deep inner need to build big Tesla
> coils.
>
> spence
=========================================================================
From: "Henry Platt" <hnplatt@massed.net>
Subject: Re: backwards amp... wuz [JN] What power supply
Date: Wed, 10 Jan 2001 19:22:59 -0400
Source: Sound Digest Archive v02.n781
Try using the field coil as a plate choke ;-)
- ----------
>From: Dan Marshall <mdaniel7@uswest.net>
>To: Spence Barton <ence-ack@rio.com>
>Cc: Joenet <sound@lists.io.com>
>Subject: Re: backwards amp... wuz [JN] What power supply
>Date: Wed, Jan 10, 2001, 10:55 AM
>
> Hi All,
>
> Spence Barton wrote:
>>
>> >>
>> >> i use some old field-coil speakers in guitar amps that i built.
>> >> the field coil is used as a filter choke in the power supply.
>> >>
>> >> i'd imagine that there is a fair amount of ripple current
>> >> thru the field, yet i don't hear it.
>> >>
>> >> that's why i doubt the field sensitivity is very high...
>>
>> Heres my theory...
>>
>> When there is ripple on the supply to the field coil it is not heard at all
>> in the absence of signal because the voice coil has no current through it
>> save what is induced by the field coil and so is not magnetized and feels no
>> force from the ripple in the field.
>
> Not so. Audible hum is not a function of whether the VC has current
> through it. It is a direct relationship between the field-induced hum
> voltage vs the VC circuit resistance, including the amp output Z. If
> ripple current exists in the field coil, it will induce a voltage into
> the VC by transformer action. When the VC is connected to an amp, which
> is roughly equivalent to shorting the VC terminals (or if the terminals
> are shorted together), the induced voltage will result in a hum current
> flowing through the voice coil, which will be translated to cone
> movement, or audible hum.
>
>> When there is a signal though voice
>> coil, the ripple does affect cone movement and is heard because it now has a
>> magnetized voice coil to work on. So not only is there hum but it amplitude
>> modulates the audio signal. Ick. ( Could be worse, I guess, if it were FM.)
>
> The induced hum would be the same (to a first-order approximation)
> whether a VC signal is present or not, assuming the hum component in the
> field is constant vs signal level. The important factor being that the
> ripple component in the field current will induce a voltage into the
> voice coil, which will cause a VC current as a result of the near short
> circuit presented by the amplifier output. As above, this is a function
> of the field-induced VC voltage and the total VC circuit resistance.
>
> Also of importance, the field, being an inductor, will tend to result in
> a relatively constant current, even in the presence of some ripple
> voltage from the first filter cap. At least the hum current is very
> considerably less than the ripple voltage across the field. This in
> itself will tend to minimize the field-induced hum.
>
=========================================================================
From: "Ellen Oler" <ellenoler@earthlink.net>
Subject: RE: backwards amp... wuz [JN] What power supply
Date: Wed, 10 Jan 2001 20:45:05 -0500
Source: Sound Digest Archive v02.n781
Excerpting just the auto former output section:
hmmm... how would we do it?
+----------+--- *GND*
| |
)__ spkr |
auto ) |
former ) |
) |
| ----- DC
PLATE --- SUPPLY
+--GRID | #3
| CATH |
| | |
| +----------+ Note *negative* wrt GND
| |
and focusing on the autoformer and speaker current loop:
+------+---GND-------)|
| )|K
)____________________)|
)
)
)
Then:
The DC current flowing through the speaker coil will relate ONLY to the
ratio of the DC resistances in the speaker coil and the DC resistance in
TOPMOST SECTION ONLY of the autoformer.
As long as the DCR of this TOP SECTION is reduced to be negligible compared
to the voice coil DCR, MOST of the current (equal to the total current
flowing through the output tube) will be flowing through the autoformer
portion of this loop.
Implies fine wire in the voice coil and honkin' fat wire in the TOP SECTION
ONLY of the autoformer.
Intuitively, we can easily see this: as long as there is negligible DCR
between the top of the autoformer and the tap then there will be a
negligible DC drop and negligible DC current through the voice coil.
Since there is a step-down in this auto former, only a relatively small
section at the "top" needs to be wound this way (phat), I think. 1/18th of
the total for a 2K5:8 tranny.
- -j
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: RE: backwards amp... wuz [JN] What power supply
Date: Thu, 11 Jan 2001 07:51:41 -0500
Source: Sound Digest Archive v02.n781
j...
60 ma through the tube...
16 ohm voice coil
.25 ohm secondary (thats low!... maybe a foil secondary???)
you still get 1ma of current through the speaker coil
i suspect that this wont do much damage even to a lowther coil, but it will
offset the driver from its normal position, i suspect depending on the
surround adding non-linearity to the cone excursion??? or maybe given that
its non-linear as it is, it could help things out? that whole air is
easier to expand than it is to compress (or is it the other way around.)
still worth some thought... speaker guru's?
i also love the idea of a f/c plate choke... definately out of the box thinking
dave
=========================================================================
From: Conrad Drake <conrad@directwest.iinet.net.au>
Subject: RE: backwards amp... wuz [JN] What power supply
Date: Fri, 12 Jan 2001 07:00:55 +0800
Source: Sound Digest Archive v02.n782
> hmmm... how would we do it?
>
> +----------+--- *GND*
> | |
> )__ spkr |
> auto ) |
> former ) |
> ) |
> | ----- DC
> PLATE --- SUPPLY
> +--GRID | #3
> | CATH |
> | | |
> | +----------+ Note *negative* wrt GND
> | |
>
What is the Vdc(speaker)?
DC current: 100mA, DCR 1K -> total DC voltage 100V. Speaker
winding will be at least 10x thicker -> 1/10th resistance. So
DCR(speaker) = 1K x 1/30 x 1/10 => 0.33V
I cannot believe that someone hasn't suggested it yet, but why
not
+__ spkr___+
) |
) |
+----------+--- *GND*
) |
auto ) |
former ) |
| ----- DC
PLATE --- SUPPLY
+--GRID | #3
| CATH |
| | |
| +----------+ Note *negative* wrt GND
| |
Which does take some extra wire:
If we've got 4k:4ohm step down that's sqrt(1000) turns or about
30:1
So the "overhead" of getting the DC out of the spkr is about 3%.
But, the real question is: if we have to wire the "speaker" part
of the "auto"former with a separate guage to the "plate" part,
how is this different to a conventional transformer?
Yours,
Conrad Drake
- --
Direct West Invs. P/L Solutions for Embedded Systems.
conrad@directwest.ii.net (ph)+61 40 747 1611
http://directwest.ii.net (fx)+61 8 9285 1011
12 Gayton Road, City Beach, WA 6015 AUSTRALIA
=========================================================================
From: Martin Seddon <mseddon@iinet.net.au>
Subject: RE: backwards amp... wuz [JN] What power supply
Date: Sun, 14 Jan 2001 00:04:24 +0800
Source: Sound Digest Archive v02.n783
Conrad wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>
I cannot believe that someone hasn't suggested it yet, but why
not
+__ spkr___+
) |
) |
+----------+--- *GND*
) |
auto ) |
former ) |
| ----- DC
PLATE --- SUPPLY
+--GRID | #3
| CATH |
| | |
| +----------+ Note *negative* wrt GND
| |
Which does take some extra wire:
If we've got 4k:4ohm step down that's sqrt(1000) turns or about
30:1
So the "overhead" of getting the DC out of the spkr is about 3%.
But, the real question is: if we have to wire the "speaker" part
of the "auto"former with a separate guage to the "plate" part,
how is this different to a conventional transformer?
<<<<<<<<<<<<<<<<<<<<<<<<<
Very neat - thanks Conrad. Auto former to 'normal' transformer in one
move. I guess a conventionally wired autoformer step down winding would
have to be heavier gauge for power balance.
But who need the amp backwards? - be like me - run your speakers at B+ ;-)
Martin
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: [JN] bad caps... bad bad caps....
Date: Thu, 25 Feb 1999 10:43:43 -0500
Source: Sound Digest Archive v02.n061
hey the ulbrich trannies showed up yesterday, and quickly were clipped into
system... and whaddya know more of those nasty nasty defib caps reared
their ugly sound... went back the the trannies that were in there and the
defib sound was gone...
I was crushed again...back in went the ulbrich's and moved on... so I did
a little balancing act and pulled out the first defibs on the 45 for an
elna... hmmm we are getting somewhere... next the second defibs were
replaced with a solen... yuck there was the solen sound I have grown to
dislike... so in went some big 'ol oils... ahhh now we are getting
somewhere...still not balanced, but getting there
I have to say that I have never heard such differences before... it hurts
my head... the amount the sound can change with swapping one pair of
caps...this has never happened to me before...
I honestly don't know what to make of it... I guess I could consider
myself lucky since there will be no hair-splitting deciding if there was a
change... just deciding which cap combo i prefer...
strange!
dave
=========================================================================
From: Steve Van Osdell <svanos@queencity.com>
Subject: [JN] Bad luck with my 2nd amp
Date: Fri, 18 Aug 2000 07:49:05 -0400
Source: Sound Digest Archive v02.n632
I finished my second amp last night and was ready to listen to some
stereo, but had a piece of bad luck. The potted military power
transformer was bad. Dead short in it (it appears) - blew the fuse as
the variac passed 30 volts.
I was wondering if some of you iron collectors out there might have one
like it before I got shopping for two new transformers (I'd have to
replace the other one too for looks).
Here are the number written on it....
Here is the number...Q-880-51 Transformer Tech TTI-5136
If anyone has an extra one they'd part with, please let me know asap,
and how much.
Thanks, Steve
=========================================================================
From: Patrick Currie <tubesguy@chorus.net>
Subject: Re: [JN] Bad luck with my 2nd amp
Date: Fri, 18 Aug 2000 08:18:16 -0500 (CDT)
Source: Sound Digest Archive v02.n632
>I finished my second amp last night and was ready to listen to some
>stereo, but had a piece of bad luck. The potted military power
>transformer was bad. Dead short in it (it appears) - blew the fuse as
>the variac passed 30 volts.
>
>I was wondering if some of you iron collectors out there might have one
>like it before I got shopping for two new transformers (I'd have to
>replace the other one too for looks).
>
>Here are the number written on it....
>Here is the number...Q-880-51 Transformer Tech TTI-5136
>
>If anyone has an extra one they'd part with, please let me know asap,
>and how much.
>
>Thanks, Steve
Steve -
What are the voltages? Maybe one of us has two of something else that
would work. - Pat
=========================================================================
From: "John Hancock" <John_Hancock@swissre.com>
Subject: [JN] bad physics and worse physics
Date: Wed, 14 Apr 1999 14:42:49 +0100
Source: Sound Digest Archive v02.n124
Christian Rintelen wrote:
>check this out -- but be warned, it's waaaay over the top....
>
snip...
>
>(To quote from the abstract: "The Vacuum Triode Amplifier (VTA)
>
snip...
That was hilarious. God bless them. I wonder if they have a recipe for
gold as well.
Well, I finally had a chance to check out the Joe list again after a
vacation and a busy period at work. Some people asked about my post
regarding the accelerating expansion of the universe. The question was how
could the universe be accelerating and my answer is I don't have a clue.
Back when I was working at Fermilab (13 years ago--I've since switched to
economics as a profession so now my knowledge is pretty much limited to
what I read in Scientific American and Astronomy magazine), there was a lot
of work being done that speculated that the expansion of the universe
accelerated in the early stages of history immediately following the big
bang. The acceleration would go along way in explaining a number of
stylized facts about the universe that are difficult to explain under the
current rules of physics. In particular, it would explain why the current
rate of expansion is so close to the critical rate at which the universe
will asymptotically stop expanding--rather than either expanding forever if
the current rate of expansion was just a little bit higher or else
collapsing back onto itself if the rate of expansion was just a little bit
slower. The acceleration would also explain why matter is distributed
throughout space so uniformly, rather than being clumped together. The
theories being thrown around at the time speculated that particles
exhibited a property called super symmetry--that is, at very high energies,
like after the big bang, all particles behave identically and so behave in
a manner similar to antigravity. Only after the particles cool do they
exhibit spin which differentiates the particles and leads to the strong and
weak forces, etc. These theories, though, only predicted an acceleration
in the very early history of the universe, so it was a bit of a surprise to
find that the universe may still be accelerating. One theory I have been
hearing about to explain this is that there is a vacuum energy--empty space
has mass. This mass impels space to expand. As space expands, there is
more of it, so the expansion accelerates. Now, why space having mass would
cause it to accelerate, I have no idea.
One other thing, if the discovery that the expansion is accelerating holds
up, Einstein would be right about his cosmological constant, but for the
wrong reason. Einstein came up with the constant to explain how the
universe could be static when gravity should cause it to collapse. Twenty
years later, Hubble discovered that the universe was in fact expanding.
Hope somebody finds this interesting and also hope that my litlle knowledge
of physics is not worse than no knowledge of physics, ie. VTA above.
John
=========================================================================
From: Jonathan Morrison <ppdiva@rcn.com>
Subject: Re: [JN] bad physics and worse physics
Date: Thu, 15 Apr 1999 12:06:38 -0400
Source: Sound Digest Archive v02.n125
At 05:07 PM 4/15/99 +0200, Adnan Arduman wrote:
>Don't you think this is a better example for this list? And also there is
>the fact that most of the Joes don't use combs (this is only a wild guess)
>:^)
>
>Adnan
Especially the ones that touch B+ ... JDM
=========================================================================
From: "John Hancock" <John_Hancock@swissre.com>
Subject: [JN] bad physics and worse physics
Date: Thu, 15 Apr 1999 13:22:34 +0100
Source: Sound Digest Archive v02.n125
Some more questions on physics:
Bart wrote:
>Is infinity purely an abstract mathematical concept which does not exist
in
>nature?
Nope, it exists, at least in terms of possibilites. Think about all the
ways you could comb your hair. Quantum theory works the same way.
>If not, then anything, no matter how low the probability, that can exist
/
>happen will exist / happen and be happenning somewhere as we speak.
>
>Somewhere Elvis will be marrying me to.....
>
>etc., etc.
>
>Whats the logic error?
This is a common misconception. You could comb your hair for all eternity,
but there are also an infinite number of ways to comb your hair, so your
hair will never be combed exactly the same way twice. The question here is
intuitively which infinity is bigger? Believe it or not, there are answers
to that question. Try algebraic topology or measure theory if you want to
know more.
>If the universe and time aren't infinite then how do you fall off the edge
>and to where / when?
The universe could be finite, but have no edge--just like a sphere is
finite, but has no edge. The universe could just fold back into itself.
This could only happen, though if there is a fourth dimension. The
implications of this are pretty cool. It would mean that what we think are
different galaxies in the sky are really the same galaxies viewed from
different angles at different times. There will be an interesting
experiment carried out once this new NASA satellite (I have forgotten the
name) goes into orbit. The satellite will be examining the low frequency
radiation left over from the big bang. If the universe is finite (and not
too large) then there should be circles of repeating patterns in the
radiation. If the circles repeat one time, then the universe is large
enough that light could travel the length of the universe twice during the
lifetime of the universe. If the circles repeat more than that, the
universe is smaller. If the circles don't repeat, then the universe is
larger.
>What was before time?
>
>Is there a DOG?
OK, now we've wondered into religion. I'll stay away from that one. Once
again--I ain't no expert. Even when I was a physicist, I worked in high
energy physics, not cosmology, so take my wisdoms with a grain of salt. I
am now an economist and economics is one of those subjects that everyone
feels they are an expert on even without knowing much about the topic. I
really get pissed off some times about the economic logic being profligated
by the likes of Ross Perot and just about every European politician and I'm
sure a real physicist would cringe at my pop-physics understandings of
these topics. But, it is fun to ponder...
John
=========================================================================
From: Adnan Arduman <adnana@turk.net>
Subject: Re: [JN] bad physics and worse physics
Date: Thu, 15 Apr 1999 17:07:55 +0200
Source: Sound Digest Archive v02.n125
>Nope, it exists, at least in terms of possibilites. Think about all the
>ways you could comb your hair. Quantum theory works the same way.
Or, think about the number of different amplifiers with different sonic
characters you can build out of a single schematic just by playing with
components and their combinations.
This is the beauty of our hobby.
Don't you think this is a better example for this list? And also there is
the fact that most of the Joes don't use combs (this is only a wild guess)
:^)
Adnan
visit my personal "NUANCE & FLUENCE" web site:
http://www.arduman.com/aa
tel: +90-216-310 44 70 (w)
fax: +90-216-343 42 01
e-mail: adnana@turk.net
=========================================================================
From: Zyxtan@aol.com
Subject: Re: [JN] bad physics and worse physics
Date: Thu, 15 Apr 1999 13:19:23 EDT
Source: Sound Digest Archive v02.n126
In a message dated 4/15/99 11:11:08 AM US Eastern Standard Time,
ppdiva@rcn.com writes:
> Especially the ones that touch B+ ... JDM
and B+ is connected to one of Tom Danley's "widow maker " 4,400uF capacitors.
paul(zyxtan@aol.com)
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: [JN] bad physics and worse politics
Date: Thu, 15 Apr 1999 15:13:11 +0200
Source: Sound Digest Archive v02.n125
> De : John Hancock <John_Hancock@swissre.com>
> Date : jeudi 15 avril 1999 14:22
> OK, now we've wondered into religion. I'll stay away from that one.
<CUT>
> I
> really get pissed off some times about the economic logic being
profligated
> by the likes of Ross Perot and just about every European politician
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
And you should stay away also on that subject!
This is out of the subject here and I prefer to know what you think about a
tube amplifier or about a loudspeaker than "about every European
politician"...
Best regards from Europe!
Jean-Michel Le Cleac'h, Paris, France
=========================================================================
From: "John Hancock" <John_Hancock@swissre.com>
Subject: Re: [JN] bad physics and worse politics
Date: Fri, 16 Apr 1999 09:16:31 +0100
Source: Sound Digest Archive v02.n126
Jean-Michel,
Please don't take what I wrote personally. I have an even lower opinion of
US politicians. I could spend equal time denigrating them if it would
please you. The only reason why I singled out European politicians is that
US politicians don't tend to have policies, instead they have "values." US
politicians, to a large extent, leave the policies to professional
economists and instead focus on uncovering scandals about one another.
It's a perverse system, but in the end it works out better than you might
think. Please understand, what I said was not a dig against Europe, I
quite like living here and I live here by choice--I wasn't transfered on
some expat contract, I found my own way here.
John
> OK, now we've wondered into religion. I'll stay away from that one.
<CUT>
> I
> really get pissed off some times about the economic logic being
profligated
> by the likes of Ross Perot and just about every European politician
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
And you should stay away also on that subject!
This is out of the subject here and I prefer to know what you think about a
tube amplifier or about a loudspeaker than "about every European
politician"...
Best regards from Europe!
Jean-Michel Le Cleac'h, Paris, France
=========================================================================
From: "hopper chu" <achu@medcaminc.com>
Subject: RE: [JN] Bad power tranny?
Date: Wed, 6 Dec 2000 09:44:36 -0800
Source: Sound Digest Archive v02.n753
Hi Dave,
(1) have you try another 5U4?
(2) 470 uF strike me as being a bit much as the first filter (might be
taxing your choke and tyranny over the years).
regards
hopper
=========================================================================
From: Dan Marshall <mdaniel7@uswest.net>
Subject: Re: [JN] Bad power tranny?
Date: Wed, 06 Dec 2000 09:52:52 +0000
Source: Sound Digest Archive v02.n753
Hi Dave,
From the symptoms you described I don't see how it could be a PT fault
other than possibly of the 5 V winding being leaky to ground, causing
the B+ current to be too high. The plates glowing red is indicative of
excessive dc load current. Since you have eliminated the rectifier tube
and filter cap by substituting others, this leaves the choke as the most
likely suspect, or perhaps a bad rectifer tube socket.
Inspect the rectifier socket carefully for cracks, or burnt areas.
Occasionally they will arc over and make a low resistance path.
Assuming the socket is OK, the first test would be to remove the
rectifer tube, turn it on, and see whether it still blows fuses, or if
the PT overheats. If it blows the fuse, or overheats, the PT is likely
bad, though I doubt that it will, since the glowing plates indicates
excessive dc current. Assuming it doesn't blow the fuse, check the
transformer secondary voltages. If they are OK and the transformer
does not overheat or blow fuses, it is probably OK, except for the
possibly of an internal 5 V to ground leakage, which would cause the B+
current to be excessive. So check to see whether this may be the case.
If this is the case you might just add a second small 5 V filament
transformer, or perhaps go to SS rectifiers, though this would give you
a fair bit higher B+ voltage.
Next, check the choke for leakage to ground and check its dc resistance
to see if it has changed, assuming you know its original resistance.
If it has leakage to ground, you have found your problem. If it has
shorted turns, it will look essentially like a short, in which case the
B+ will be quite a bit higher than normal, perhaps exceeding the filter
caps rated voltage thus causing excessive leakage current. Check the B+
at initial turn-on, before it blows the fuse, and see whether the B+ is
excessive. If so perhaps the choke has shorted turns. Otherwise, a
short/gnd has occurred somewhere.
DM
Dave Stagner wrote:
>
> I need some help debugging a power supply... i suspect i have a blown
> power transformer, but i'd like some confirmation from my symptoms.
>
> The power xformer is a big UTC welded steel can thing that has been in use
> on this amp for ~3 years. The power supply circuit is a basic choke
> supply, 5U4 into a huge low-DCR choke, followed by a 470uf cap. Grounding
> is a 12ga copper buss wire from the input jacks to the HT center tap on
> the power xformer. The AC line follows standard safety procedures
> (three-prong cord, chassis grounded, surge suppressor). Fuses are 3A
> slow-blow. Overall, the supply makes about 310v, and has powered stereo
> PP 6B4Gs for years without ever getting hot or behaving at all strangely.
> Until now.
>
> When i turn it on, the rectifier tube gets VERY hot quickly - the plates
> glow cherry red. After a little while (no longer than 30 seconds), the
> fuse blows. This seems like a short, so i've systematically disconnected
> everything downstream or parallel (filament supplies, output xformers,
> additional filter stages). All that's left is HT to the rectifier tube,
> then the choke, the cap, and a 330k wirewound resistor from the cap to the
> ground buss. I've tried swapping rectifiers, caps, even wire. Careful
> checking with a VOM can't find any unexpected continuities in this
> simplified circuit. The cap has a charge and is draining normally across
> the bleed resistor after the fuse blows.
>
> So now i suspect the power transformer. Does it seem like i'm on the
> right track? Please tell me before i have to drill new holes in the
> chassis to accomodate a new xformer...
> --
> Dave Stagner <dstagner@talkware.net>
> Universal Talkware Corporation
> 10 Second St. NE Suite 400, Minneapolis MN 55413
> ph: 612-843-6749 fax: 612-843-6707
=========================================================================
From: Dave Stagner <dstagner@talkware.net>
Subject: [JN] Bad power tranny?
Date: Wed, 6 Dec 2000 10:22:24 -0600
Source: Sound Digest Archive v02.n753
I need some help debugging a power supply... i suspect i have a blown
power transformer, but i'd like some confirmation from my symptoms.
The power xformer is a big UTC welded steel can thing that has been in use
on this amp for ~3 years. The power supply circuit is a basic choke
supply, 5U4 into a huge low-DCR choke, followed by a 470uf cap. Grounding
is a 12ga copper buss wire from the input jacks to the HT center tap on
the power xformer. The AC line follows standard safety procedures
(three-prong cord, chassis grounded, surge suppressor). Fuses are 3A
slow-blow. Overall, the supply makes about 310v, and has powered stereo
PP 6B4Gs for years without ever getting hot or behaving at all strangely.
Until now.
When i turn it on, the rectifier tube gets VERY hot quickly - the plates
glow cherry red. After a little while (no longer than 30 seconds), the
fuse blows. This seems like a short, so i've systematically disconnected
everything downstream or parallel (filament supplies, output xformers,
additional filter stages). All that's left is HT to the rectifier tube,
then the choke, the cap, and a 330k wirewound resistor from the cap to the
ground buss. I've tried swapping rectifiers, caps, even wire. Careful
checking with a VOM can't find any unexpected continuities in this
simplified circuit. The cap has a charge and is draining normally across
the bleed resistor after the fuse blows.
So now i suspect the power transformer. Does it seem like i'm on the
right track? Please tell me before i have to drill new holes in the
chassis to accomodate a new xformer...
- --
Dave Stagner <dstagner@talkware.net>
Universal Talkware Corporation
10 Second St. NE Suite 400, Minneapolis MN 55413
ph: 612-843-6749 fax: 612-843-6707
=========================================================================
From: Dave Stagner <dstagner@talkware.net>
Subject: Re: [JN] Bad power tranny?
Date: Wed, 6 Dec 2000 11:17:41 -0600
Source: Sound Digest Archive v02.n753
On Wed, Dec 06, 2000 at 12:03:58PM -0500, Roscoe Primrose spake thusly:
> Dave Stagner wrote:
>
> >
> > When i turn it on, the rectifier tube gets VERY hot quickly - the plates
> > glow cherry red. After a little while (no longer than 30 seconds), the
> > fuse blows. This seems like a short, so i've systematically disconnected
> > everything downstream or parallel (filament supplies, output xformers,
> > additional filter stages). All that's left is HT to the rectifier tube,
> > then the choke, the cap, and a 330k wirewound resistor from the cap to the
> > ground buss. I've tried swapping rectifiers, caps, even wire. Careful
> > checking with a VOM can't find any unexpected continuities in this
> > simplified circuit. The cap has a charge and is draining normally across
> > the bleed resistor after the fuse blows.
>
> I'm guessing it's not the transformer if the rectifier is glowing red,
> sounds like too much current downstream of the rectifier. Possibly an
> insulation breakdown in the choke that you can't detect with the low
> voltage from your VOM. Can you hook your VOM up to measure the current
> output from the recitifier?
I'm not sure... the DCR on the choke seems okay (77 ohms), but of course
the VOM doesn't put hundreds of volts on it. And it's not grounded
anywhere, so at worst it would stop the choke action... the only load to
ground now is a 330k resistor, which shouldn't pass much current at 310v
(or the 450 or so volts if the choke is failing so it behaves like cap
input). On the other hand, if the choke is shorting to its housing, which
is bolted to the chassis, and only doing so under high voltage conditions,
that could explain it.
- --
Dave Stagner <dstagner@talkware.net>
Universal Talkware Corporation
10 Second St. NE Suite 400, Minneapolis MN 55413
ph: 612-843-6749 fax: 612-843-6707
=========================================================================
From: russ arbuthnot <russ3@southern.com>
Subject: Re: [JN] Bad power tranny?
Date: Wed, 6 Dec 2000 11:22:47 -0600
Source: Sound Digest Archive v02.n753
Dave, when i built my first amp, I accidentally had the center tap of the
5V filiment supply to my rectifier grounded. I had the cherry plates and
the blown fuses just like you mentioned until i figured it out.
Unfortunately, if your amp has been working for years in its current
configuration, I doubt this is the problem.
Russ
On Wed, 6 Dec 2000, Tim Reese wrote:
> Dave, following the usual disclaimer that I'm only a hack at this stuff,
> I'd first pull the rectifier and power up the transformer with no load.
> If the fuse blows, I'd say that's conclusive that you have a shorted
> transformer. With no load, I'd then measure the AC volts across the HT
> checking for symmetry with the center tap. I've seen this before - an
> internal short in one half of the HT winding makes the CT no longer at
> center. Also made the PT hot like a stove... and changes the B+ volts.
>
> Not sure how this fits with your red plate symptoms though. I'd be more
> suspect of a shorted choke or cap downstream in that case.
>
> hth tr
> ----------------------------------------------------------------------
> Visit http://www.nmr.MGH.harvard.edu/~reese MRI, tube audio, reptiles
> Tim Reese, MGH NMR Center reese@nmr.MGH.harvard.edu
>
> >I need some help debugging a power supply... i suspect i have a blown
> >power transformer, but i'd like some confirmation from my symptoms.
> >
> >The power xformer is a big UTC welded steel can thing that has been in use
> >on this amp for ~3 years. The power supply circuit is a basic choke
> >supply, 5U4 into a huge low-DCR choke, followed by a 470uf cap. Grounding
> >is a 12ga copper buss wire from the input jacks to the HT center tap on
> >the power xformer. The AC line follows standard safety procedures
> >(three-prong cord, chassis grounded, surge suppressor). Fuses are 3A
> >slow-blow. Overall, the supply makes about 310v, and has powered stereo
> >PP 6B4Gs for years without ever getting hot or behaving at all strangely.
> >Until now.
> >
> >When i turn it on, the rectifier tube gets VERY hot quickly - the plates
> >glow cherry red. After a little while (no longer than 30 seconds), the
> >fuse blows. This seems like a short, so i've systematically disconnected
> >everything downstream or parallel (filament supplies, output xformers,
> >additional filter stages). All that's left is HT to the rectifier tube,
> >then the choke, the cap, and a 330k wirewound resistor from the cap to the
> >ground buss. I've tried swapping rectifiers, caps, even wire. Careful
> >checking with a VOM can't find any unexpected continuities in this
> >simplified circuit. The cap has a charge and is draining normally across
> >the bleed resistor after the fuse blows.
> >
> >So now i suspect the power transformer. Does it seem like i'm on the
> >right track? Please tell me before i have to drill new holes in the
> >chassis to accomodate a new xformer...
> >--
> >Dave Stagner <dstagner@talkware.net>
> >Universal Talkware Corporation
> >10 Second St. NE Suite 400, Minneapolis MN 55413
> >ph: 612-843-6749 fax: 612-843-6707
> >
>
=========================================================================
From: Tim Reese <tgrmail@nmr.MGH.harvard.EDU>
Subject: Re: [JN] Bad power tranny?
Date: Wed, 6 Dec 2000 11:45:51 -0500 (EST)
Source: Sound Digest Archive v02.n753
Dave, following the usual disclaimer that I'm only a hack at this stuff,
I'd first pull the rectifier and power up the transformer with no load.
If the fuse blows, I'd say that's conclusive that you have a shorted
transformer. With no load, I'd then measure the AC volts across the HT
checking for symmetry with the center tap. I've seen this before - an
internal short in one half of the HT winding makes the CT no longer at
center. Also made the PT hot like a stove... and changes the B+ volts.
Not sure how this fits with your red plate symptoms though. I'd be more
suspect of a shorted choke or cap downstream in that case.
hth tr
- ----------------------------------------------------------------------
Visit http://www.nmr.MGH.harvard.edu/~reese MRI, tube audio, reptiles
Tim Reese, MGH NMR Center reese@nmr.MGH.harvard.edu
>I need some help debugging a power supply... i suspect i have a blown
>power transformer, but i'd like some confirmation from my symptoms.
>
>The power xformer is a big UTC welded steel can thing that has been in use
>on this amp for ~3 years. The power supply circuit is a basic choke
>supply, 5U4 into a huge low-DCR choke, followed by a 470uf cap. Grounding
>is a 12ga copper buss wire from the input jacks to the HT center tap on
>the power xformer. The AC line follows standard safety procedures
>(three-prong cord, chassis grounded, surge suppressor). Fuses are 3A
>slow-blow. Overall, the supply makes about 310v, and has powered stereo
>PP 6B4Gs for years without ever getting hot or behaving at all strangely.
>Until now.
>
>When i turn it on, the rectifier tube gets VERY hot quickly - the plates
>glow cherry red. After a little while (no longer than 30 seconds), the
>fuse blows. This seems like a short, so i've systematically disconnected
>everything downstream or parallel (filament supplies, output xformers,
>additional filter stages). All that's left is HT to the rectifier tube,
>then the choke, the cap, and a 330k wirewound resistor from the cap to the
>ground buss. I've tried swapping rectifiers, caps, even wire. Careful
>checking with a VOM can't find any unexpected continuities in this
>simplified circuit. The cap has a charge and is draining normally across
>the bleed resistor after the fuse blows.
>
>So now i suspect the power transformer. Does it seem like i'm on the
>right track? Please tell me before i have to drill new holes in the
>chassis to accomodate a new xformer...
>--
>Dave Stagner <dstagner@talkware.net>
>Universal Talkware Corporation
>10 Second St. NE Suite 400, Minneapolis MN 55413
>ph: 612-843-6749 fax: 612-843-6707
>
=========================================================================
From: Roscoe Primrose <roscoe@aiko.com>
Subject: Re: [JN] Bad power tranny?
Date: Wed, 06 Dec 2000 12:03:58 -0500
Source: Sound Digest Archive v02.n753
Dave Stagner wrote:
>
> When i turn it on, the rectifier tube gets VERY hot quickly - the plates
> glow cherry red. After a little while (no longer than 30 seconds), the
> fuse blows. This seems like a short, so i've systematically disconnected
> everything downstream or parallel (filament supplies, output xformers,
> additional filter stages). All that's left is HT to the rectifier tube,
> then the choke, the cap, and a 330k wirewound resistor from the cap to the
> ground buss. I've tried swapping rectifiers, caps, even wire. Careful
> checking with a VOM can't find any unexpected continuities in this
> simplified circuit. The cap has a charge and is draining normally across
> the bleed resistor after the fuse blows.
I'm guessing it's not the transformer if the rectifier is glowing red,
sounds like too much current downstream of the rectifier. Possibly an
insulation breakdown in the choke that you can't detect with the low
voltage from your VOM. Can you hook your VOM up to measure the current
output from the recitifier?
Peace
- --
Roscoe Primrose -- mailto:roscoe@aiko.com --
http://www.aiko.com/roscoe
"Once in a while you get shown the light
In the strangest of places if you look at it right." Robert Hunter
"640K ought to be enough for anybody" , Bill Gates, 1981
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] Bad power tranny?
Date: Wed, 06 Dec 2000 12:28:29 -0500
Source: Sound Digest Archive v02.n753
i'd have to second tim's approach.
pull the rectifier and measure the HV AC.
not sure how a short in the secondary would cause the rectifiers to glow red.
but perhaps a short in the primary (shorting out some # of turns).
this would cause the output voltage to rise and perhaps overdissipate the
rectifier....
perhaps also a short from the rectifier filament or filament winding to ground.
also trace out the associated wiring for possible shorts.
you could also check the cap.
put an ohmmeter across and see if it continues to climb in impedance...
i should also mention that the 5u4 probably does not like the turn-on surge that it gets
with a 470uF cap (given the low DCR choke).
also, 240mA + is also very near the rating of a single 5u4
and what is the voltage rating of the cap?
the turn-on surge must be over 450V (since the 330k bleeder is not enough
to wet the choke).
these last few comments are simple general guidelines, that i'm sure you are aware of.
5u4's are rugged and cheap, and it's worked til now.
but they might be contributing factors.
but usually i find a wiring or component lead short somewhere..
bob.d.
> ----------
> From: Tim Reese[SMTP:tgrmail@nmr.MGH.harvard.EDU]
> Sent: Wednesday, December 06, 2000 11:45 AM
> To: dstagner@talkware.net
> Cc: sound@lists.io.com
> Subject: Re: [JN] Bad power tranny?
>
> Dave, following the usual disclaimer that I'm only a hack at this stuff,
> I'd first pull the rectifier and power up the transformer with no load.
> If the fuse blows, I'd say that's conclusive that you have a shorted
> transformer. With no load, I'd then measure the AC volts across the HT
> checking for symmetry with the center tap. I've seen this before - an
> internal short in one half of the HT winding makes the CT no longer at
> center. Also made the PT hot like a stove... and changes the B+ volts.
>
> Not sure how this fits with your red plate symptoms though. I'd be more
> suspect of a shorted choke or cap downstream in that case.
>
> hth tr
> ----------------------------------------------------------------------
> Visit http://www.nmr.MGH.harvard.edu/~reese MRI, tube audio, reptiles
> Tim Reese, MGH NMR Center reese@nmr.MGH.harvard.edu
>
> >I need some help debugging a power supply... i suspect i have a blown
> >power transformer, but i'd like some confirmation from my symptoms.
> >
> >The power xformer is a big UTC welded steel can thing that has been in use
> >on this amp for ~3 years. The power supply circuit is a basic choke
> >supply, 5U4 into a huge low-DCR choke, followed by a 470uf cap. Grounding
> >is a 12ga copper buss wire from the input jacks to the HT center tap on
> >the power xformer. The AC line follows standard safety procedures
> >(three-prong cord, chassis grounded, surge suppressor). Fuses are 3A
> >slow-blow. Overall, the supply makes about 310v, and has powered stereo
> >PP 6B4Gs for years without ever getting hot or behaving at all strangely.
> >Until now.
> >
> >When i turn it on, the rectifier tube gets VERY hot quickly - the plates
> >glow cherry red. After a little while (no longer than 30 seconds), the
> >fuse blows. This seems like a short, so i've systematically disconnected
> >everything downstream or parallel (filament supplies, output xformers,
> >additional filter stages). All that's left is HT to the rectifier tube,
> >then the choke, the cap, and a 330k wirewound resistor from the cap to the
> >ground buss. I've tried swapping rectifiers, caps, even wire. Careful
> >checking with a VOM can't find any unexpected continuities in this
> >simplified circuit. The cap has a charge and is draining normally across
> >the bleed resistor after the fuse blows.
> >
> >So now i suspect the power transformer. Does it seem like i'm on the
> >right track? Please tell me before i have to drill new holes in the>
> >chassis to accomodate a new xformer...
> >--
> >Dave Stagner <dstagner@talkware.net>
> >Universal Talkware Corporation
> >10 Second St. NE Suite 400, Minneapolis MN 55413
> >ph: 612-843-6749 fax: 612-843-6707
> >
>
=========================================================================
From: Roscoe Primrose <roscoe@aiko.com>
Subject: Re: [JN] Bad power tranny?
Date: Wed, 06 Dec 2000 12:30:42 -0500
Source: Sound Digest Archive v02.n753
Dave Stagner wrote:
> On the other hand, if the choke is shorting to its housing, which
> is bolted to the chassis, and only doing so under high voltage conditions,
> that could explain it.
>
This is what I was suggesting as a possibility...
Peace
- --
Roscoe Primrose -- mailto:roscoe@aiko.com --
http://www.aiko.com/roscoe
"Once in a while you get shown the light
In the strangest of places if you look at it right." Robert Hunter
"640K ought to be enough for anybody" , Bill Gates, 1981
=========================================================================
From: AnnaLogg@aol.com
Subject: [JN] Bad URL
Date: Sun, 28 Feb 1999 15:44:59 EST
Source: Sound Digest Archive v02.n064
In a message dated 99-02-28 13:25:40 EST, I wrote:
> Yes, I heard that this group (which is only of interest to US citizens) at
> www.defendyourprivacy.com is an excellent and respected organization. In
> additon to t
Sorry. That URL doesn't work. I was working from an obviously faulty memory
- -- heard it on the radio in the car and wrote it down there; I'll check it out
and repost it (probably tomorrow) for those who are interested.
Anna
=========================================================================
From: DocGaw@cs.com
Subject: [JN] Bad weekend- Blown TAD 2001 and 2002
Date: Sun, 30 Jan 2000 15:17:27 EST
Source: Sound Digest Archive v02.n426
My wife got me to take my equipment apart this weekend to dust behind it. It
didn't really need it, but I did find a two year old magazine I thought I had
lost.
Anyway, on putting the system back together, on turning on the units. I blew
the membranes to t TAD 2001 and a 2002 driver. Does anybody know where I can
purchase them other thanTAD which wants a small fortune?
Bill Gaw
=========================================================================
From: "Peter Empson" <empson@lineone.net>
Subject: [JN] Bahnsen cornerhorns
Date: Tue, 7 Aug 2001 22:08:17 +0100
Source: Sound Digest Archive v02.n941
I have just seen the pictures from the Århus Festival, thanks for posting
them for those of us who couldn't attend (maybe next year...).
Anyway, the photos of the Bahnsen cornerhorns look stunning.
Is there any info about these on the web?
I am curious to know where the bass horn vents, is it from underneath? What
are they made from? What drivers?
Any information would be gratefully received.
Apologies in advance if they have been covered in previous threads.
Peter.
=========================================================================
From: "Peter Empson" <empson@lineone.net>
Subject: Re: [JN] Bahnsen cornerhorns
Date: Tue, 7 Aug 2001 22:59:07 +0100
Source: Sound Digest Archive v02.n941
Bjorn and Jan,
Thanks for the link, I'll go have a look now.
Peter.
=========================================================================
From: =?iso-8859-1?Q?Bj=F8rn_Aaholm?= <boulevarden@get2net.dk>
Subject: SV: [JN] Bahnsen cornerhorns
Date: Tue, 7 Aug 2001 23:23:59 +0200
Source: Sound Digest Archive v02.n941
Hi Peter.
Peter Bahnsen has a website about his horns:
http://www.bahnsenengineering.dk/
The bass horn vents underneath, by the vertical "seperators" you can
see by the floor.
You should find extensive info on his site.
Regards,
Bjørn Aaholm
=========================================================================
From: "John K. Dahlman" <jkdahlman@home.com>
Subject: Re: SV: [JN] Bahnsen cornerhorns
Date: Wed, 8 Aug 2001 00:49:08 -0400
Source: Sound Digest Archive v02.n941
Hi all. Showed my long suffering wife these, and I quote "If you can build
something that looks like that you can have them anywhere in the house you'd
like." The ultimate DIY horn? I gotta try! How often am I going to get the
green light on something like this? Any ideas out there?
Have fun,
John
On Tuesday 07 August 2001 17:23, you wrote:
> Hi Peter.
>
> Peter Bahnsen has a website about his horns:
> http://www.bahnsenengineering.dk/
>
> The bass horn vents underneath, by the vertical "seperators" you can
> see by the floor.
>
> You should find extensive info on his site.
>
> Regards,
> Bjørn Aaholm
=========================================================================
From: Dragos Bora <dsbora@mic.ro>
Subject: [JN] Balanced outputs & inputs and the phase splitter stage
Date: Mon, 16 Aug 1999 18:10:44 +0300
Source: Sound Digest Archive v02.n248
Dear sirs,
I would like to know if it is possible to input the signal from the
balanced ouputs of my DAC (PARASOUND D/AC 1500)
after the phase splitter stage of a push-pull power amplifier, knowing that
the balanced signal is already phase-shifted.
I want to try this in a tube amp and in a solid state one.
I know that problems may appear at least from adapting the impedances.
That's why I am asking if someone has some ideas on this.
Thank you for your kind answer.
Yours much obliged,
Dragos BORA
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: [JN] Balanced outputs & inputs and the phase splitter stage
Date: Tue, 17 Aug 1999 20:50:59 -0400
Source: Sound Digest Archive v02.n250
Dragos, have you looked at TubeCad Journal, the on-line magazine at
www.glassware.com? They have a series of articles on balanced line circuits,
including some comments about using balanced preamps to drive a PP circuit.
- --
Grover Gardner
groverg@postoffice.att.net
=========================================================================
From: Peter Allen <ptrallen@melbpc.org.au>
Subject: [JN] Balanced Power at home
Date: Tue, 02 Feb 1999 14:43:36 +1100
Source: Sound Digest Archive v02.n021
- --=====================_23586565==_.ALT
Content-Type: text/plain; charset="us-ascii"
Guys:
Can we have a brains trust on the feasibility of (getting a registered
electrician to) creating one balanced circuit in a home for audio purposes.
Is it valid, has anyone done it with good results, or is it just a w.... ell a
waste of time?
The naive in me hopes that it only needed a transformer and you could then set
up a
dedicated circuit just for your audio.
Thanks for your considerations.
- -peter
Lance Dow in London started it all off:
If you want to find out about balanced power, check out EquiTech at;
www.equitech.com/
This page has an index to a number of articles on the subject. They're
not too technical and they're well illustrated so you can follow what's
being said.
A year-or-so ago I downloaded and read HUGE amounts on balanced power
from the EquiTech site and spent weeks contemplating a DIY version of their
conditioner. I wasn't sure just how accurately the two phases needed
to be for a start - whether I could use a pair of 240:120 step-downs
with the primaries in parallel and the secondaries in series to give a
centre-tapped 240v (+/- 120v). Or whether I need something more
specialised (both secondaries exactly the same on a common core).
My concern was just how well matched the two halves of the transformer
needed to be. Obvious you get the best result when they match
perfectly, but how far can they slip before you lose it completely?
The articles weren't technical enough to give me this info, nor could
I glean it from the specs of their commercial transformers. My gut
feeling is that you get a large proportion of the benefit by just
having it balanced about earth, with the best cancellation etc coming
when the balance is perfect. Unfortunately, I didn't have a spare
isolation tranny to play around with.
Perhaps the arrangement might contravene local wiring regulations.
Peter Allen: editor, Melbourne Audio Club News
_______________________________________
*25th Anniversary year* Do visit us
http://vicnet.net.au/~macinc
- --=====================_23586565==_.ALT
Content-Type: text/html; charset="us-ascii"
<html>
Guys:<br>
Can we have a brains trust on the feasibility of (getting a registered
electrician to) creating one balanced circuit in a home for audio
purposes. <br>
Is it valid, has anyone done it with good results, or is it just a w....
ell a waste of time?<br>
The naive in me hopes that it only needed a transformer and you could
then set up a <br>
dedicated circuit just for your audio.<br>
<br>
Thanks for your considerations.<br>
- -peter<br>
<br>
Lance Dow in London started it all off: <br>
If you want to find out about balanced power, check out
EquiTech at; <br>
<a href="http://www.equitech.com/" eudora="autourl"><font color="#0000FF"><u>www.equitech.com/
</a></font></u>
<br>
<br>
This page has an index to a number of articles on the subject.
They're <br>
not too technical and they're well illustrated so you can follow
what's <br>
being said.<br>
<br>
A year-or-so ago I downloaded and read HUGE amounts on balanced power
<br>
from the EquiTech site and spent weeks contemplating a DIY version
of their <br>
conditioner. I wasn't sure just how accurately the two phases needed
<br>
to be for a start - whether I could use a pair of 240:120 step-downs
<br>
with the primaries in parallel and the secondaries in series to give a
<br>
centre-tapped 240v (+/- 120v). Or whether I need something more <br>
specialised (both secondaries exactly the same on a common core). <br>
<br>
My concern was just how well matched the two halves of the transformer
<br>
needed to be. Obvious you get the best result when they match <br>
perfectly, but how far can they slip before you lose it completely?
<br>
The articles weren't technical enough to give me this info, nor could
<br>
I glean it from the specs of their commercial transformers. My gut <br>
feeling is that you get a large proportion of the benefit by just <br>
having it balanced about earth, with the best cancellation etc coming
<br>
when the balance is perfect. Unfortunately, I didn't have a spare <br>
isolation tranny to play around with.<br>
<br>
Perhaps the arrangement might contravene local wiring regulations. <br>
<br>
<br>
<br>
<div>Peter Allen: editor, Melbourne Audio Club News</div>
<div>_______________________________________</div>
<div> *25th Anniversary
year*  
;
Do visit us</div>
http://vicnet.net.au/~macinc &n
bsp;
</html>
- --=====================_23586565==_.ALT--
=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: Re: [JN] Balanced Power at home
Date: Tue, 02 Feb 1999 05:39:55 PST
Source: Sound Digest Archive v02.n022
Hi all,
>Can we have a brains trust on the feasibility of (getting a
>registered electrician to) creating one balanced circuit in
>a home for audio purposes.
Why not.
>Is it valid,
Yes.
>has anyone done it with good results,
No-one I know.
>or is it just a w.... ell a waste of time?
Hard to say. All concidered, with suitable treatements to the normal
mains I believe a similar effect can be obtained much cheaper.
>The naive in me hopes that it only needed a transformer
That is correct. But in order not to constrict dynamics of Amplifiers
connect you need a WHOPPING BIG MONSTER Transformer.
I mean not some wimpy 1KVA Unit, but something more close to 5-10KVA.
This will depend upon your Amplifiers of course.
>and you could then set up a dedicated circuit just for your audio.
Sure.
Kind regards Thorsten.
======================================
e-mail:
Thorsten@tnt-audio.com
Visit TNT-Audio on the Web - the only advertising
free audio web-zine.
http://www.tnt-audio.com
======================================
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
=========================================================================
From: David Bardes <David_Bardes@zd.com>
Subject: [JN] Re: Balanced Power at home
Date: Thu, 04 Feb 1999 14:30:44 -0800
Source: Sound Digest Archive v02.n028
Bruce,
May I be so bold as to ask "How Much?$?"
David
>I have gone to a balanced power line. It's quieter more and more details
>come through.
=========================================================================
From: "Bruce Nilson" <bnilson@FCB.COM>
Subject: Re: [JN] Balanced Power at home
Date: Thu, 04 Feb 1999 16:19:36 +0000
Source: Sound Digest Archive v02.n028
I have gone to a balanced power line. It's quieter more and more details
come through.
It goes from 240v to 60-0-60v with some filtering. A true seperate
ground makes the difference.
Another John Camille design.
Bruce Nilson
=========================================================================
From: David Bardes <David_Bardes@zd.com>
Subject: Re: [JN] Re: Balanced Power at home
Date: Thu, 04 Feb 1999 16:19:41 -0800
Source: Sound Digest Archive v02.n028
Ahh, not so bad. Much less expensive than the commercial balanced power
products.
>About $350-$400, using a combination of surplus and new parts.
David
=========================================================================
From: "Bruce Nilson" <bnilson@FCB.COM>
Subject: [JN] Re: Balanced Power at home
Date: Thu, 04 Feb 1999 17:03:06 +0000
Source: Sound Digest Archive v02.n028
- --------------F0A4D2BE321F89DA44F25CED
Content-Type: text/plain; charset=us-ascii; x-mac-type="54455854"; x-mac-creator="4D4F5353"
Content-Transfer-Encoding: 7bit
Bruce,
May I be so bold as to ask "How Much?$?"
David
About $350-$400, using a combination of surplus and new parts.
It's only good for about 4 amps I think.
- --------------F0A4D2BE321F89DA44F25CED
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: 7bit
<HTML>
<I>Bruce,</I>
<P><I>May I be so bold as to ask "How Much?$?"</I>
<P><I>David</I>
<BR>
<P>About $350-$400, using a combination of surplus and new parts.
<BR>It's only good for about 4 amps I think.</HTML>
- --------------F0A4D2BE321F89DA44F25CED--
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] Balanced Power at home
Date: Thu, 04 Feb 1999 19:58:01 +0100
Source: Sound Digest Archive v02.n028
Why would you like to have a balanced system ?
Are you talking mains ?
Guido
At 14:43 2-2-99 +1100, Peter Allen wrote:
>>>>
<excerpt>Guys:
Can we have a brains trust on the feasibility of (getting a registered
electrician to) creating one balanced circuit in a home for audio
purposes.
Is it valid, has anyone done it with good results, or is it just a w....
ell a waste of time?
The naive in me hopes that it only needed a transformer and you could
then set up a
dedicated circuit just for your audio.
Thanks for your considerations.
- -peter
Lance Dow in London started it all off:
If you want to find out about balanced power, check out EquiTech at;
<<http://www.equitech.com/><underline><color><param>0000,0000,ffff</param>www.equitech.com/</color>
</underline>
This page has an index to a number of articles on the subject. They're
not too technical and they're well illustrated so you can follow what's
being said.
A year-or-so ago I downloaded and read HUGE amounts on balanced power
from the EquiTech site and spent weeks contemplating a DIY version of
their
conditioner. I wasn't sure just how accurately the two phases needed
to be for a start - whether I could use a pair of 240:120 step-downs
with the primaries in parallel and the secondaries in series to give a
centre-tapped 240v (+/- 120v). Or whether I need something more
specialised (both secondaries exactly the same on a common core).
My concern was just how well matched the two halves of the transformer
needed to be. Obvious you get the best result when they match
perfectly, but how far can they slip before you lose it completely?
The articles weren't technical enough to give me this info, nor could
I glean it from the specs of their commercial transformers. My gut
feeling is that you get a large proportion of the benefit by just
having it balanced about earth, with the best cancellation etc coming
when the balance is perfect. Unfortunately, I didn't have a spare
isolation tranny to play around with.
Perhaps the arrangement might contravene local wiring regulations.
Peter Allen: editor, Melbourne Audio Club News
_______________________________________ *25th Anniversary year*
Do visit us
<<http://vicnet.net.au/~macinc>http://vicnet.net.au/~macinc
</excerpt>
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] Balanced Power at home
Date: Sat, 06 Feb 1999 13:33:55 +0100
Source: Sound Digest Archive v02.n030
Hi Joes,
I believe the advantage of another transformer, separating or balancing the
mains, only is exploited if a transformer with low parasytic capacitance is
used
Such transformers can oten be found from the medical industry
Commonly available transformers have relative high capacitance (say up to 1
nF) between primary and secundary and as such have relative low coupling
impedance for common mode currents.
Transformers with a low capacitance behave as a high impedance and therefor
reduce common mode currents
It is my believe and perception that more detail remains resolved
My 2 euro cent
Guido
At 16:19 4-2-99 +0000, Bruce Nilson wrote:
>I have gone to a balanced power line. It's quieter more and more details
>come through.
>It goes from 240v to 60-0-60v with some filtering. A true seperate
>ground makes the difference.
>Another John Camille design.
>
>
>Bruce Nilson
>
>
=========================================================================
From: "Remco Stoutjesdijk" <r.m.stoutjesdijk@student.utwente.nl>
Subject: [JN] balanced riaa preamp questions
Date: Thu, 25 Jan 2001 16:37:46 +0100
Source: Sound Digest Archive v02.n792
Hi,
I'm preparing to build a new balanced riaa preamp, and have a few questions:
- - is it worth it to follow the riaa curve to within, say 0.1 dB? I have a
fairly accurate unit right now, but I notice a lot of tonal differences
between records, especially in the bass region. It seems most records don't
follow the eq curve as well as the preamp. Dare I include some tonal
controls or will that ban me from the Joelist? ;)
- - are there any cool (unusual) designs out there? I have an all-transformer
design from Christian Rintelen and have taken a look at Allen Wright's
designs. These are almost orthagonal, I like that, it yields a lot of
insights. But I'd welcome some more suggestions.
TIA!
Remco
- --
http://listen.to/rmsaudio
=========================================================================
From: Christian Rintelen <christian@rintelen.ch>
Subject: Re: [JN] balanced riaa preamp questions
Date: Thu, 25 Jan 2001 21:24:37 +0100
Source: Sound Digest Archive v02.n793
To do the RIAA *differential i.e. mirrored for both phases* is possible, but
probably not adviseable... If the two RIAAs are not 100% identical, the errors
will add up and you'll deviate more than just 0.1 dB from the RIAA curve.
That's why I chose to leave the fully balanced path and float the LCR-RIAA.
Christian
Remco Stoutjesdijk wrote:
> I'm preparing to build a new balanced riaa preamp, and have a few questions:
>
> - is it worth it to follow the riaa curve to within, say 0.1 dB? I have a
> fairly accurate unit right now, but I notice a lot of tonal differences
> between records, especially in the bass region. It seems most records don't
> follow the eq curve as well as the preamp. Dare I include some tonal
> controls or will that ban me from the Joelist? ;)
=========================================================================
From: "=?ISO-8859-1?Q?Torbj=F8rn_Lien?=" <mdrivekl@online.no>
Subject: [JN] Balanced x-formers/was Help with 300B operating points please...
Date: Sat, 3 Apr 1999 22:51:18 +0200
Source: Sound Digest Archive v02.n108
Hello all
Pearl wrote:
> Hi All:
> The SE phenomena caused me to seriously rethink push-pull
> and I spent several years on that. The upshot is that single
> coil PP OTs are never wound so that they balance.. neither AC
> nor DC. Now, if one of the most crucial parts of the circuit >
simply does not work proporely, the entire can NEVER
> work properly. So, I figured out haw to buil PP OTs that
> ARE balanced. . .easire said than done and by a good long way . .
>
> Bill - PEARL
Ehm,- I'm intruiged! :)
Why don't you share your findings? Are they beond Reuben Lee?!
He did advocate this....(more or less, my interpretation....)
- -Since good pri to pri coupling is never perfect,- class "A"
output stage is the only thing to work with in PP...
- -In class "A" close pri-pricoupling is not essential. So now a
perfectly balanced x-former can be made, if using a
single C/double coil x-former type.
Of course later on there was the voltage-feedback/unity coupling
by McIntosh.And the "in same family" circlotrone-consept from
Electrovoice....
Regards,
T.Lien
>
>
>
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: [JN] Bal'd Pwr, Grnds, Loops and the like
Date: Mon, 08 Feb 1999 18:20:17 -0700
Source: Sound Digest Archive v02.n034
Joes:
Here's a good URL, check it out:
http://www.equitech.com/articles/articles.htm
Bill Perkins, PEARL Inc.
2528 19 St. S.W., Calgary, Ab.,
Canada T2T 4X3
Ph. 1 403 244 4434 Fx. 1 403 244 9026
=========================================================================
From: "Nikita Kamka" <nikita@int.mew.co.jp>
Subject: Re: [JN] balloon 300B
Date: Wed, 6 Dec 2000 08:18:39 +0700
Source: Sound Digest Archive v02.n752
Hi!
- ----- Original Message -----
From: C.snoeren <c.snoeren@tip.nl>
>
> Ps. anyone heared (of) the brand new BALLOON 300B tubes?
>
Do you mean those taiwanese?
They said in japanese list, the soundit is not good, very disappointing,
except the retro-shape (and the price:)
Regards,
Nikita Kamka
=========================================================================
From: Norm Luttbeg <nluttbeg@politics.tamu.edu>
Subject: Re: [JN] balloon 300B
Date: Wed, 06 Dec 2000 13:22:24 -0500
Source: Sound Digest Archive v02.n753
on 12/5/00 8:18 PM, Nikita Kamka at nikita@int.mew.co.jp wrote:
> Hi!
>
> ----- Original Message -----
> From: C.snoeren <c.snoeren@tip.nl>
>>
>> Ps. anyone heared (of) the brand new BALLOON 300B tubes?
>>
>
> Do you mean those taiwanese?
> They said in japanese list, the soundit is not good, very disappointing,
> except the retro-shape (and the price:)
>
> Regards,
> Nikita Kamka
Apparently, AVVT also has a globe 2A3 which is also said to not be the equal
of the ST
Norm
=========================================================================
From: "Quest quest" <hoshum2@hotmail.com>
Subject: Re: [JN] balloon 300B
Date: Thu, 07 Dec 2000 06:55:13 -0800
Source: Sound Digest Archive v02.n755
Fellow Joes!
Yeash! These ballon shaped 300B tubes was originally designed and hand-made
by a Taiwanese Audio Shop owner who got most of his tube-making expertise
from some ex-NEC production line. Initial prototype includes WE205D, etc.
and they all performed well (remember: these are just clones of original WE
300B or WE205D just like any other else).
As he finally decided to mass-produce these tubes he negotiated with a few
ex-mil tube factories in Mainland China (noticeably from TianTsin, China) to
have them made under contract. Things went well and what you see now is the
mass-produced Chinese version of the Taiwanese "Full Music" 300B (original
Taiwanese versions are all hand-made and are not meant to be sold to the
public, mind you).
The very unfortunatly part is, like any other corporate contractors in
mainland, many of these guys also make some extras by going out of quotas
and sell the excess under a different brand name. (this is very common in
mainland these days, from fake shampoo bottles with different stuff other
than the "real" thing in it to fake Duracell batteries to God-knows-what.
Assuming that these balloon shaped tubes are highly popular, these side-line
guys will do anything just to make a buck.
Oh and BTW: from what I understand these tubes have a slightly different
characteristics compared to the original WE300B. I do not have the spec. at
this moment so plse don't ask me for it....
That's all the information I have for now.
Good luck!
Quest;^>
>From: Norm Luttbeg <nluttbeg@politics.tamu.edu>
>To: Nikita Kamka <nikita@int.mew.co.jp>, <c.snoeren@tip.nl>, Joelist
><sound@deliverator.io.com>
>Subject: Re: [JN] balloon 300B
>Date: Wed, 06 Dec 2000 13:22:24 -0500
>
>on 12/5/00 8:18 PM, Nikita Kamka at nikita@int.mew.co.jp wrote:
>
> > Hi!
> >
> > ----- Original Message -----
> > From: C.snoeren <c.snoeren@tip.nl>
> >>
> >> Ps. anyone heared (of) the brand new BALLOON 300B tubes?
> >>
> >
> > Do you mean those taiwanese?
> > They said in japanese list, the soundit is not good, very disappointing,
> > except the retro-shape (and the price:)
> >
> > Regards,
> > Nikita Kamka
>Apparently, AVVT also has a globe 2A3 which is also said to not be the
>equal
>of the ST
>
>Norm
>
_____________________________________________________________________________________
Get more from the Web. FREE MSN Explorer download : http://explorer.msn.com
=========================================================================
From: "J. Gordon Rankin" <waudio@cinti.net>
Subject: Re: [JN] balloon 300B *More info*
Date: Thu, 7 Dec 00 10:33:06 -0500
Source: Sound Digest Archive v02.n755
Gang,
Just a little more info...
Peter Chang is the person in charge and his email addres is:
allmusic@ms22.hinet.net
The company in Taiwan is AllMusic and the China company is Full Music. As
usual the tubes are only suppose to be All Music branded but we know how
that is. You can get the All Music version of these tubes from New
Sensor. I have the 101 and 205 and the 205 are real sweet but they are a
bit of the norm. Also these use UX-4 style basses insted of the UV-4
bases used in the original items (arg......).
The NOV issue of MJ has all the specs and differences for the tubes.
Gordon
>Yeash! These ballon shaped 300B tubes was originally designed and hand-made
>by a Taiwanese Audio Shop owner who got most of his tube-making expertise
>from some ex-NEC production line. Initial prototype includes WE205D, etc.
>and they all performed well (remember: these are just clones of original WE
>300B or WE205D just like any other else).
>
> As he finally decided to mass-produce these tubes he negotiated with a few
>ex-mil tube factories in Mainland China (noticeably from TianTsin, China) to
>have them made under contract. Things went well and what you see now is the
>mass-produced Chinese version of the Taiwanese "Full Music" 300B (original
>Taiwanese versions are all hand-made and are not meant to be sold to the
>public, mind you).
>
> The very unfortunatly part is, like any other corporate contractors in
>mainland, many of these guys also make some extras by going out of quotas
>and sell the excess under a different brand name. (this is very common in
>mainland these days, from fake shampoo bottles with different stuff other
>than the "real" thing in it to fake Duracell batteries to God-knows-what.
>Assuming that these balloon shaped tubes are highly popular, these side-line
>guys will do anything just to make a buck.
>
>
>Oh and BTW: from what I understand these tubes have a slightly different
>characteristics compared to the original WE300B. I do not have the spec. at
>this moment so plse don't ask me for it....
>
> That's all the information I have for now.
=====> Wavelength Audio <=====
mailto:waudio@cinti.net
mailto:wavelength@fuse.net
http://www.WavelengthAudio.com
ph.fx. 513-271-4186 USA
=========================================================================
From: "Thomas Sylvester" <TRS@carlsmith.com>
Subject: Re: [JN] balloon 300B *More info*
Date: Fri, 15 Dec 2000 08:52:56 -1000
Source: Sound Digest Archive v02.n760
The "Full Music" 300B tested by MJ looks like it has an ST-type bulb; the tests show it is less line
ar than the WE300B (surprise!) and a CR300B. The 101D, 102D and 205D look gorgeous, but most intere
sting may be the fact that the company also makes a WE274A copy. . .
>>> "J. Gordon Rankin" <waudio@cinti.net> 12/07/00 05:33AM >>>
<snip>
The NOV issue of MJ has all the specs and differences for the tubes.
Gordon
=
=========================================================================
From: "Fred Volz" <fcv@emotiveaudio.com>
Subject: Re: [JN] balloon 300B *More info*
Date: Fri, 15 Dec 2000 18:09:52 -0500
Source: Sound Digest Archive v02.n760
I picked up a pair of the All Music balloon 300Bs from New Sensor and,
contrary to what I've been reading on the list, they sound very good. I
haven't been able to compare them to Westerns yet, but, in our circuit and
in some Fi monos, they sound great--very smooth and detailed, less crud than
the Sovtek 300Bs. And, I like the Sovteks. The only down side is that one of
the tubes "bought the farm" after about an hour of use (non-violent type of
death). I have a new pair on the way. I would be interested in hearing from
other people who have actually tried them.
Fred Volz
fcv@emotiveaudio.com
- ----- Original Message -----
From: "Thomas Sylvester" <TRS@carlsmith.com>
To: <waudio@cinti.net>; <sound@deliverator.io.com>
Sent: Friday, December 15, 2000 1:52 PM
Subject: Re: [JN] balloon 300B *More info*
> The "Full Music" 300B tested by MJ looks like it has an ST-type bulb; the
tests show it is less linear than the WE300B (surprise!) and a CR300B. The
101D, 102D and 205D look gorgeous, but most interesting may be the fact that
the company also makes a WE274A copy. . .
>
> >>> "J. Gordon Rankin" <waudio@cinti.net> 12/07/00 05:33AM >>>
> <snip>
> The NOV issue of MJ has all the specs and differences for the tubes.
>
> Gordon
>
>
> =
>
=========================================================================
From: =?iso-8859-1?Q?Bj=F8rn_Aaholm?= <bjorn@vt52.com>
Subject: [JN] Ballpark figure for acceptable PS ripple?
Date: Tue, 29 May 2001 22:22:51 +0200
Source: Sound Digest Archive v02.n895
Hello guys...
Could someone give me a ballpark figure of how low I need to get the
PS ripple for a SE 10Y power amp driving ~100dB speakers in order for
it to NOT cause audible hum?
I'm playing around with PSUD II and what gives the best dynamical
behaviour is not what gives the lowest "static" ripple, and I'd like
to know how low I NEED to get the ripple...
Thanks for pouring of your knowledge and experience!
regards,
Bjørn Aaholm
(Århus fever beginning...)
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] Ballpark figure for acceptable PS ripple?
Date: Tue, 29 May 2001 23:51:39 +0200
Source: Sound Digest Archive v02.n895
Bjorn
It depends on the anode load versus Rp
Second, I guess that in some occasions the heater ripple causes more hum
100dB sens speakers - at what level do you want the hum ? I gues 1 mV is
already too much
If you have that figure you can calculate the rest yourself (given a
certain transformer ratio etc)
regards
- -
Guido
At 22:22 29-5-01 +0200, Bjørn Aaholm wrote:
>Hello guys...
>
>Could someone give me a ballpark figure of how low I need to get the
>PS ripple for a SE 10Y power amp driving ~100dB speakers in order for
>it to NOT cause audible hum?
>
>I'm playing around with PSUD II and what gives the best dynamical
>behaviour is not what gives the lowest "static" ripple, and I'd like
>to know how low I NEED to get the ripple...
>
>Thanks for pouring of your knowledge and experience!
>
>regards,
>Bjørn Aaholm
>(Århus fever beginning...)
=========================================================================
From: =?iso-8859-1?Q?Bj=F8rn_Aaholm?= <bjorn@vt52.com>
Subject: SV: [JN] Ballpark figure for acceptable PS ripple?
Date: Wed, 30 May 2001 00:43:15 +0200
Source: Sound Digest Archive v02.n895
Guido wrote:
>
> It depends on the anode load versus Rp
How? Rp is 5K, load is 10K.
>
> Second, I guess that in some occasions the heater ripple
> causes more hum
Yep, I know.
>
> 100dB sens speakers - at what level do you want the hum ? I
> gues 1 mV is
> already too much
Maybe yes... On the output. I hope 1mV PS ripple is far more than good
enough.
> If you have that figure you can calculate the rest yourself (given a
> certain transformer ratio etc)
Yes, but is it as simple as the PS ripple stepped down? I guess not
from your remark about dependancy of load vs. Rp.
regards,
Bjørn
=========================================================================
From: Jim de Kort <jim@vt52.com>
Subject: Re: [JN] Ballpark figure for acceptable PS ripple?
Date: Wed, 30 May 2001 01:02:44 +0200
Source: Sound Digest Archive v02.n895
Hello,
>Second, I guess that in some occasions the heater ripple causes more hum
True, filament supplies and grounding are almost always the cause for any
hum. I've almost never had any real problems with the B+.
>100dB sens speakers - at what level do you want the hum ? I gues 1 mV is
>already too much
On the secondary side you mean? <5mV is indeed essential with these kinds
of speakers. Ripply on the PS can be a bit higher, I've had no problems
with 25-30mV on my Oris 150 (104dB?).
Regards,
Jim de Kort
jim@vt52.com
Visit www.VT52.com for tube
DIY projects and datasheets
=========================================================================
From: Jim de Kort <jim@vt52.com>
Subject: Re: SV: [JN] Ballpark figure for acceptable PS ripple?
Date: Wed, 30 May 2001 01:06:43 +0200
Source: Sound Digest Archive v02.n895
Hi,
> > If you have that figure you can calculate the rest yourself (given a
> > certain transformer ratio etc)
>Yes, but is it as simple as the PS ripple stepped down? I guess not
>from your remark about dependancy of load vs. Rp.
The OPT acts as a choke for the ripple. You'd need the inductance value to
figure out the ratio between tube (Rp) and OPT (Xf).
Regards,
Jim de Kort
jim@vt52.com
Visit www.VT52.com for tube
DIY projects and datasheets
=========================================================================
From: Christian Rintelen <christian@rintelen.ch>
Subject: Re: [JN] Ballpark figure for acceptable PS ripple?
Date: Wed, 30 May 2001 09:38:54 +0200
Source: Sound Digest Archive v02.n896
> >100dB sens speakers - at what level do you want the hum ? I gues 1 mV is
> >already too much
>
> On the secondary side you mean? <5mV is indeed essential with these kinds
> of speakers. Ripply on the PS can be a bit higher, I've had no problems
> with 25-30mV on my Oris 150 (104dB?).
>
Depends on the speaker - PS ripple is mostly 100 or 120 Hz and should
therefore be inaudible on a midrange compression driver even in active use
w/o high pass filter. Should... I had 2 mV ripple on the terminals of my 110
dB/W/m TAD TD-4001 and it was intolerable. It turned out not to be the B+
supply but a faulty input pot, so the hum had a higher frequency than just
twice the mains.... (took me a while to figure out...) 2 mV ripple on the
speaker terminals of the 96 dB/W/m Blue Thunder bass chassis are inaudible.
10 mV of power supply ripple on the speaker terminals of a Fostex 925 horn
tweeter are inaudible because f is too low for the speaker.
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: SV: [JN] Ballpark figure for acceptable PS ripple?
Date: Wed, 30 May 2001 23:23:59 +0200
Source: Sound Digest Archive v02.n896
Jim wrote:
>The OPT acts as a choke for the ripple.
No, it does not: The primary is coupled to the secondary (at least at 100
Hz I hope) and reflects a real impedance
Guido
>You'd need the inductance value to
>figure out the ratio between tube (Rp) and OPT (Xf).
>
>
>
>Regards,
>
>
>Jim de Kort
>jim@vt52.com
>
>
>Visit www.VT52.com for tube
>DIY projects and datasheets
=========================================================================
From: Remco Stoutjesdijk <remco@ultranalog.com>
Subject: [JN] Ballpark figure for acceptable PS shocks per day?
Date: Thu, 31 May 2001 00:54:45 +0200
Source: Sound Digest Archive v02.n896
I thought that the two of tonight were enough for one day...
Remco
- --
http://www.ultranalog.com
=========================================================================
From: Richard C Nevill <rnevill@is.dal.ca>
Subject: [JN] Bandpass Box
Date: Mon, 29 Jan 2001 12:46:05 -0400 (AST)
Source: Sound Digest Archive v02.n795
Could anyone point me to a link for a program to calculate box volumes for
a 4th order bandpass box, please?
I had found one over the weekend but it doesn't seem to want to let me use
my own data, just the drivers it comes with. Pretty neat program, I'll
post the link for it this evening if any one is interested (it also does
sealed and vented, even has Lowthers loaded in).
Thanks people
Richard Nevill
=========================================================================
From: "Jon Lane" <jhlane@reflexnet.net>
Subject: RE: [JN] Bandpass Box
Date: Mon, 29 Jan 2001 18:31:45 -0700
Source: Sound Digest Archive v02.n795
> Could anyone point me to a link for a program to
> calculate box volumes for
> a 4th order bandpass box, please?
I wrote one once but then I got smart(er) and bought this
one instead:
www.linearx.com Look for LEAP 4.0.
If you have a driver spec, email it over and I'd be happy to
model it for you.
Jon Lane
=========================================================================
From: "John Levreault" <jlevro@mediaone.net>
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range
Date: Thu, 20 Sep 2001 10:12:39 -0400
Source: Sound Digest Archive v02.n980
- ----- Original Message -----
From: "evaguido" <EvaGuido@iaehv.nl>
To: "dave slagle" <dslagle@earthlink.net>; <sound@lists.io.com>
Sent: Thursday, September 20, 2001 5:17 AM
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range
> I have yet to see a tubed circuit suffering from 1nH added
inductance.........
An old microwave engineer's rule of thumb is "a nh per inch".
JL
=========================================================================
From: "John Levreault" <jlevro@mediaone.net>
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range
Date: Thu, 20 Sep 2001 14:21:12 -0400
Source: Sound Digest Archive v02.n980
- ----- Original Message -----
From: "evaguido" <EvaGuido@iaehv.nl>
To: "John Levreault" <jlevro@mediaone.net>; "dave slagle"
<dslagle@earthlink.net>; <sound@lists.io.com>
Sent: Thursday, September 20, 2001 10:50 AM
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range
> At 10:12 20-9-01 -0400, John Levreault wrote:
>
> >An old microwave engineer's rule of thumb is "a nh per inch".
>
> I wish that where true.........
>
1" of #22AWG wire _in space_ is ~1.2nh.
This "rule of thumb" dates back to the good old days when point-to-point
wiring was the order of the day. And yes, PTP works nearly to the GHz
region.
JL
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range
Date: Thu, 20 Sep 2001 16:50:19 +0200
Source: Sound Digest Archive v02.n980
At 10:12 20-9-01 -0400, John Levreault wrote:
>An old microwave engineer's rule of thumb is "a nh per inch".
I wish that where true.........
1 nH per mm, assumed that the return current runs at a distance 10 times
the diameter of the actual conductor, that is what I use.
1 nH per inch is the net inductance (transfer impedance) of a lousy coax
A copper trace (1mm) above a groundplane (double sided PCB, 1.6 mm thick)
has an inductance of about 0.2 nH per mm
best
Guido
>JL
>
=========================================================================
From: Rich Conte <rconte@attglobal.net>
Subject: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 14:34:08 -0400
Source: Sound Digest Archive v02.n978
Dear Experts,
Ok. Here is a lively discussion.
A few engineers at the largest Telecom company in the work, specifically
the labs were discussing the new SONY SACD players and the playable
output bandwidth being almost 2Hz to 100Khz and above.
We then started to talk about the limits of human hearing, Internet
Compression ratios and standards for Voice (music) over IP...h.323
standards etc...then the amplifiers came up and the discussion
surrounded wide bandwidth audio amplifier output transformers, old WE
and new Vac. Tube one's like Tango and Tamura...
Can someone briefly educate me as to why you would want a ultrawide
bandwidth output transformer for mega $$$'s made of exotic permalloy',
silver etc...with bandwidth like the SACD Players if we cannot hear
about say 15Khz....in the data/analog/digital world the voice stuff is
300Hz-3KHz...so what do we miss.
If you could only hear from say 40Hz and only had drivers that ran down
that low before rolloff and could only hear say to 15Khz and speakers
to match, why would you need super wide bandwidth...Intruments that make
music/noise don't go to 100KHz do they?
So what is the sound from 20Khz-100Khz beside sideband and maybe
noise/subsonic stuff?
The dogs in the neighborhood love SACD?
Please a serious discussion, I am not a lab person, but a wise
data/voice person and just want to know why specifications?
Thanks for the conscientious kind replies.
Rich Conte
=========================================================================
From: ToobWiz@aol.com
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 15:00:46 EDT
Source: Sound Digest Archive v02.n978
Rich,
I'll handle just one little bit of the question... Why would we want output
which is above our hearing?
Take two sounds at 20KHz and at 16 Khz. Play them together and what do you
get? You'll get those two frequencies, plus all sum and difference
frequencies, due to heterodyning. Some of those frequencies will be in the
audible range.
But that is just a lab experiment. Now take an instrument or two instruments
that have overtones at the above two frequencies. The characteristic cound of
that instrument contains all those sum and difference frequencies. If your
system doesn't produce those frequencies, then the reproduction will lack
*that* specific bit of harmonic richness.
To make the exercise even more demanding, think about a 16Khz overtone and a
30Khz overtone combined. There is a 14Khz difference pitch that you'd miss if
your tweeters didn't extend to above 30Khz. There are overtones up there in
real live musical instruments, not that they'd come through on a *CD*
recording.
Hope this helps/Don
=========================================================================
From: Jan Nielsen <hifi@ishoejby.dk>
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 21:11:01 +0200
Source: Sound Digest Archive v02.n978
Hi Rich,
Basically there are two answers:
1. The larger digital bandwith makes it possible to omit the brickwall 20
kHz filter found in all CD-players. These very steep filters gives a lot of
problems -technically as well as sonically. Moving the samplefrequency up
you can do with a simpe 1st. order low-pass filter.
2. Phaseproblems. Any filter (especially the very steep ones) will give
phaseproblems and that may cause degration of the signal.
This was a very short answer, other may give you all the technical
explanations.
BTW SACD will only go op to 50 kHz. Alle Sony players are equipped with an
internal 1st. order lowpass filter at the output. Due to heavy noise shaping
the signal to noise ratio above 50 kHz is very limited.
Regards,
Jan
Rich Conte wrote:
> Dear Experts,
>
> Ok. Here is a lively discussion.
>
> A few engineers at the largest Telecom company in the work, specifically
> the labs were discussing the new SONY SACD players and the playable
> output bandwidth being almost 2Hz to 100Khz and above.
>
> We then started to talk about the limits of human hearing, Internet
> Compression ratios and standards for Voice (music) over IP...h.323
> standards etc...then the amplifiers came up and the discussion
> surrounded wide bandwidth audio amplifier output transformers, old WE
> and new Vac. Tube one's like Tango and Tamura...
>
> Can someone briefly educate me as to why you would want a ultrawide
> bandwidth output transformer for mega $$$'s made of exotic permalloy',
> silver etc...with bandwidth like the SACD Players if we cannot hear
> about say 15Khz....in the data/analog/digital world the voice stuff is
> 300Hz-3KHz...so what do we miss.
>
> If you could only hear from say 40Hz and only had drivers that ran down
> that low before rolloff and could only hear say to 15Khz and speakers
> to match, why would you need super wide bandwidth...Intruments that make
> music/noise don't go to 100KHz do they?
>
> So what is the sound from 20Khz-100Khz beside sideband and maybe
> noise/subsonic stuff?
>
> The dogs in the neighborhood love SACD?
>
> Please a serious discussion, I am not a lab person, but a wise
> data/voice person and just want to know why specifications?
>
> Thanks for the conscientious kind replies.
>
> Rich Conte
=========================================================================
From: michael knapp <sound@auriculum.com>
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 12:49:37 -0700
Source: Sound Digest Archive v02.n979
>
>I'll handle just one little bit of the question... Why would we want output
>which is above our hearing?
[big snip]
fwiw, i remember keith johnson (reference recordings, pacific microsonics,
spectral, etc) discussed in a an interview experiments (military, i
believe) researching human auditory response. the gist was that while they
didn't find anything new in terms of steady state fr, they were able to
show audibility of transient response up to 100kHz. ie, restricting
bandwidth below 100kHz was audible w/ highly transient material.
anyone else know anything about this? one would have to look at 15
year-old copies of tas and sterophile for the reference....
mike
=========================================================================
From: Dan Marshall <mdaniel7@uswest.net>
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 15:04:13 +0000
Source: Sound Digest Archive v02.n979
Paul De Raymond Leclercq wrote:
>
> I recall an experiment conducted amongst old people whose hearing did not
> extend above 7kHz.
> They were played music with and without a filter that rolled off at 7kHz -
> all preferred the complete music.
>
> By the way, a resistor is NOT an impedance; it is a resistance - the same
> goes for the internal resistance of valves.
>
> Paul
Sez who? The general case for impedance consists of a resistive (real)
part and a reactive (imaginary) part, either capacitive, inductive, or a
combination thereof. If the imaginary part is shrunk to zero, the
impedance consists of the real part only. Still an impedance, except
with no reactive component. Likewise, if the real part is zero, the
capacitive, or inductive part will be the remaining component, but still
an impedance, nevertheless, just with a zero real term.
> > [big snip]
> >
> > fwiw, i remember keith johnson (reference recordings, pacific microsonics,
> > spectral, etc) discussed in a an interview experiments (military, i
> > believe) researching human auditory response. the gist was that while
> they
> > didn't find anything new in terms of steady state fr, they were able to
> > show audibility of transient response up to 100kHz. ie, restricting
> > bandwidth below 100kHz was audible w/ highly transient material.
> >
> > anyone else know anything about this? one would have to look at 15
> > year-old copies of tas and sterophile for the reference....
> >
> > mike
My steady state hearing only extends to about 10 kHz, but I can tell a
hell of an improvement when a supertweeter is cut in at 10 kHz, even
with speakers that are substantially flat go well beyond 10 kHz. This
was discussed here a while back, when adding supertweeters to Tannoy
speakers was the topic of discussion.
Dan Marshall
=========================================================================
From: ToobWiz@aol.com
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 17:28:28 EDT
Source: Sound Digest Archive v02.n979
In a message dated 09/19/2001 5:<BR16:<BR35 PM
Eastern Daylight , Pderl@btinternet.com writes:
>
> By the way, a resistor is NOT an impedance; it is a resistance - the same
> goes for the internal resistance of valves.
Hmmm, is not a resistance just a special case of impedance? Like a parallel
twin engine is a special case of a v-twin.
Cheers/Don
=========================================================================
From: ToobWiz@aol.com
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 18:20:41 EDT
Source: Sound Digest Archive v02.n979
In a message dated 09/19/2001 6:<BR06:<BR13 PM
Eastern Daylight , Pderl@btinternet.com writes:> I would happily accept that
a flat twin is a 180 degree "V". The same
> cannot be said of a parallel twin. There cannot be a 0 degree V!
Paul,
you gotta look at it from the point of view of the pistons. What if the
flat twin is alternate firing? The configuration is the same, but the firing
interval changes. Naaah; they're all v-twins :-)
Cheers/Don
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range +NEW SACD
Date: Wed, 19 Sep 2001 20:59:47 -0500
Source: Sound Digest Archive v02.n979
michael knapp wrote:
> >
> >I'll handle just one little bit of the question... Why would we want output
> >which is above our hearing?
>
> [big snip]
>
> fwiw, i remember keith johnson (reference recordings, pacific microsonics,
> spectral, etc) discussed in a an interview experiments (military, i
> believe) researching human auditory response. the gist was that while they
> didn't find anything new in terms of steady state fr, they were able to
> show audibility of transient response up to 100kHz. ie, restricting
> bandwidth below 100kHz was audible w/ highly transient material.
>
> anyone else know anything about this? one would have to look at 15
> year-old copies of tas and sterophile for the reference....
>
> mike
Yes, I did some work for Gary Kendall at Northwestern a few years ago, his
auditory research suggested the same thing you mention except his figure was 200
kHz.
I know he had papers on it etc., maybe do a search.
Tom Danley
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 21:20:45 -0400
Source: Sound Digest Archive v02.n979
>Resistance are defined according to DC.
>Impedance are definied according to AC.
thats the way i understand it... but here is a question...
at what point does DC become AC????
if we add a 20K signal to a 20hz sinewave, does each cycle of the 20K
signal see the point in the 20hz signal as a different DC potential?
where do we draw the line... 10hz??? .1hz??? .00001hz??? its all AC
dave
=========================================================================
From: "Emile Sprenger" <tubes@euronet.nl>
Subject: RE: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 21:42:49 +0200
Source: Sound Digest Archive v02.n979
Rich,
Studies have shown that frequencies > 20KHz are perceptible, even for us
moral humans. We can't hear them as such, but we do notice that they are
there. How? I have no idea.
Also instruments have lots of hamonics way beyond the standard audio
bandwidth. If we want to reproduce what happens in a concert hall, we have
to reproduce these as well.
One final thought: we don't want phase shifts in the audio bandwidth, so you
need to go out a lot further. For a preamp I try to get 200KHz; a poweramp
100KHz (-3dB).
Emile
=========================================================================
From: Douglas Purl <dcp@selway.umt.edu>
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 21:55:02 -0600 (MDT)
Source: Sound Digest Archive v02.n979
On Wed, 19 Sep 2001, dave slagle wrote:
> >Resistance are defined according to DC.
> >Impedance are definied according to AC.
>
> thats the way i understand it... but here is a question...
>
> at what point does DC become AC????
>
> if we add a 20K signal to a 20hz sinewave, does each cycle of the 20K
> signal see the point in the 20hz signal as a different DC potential?
>
> where do we draw the line... 10hz??? .1hz??? .00001hz??? its all AC
For me the issue here is whether you are trifling with a perspective
puzzle, such as a convex/concave illusion, or confusing matters. From a
practical point of view what signifies in this question/conundrum is how
the two kinds of reactances respond to the instantaneous condition. DC
can be modulated by AC. What it cannot do is change polarity with respect
to ground. And a diode bridge can produce a pulsing DC out of AC, as in
transformer-fed power supplies and automobile alternators.
It isn't all AC. There may be a fine line between running and sprinting,
but there is none between hopping and skipping.
But draw back the curtains and reveal the wonder you have concealed behind
the proscenium arch.
Doug Purl
=========================================================================
From: "Paul De Raymond Leclercq" <Pderl@btinternet.com>
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 22:17:23 -0700
Source: Sound Digest Archive v02.n979
I recall an experiment conducted amongst old people whose hearing did not
extend above 7kHz.
They were played music with and without a filter that rolled off at 7kHz -
all preferred the complete music.
By the way, a resistor is NOT an impedance; it is a resistance - the same
goes for the internal resistance of valves.
Paul
- ----- Original Message -----
From: michael knapp <sound@auriculum.com>
To: <ToobWiz@aol.com>; <rconte@attglobal.net>; <sound@lists.io.com>
Sent: Wednesday, September 19, 2001 12:49 PM
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW
SACD
>
> >
> >I'll handle just one little bit of the question... Why would we want
output
> >which is above our hearing?
>
> [big snip]
>
> fwiw, i remember keith johnson (reference recordings, pacific microsonics,
> spectral, etc) discussed in a an interview experiments (military, i
> believe) researching human auditory response. the gist was that while
they
> didn't find anything new in terms of steady state fr, they were able to
> show audibility of transient response up to 100kHz. ie, restricting
> bandwidth below 100kHz was audible w/ highly transient material.
>
> anyone else know anything about this? one would have to look at 15
> year-old copies of tas and sterophile for the reference....
>
> mike
>
=========================================================================
From: "Fred Volz" <fcv@emotiveaudio.com>
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range +NEW SACD
Date: Wed, 19 Sep 2001 23:00:30 -0400
Source: Sound Digest Archive v02.n979
SAP loudspeakers extend to above 30kHz because Vincenzo (the designer)
believes that, while we can't hear those upper frequencies, we can "feel"
them. I don't have a good understanding of the science behind this
statement, but, as I am familiar with how great his speakers sound--I
believe him. My SAP Trios use a piezo horn for stuff over 17kHz.
Fred Volz
fcv@emotiveaudio.com
- ----- Original Message -----
From: "Thomas Danley" <Tom@ppci.com>
To: "michael knapp" <sound@auriculum.com>
Cc: <ToobWiz@aol.com>; <rconte@attglobal.net>; <sound@lists.io.com>
Sent: Wednesday, September 19, 2001 9:59 PM
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range +NEW
SACD
>
>
> michael knapp wrote:
>
> > >
> > >I'll handle just one little bit of the question... Why would we want
output
> > >which is above our hearing?
> >
> > [big snip]
> >
> > fwiw, i remember keith johnson (reference recordings, pacific
microsonics,
> > spectral, etc) discussed in a an interview experiments (military, i
> > believe) researching human auditory response. the gist was that while
they
> > didn't find anything new in terms of steady state fr, they were able to
> > show audibility of transient response up to 100kHz. ie, restricting
> > bandwidth below 100kHz was audible w/ highly transient material.
> >
> > anyone else know anything about this? one would have to look at 15
> > year-old copies of tas and sterophile for the reference....
> >
> > mike
>
> Yes, I did some work for Gary Kendall at Northwestern a few years ago, his
> auditory research suggested the same thing you mention except his figure
was 200
> kHz.
> I know he had papers on it etc., maybe do a search.
>
> Tom Danley
>
>
=========================================================================
From: "Paul De Raymond Leclercq" <Pderl@btinternet.com>
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Wed, 19 Sep 2001 23:07:32 -0700
Source: Sound Digest Archive v02.n979
I would happily accept that a flat twin is a 180 degree "V". The same
cannot be said of a parallel twin. There cannot be a 0 degree V!
A resistance is a resistance regardless of whether or not the current
flowing through it is direct or alternating - the resistance is the same.
It is not a reactance - an "X"!
Paul
- ----- Original Message -----
From: <ToobWiz@aol.com>
To: <pderl@btinternet.com>; <rconte@attglobal.net>; <sound@lists.io.com>;
<sound@auriculum.com>
Sent: Wednesday, September 19, 2001 2:28 PM
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW
SACD
> In a message dated 09/19/2001 5:<BR16:<BR35 PM
> Eastern Daylight , Pderl@btinternet.com writes:
> >
> > By the way, a resistor is NOT an impedance; it is a resistance - the
same
> > goes for the internal resistance of valves.
>
> Hmmm, is not a resistance just a special case of impedance? Like a
parallel
> twin engine is a special case of a v-twin.
>
> Cheers/Don
=========================================================================
From: "Steve Berger" <aprilsound@earthlink.net>
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Thu, 20 Sep 2001 00:18:42 -0400
Source: Sound Digest Archive v02.n979
Dave:
You are a devil!
Steve
- -----Original Message-----
From: dave slagle <dslagle@earthlink.net>
To: sound@lists.io.com <sound@lists.io.com>
Date: Wednesday, September 19, 2001 9:19 PM
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range +
NEW SACD
>
>>Resistance are defined according to DC.
>>Impedance are definied according to AC.
>
>thats the way i understand it... but here is a question...
>
>at what point does DC become AC????
>
>if we add a 20K signal to a 20hz sinewave, does each cycle of the 20K
>signal see the point in the 20hz signal as a different DC potential?
>
>where do we draw the line... 10hz??? .1hz??? .00001hz??? its all AC
>
>dave
>
>
=========================================================================
From: "Kurt Steffensen" <kurt-steffensen@teliamail.dk>
Subject: Sv: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Thu, 20 Sep 2001 02:27:36 +0200
Source: Sound Digest Archive v02.n979
> > By the way, a resistor is NOT an impedance; it is a resistance - the same
> > goes for the internal resistance of valves.
>
> Hmmm, is not a resistance just a special case of impedance? Like a parallel
> twin engine is a special case of a v-twin.
Resistance are defined according to DC.
Impedance are definied according to AC.
At least it is so in Danish and German engineering.
( And as far as I know also in English and American etc.)
- - Kurt
=========================================================================
From: "Kurt Steffensen" <kurt-steffensen@teliamail.dk>
Subject: Sv: Sv: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Thu, 20 Sep 2001 04:19:17 +0200
Source: Sound Digest Archive v02.n979
> at what point does DC become AC????
It will depend upon the actual situation.
>
> if we add a 20K signal to a 20hz sinewave, does each cycle of the 20K
> signal see the point in the 20hz signal as a different DC potential?
The signal as such excists according to the circuit and value , hence it will depend on that.
It is not really possible , to view it the way you ask , I think.
> where do we draw the line... 10hz??? .1hz??? .00001hz??? its all AC
Again it depends.
DC are a signal , that compared to a reference , does not change polarity. ( Direction )
In fact if you connect your measuring tool directly to the anode on a working tube in a normal set u
p , using ground as reference , ALL signals
are MODULATED DC...
If , however , you measure through a capacitor , they are AC.
It is rather like asking all people in the world , "When does winter start" ?
The anwser will depend upon , whom you are , where you are situated , how you define winter etc..
Some will even reply , "Never" , and "Always"..
Or the 1'st of November 24 Midnight.
And they will all be right.. , right ?
:-)
Glad to know you are fine , Slagle.
- - I am going to bed now...
When is it morning ?
;-)
- - Kurt
>
> dave
>
>
=========================================================================
From: "Paul De Raymond Leclercq" <Pderl@btinternet.com>
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Thu, 20 Sep 2001 09:06:13 -0700
Source: Sound Digest Archive v02.n979
But the definition of an impedance is surely: a mix of resistance and
reactance; if you reduce the reactance to zero, then ergo, you have a
resistance.
PAul
- ----- Original Message -----
From: Dan Marshall <mdaniel7@uswest.net>
To: Paul De Raymond Leclercq <pderl@btinternet.com>
Cc: <ToobWiz@aol.com>; <rconte@attglobal.net>; <sound@lists.io.com>;
<sound@io.com>
Sent: Wednesday, September 19, 2001 8:04 AM
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW
SACD
> Paul De Raymond Leclercq wrote:
> >
> > I recall an experiment conducted amongst old people whose hearing did
not
> > extend above 7kHz.
> > They were played music with and without a filter that rolled off at
7kHz -
> > all preferred the complete music.
> >
> > By the way, a resistor is NOT an impedance; it is a resistance - the
same
> > goes for the internal resistance of valves.
> >
> > Paul
>
> Sez who? The general case for impedance consists of a resistive (real)
> part and a reactive (imaginary) part, either capacitive, inductive, or a
> combination thereof. If the imaginary part is shrunk to zero, the
> impedance consists of the real part only. Still an impedance, except
> with no reactive component. Likewise, if the real part is zero, the
> capacitive, or inductive part will be the remaining component, but still
> an impedance, nevertheless, just with a zero real term.
>
> > > [big snip]
> > >
> > > fwiw, i remember keith johnson (reference recordings, pacific
microsonics,
> > > spectral, etc) discussed in a an interview experiments (military, i
> > > believe) researching human auditory response. the gist was that while
> > they
> > > didn't find anything new in terms of steady state fr, they were able
to
> > > show audibility of transient response up to 100kHz. ie, restricting
> > > bandwidth below 100kHz was audible w/ highly transient material.
> > >
> > > anyone else know anything about this? one would have to look at 15
> > > year-old copies of tas and sterophile for the reference....
> > >
> > > mike
>
> My steady state hearing only extends to about 10 kHz, but I can tell a
> hell of an improvement when a supertweeter is cut in at 10 kHz, even
> with speakers that are substantially flat go well beyond 10 kHz. This
> was discussed here a while back, when adding supertweeters to Tannoy
> speakers was the topic of discussion.
>
> Dan Marshall
=========================================================================
From: "Paul De Raymond Leclercq" <Pderl@btinternet.com>
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Thu, 20 Sep 2001 09:10:24 -0700
Source: Sound Digest Archive v02.n979
Well, take a non-inductive resistor; at all frequencies of interest its
value does not change (ignoring heat etc.).
Now who is going to say the same about a choke or capacitor?
Paul
- ----- Original Message -----
From: dave slagle <dslagle@earthlink.net>
To: <sound@lists.io.com>
Sent: Wednesday, September 19, 2001 6:20 PM
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range +
NEW SACD
>
> >Resistance are defined according to DC.
> >Impedance are definied according to AC.
>
> thats the way i understand it... but here is a question...
>
> at what point does DC become AC????
>
> if we add a 20K signal to a 20hz sinewave, does each cycle of the 20K
> signal see the point in the 20hz signal as a different DC potential?
>
> where do we draw the line... 10hz??? .1hz??? .00001hz??? its all AC
>
> dave
>
>
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Thu, 20 Sep 2001 11:14:27 +0200
Source: Sound Digest Archive v02.n979
At 02:27 20-9-01 +0200, Kurt Steffensen wrote:
>Resistance are defined according to DC.
>Impedance are definied according to AC.
>
>At least it is so in Danish and German engineering.
>( And as far as I know also in English and American etc.)
Impedance is an extension towards ac, as resistance does not cover
capacitve and or inductive parts
Once imnpedance is used, no mistakes can be made. Once the imaginary part
is near zero, resistive behaviour is to be expected......
By the way, every resistor has an inductance, and some capacitance, like it
or not......
In audio most of the times they do not bother....
best regards
=
Guido
>- Kurt
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Thu, 20 Sep 2001 11:17:09 +0200
Source: Sound Digest Archive v02.n979
At 21:20 19-9-01 -0400, dave slagle wrote:
>at what point does DC become AC????
just above 0 Hz.......
>if we add a 20K signal to a 20hz sinewave, does each cycle of the 20K
>signal see the point in the 20hz signal as a different DC potential?
>
>where do we draw the line... 10hz??? .1hz??? .00001hz??? its all AC
It depends on the circuit, the frequencies and impedances, that play a
role. 1 nH can be a problem in driving a DVD laser within 800 ps.......
I have yet to see a tubed circuit suffering from 1nH added inductance.........
Guido
>dave
>
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: Sv: Sv: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Thu, 20 Sep 2001 11:20:43 +0200
Source: Sound Digest Archive v02.n979
At 04:19 20-9-01 +0200, Kurt Steffensen wrote:
>It is rather like asking all people in the world , "When does winter start" ?
:-))))
(it depends on the definition of winter......)
Guido (from rainy Eindhoven , no winter yet)
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Thu, 20 Sep 2001 11:26:28 +0200
Source: Sound Digest Archive v02.n979
At 09:10 20-9-01 -0700, Paul De Raymond Leclercq wrote:
>Well, take a non-inductive resistor; at all frequencies of interest its
>value does not change (ignoring heat etc.).
non inductive does not exist..........
Low inductance could be used as a correct definition, OK ?
Guido
>Now who is going to say the same about a choke or capacitor?
>
>Paul
>----- Original Message -----
>From: dave slagle <dslagle@earthlink.net>
>To: <sound@lists.io.com>
>Sent: Wednesday, September 19, 2001 6:20 PM
>Subject: Re: Sv: [JN] Bandwidth of Output Transformer and Hearing Range +
>NEW SACD
>
>
>>
>> >Resistance are defined according to DC.
>> >Impedance are definied according to AC.
>>
>> thats the way i understand it... but here is a question...
>>
>> at what point does DC become AC????
>>
>> if we add a 20K signal to a 20hz sinewave, does each cycle of the 20K
>> signal see the point in the 20hz signal as a different DC potential?
>>
>> where do we draw the line... 10hz??? .1hz??? .00001hz??? its all AC
>>
>> dave
>>
>>
=========================================================================
From: Richard C Nevill <rnevill@is.dal.ca>
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Thu, 20 Sep 2001 10:25:40 -0300 (ADT)
Source: Sound Digest Archive v02.n980
On Wed, 19 Sep 2001, michael knapp wrote:
>
> [big snip]
>
> fwiw, i remember keith johnson (reference recordings, pacific microsonics,
> spectral, etc) discussed in a an interview experiments (military, i
> believe) researching human auditory response. the gist was that while they
I seem to recall it was the Swedish army and they were testing the effects
of hearing in humans when REALLY big guns go off next to you. They found
that the little hairs in our ears (starts with "C" but I can't remember
the word) were sensetive up to around 80,000 hz.
Cheers
Richard Nevill
> didn't find anything new in terms of steady state fr, they were able to
> show audibility of transient response up to 100kHz. ie, restricting
> bandwidth below 100kHz was audible w/ highly transient material.
>
> anyone else know anything about this? one would have to look at 15
> year-old copies of tas and sterophile for the reference....
>
> mike
>
>
=========================================================================
From: rchamber@norwich.edu
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Thu, 20 Sep 2001 14:13:18 GMT
Source: Sound Digest Archive v02.n980
Richard C
Nevill To: michael knapp <sound@auriculum.com>
<rnevill@is.da cc: ToobWiz@aol.com, rconte@attglobal.net, sound@lists
.io.com
l.ca> Subject: Re: [JN] Bandwidth of Output Transformer and
Hearing
Sent by: Range + NEW SACD
owner-sound@li
sts.io.com
09/20/2001
09:55 AM
On Wed, 19 Sep 2001, michael knapp wrote:
Clip
> didn't find anything new in terms of steady state fr, they were able to
> show audibility of transient response up to 100kHz. ie, restricting
> bandwidth below 100kHz was audible w/ highly transient material.
Is it not a direct relationship between frequency response and slewing rate
that explains improved transient response with increased bandwidth?
Robert
=========================================================================
From: "Le Cleac'h Jean-Michel" <lecleach@paris.ensmp.fr>
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW SACD
Date: Fri, 21 Sep 2001 09:20:25 +0200
Source: Sound Digest Archive v02.n980
Hello,
Several elements have been given, e.g.:
- - intermodulation between "non audible" frequencies that create audible new
frequencies;
- - out band distortion products that participate to the character of the
sound;
- - a different behaviour of our hearing for a transient sound and for a
continuous frequency;
I want to add another good reason to try to cover frequencies over 20kHz:
our ear is very sensible to the envelop of the signal and high frequency
components participate to the envelop.
If you take off the high frequencies, the envelop roughness is higher. To
vizualize that effect, remember those square waves at the output of the
first generations of CD players, there was a huge ripple due to the fact
that the frequencies aboce 22kHz were missing. Then put the higher
frequencies and the top of that square wave will be flat.
This is just an image but it is the same with a natural sound, take off the
high frequencies and its envelop becomes very rough. Now try to reproduce
correctly the high frequency component and the envelop is smoother and the
sound is more natural.
There was once in Japan a device (with a name like "harmonizer" or something
like that) that try to re-create the missing harmonics from a CD player,
those high frequencies then were added to the <22kHz signal and the result
was said "more natural".
Best regards,
Jean-Michel Le Cleac'h, Paris, France
- ----- Original Message -----
From: "Paul De Raymond Leclercq" <Pderl@btinternet.com>
To: <ToobWiz@aol.com>; <rconte@attglobal.net>; <sound@lists.io.com>;
"michael knapp" <sound@auriculum.com>
Sent: Thursday, September 20, 2001 7:17 AM
Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW
SACD
> I recall an experiment conducted amongst old people whose hearing did not
> extend above 7kHz.
> They were played music with and without a filter that rolled off at 7kHz -
> all preferred the complete music.
>
> By the way, a resistor is NOT an impedance; it is a resistance - the same
> goes for the internal resistance of valves.
>
> Paul
>
> ----- Original Message -----
>
>
>
>
> From: michael knapp <sound@auriculum.com>
> To: <ToobWiz@aol.com>; <rconte@attglobal.net>; <sound@lists.io.com>
> Sent: Wednesday, September 19, 2001 12:49 PM
> Subject: Re: [JN] Bandwidth of Output Transformer and Hearing Range + NEW
> SACD
>
>
> >
> > >
> > >I'll handle just one little bit of the question... Why would we want
> output
> > >which is above our hearing?
> >
> > [big snip]
> >
> > fwiw, i remember keith johnson (reference recordings, pacific
microsonics,
> > spectral, etc) discussed in a an interview experiments (military, i
> > believe) researching human auditory response. the gist was that while
> they
> > didn't find anything new in terms of steady state fr, they were able to
> > show audibility of transient response up to 100kHz. ie, restricting
> > bandwidth below 100kHz was audible w/ highly transient material.
> >
> > anyone else know anything about this? one would have to look at 15
> > year-old copies of tas and sterophile for the reference....
> >
> > mike
> >
>
>
=========================================================================
From: TubeGarden@aol.com
Subject: Re: Sv: [JN] Bandwidth splurge
Date: Wed, 19 Sep 2001 21:15:24 EDT
Source: Sound Digest Archive v02.n979
- --part1_18.128cf4d3.28da9d2c_boundary
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
In a message dated 9/19/01 5:42:13 PM US Mountain Standard Time,
kurt-steffensen@teliamail.dk writes:
> Resistance are defined according to DC.
> Impedance are definied according to AC.
>
and, resistance is futile! :)
Al
- --part1_18.128cf4d3.28da9d2c_boundary
Content-Type: text/html; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
<HTML><FONT FACE=arial,helvetica><BODY BGCOLOR="#ffffff"><FONT SIZE=2>In a message dated 9/19/01 5:
42:13 PM US Mountain Standard Time, kurt-steffensen@teliamail.dk writes:
<BR>
<BR>
<BR><BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px
; PADDING-LEFT: 5px">Resistance are defined according to DC.
<BR>Impedance are definied according to AC.
<BR></FONT><FONT COLOR="#000000" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"></BLOCKQUOTE>
<BR></FONT><FONT COLOR="#000000" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0">
<BR>and, resistance is futile! :)
<BR>
<BR>Al</FONT></HTML>
- --part1_18.128cf4d3.28da9d2c_boundary--
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: [JN] Bandwith Police
Date: Wed, 15 Nov 2000 10:21:55 -0500
Source: Sound Digest Archive v02.n734
John sez:
>>>I don't know who the bandwidth police are, but I doubt very much that
they speak for the group<<<
I don't know who they are either, but the word on the street is they have
no beef with any interesting technical topic - but get real testy at the
lazy bones who write an (often valid) one line reply to a post, but then
have their email pgm automatically copy THE WHOLE OF THE FRIGGIN' ORIGINAL
MESSAGE, turning their 200 characters into 10k of bloat.
And those who send HTML as well as text are close behind these guys...
Allen (VSE)
=========================================================================
From: John Niven <jn@cypress.com>
Subject: [JN] (Bangers and) MASH!
Date: Wed, 23 Aug 2000 11:51:56 -0700
Source: Sound Digest Archive v02.n639
Hi DAC experts!
I just bought a Technics SL-PG300 CD player in a garage sale for $20!
It was built in 1992, works very well, and has some nice features.
Instruction booklet says that the DAC is a "MASH (1bit)".
The front of the machine says "MASH Multi-stage noise shaping" and
"4DAC".
So what does this all mean? How do you make a "1-bit" DAC? Are there any
recommended mods to be made with this system?
Thanks,
John
=========================================================================
From: E W DAILEY <lazareth@mindspring.com>
Subject: [JN] Bang&Olufsen turntable question
Date: Thu, 28 Jan 1999 21:50:36 -0800
Source: Sound Digest Archive v02.n016
>Date: Thu, 28 Jan 1999 21:47:01 -0800
>To: sound@list.io.com
>From: E W DAILEY <lazareth@mindspring.com>
>Subject: Bang&Olufsen turntable question
>
>I just picked up a beogram 2400 turntable but need a headshell.
>If the built in arm is ok I would perfere to use it for a while
>and later replace it with a formula 4 arm that I already have.
>But if this arm is realy bad I would hate to spend anything for
>the headshell. Any comment? anyone replace the arm on a B&O 2400?
>Sure I would perfere a good table but my money is realy tight right
>now.
>
>Thanks
>
>E.W. Dailey
=========================================================================
From: Kalman Rubinson <kr4@is2.nyu.edu>
Subject: Re: [JN] Bang&Olufsen turntable question
Date: Thu, 28 Jan 1999 22:41:08 -0500 (EST)
Source: Sound Digest Archive v02.n016
On Thu, 28 Jan 1999, E W DAILEY wrote:
> >I just picked up a beogram 2400 turntable but need a headshell.
> >If the built in arm is ok I would perfere to use it for a while
> >and later replace it with a formula 4 arm that I already have.
> >But if this arm is realy bad I would hate to spend anything for
> >the headshell. Any comment? anyone replace the arm on a B&O 2400?
> >Sure I would perfere a good table but my money is realy tight right
> >now.
I haven't seen a Beogram yet that had a headshell. B&O's
had plug-in cartridges and you'll have to hunt down the
appropriate one for the 2400. As for changing the arm for a
Formula 4 or any other, you'll have to deal with the tight
quarters and fixed suspension of the 2400.
Good luck, you'll need it.
Kal
=========================================================================
From: Robert =?iso-8859-1?Q?J=F8rgensen?= <robert.jorgensen@advalvas.be>
Subject: Ban on digital copying Was Re: [JN] CD blanks
Date: Fri, 19 May 2000 09:00:08 +0200
Source: Sound Digest Archive v02.n552
Well that has been the case for some time. In Europe there are a number
of companies who provides small circuits which disable this check.
In theory the artists should be compensated from the extra charge, but
as far as I know they see nothing of this surcharge.
Much more alarming is the fact that it seems like all digital copying
will be (might be, if you are less alarmist) completely banned. This
would include the copy you make for yourself from your own privately
purchased CD. In Denmark this is already the LAW, it might be soon for
all of Europe and perhaps further.
The influence of the big Record and SW companies in convincing the
lawmakers that they are loosing the shop due to pirating is on the
rise.
Of course if you are talking about only banning digital copying you
could ask if all the Britney - Metallica or what else fans would care a
hoot if their CD had been through a D/A - A/D convertion. I don't think
they would notice the least.
I for one remain convinced that if the prices would be somewhat more
reasonable much of the pirating (certainly the private copying) would go
away.
Greetings from Brussels
Robert
David Crittle wrote:
>
> >From: "P. de R. L." <triode@bow-tie.org.uk>
> >My brother has investigated this; he insists that the blue ones are for
> >music and the gold ones for "digits"!
>
> I've heard that some of the newer audio cd recorders (Yamaha?Pioneer?) will
> only record on 'audio' disks and not computer blanks. The extra money
> charged for the audio types is a copyright surcharge. I may have heard
> wrong...............anyone else know about this?
>
> David
=========================================================================
From: Frank_Deutschmann@trepp.com
Subject: Re: Ban on digital copying Was Re: [JN] CD blanks
Date: Fri, 19 May 2000 09:40:00 -0400
Source: Sound Digest Archive v02.n552
Robert Jørgensen <robert.jorgensen@advalvas.be>@lists.io.com on 05/19/2000
03:00:08 AM
Sent by: owner-sound@lists.io.com
To: David Crittle <retrovox@bigpond.com>
cc: sound@lists.io.com
Subject: Ban on digital copying Was Re: [JN] CD blanks
R Joergensen sez:
> I for one remain convinced that if the prices would be somewhat more
> reasonable much of the pirating (certainly the private copying) would go
>away.
Of course, if CD prices were more reasonable, the music/entertainment
industry couldn't afford to do quite so much lobbying as they do today....
(With all the CD's I've bought I should have a Senator in my back pocket by
now!)
- -frank, saying "Big wheel keeps a-turnin'".....
=========================================================================
From: "Timothy James Bailey" <tim_bailey@bigpond.com>
Subject: [JN] Re: Barkhausen and Weisz
Date: Sat, 14 Jul 2001 15:15:21 +1000
Source: Sound Digest Archive v02.n925
Hi Guys,
ummm, oh the hell with it. This Barkhausen stuff, similar results by
Weisz. - most magnetic materials have a Weisz complex, causing step
functions in the amplification of magnetised materials at very low levels.
It is possible to design magnets that are almost Weisz complex free, ask
VdH, the effect is to increase low level resolution and smoothness of
dynamic transitions, lower noise too. NB This is all from memory and
appeared in literature about the Grasshopper IV series.
IME some very good transformers just eat fully active step-ups no matter
whether SS or tube. The Verion for example.A TX and then tubes seems to me
the way to go, unless you can afford VLN SS devices and probably in multiple
parallel.
I remember a review in HI-Fi World, Noel Keywood's measurements for a
typical MC showed the actual audibly significant noise (voltage noise?!) of
TdP's little stand alone phono stage was significantly lower than most of
the top SS jobs compared to, including Michell's and the high tech
Cambridge.
[NB this may depend on the actual power output of the MC in use, some really
are surprisingly strong current sources.]
Warmest
Tim B
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 07:18:30 -0400
Source: Sound Digest Archive v02.n924
Gents,
Those of you who know me personally know of my adversion to the use of
signal transformers, except where 100% unadvoidable (like OPTs in a 845
poweramp). I personally find every transformer I have tried looses information
(IME certainly more than the best capacitors) and I try to maximise
information transfer in my designs.
I had heard of the Barkhausen Effect before, and thought it may have something
to do with problem, but never found a definition for it until this morning:
- --------------------------------------------
Heinrich Barkhausen, a German physicist, discovered in 1919 that a slow,
smooth increase of a magnetic field applied to a piece of ferromagnetic
material, such as iron, causes it to become magnetized, not continuously but
in minute steps. The sudden, discontinuous jumps in magnetization may be
detected by a coil of wire wound on the ferromagnetic material; the sudden
transitions in the magnetic field of the material produce pulses of current in
the coil that, when amplified, produce a series of clicks in a
loudspeaker. These jumps are interpreted as discrete changes in the size or
rotation of ferromagnetic domains. Some microscopic clusters of similarly
oriented magnetic atoms aligned with the external magnetizing field increase
in size by a sudden aggregation of neighboring atomic magnets; and, especially
as the magnetizing field becomes relatively strong, other whole domains
suddenly turn into the direction of the external field." -
ENCYCLOPEDIA BRITANNICA
______________________________________________
Would some of you theory heavy types (Simon B?) care to comment on the
relevance of this effect in low level signal transformers? (the sort I find
_most_ sonically objectional)
Prof. Hawksford has calculated that a low output MC cartridge is dealing with
changes in signal level in the order of +/- one electron at the lower end of
an LP's resolution - what happens to this level of definition if sent through
a MC step-up transformer?
Allen (VSE)
=========================================================================
From: "John Levreault" <jlevro@mediaone.net>
Subject: Re: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 08:27:31 -0400
Source: Sound Digest Archive v02.n924
- ----- Original Message -----
From: "Christian Rintelen" <christian@rintelen.ch>
To: "Joelist" <sound@lists.io.com>
Sent: Friday, July 13, 2001 8:10 AM
Subject: Re: [JN] Barkhausen Effect
> Allen,
>
> please consider that a MC cartridge already is a magnet dealing with very
very
> very small signals. IIRC the loudest signals of a 0.2 µV-cartridge are
just about
> as strong as the strongest brain waves to be picked up during an EEG...
... And
> contrary to you, I find low level transformers *less* objectional since
the
> absence of current allows the use of rare earth materials with different
> magnetising behaviour. I suppose Barkhausen didn't have Alnico or
Neodymium at
> hand when he established his theory...
I agree with Christian's assessment on sonic grounds, but I'm confused about
the physics. Does the Barkhausen Effect just apply to ferromagnetics and not
to Alnico or Neo?
JL
=========================================================================
From: Phil <tube@jump.net>
Subject: Re: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 08:52:32 -0500
Source: Sound Digest Archive v02.n924
Allen Wright wrote:
[Snip]
> Prof. Hawksford has calculated that a low output MC cartridge is dealing with
> changes in signal level in the order of +/- one electron at the lower end of
> an LP's resolution - what happens to this level of definition if sent through
> a MC step-up transformer?
Hmmm, a MM cartridge has a much higher impedance than a MC cartridge,
meaning it has much less current and much more voltage ... Gee, I guess this
means that it deals with 1/10 of an electron at the lower end! ;-)
Phil
=========================================================================
From: Phil <tube@jump.net>
Subject: Re: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 09:01:19 -0500
Source: Sound Digest Archive v02.n924
S.C.Busbridge@bton.ac.uk wrote:
> Now you could choose a different magnetic material. A single crystal with
> few pinning sites would be quite expensive, but amorphous materials tend not
> to exhibit Barkausen noise because the pinning 'sites' are randomly
> distributed throughout the structure so the stepped nature of the BH loop
> does not appear.
>
> Simon
Didn't we just have a discussion on this, or was it RAT? Netscape just lost the
last year of emails, so I don't know (does anybody know how to FORCE
netscape to reload the inbox summary file??? Thanks in advance if so!)
I think the conclusion from people who know much more than me was that
using a material with a minimum variation from intial mu to maximum mu would
also minimize the Barkausen effect. There are cobalt alloys with an initial mu
of
1100 and a max mu of 1150 that are largely free of this or any other defect,
and in small sizes they are almost affordable! Grain oriented silicon steel, in
contrast, has an initial mu of 1500 and a max mu of 40,000.
Phil
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: Re: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 09:55:14 -0400
Source: Sound Digest Archive v02.n924
i think ken pointed us to this link a few weeks back:
http://www.lassp.cornell.edu/sethna/hysteresis/hysteresis.html
i think magnetics are a wonderful thing, i used to be a more trannies the
better guy, but i have slowly been removing the trannies but still keeping
the magnetics guy...
if we consider the barkhausen effect as a form of noise or distortion, we
also have to consider the noise and distortion that the passive componants
they replace make. I love magnetics for impedance matching, loading tubes
and coupling, they just seem more real sounding than resistors caps and
cathode followers... not to say one is right or wrong, just different ways
to get the same goal... and great results can be had with both, i've just
had better luck laughing in mr barkhausens face....
sure it may be digital, anybody got a guess what the sampling rate is :-)
dave
=========================================================================
From: longrie@mmace.nrl.navy.mil
Subject: Re: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 09:57:48 +0100
Source: Sound Digest Archive v02.n924
Allen,
We had a discussion on this on the joe list a few months ago.
A search should turn it up. I have made a first attempt at
constructing a demonstrator for this effect, using about a
thousand turns of 28 ga wire. What I get is swamped by room
electrical noise. Am working on shielding issues and making
another bobbin for sense coil so that I can throw maybe 10000
turns of 40 ga wire on there.
That Brittanica definition is a pretty good start. Another
good place for you to check would be the Feynman lecture notes
on physics. He explains the effect very well and puts it on
a more physical basis.
best regards
gary
At 07:18 AM 7/13/01 -0400, you wrote:
>Gents,
> Those of you who know me personally know of my adversion to the use of
>signal transformers, except where 100% unadvoidable (like OPTs in a 845
>poweramp). I personally find every transformer I have tried looses information
>(IME certainly more than the best capacitors) and I try to maximise
>information transfer in my designs.
>
>I had heard of the Barkhausen Effect before, and thought it may have something
>to do with problem, but never found a definition for it until this morning:
>
>--------------------------------------------
>Heinrich Barkhausen, a German physicist, discovered in 1919 that a slow,
>smooth increase of a magnetic field applied to a piece of ferromagnetic
>material, such as iron, causes it to become magnetized, not continuously but
>in minute steps. The sudden, discontinuous jumps in magnetization may be
>detected by a coil of wire wound on the ferromagnetic material; the sudden
>transitions in the magnetic field of the material produce pulses of current in
>the coil that, when amplified, produce a series of clicks in a
>loudspeaker. These jumps are interpreted as discrete changes in the size or
>rotation of ferromagnetic domains. Some microscopic clusters of similarly
>oriented magnetic atoms aligned with the external magnetizing field increase
>in size by a sudden aggregation of neighboring atomic magnets; and, especially
>as the magnetizing field becomes relatively strong, other whole domains
>suddenly turn into the direction of the external field." -
>ENCYCLOPEDIA BRITANNICA
>______________________________________________
>
>Would some of you theory heavy types (Simon B?) care to comment on the
>relevance of this effect in low level signal transformers? (the sort I find
>_most_ sonically objectional)
>
>Prof. Hawksford has calculated that a low output MC cartridge is dealing with
>changes in signal level in the order of +/- one electron at the lower end of
>an LP's resolution - what happens to this level of definition if sent through
>a MC step-up transformer?
>
>Allen (VSE)
>
>
gary longrie
vacuum electronics branch
code 6840
naval research laboratory
washington DC 20375
longrie@mmace.nrl.navy.mil
=========================================================================
From: S.C.Busbridge@bton.ac.uk
Subject: RE: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 13:02:16 +0100
Source: Sound Digest Archive v02.n924
Hi Allen,
What's all this 'heavy' stuff? ;-)
I too dislike low level transformers and feel that they lose information
easily.
Here's how I would interpret it. A given domain wall will bow with small
applied fields but will not move very far until the field is strong enough
to break away from its pinning site. If you look in detail at the BH loops
you will find that it is not a continuous curve but made up of lots of
steps, and it is the jump from one step to another - as domain walls jump
from one pinning site to another - that causes the Barkhausen clicks.
So if you put a small audio signal onto such a material the output will get
sort of quantised in a random way - ie nicely scrambled - losing information
between the jumps.
Now you could choose a different magnetic material. A single crystal with
few pinning sites would be quite expensive, but amorphous materials tend not
to exhibit Barkausen noise because the pinning 'sites' are randomly
distributed throughout the structure so the stepped nature of the BH loop
does not appear.
Simon
Simon Busbridge, BSc(Hons) PhD CPhys MInstP
School of Engineering
University of Brighton
Lewes Road
Moulsecoomb
Brighton BN2 4GJ
UNITED KINGDOM
Tel: 0044 (0)1273 642542
Fax: 0044 (0)1273 642327/642301
e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com
Audio www site: http://audio.eng.bton.ac.uk
> ----------
> From: Allen Wright[SMTP:AllenVSE@compuserve.com]
> Sent: 13 July 2001 12:18
> To: AAJoeNet
> Subject: [JN] Barkhausen Effect
>
> Gents,
> Those of you who know me personally know of my adversion to the use
> of
> signal transformers, except where 100% unadvoidable (like OPTs in a 845
> poweramp). I personally find every transformer I have tried looses
> information
> (IME certainly more than the best capacitors) and I try to maximise
> information transfer in my designs.
>
> I had heard of the Barkhausen Effect before, and thought it may have
> something
> to do with problem, but never found a definition for it until this
> morning:
>
> --------------------------------------------
> Heinrich Barkhausen, a German physicist, discovered in 1919 that a slow,
> smooth increase of a magnetic field applied to a piece of ferromagnetic
> material, such as iron, causes it to become magnetized, not continuously
> but
> in minute steps. The sudden, discontinuous jumps in magnetization may be
> detected by a coil of wire wound on the ferromagnetic material; the sudden
>
> transitions in the magnetic field of the material produce pulses of
> current in
> the coil that, when amplified, produce a series of clicks in a
> loudspeaker. These jumps are interpreted as discrete changes in the size
> or
> rotation of ferromagnetic domains. Some microscopic clusters of similarly
> oriented magnetic atoms aligned with the external magnetizing field
> increase
> in size by a sudden aggregation of neighboring atomic magnets; and,
> especially
> as the magnetizing field becomes relatively strong, other whole domains
> suddenly turn into the direction of the external field." -
> ENCYCLOPEDIA BRITANNICA
> ______________________________________________
>
> Would some of you theory heavy types (Simon B?) care to comment on the
> relevance of this effect in low level signal transformers? (the sort I
> find
> _most_ sonically objectional)
>
> Prof. Hawksford has calculated that a low output MC cartridge is dealing
> with
> changes in signal level in the order of +/- one electron at the lower end
> of
> an LP's resolution - what happens to this level of definition if sent
> through
> a MC step-up transformer?
>
> Allen (VSE)
>
=========================================================================
From: "Chris Vryonides" <chrisvryonides@hotmail.com>
Subject: Re: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 13:23:49 -0000
Source: Sound Digest Archive v02.n924
Yep, it's true, as soon as you put a signal through a transformer, it
becomes digital...
_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
=========================================================================
From: Christian Rintelen <christian@rintelen.ch>
Subject: Re: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 14:10:06 +0200
Source: Sound Digest Archive v02.n924
Allen,
please consider that a MC cartridge already is a magnet dealing with very very
very small signals. IIRC the loudest signals of a 0.2 µV-cartridge are just about
as strong as the strongest brain waves to be picked up during an EEG... ... And
contrary to you, I find low level transformers *less* objectional since the
absence of current allows the use of rare earth materials with different
magnetising behaviour. I suppose Barkhausen didn't have Alnico or Neodymium at
hand when he established his theory...
©
Allen Wright wrote:
> Gents,
> Those of you who know me personally know of my adversion to the use of
> signal transformers, except where 100% unadvoidable (like OPTs in a 845
> poweramp). I personally find every transformer I have tried looses information
> (IME certainly more than the best capacitors) and I try to maximise
> information transfer in my designs.
>
> I had heard of the Barkhausen Effect before, and thought it may have something
> to do with problem, but never found a definition for it until this morning:
>
> --------------------------------------------
> Heinrich Barkhausen, a German physicist, discovered in 1919 that a slow,
> smooth increase of a magnetic field applied to a piece of ferromagnetic
> material, such as iron, causes it to become magnetized, not continuously but
> in minute steps. The sudden, discontinuous jumps in magnetization may be
> detected by a coil of wire wound on the ferromagnetic material; the sudden
> transitions in the magnetic field of the material produce pulses of current in
> the coil that, when amplified, produce a series of clicks in a
> loudspeaker. These jumps are interpreted as discrete changes in the size or
> rotation of ferromagnetic domains. Some microscopic clusters of similarly
> oriented magnetic atoms aligned with the external magnetizing field increase
> in size by a sudden aggregation of neighboring atomic magnets; and, especially
> as the magnetizing field becomes relatively strong, other whole domains
> suddenly turn into the direction of the external field." -
> ENCYCLOPEDIA BRITANNICA
> ______________________________________________
>
> Would some of you theory heavy types (Simon B?) care to comment on the
> relevance of this effect in low level signal transformers? (the sort I find
> _most_ sonically objectional)
>
> Prof. Hawksford has calculated that a low output MC cartridge is dealing with
> changes in signal level in the order of +/- one electron at the lower end of
> an LP's resolution - what happens to this level of definition if sent through
> a MC step-up transformer?
>
> Allen (VSE)
- --
Konzept und Text: Christian Rintelen
Dufourstrasse 165 - CH-8008 Zurich - Switzerland
Voice: +41 1 420 11 55 - Fax: +41 1 420 11 57
mailto:christian@rintelen.ch
=========================================================================
From: David Home <David_Home@creoscitex.com>
Subject: RE: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 14:31:17 +0200
Source: Sound Digest Archive v02.n924
Hello Christian.
I am no expert on magnetics by a long shot, but is this the same thing?
The cartridge is a fixed magnet without large changes in field strength.
The original discussion was about changing field strength by a lot and its
ratcheting effect on the iron.
Regards, DAvid
- -----Original Message-----
From: Christian Rintelen [mailto:christian@rintelen.ch]
Sent: Friday, July 13, 2001 2:10 PM
To: Joelist
Subject: Re: [JN] Barkhausen Effect
Allen,
please consider that a MC cartridge already is a magnet dealing with very
very
very small signals. IIRC the loudest signals of a 0.2 µV-cartridge are just
about
as strong as the strongest brain waves to be picked up during an EEG... ...
And
contrary to you, I find low level transformers *less* objectional since the
absence of current allows the use of rare earth materials with different
magnetising behaviour. I suppose Barkhausen didn't have Alnico or Neodymium
at
hand when he established his theory...
©
Allen Wright wrote:
> Gents,
> Those of you who know me personally know of my adversion to the use
of
> signal transformers, except where 100% unadvoidable (like OPTs in a 845
> poweramp). I personally find every transformer I have tried looses
information
> (IME certainly more than the best capacitors) and I try to maximise
> information transfer in my designs.
>
> I had heard of the Barkhausen Effect before, and thought it may have
something
> to do with problem, but never found a definition for it until this
morning:
>
> --------------------------------------------
> Heinrich Barkhausen, a German physicist, discovered in 1919 that a slow,
> smooth increase of a magnetic field applied to a piece of ferromagnetic
> material, such as iron, causes it to become magnetized, not continuously
but
> in minute steps. The sudden, discontinuous jumps in magnetization may be
> detected by a coil of wire wound on the ferromagnetic material; the sudden
> transitions in the magnetic field of the material produce pulses of
current in
> the coil that, when amplified, produce a series of clicks in a
> loudspeaker. These jumps are interpreted as discrete changes in the size
or
> rotation of ferromagnetic domains. Some microscopic clusters of similarly
> oriented magnetic atoms aligned with the external magnetizing field
increase
> in size by a sudden aggregation of neighboring atomic magnets; and,
especially
> as the magnetizing field becomes relatively strong, other whole domains
> suddenly turn into the direction of the external field." -
> ENCYCLOPEDIA BRITANNICA
> ______________________________________________
>
> Would some of you theory heavy types (Simon B?) care to comment on the
> relevance of this effect in low level signal transformers? (the sort I
find
> _most_ sonically objectional)
>
> Prof. Hawksford has calculated that a low output MC cartridge is dealing
with
> changes in signal level in the order of +/- one electron at the lower end
of
> an LP's resolution - what happens to this level of definition if sent
through
> a MC step-up transformer?
>
> Allen (VSE)
- --
Konzept und Text: Christian Rintelen
Dufourstrasse 165 - CH-8008 Zurich - Switzerland
Voice: +41 1 420 11 55 - Fax: +41 1 420 11 57
mailto:christian@rintelen.ch
=========================================================================
From: S.C.Busbridge@bton.ac.uk
Subject: RE: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 15:21:16 +0100
Source: Sound Digest Archive v02.n924
I don't think so - but I can't really remember.
I have measured the mu of rare-earth iron materials and found it to vary
greatly with the magnitude of the signal applied. If the mu changes in the
way you describe it will be bad news, grossly distorting the signal! The
nature of Barkhausen noise will be tied up with the value of the mu because
pinning sites do in general reduce the permeability. Whether or not a
particular material is 'free' of defects largely depends on how it is made,
more than on the composition. That is one reason why magneticians prefer
to work with single crystals (the other being knowing the direction, because
magnetic effects are directional).
Simon
Simon Busbridge, BSc(Hons) PhD CPhys MInstP
School of Engineering
University of Brighton
Lewes Road
Moulsecoomb
Brighton BN2 4GJ
UNITED KINGDOM
Tel: 0044 (0)1273 642542
Fax: 0044 (0)1273 642327/642301
e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com
Audio www site: http://audio.eng.bton.ac.uk
> ----------
> From: Phil[SMTP:tube@jump.net]
> Sent: 13 July 2001 15:01
> Cc: sound@lists.io.com
> Subject: Re: [JN] Barkhausen Effect
>
> S.C.Busbridge@bton.ac.uk wrote:
>
> > Now you could choose a different magnetic material. A single crystal
> with
> > few pinning sites would be quite expensive, but amorphous materials tend
> not
> > to exhibit Barkausen noise because the pinning 'sites' are randomly
> > distributed throughout the structure so the stepped nature of the BH
> loop
> > does not appear.
> >
> > Simon
>
> Didn't we just have a discussion on this, or was it RAT? Netscape just
> lost the
> last year of emails, so I don't know (does anybody know how to FORCE
> netscape to reload the inbox summary file??? Thanks in advance if so!)
>
> I think the conclusion from people who know much more than me was that
> using a material with a minimum variation from intial mu to maximum mu
> would
> also minimize the Barkausen effect. There are cobalt alloys with an
> initial mu
> of
> 1100 and a max mu of 1150 that are largely free of this or any other
> defect,
> and in small sizes they are almost affordable! Grain oriented silicon
> steel, in
> contrast, has an initial mu of 1500 and a max mu of 40,000.
>
> Phil
>
>
=========================================================================
From: =?iso-8859-1?Q?Pierre-Fr=E9d=E9ric_Caillaud?= <pfcaillaud@cryptalis.com>
Subject: Re: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 15:24:09 +0200
Source: Sound Digest Archive v02.n924
How does a transformer (or choke) core work ?
Simply, the atoms (or molecules) in the core are like microscopic
magnets ("magnetic dipoles"), which are more or less free to rotate.
When no external magnetic field is applied, the dipoles are in chaotic
order and the field they generate sums to zero.
If all dipoles are aligned in a the same orientation, you get a
permanent magnet.
When an external magnetic field is applied, these dipoles tend to align
themselves with that field (think of tiny compass needles). And their own
field reinforces the external magnetic field.
The density of dipoles you have, their eagerness to orient themselves
according to the field, and their individual contribution, all determine the
Mu (magnetic permeability) of the material. More dipoles mean more Mu.
Vacuum has no magnetic dipoles so it has a Mu of 1.
Some materials will allow their dipoles to rotate freely (so we use them
as transformer cores), others keep their orientation and need a very strong
field, or heat, to move (so we use them as permanent magnets).
Domains are a cluster of dipoles having the same orientation.
Now I will need a low-level signal transformer soon (to convert the
balanced output of a sigma-delta DAC to single-ended) so I'm concerned about
this.
I don't know the difference between Neodymium and Alnico and rare earths
and ferromagnetic materials so if anyone knowledgeable could teach me on
that ?
Actually I'm pretty new on transformers so if anyone knows of a webpage
about that...
I would like to implement Remco's cd-enhancer II (hi Remco :-)
http://www.ultranalog.com/cdenhancer/cdenhancer2.html
Anyone, advice on the transformer ?
What about toroids ?
What about air-core transformers ? This is low-power, so we can use many
many turns of fine wire ?
On the schematic, it looks like the differential stage converts V to I,
then the transformer converts I back to V...
Thanks for your advice,
Pierre Caillaud
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: RE: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 11:42:46 -0400
Source: Sound Digest Archive v02.n925
>What is the difference between "trannies" and "magnetics for
>impedance matching and coupling"?
probably not much... some of this "fuzzy theory" stuff i am known for
impedance matching can be had with autoformers with a marked improvement in
bandwidth
direct coupling with plate chokes also increases bandwidth.
i think at some point we have to break down what it is a transformer does
and how that works for us, for the most part the trannie can serve 3
purposes (add more if you think of them)
loading a tube
coupling
impedance matching
i find that the thing that robs us of the bandwidth is the coupling aspect
of the transformer... and that loss of bandwidth seems to be the biggest
thing the opponants of transformers cite... but the magnetics can still
allow a great way to load a tube, and possible impedance matches without
limiting the bandwidth as much...
man talk about fuzzy... as of late i have found marked improvements keeping
the magnetics, but ditching the transformers, but i reserve the right to
change my opinion at any time :-)
dave
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: RE: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 12:03:02 -0400
Source: Sound Digest Archive v02.n925
> If the mu changes in the
>way you describe it will be bad news, grossly distorting the signal!
since i am on the "fuzzy theory kick"
i think thats exactly the point... this is just another one of those
magnetic tradeoffs... we can have high but volitile mu, or low and constant
mu, the main difference in the bulk of magnetics we use is just a result
of the mu (perm) being tempered with air which has a constant perm.
i'm not familair with the material phil refers to, but there are lots of
powdered cores that have near constant perms ant these are merly a result
of the size of the distributed airgap of the mix, the lower the perm the
more constant it becomes, on the other end, the materials we seek out for
their high perms (nickels) are all over the place without air to linearize
them. a simple interleaved nickel transformer can have ove 10X the
variation in inductance with frequency, and since that is tied directly to
perm, it goes to show that the perm must also vary with those frequencies
which by your words would grossly distort the signal. the saving grace is
even the interleaved core has at least some air gap, it would be
interesting to see the behavior of the ideal gapless nickel core with
frequency and signal...
i think this goes to the whole thing crowhurst and partridge point to with
their gapped PP trannies, his claims that it reduces core distortion i
think follows the idea of trying to get a more consistant perm in the core
by the inroduction of air...
the one aspect that clouds this is the use of ungapped (trying to get the
smallest gap) in all the low level signal stuff, the only thing i can come
up with is that these distorions with varying perms are also AC flux
dependant, and the higher tha AC flux, the more they rear their ugly head,
i also suppose that the high AC flux means high and varying AC signal
levels which also wreaks havok on ungapped hiperm cores.
anyone?
=========================================================================
From: Phil <tube@jump.net>
Subject: Re: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 13:28:40 -0500
Source: Sound Digest Archive v02.n925
"Sellek, Grant (TSA)" wrote:
> > Hmmm, a MM cartridge has a much higher impedance than a MC cartridge,
> > meaning it has much less current and much more voltage ...
> > Gee, I guess this
> > means that it deals with 1/10 of an electron at the lower end! ;-)
>
> I think the cartridge impedance doesn't enter into it, only the load counts.
> Some low-op MC's have small typical loads like 100 ohms, and some have 1k,
> some have 47k typical loads. In the latter case the MC would have less
> current, the middle case about the same, and in the former case, indeed, the
> MM would have less current.
>
> However, the quote refers to changes in *signal level* approaching one
> electron. To me, signal level means voltage, and I would expect the
> reference to electrons is talking about their charge. I think the low-op MC
> is going to have the lower voltage change, meaning lower number of electron
> charges. Current doesn't come into it, I think. The MM cartridge will put a
> whole lot more electrons on the (briefly) -'ve side of the coil at any point
> in time; otherwise it won't have produced a higher signal level.
>
> Grant
> PS yes I saw your ;-)
> ;-)
Okay, I'll be serious for a bit myself. That's a good point about the loading
of the cartridge, but if we assume that the load for a MC is much lower
than for a MM, then I *think* (not going to bet money, but ...) that you
are wrong about the MM having more electrons. Voltage is pressure, or
if you like an attempt to compress an electron gas within a wire. Current
is the quantity of electrons moving past a certain point per second. This
is the reason that utilities step up the voltage so high -- there is very little
actual movement of electrons, and therefore little wasted heat. A low
impedance does mean more electron flow.
On the other hand, the quote about "changes in signal level" implies
voltage to me too. The only problem is that that doesn't make sense,
because voltage isn't measured in electrons -- only current can be
measured in electrons. Well, unless you count the number of extra
electrons stuffed into a wire (or capacitor) in order to build up the
pressure known as voltage, but that would be the weirdest definition
of voltage I ever heard.
Perhaps an accurate understanding of what Hawksford had in mind
would be that the MC cartridge would have 10 electrons where the
MC had just one, implying that the MC could go to a level of resolution
10 times lower than the MM cartridge.
But I still like my 1/10 of an electron better. :-)
1/10 Phil
=========================================================================
From: Phil <tube@jump.net>
Subject: Re: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 13:59:12 -0500
Source: Sound Digest Archive v02.n925
Pierre-Frédéric Caillaud wrote:
> Now I will need a low-level signal transformer soon (to convert the
> balanced output of a sigma-delta DAC to single-ended) so I'm concerned about
> this.
> I don't know the difference between Neodymium and Alnico and rare earths
> and ferromagnetic materials so if anyone knowledgeable could teach me on
> that ?
I have put this site up here before, but if you want to see some VERY cool
core materials look at:
http://gammamet.uralinfo.ru/english/gamma.htm
Go to Magnetic Cores, then Tape Wound Boxed Cores, and look at 503B,
and 515B. The later has the most perfect looking hysteresis curve I have ever
seen or heard of -- almost flawless. Mu varies from 1500 to 1550. The 503B
isn't as good, but with a mu from 40000 to 50000 it could be used with far
fewer turns of wire -- or of silver foil, if you want to go all the way!
Unfortunately, Dave thinks that these are impossible to get here in the States,
although our European cousins may have better luck. The 503B is nickel,
the 515B is cobalt, so be prepared for sticker shock (no I haven't asked).
Phil
=========================================================================
From: Roscoe Primrose <roscoe@aiko.com>
Subject: Re: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 14:23:20 -0400
Source: Sound Digest Archive v02.n925
Chris Vryonides wrote:
> Yep, it's true, as soon as you put a signal through a transformer, it
> becomes digital...
In the level domain only, it's still continuous time. Of course, the
signal that went is was also discreet level, the potential between two
conductors can't change by less the 1eV. I did the math once years
ago, if I remember correctly that's about 61-bit resolution on a line
level signal...
Peace
- --
Roscoe Primrose -- mailto:roscoe@aiko.com -- http://www.aiko.com/roscoe
"Once in a while you get shown the light
In the strangest of places if you look at it right." Robert Hunter
"640K ought to be enough for anybody" , Bill Gates, 1981
=========================================================================
From: Loesch Thorsten <TORSTEN.LOESCH@enhar-ha.nthames.nhs.uk>
Subject: RE: [JN] Barkhausen Effect
Date: Fri, 13 Jul 2001 16:20:28 +0100
Source: Sound Digest Archive v02.n925
Hi Allan,
>Prof. Hawksford has calculated that a low output MC cartridge is
dealing with
>changes in signal level in the order of +/- one electron at the
lower end of
>an LP's resolution - what happens to this level of definition if
sent through
>a MC step-up transformer?
Well Allan, with those Transformers I have at hand (Mu Metal cored
antique Grampian Ribbon Mic Stepups and some Mic Stepups made for Rupert
Neve at Audix) the low level is fine. The Low end too. As usual, it's not
what you do, it's how you do it. I know plenty of crap MC Stepus too....
Later T
=========================================================================
From: "Sellek, Grant (TSA)" <Grant.Sellek@transport.sa.gov.au>
Subject: RE: [JN] Barkhausen Effect
Date: Sat, 14 Jul 2001 00:18:26 +0930
Source: Sound Digest Archive v02.n925
> -----Original Message-----
> From: dslagle@earthlink.net [mailto:dslagle@earthlink.net]
> Sent: Friday, 13 July 2001
> ............
> i think magnetics are a wonderful thing, i used to be a more
> trannies the
> better guy, but i have slowly been removing the trannies but
> still keeping the magnetics guy...
Not sure what you mean here, Dave?
>
> if we consider the barkhausen effect as a form of noise or
> distortion, we
> also have to consider the noise and distortion that the
> passive componants
> they replace make. I love magnetics for impedance matching,
> loading tubes
> and coupling,
What is the difference between "trannies" and "magnetics for
impedance matching and coupling"?
Thanks,
Grant
=========================================================================
From: "Sellek, Grant (TSA)" <Grant.Sellek@transport.sa.gov.au>
Subject: RE: [JN] Barkhausen Effect
Date: Sat, 14 Jul 2001 00:46:50 +0930
Source: Sound Digest Archive v02.n925
> -----Original Message-----
> From: Phil [mailto:tube@jump.net]
> Sent: Friday, 13 July 2001
>
> Allen Wright wrote:
>
> [Snip]
>
> > Prof. Hawksford has calculated that a low output MC
> cartridge is dealing with
> > changes in signal level in the order of +/- one electron at
> the lower end of
> > an LP's resolution - what happens to this level of
> definition if sent through a MC step-up transformer?
>
> Hmmm, a MM cartridge has a much higher impedance than a MC cartridge,
> meaning it has much less current and much more voltage ...
> Gee, I guess this
> means that it deals with 1/10 of an electron at the lower end! ;-)
I think the cartridge impedance doesn't enter into it, only the load counts.
Some low-op MC's have small typical loads like 100 ohms, and some have 1k,
some have 47k typical loads. In the latter case the MC would have less
current, the middle case about the same, and in the former case, indeed, the
MM would have less current.
However, the quote refers to changes in *signal level* approaching one
electron. To me, signal level means voltage, and I would expect the
reference to electrons is talking about their charge. I think the low-op MC
is going to have the lower voltage change, meaning lower number of electron
charges. Current doesn't come into it, I think. The MM cartridge will put a
whole lot more electrons on the (briefly) -'ve side of the coil at any point
in time; otherwise it won't have produced a higher signal level.
Grant
PS yes I saw your ;-)
;-)
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: RE: [JN] Barkhausen Effect
Date: Sun, 15 Jul 2001 07:48:27 -0400
Source: Sound Digest Archive v02.n925
Simon replied:
>>> A given domain wall will bow with small
applied fields but will not move very far until the field is strong enough
to break away from its pinning site. If you look in detail at the BH
loops
you will find that it is not a continuous curve but made up of lots of
steps, and it is the jump from one step to another - as domain walls jump
from one pinning site to another - that causes the Barkhausen clicks.
So if you put a small audio signal onto such a material the output will get
sort of quantised in a random way - ie nicely scrambled - losing
information
between the jumps<<<
Agreed - that's what this Barkhausen Effect is about - but do you have any
theoretical numbers (or better still, some practical measured ) NUMBERS to
answer my original question - at what signal level will wee find this
effect in signal transformers?
Allen (VSE)
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: Re: [JN] Barkhausen Effect
Date: Sun, 15 Jul 2001 07:48:32 -0400
Source: Sound Digest Archive v02.n925
CR wrote:
>>>please consider that a MC cartridge already is a magnet dealing
with very very very small signals<<<
Not as I see it - in a MC the magnet remains (hopefully) "constant" and the
current in/around the wires of the MC (moving coil) change - so I don't see
your point.
A MC that uses a magnetic core in the windings should have this Barkhausen
Effect but not one with an air core - such as my IKEDA.
>>>And contrary to you, I find low level transformers *less*
objectional...<<<
1/ I's like to try a MC step-up traffo that you prefer - 'cause I've never
heard one
>>>since the absence of current allows the use of rare earth materials with
different
magnetising behaviour. I suppose Barkhausen didn't have Alnico or Neodymium
at
hand when he established his theory...
2/ Barkhausen Effect should be there in _any_ magnetic material - but maybe
at a much lower level in materials intended to reduce the effect. Yes?
Allen
PS Any news from Reto on my cartridges?
=========================================================================
From: "Sellek, Grant (TSA)" <Grant.Sellek@transport.sa.gov.au>
Subject: RE: [JN] Barkhausen Effect
Date: Mon, 16 Jul 2001 08:40:48 +0930
Source: Sound Digest Archive v02.n925
> -----Original Message-----
> From: Allen Wright [mailto:AllenVSE@compuserve.com]
> Sent: Sunday, 15 July 2001
>
> - at what signal level will wee find this
> effect in signal transformers?
fortuitous typo!
=========================================================================
From: "Chris Vryonides" <chrisvryonides@hotmail.com>
Subject: Re: [JN] Barkhausen Effect
Date: Mon, 16 Jul 2001 09:16:38 -0000
Source: Sound Digest Archive v02.n926
Hiya,
Yeah, I know, just being a facetious s.o.b.
Will be a while before digital gets up to 60 odd bits and continuous
sampling...
Cheers
Chris
>>In the level domain only, it's still continuous time. Of course, the
signal that went is was also discreet level, the potential between two
conductors can't change by less the 1eV. I did the math once years
ago, if I remember correctly that's about 61-bit resolution on a line
level signal...
>Yep, it's true, as soon as you put a signal through a transformer, it
>becomes digital...
_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
=========================================================================
From: rcjones1@mmm.com
Subject: Re: [JN] RE: Barkhausen Effect
Date: Mon, 16 Jul 2001 16:27:03 -0500
Source: Sound Digest Archive v02.n926
Well, I agree with you, this is an interesting discussion. BTW, do a
search for Barkhausen Effect on the web, there is a lot of info out there.
I would think a 50Hz / 100Hz signal would reduce the effect only when the
signal is positive or negative, not when it crosses that zero point.
At that point you'd lose some small signal detail (In theory anyhow).
Something tells me that there are more important concerns in an amplifier
design than this. There are a lot of other parts in an amplifier that
would contribute to loss of low level detail before the Barkhausen Effect
takes place.
Richard
evaguido
<EvaGuido@iaehv To: "Emile Sprenger" <tubes@euronet.nl>
.nl> sound@lists.io.com
cc: "Allen Wright" <allen@vacuumstate.com>
07/16/01 03:52 (bcc: Richard - BIE C. Jones/US-Corporate/3M/US)
PM Subject: Re: [JN] RE: Barkhausen Effect
dear all,
Interesting discussion !
One thing comes to my mind: Could a small 50 Hz / 100 Hz current through
the transformer also reduce the effects due to the Barkhauzen effect ?
Guido
At 21:00 16-7-01 +0200, Emile Sprenger wrote:
>Picked this snippet of the BelCanto Website SET white paper:
>
>--------------
>The DC current bias of the core also reduces a little understood
distortion
>and small signal loss
>mechanism which virtually all push pull transformer coupled amplifiers
>suffer from. There is a hysteresis
>caused by the energy required to get the small magnetic domains in the
iron
>core to move and respond to
>a signal. This is a kind of magnetic stiction. The result is a potential
for
>small signals to be greatly
>distorted or lost by this mechanism, called the Barkhausen effect. This
>effect defines the small signal
>noise floor, in the presence of large signals, below which linear signal
>transfer is no longer possible. This
>could also be thought of as a quantisation noise limit in the signal
>transfer, somewhat analogous to the
>quantisation limit in a digital system. The DC bias in an SET amplifier
>constantly energizes the magnetic
>domains and supplies the energy to eliminate this stiction effect and
>greatly enhances the output
>transformer's ability to handle small signal information linearly. The
only
>other way to reduce this effect
>is to use high nickel content cores which have much lower magnetic domain
>energy. This core material is
>used in the small signal, zero bias transformers that we use for input
>signal coupling in our top
>amplifiers.
>--------------
>
>___________________
>
>E.M.T. Sprenger
>Rochussenstraat 65A
>3015 ED Rotterdam
>Netherlands
>___________________
>
=========================================================================
From: Phil <tube@jump.net>
Subject: Re: [JN] RE: Barkhausen Effect
Date: Mon, 16 Jul 2001 18:52:48 -0500
Source: Sound Digest Archive v02.n926
We had a discussion on this a while back. The "zero point" actually occurs
whenever the signal changes direction, so SET amps do NOT avoid the
Barkhausen effect, or if you prefer, the initial low mu/flat hysteresis curve.
Very high frequency might help; I think that's what they use in tape
recorders. By and lrge, however, only better materials will reduce the
problem.
evaguido wrote:
> dear all,
>
> Interesting discussion !
>
> One thing comes to my mind: Could a small 50 Hz / 100 Hz current through
> the transformer also reduce the effects due to the Barkhauzen effect ?
>
> Guido
>
> At 21:00 16-7-01 +0200, Emile Sprenger wrote:
> >Picked this snippet of the BelCanto Website SET white paper:
> >
> >--------------
> >The DC current bias of the core also reduces a little understood distortion
> >and small signal loss
> >mechanism which virtually all push pull transformer coupled amplifiers
> >suffer from. There is a hysteresis
> >caused by the energy required to get the small magnetic domains in the iron
> >core to move and respond to
> >a signal. This is a kind of magnetic stiction. The result is a potential for
> >small signals to be greatly
> >distorted or lost by this mechanism, called the Barkhausen effect. This
> >effect defines the small signal
> >noise floor, in the presence of large signals, below which linear signal
> >transfer is no longer possible. This
> >could also be thought of as a quantisation noise limit in the signal
> >transfer, somewhat analogous to the
> >quantisation limit in a digital system. The DC bias in an SET amplifier
> >constantly energizes the magnetic
> >domains and supplies the energy to eliminate this stiction effect and
> >greatly enhances the output
> >transformer's ability to handle small signal information linearly. The only
> >other way to reduce this effect
> >is to use high nickel content cores which have much lower magnetic domain
> >energy. This core material is
> >used in the small signal, zero bias transformers that we use for input
> >signal coupling in our top
> >amplifiers.
> >--------------
> >
> >___________________
> >
> >E.M.T. Sprenger
> >Rochussenstraat 65A
> >3015 ED Rotterdam
> >Netherlands
> >___________________
> >
=========================================================================
From: "Emile Sprenger" <tubes@euronet.nl>
Subject: [JN] RE: Barkhausen Effect
Date: Mon, 16 Jul 2001 21:00:38 +0200
Source: Sound Digest Archive v02.n926
Picked this snippet of the BelCanto Website SET white paper:
- --------------
The DC current bias of the core also reduces a little understood distortion
and small signal loss
mechanism which virtually all push pull transformer coupled amplifiers
suffer from. There is a hysteresis
caused by the energy required to get the small magnetic domains in the iron
core to move and respond to
a signal. This is a kind of magnetic stiction. The result is a potential for
small signals to be greatly
distorted or lost by this mechanism, called the Barkhausen effect. This
effect defines the small signal
noise floor, in the presence of large signals, below which linear signal
transfer is no longer possible. This
could also be thought of as a quantisation noise limit in the signal
transfer, somewhat analogous to the
quantisation limit in a digital system. The DC bias in an SET amplifier
constantly energizes the magnetic
domains and supplies the energy to eliminate this stiction effect and
greatly enhances the output
transformer's ability to handle small signal information linearly. The only
other way to reduce this effect
is to use high nickel content cores which have much lower magnetic domain
energy. This core material is
used in the small signal, zero bias transformers that we use for input
signal coupling in our top
amplifiers.
- --------------
___________________
E.M.T. Sprenger
Rochussenstraat 65A
3015 ED Rotterdam
Netherlands
___________________
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] RE: Barkhausen Effect
Date: Mon, 16 Jul 2001 22:22:20 EDT
Source: Sound Digest Archive v02.n926
- --part1_8e.186f1a64.2884fb5c_boundary
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In a message dated 7/16/01 3:52:50 PM US Mountain Standard Time,
rcjones1@mmm.com writes:
> Something tells me that there are more important concerns in an amplifier
> design than this.
Greets!
Well, maybe, but, we are without management :)
We follow our ears and susses.
In the old real world, everything was prioritized, and my system sounded like
hifi.
Now, I am able to listen for six months to an open system with no volume
control. Then, when the arrival after over a year of Nick's drivers in
Bruce's ehorns, I put in a linear 25K 2W carbon pot with a 3.9K 2W 2%
resistor from wiper to ground and it gets better.
Clearly reasoned logic is good for giving management warm fuzzies.
Out here in reality, things are not so tidy :)
Bark bark bark. Wag wag wag.
Happy Ears!
Al B^}
- --part1_8e.186f1a64.2884fb5c_boundary
Content-Type: text/html; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
<HTML><FONT FACE=arial,helvetica><BODY BGCOLOR="#ffffff"><FONT SIZE=2>In a message dated 7/16/01 3:
52:50 PM US Mountain Standard Time,
<BR>rcjones1@mmm.com writes:
<BR>
<BR>
<BR><BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px
; PADDING-LEFT: 5px">Something tells me that there are more important concerns in an amplifier
<BR>design than this.</FONT><FONT COLOR="#000000" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><
/BLOCKQUOTE>
<BR></FONT><FONT COLOR="#000000" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0">
<BR>Greets!
<BR>
<BR>Well, maybe, but, we are without management :)
<BR>
<BR>We follow our ears and susses.
<BR>
<BR>In the old real world, everything was prioritized, and my system sounded like
<BR>hifi.
<BR>
<BR>Now, I am able to listen for six months to an open system with no volume
<BR>control. Then, when the arrival after over a year of Nick's drivers in
<BR>Bruce's ehorns, I put in a linear 25K 2W carbon pot with a 3.9K 2W 2%
<BR>resistor from wiper to ground and it gets better.
<BR>
<BR>Clearly reasoned logic is good for giving management warm fuzzies.
<BR>
<BR>Out here in reality, things are not so tidy :)
<BR>
<BR>Bark bark bark. Wag wag wag.
<BR>
<BR>Happy Ears!
<BR>Al B^}
<BR>
<BR></FONT></HTML>
- --part1_8e.186f1a64.2884fb5c_boundary--
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] RE: Barkhausen Effect
Date: Mon, 16 Jul 2001 22:52:14 +0200
Source: Sound Digest Archive v02.n926
dear all,
Interesting discussion !
One thing comes to my mind: Could a small 50 Hz / 100 Hz current through
the transformer also reduce the effects due to the Barkhauzen effect ?
Guido
At 21:00 16-7-01 +0200, Emile Sprenger wrote:
>Picked this snippet of the BelCanto Website SET white paper:
>
>--------------
>The DC current bias of the core also reduces a little understood distortion
>and small signal loss
>mechanism which virtually all push pull transformer coupled amplifiers
>suffer from. There is a hysteresis
>caused by the energy required to get the small magnetic domains in the iron
>core to move and respond to
>a signal. This is a kind of magnetic stiction. The result is a potential for
>small signals to be greatly
>distorted or lost by this mechanism, called the Barkhausen effect. This
>effect defines the small signal
>noise floor, in the presence of large signals, below which linear signal
>transfer is no longer possible. This
>could also be thought of as a quantisation noise limit in the signal
>transfer, somewhat analogous to the
>quantisation limit in a digital system. The DC bias in an SET amplifier
>constantly energizes the magnetic
>domains and supplies the energy to eliminate this stiction effect and
>greatly enhances the output
>transformer's ability to handle small signal information linearly. The only
>other way to reduce this effect
>is to use high nickel content cores which have much lower magnetic domain
>energy. This core material is
>used in the small signal, zero bias transformers that we use for input
>signal coupling in our top
>amplifiers.
>--------------
>
>___________________
>
>E.M.T. Sprenger
>Rochussenstraat 65A
>3015 ED Rotterdam
>Netherlands
>___________________
>
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: Re: [JN] RE: Barkhausen Effect
Date: Tue, 17 Jul 2001 13:13:54 -0400
Source: Sound Digest Archive v02.n926
>But if the audio signal gets modulated by another current, the signal
>current and magnetic change are decorrelated, not ?
isn't that whats already happening? wouldn't we have to somehow demodulate
the signal to remove the 50hz wave.
this idea does open up a very interesting subject though.... isn' t music
just a bunch of differnet frequencies modulating one another?
if we look at the low frequencies having the most dramatic effect on the
core, wouldn't we expect the highest frequencies to be the ones with the
smallest signals thus be the ones that het lost in the core (isn't this
what really happens notice how core losses always increase with frequency)
in any event if we look at the low frequencies as the modulation signal,
and the high frequencies as riding upon that signal suddenly don't we have
a situation very similar to what guido suggests without the need for
demodulation?
i'm sure at some level and at some point there are drastically different
levels of modulation which *could* show up as a change in perceived low
level (read high frequency) information, and at some point the "modulatior"
is so small it doesn't do its job..
also if we can look at it in this manner what happens when our modulator
(music) drastically changes the behavior of the core??
>We might do some experiments with RF bias of output trannies: Anyone ?
gee... i would think the rf biasing of phono stepups would be more where we
want to look... but again wouldn't the RF have to be at a level much
larger than the signals we are dealing with are... or am i not
understanding the way the rf would bias the core?
i do not know how tape heads work... i do know they use permalloy though :-)
with the impending death of the modem industry... the uses of the nickels
seems to be disappearing by the day :-(
dave
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] RE: Barkhausen Effect
Date: Tue, 17 Jul 2001 18:52:27 +0200
Source: Sound Digest Archive v02.n926
Hi all
At 18:52 16-7-01 -0500, Phil wrote:
>We had a discussion on this a while back. The "zero point" actually occurs
>whenever the signal changes direction, so SET amps do NOT avoid the
>Barkhausen effect, or if you prefer, the initial low mu/flat hysteresis curve.
But if the audio signal gets modulated by another current, the signal
current and magnetic change are decorrelated, not ?
>Very high frequency might help; I think that's what they use in tape
>recorders.
That is what came in my mind as well
>By and lrge, however, only better materials will reduce the problem.
We might do some experiments with RF bias of output trannies: Anyone ?
Guido
>evaguido wrote:
>
>> dear all,
>>
>> Interesting discussion !
>>
>> One thing comes to my mind: Could a small 50 Hz / 100 Hz current through
>> the transformer also reduce the effects due to the Barkhauzen effect ?
>>
>> Guido
>>
>> At 21:00 16-7-01 +0200, Emile Sprenger wrote:
>> >Picked this snippet of the BelCanto Website SET white paper:
>> >
>> >--------------
>> >The DC current bias of the core also reduces a little understood distortion
>> >and small signal loss
>> >mechanism which virtually all push pull transformer coupled amplifiers
>> >suffer from. There is a hysteresis
>> >caused by the energy required to get the small magnetic domains in the iron
>> >core to move and respond to
>> >a signal. This is a kind of magnetic stiction. The result is a
potential for
>> >small signals to be greatly
>> >distorted or lost by this mechanism, called the Barkhausen effect. This
>> >effect defines the small signal
>> >noise floor, in the presence of large signals, below which linear signal
>> >transfer is no longer possible. This
>> >could also be thought of as a quantisation noise limit in the signal
>> >transfer, somewhat analogous to the
>> >quantisation limit in a digital system. The DC bias in an SET amplifier
>> >constantly energizes the magnetic
>> >domains and supplies the energy to eliminate this stiction effect and
>> >greatly enhances the output
>> >transformer's ability to handle small signal information linearly. The only
>> >other way to reduce this effect
>> >is to use high nickel content cores which have much lower magnetic domain
>> >energy. This core material is
>> >used in the small signal, zero bias transformers that we use for input
>> >signal coupling in our top
>> >amplifiers.
>> >--------------
>> >
>> >___________________
>> >
>> >E.M.T. Sprenger
>> >Rochussenstraat 65A
>> >3015 ED Rotterdam
>> >Netherlands
>> >___________________
>> >
=========================================================================
From: "Bart Shepherd" <bart.shepherd@ttm.com.sg>
Subject: [JN] Bart off the air
Date: Sat, 23 Jan 1999 16:31:13 +1100
Source: Sound Digest Archive v02.n009
This is a multi-part message in MIME format.
- ------=_NextPart_000_01AD_01BE46ED.CAEAC6D0
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
No wisecracks thanks!
I will be offline from now until about February 6.
Grover, Jean-Michel: airmail heading your way!
Cheers,
Bart
- ------=_NextPart_000_01AD_01BE46ED.CAEAC6D0
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
<HTML>
<HEAD>
<META content=3Dtext/html;charset=3Diso-8859-1 =
http-equiv=3DContent-Type>
<META content=3D'"MSHTML 4.72.3110.7"' name=3DGENERATOR>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#000000 size=3D2>No wisecracks thanks!</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>I will be offline from now until =
about February=20
6.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Grover, Jean-Michel: airmail heading your =
way!</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>Cheers,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>Bart</FONT></DIV></BODY></HTML>
- ------=_NextPart_000_01AD_01BE46ED.CAEAC6D0--
=========================================================================
From: houndman@onix.com
Subject: [JN] basement/workshop stereo
Date: Wed, 10 Jan 2001 01:57:28 -0500
Source: Sound Digest Archive v02.n779
I am trying to figure how fancy I should get with speakers in rooms
like the basement, kitchen, and bath I want to install. I want them for
listening while in the rooms more than quality so imaging isn't very
important but sound quality would be nice. I had picked up some 8" DVC
woofers and some 1" domed tweeters to use but have a bunch I have used
and liked that I have options. What I am wondering about is should I
just enclose the 3 speakers together and just make the package easily
placeable or consider the placement. With a DVC woofer maybe crossed
over at 2-3Khz it doesn't seem like I can do much but would like to do
it as well as possible.
In the basement a corner ceiling location seems about the best with a
tweeter on either side of the woofer and them spaced no more than a foot
from it. Any more seems like it might affect the sound. Any thoughts ??
- -----------------
\/ince ++
working on breeding an Afghan that Doesn't mat.... And
comes when called... I want a Toucan that won't wake me during the day.
Impossable they say.... I have a Snapper to feed.
Playing around with SE tube amps. Think I'd try something easy ??
=========================================================================
From: "Rice, Doug" <RICEDA@phibred.com>
Subject: [JN] basic question
Date: Thu, 31 Aug 2000 08:53:09 -0500
Source: Sound Digest Archive v02.n648
Hello everyone,
I have been woodworking lately - building a cabinet for the hi-fi to improve
the WAF.
No time for amps, but I am itching to start again. I want to work on the
power supplies first to get the voltages in the ball park.
I would like to simulate a load of 80-90mA at 400-450 volts that the amp
will use.
What is the best way to do this? Hook up a 50W or 100W resistor? How about a
light bulb,
would it stand the voltages?
Thanks,
Doug Rice
Des Moines
=========================================================================
From: "Epstein, Jeremy" <JEpstein@ndbcap.com>
Subject: [JN] Bass Guitar Preamp, intro to The Ampage
Date: Fri, 7 Sep 2001 09:03:05 -0400
Source: Sound Digest Archive v02.n961
#1, how in the hell would this be considered "Off Topic," Timo? Where the
hell do you think all this music COMES FROM?
I removed the OT and refuse to consider it applicable. So there. :P
#2, Ken gave this advice:
>definitely check out http://www.firebottle.com/ampage/bbs
>i hang there regularly, and j epstein occasionally pops his head in.
I second Ken's recommendation and I thought I'd give you a few tips based on
reading that BBS for several years.
Valuable contributors include:
Mark Hammer
RG Keen
Carl Z
Bruce (Mission Amps)
Trace - Voodoo Amps
Kevin O'Connor
Steve A(hola)
Randall Aiken
kg (Ken Gilbert, a dangerous madman. Do not open any of his posts without
one hand in your pocket, rubber-soled shoes on your feet, and a sturdy
hairnet to contain the brain explosion.)
These are by no means the only users of merit, just the ones I remember off
the top of my head as being almost-invariably worth reading. If you see any
two of these guys in one discussion, it is going to be worth looking at. I'm
probably forgetting some good contributors.
A special acronym: BAGA - this refers to Ken Gilbert's Big-Ass Guitar Amp, a
feat of engineering to rival the surgical truss in its sheer overkill
factor. Ken's pants flap even when he is only wearing his wife's underwear,
a situation that happens far more often than he'd care to admit.
Navigating the site:
From the front page, you can find your way into a few categories:
Open Forum means anything goes, that is where the beer, politics, and
motorcycle discussions tend to get filed. Well worth a side trip at times.
Effects is home to a very active group of stompbox builders - these guys
represent an amazing collection of resources. If it has two 1/4" phone jacks
on it, these guys can figure it out.
Guitar Amps is subdivided into several subcategories, including Vintage,
Repair/Modify, Homebrew Troubleshooting, Design, General Discussion, etc.
There is a choice box for the subcategories at the bottom of the screen once
you have selected Guitar Amps from the front page, which lands you in
General Discussion as the default.
The front page also accesses several great resources (the Homebrew Gallery
is a favorite of mine) and the sponsor's sites. Note that entering a
specific area will start you off with a list of user-suggested, user-ranked
resources in the right-hand panel and these are well selected.
The site administrator is Tboy and he most often comments on administrative
stuff, but not always. I would have to say that the Ampage, of all the
online communities I have joined, has the best software interface by a VERY
wide margin and it is Tboy who makes this happen. He started with an
off-the-shelf BBS package and has tweaked and recoded it quite a bit over
the years, making constant improvements to its functionality, all despite
the usual disappearing ISPs and other common problems of cyberspace. (Hit
"refresh" a couple of times when you load the front page and you will get an
idea of the kind of cyber-subtlety Tboy is partial to.) One specific note:
clicking on the first header of a thread will open ALL the posts in the
thread, clicking on the individual posters names will open their posts one
at a time.
Enjoy!
- -j
=========================================
Jeremy Epstein........jepstein@ndbcap.com
=========================================
=========================================================================
From: "J. Gordon Rankin" <waudio@cinti.net>
Subject: Re: [JN] Bass Guitar Preamp, intro to The Ampage
Date: Fri, 7 Sep 2001 10:15:56 -0400
Source: Sound Digest Archive v02.n961
Gang,
As some know I am making Guitar amps now. I will have the first one on my
site next week. Sorry about not chiming in earlier but lost my harddrive
to a bad motor.
Anyway... I did have a great pdf from Leo from the 50's on amp building
lost again by not backing up my junk folder.
This fender heaven site is great source of stuff:
http://www.ampwares.com/ffg/
Also there was a good article in Glass Audio issue 4/2 1992 on Remaking
the Champ, has some good grounding stuff.
Also on the Duncan tube site is a Tone Stack calculator for you PC folks
or us MAC guys using Vpc...
http://www.duncanamps.com/tsc/index.html
Best source of information has been from the locals. They are eager to
find someone who knows a little about this stuff and what sounds good,
better best and terrible.
Many of you na sayers to this being relavent should understand that my
guitar amp has a gain of 70dB, all ac heaters, and low noise. After doing
these back flips, I think I might retackle a phono section.
Later!
Gordon
=====> Wavelength Audio, ltd. <=====
mailto:waudio@cinti.net
mailto:wavelength@fuse.net
http://www.WavelengthAudio.com
ph.fx. 513-271-4186 USA
=========================================================================
From: "Epstein, Jeremy" <JEpstein@ndbcap.com>
Subject: RE: [JN] Bass Guitar Preamp, intro to The Ampage
Date: Fri, 7 Sep 2001 10:27:18 -0400
Source: Sound Digest Archive v02.n961
Gordon wrote:
> Many of you nay sayers to this being relevant should
> understand that my
> guitar amp has a gain of 70dB, all ac heaters, and low noise.
> After doing
> these back flips, I think I might retackle a phono section.
Exactly! Good construction is good construction, good tone is good tone (and
is of course due to the use of tubes ;) )
I was introduced to the world of tubes by building a tube guitar amp, I
learned a lot and it all came in handy later as I made the transition to
building hi fi gear. The guitar amp guys have a lot of good info about how
to make your construction and circuits DURABLE and RELIABLE which is nice
stuff to know.
I was on AMPAGE long before I was on Joenet.
dnb - do you still visit AMPAGE?
Let's not forget our Joenet brother Blackie Pagano - I think he'd agree that
guitar amps are worthy gear. One time he showed me why Hiwatt amps were
legendary for their mil-spec construction - even Larry Moore would be proud
to build something as clean inside as a Hiwatt head. You could do a lot
worse and I surely have.
- -j
=========================================
Jeremy Epstein........jepstein@ndbcap.com
=========================================>
=========================================================================
From: David Barnett <d_n_b@swbell.net>
Subject: Re: [JN] Bass Guitar Preamp, intro to The Ampage
Date: Fri, 07 Sep 2001 13:30:30 -0500
Source: Sound Digest Archive v02.n961
On Fri, 07 Sep 2001 10:27:18 -0400, "Epstein, Jeremy"
<JEpstein@ndbcap.com> wrote:
>dnb - do you still visit AMPAGE?
Not as often as I should.
- --dnb
=========================================================================
From: Timo Christ <carnivor@uni-bremen.de>
Subject: [JN] Re: Bass Guitar Preamp, intro to The Ampage
Date: Fri, 07 Sep 2001 15:57:41 +0200
Source: Sound Digest Archive v02.n961
Hello,
thanks to Jeremy & Ken for the intro to the The Ampage BBS. I have
posted a few questions there (Guitar Amps => Design).
Thanks to all, we have indeed settled on the Bassman preamp.
Regards
Timo
- --
/ /--' Timo Christ carnivore@uni-bremen.de
/ /<-. Electronics Engineering Student
__/ /__/ Horns 'r more fun:
' http://www-user.uni-bremen.de/~carnivor/
=========================================================================
From: James Melhuish <james@melhuish.org>
Subject: [JN] Bass horn drivers?
Date: Thu, 27 Jan 2000 16:47:12 -0500
Source: Sound Digest Archive v02.n420
Hi All,
I am considering building a separate bass horn for approx 50 Hz to 250
Hz to mate with Lowther DX3s in small front horns. I have reasonable
knowledge of horn design, but would like some advice as to what are
considered some of the good bass horn drivers. I would prefer one
driver per horn, and something "quick" to match the Lowther's
responsiveness. Price isn't much of an issue, unless we talk silly
money (I'd like to keep the bass driver costs under 3 or 4 hundred
dollars for the pair, preferably less). Any ideas? Thanks.
James
- --
James Melhuish & Jennifer Shearman
82 Harvard Street, Newtonville MA 02460, USA
tel: 617 965 8859
fax: 617 964 3249
mailto:jjms@melhuish.org
http://melhuish.org
=========================================================================
From: "jhlane" <jhlane@email.msn.com>
Subject: Re: [JN] Bass horn drivers?
Date: Thu, 27 Jan 2000 19:13:01 -0800
Source: Sound Digest Archive v02.n420
- ----- Original Message -----
From: Douglas Purl <dcp@selway.umt.edu>
To: <sound@deliverator.io.com>
Sent: Thursday, January 27, 2000 6:25 PM
Subject: Re: [JN] Bass horn drivers?
> Perhaps you confound even those who wish to help. Though
"quick" and
> "fast" are epithets commonly applied to loudspeakers by some,
they don't
> express anything scientific about a speaker.
Yes, but having indicated your need for a scientific explanation
of reproduced bass quality, which is the context of this
discussion, you will next be asked to discuss the SUBJECTIVE
"speed" of a bass system. That inmistakable characteristic of
tremendous texture, of a certain lightness (but certainly not
without fundamental power) and vast depth in the bass so
reminiscent of the real sound. While bandwidth as an indicator
of "scientific" speed - your word - is correct, I've never heard
a plausible scientific explanation of how/why any given 2-octave
woofer sounds subjectively "quick", or any of numerous other
subjective terms describing the special, super-realistic sound
the original poster was obviously referring to.
> I'll bet you can get varying opinions on this one. Loading a
Lowther
> seems a contentious issue; complementing it with an ideal
woofer may be no
> less so.
On Joelist awhile back I ran on about the sound of the REPS-1 I
heard at THE Show 2000 in Vegas. What I didn't say was how
superb the bass was. And exactly as I suspect our other Joe
would have wanted it: That special texture, quickness, depth and
lack of electronic or mechanical signature, lousy cube-shaped
hotel room notwithstanding. But in this case, complimenting Moth
Audio's version of - what I think was - a couple Lamhorn-loaded
REPS-1 (variants on the Lowther theme) was a single 18" in a
Volkswagen-sized, boxed horn behind a cloth screen. An imposing
plywood affair from which issued a couple of the more
spectacularly realistic lower octaves I've heard in the past 20
years. I'd suggest a call to Moth Audio to learn more.
We still can't apply a neat little number to THIS sort of bass
quality. Q numbers, I think, won't cut it.
Jon Lane
=========================================================================
From: Douglas Purl <dcp@selway.umt.edu>
Subject: Re: [JN] Bass horn drivers?
Date: Thu, 27 Jan 2000 19:25:55 -0700 (MST)
Source: Sound Digest Archive v02.n420
On Thu, 27 Jan 2000, James Melhuish wrote:
> I am considering building a separate bass horn for approx 50 Hz to 250
> Hz to mate with Lowther DX3s in small front horns. I have reasonable
> knowledge of horn design, but would like some advice as to what are
> considered some of the good bass horn drivers. I would prefer one
> driver per horn, and something "quick" to match the Lowther's
> responsiveness.
Perhaps you confound even those who wish to help. Though "quick" and
"fast" are epithets commonly applied to loudspeakers by some, they don't
express anything scientific about a speaker. If a driver is not quick
enough to generate a given frequency, it simply reduces its amplitude.
That's called rolloff. Speed, as applied to drivers, is really an
expression of its bandwidth. Presumably you are looking for a slow
driver, a woofer, to complement the Lowther in frequencies it cannot
cover, the bass, without forfeiting the qualities that make it a Lowther.
In general horns do not exhibit the underdamped response found in many
woofers, especially vented ones, where the system Q is set fairly high,
greater than 0.7, to give a fuller response, though at the expense of
transients.
Not to be overlooked is the contribution of room modes, which can make a
neutral woofer seem boomy -- and give the impression that the "quick"
Lowther has gone muddy. Perhaps you need to calculate your room modes and
match up bass-horn cutoff or even consider notching your woofer drive --
if room coupling proves troublesome.
I'll bet you can get varying opinions on this one. Loading a Lowther
seems a contentious issue; complementing it with an ideal woofer may be no
less so.
Doug Purl
=========================================================================
From: "Carter Hendricks" <carter@i1.net>
Subject: Re: [JN] Bass horn drivers?
Date: Thu, 27 Jan 2000 22:22:42 -0600
Source: Sound Digest Archive v02.n420
- -----Original Message-----
From: jhlane <jhlane@email.msn.com>
To: Joelist <sound@deliverator.io.com>
Date: 27 January, 2000 9:40 PM
Subject: Re: [JN] Bass horn drivers?
>----- Original Message -----
>From: Douglas Purl <dcp@selway.umt.edu>
>To: <sound@deliverator.io.com>
>Sent: Thursday, January 27, 2000 6:25 PM
>Subject: Re: [JN] Bass horn drivers?
>
>> Perhaps you confound even those who wish to
>>help. Though "quick" and "fast" are epithets
>>commonly applied to loudspeakers by some,
>>they don't express anything scientific about a
>>speaker.
>
>Yes, but having indicated your need...
Let's not get in to Purl's needs. But:
I think the first time I replied to Purl about this, my
little Anna was just five or six. It still doesn't matter
what some think about the right or wrong of fast
bass. Anna [now 8] can tell whether a speaker
has fast, or slow bass. The language makes sense.
If you want to talk about some special use of the language, then choose a
different description, like maybe "green" bass.
This afternoon I was describing a speaker project
to friends and I said that the new speaker had
better tone but was just as fast as the Diatones.
We understood each other clearly.
I just wish the Diatones had more of that Green
Bass.
--Carter
=========================================================================
From: Douglas Purl <dcp@selway.umt.edu>
Subject: Re: [JN] Bass horn drivers?
Date: Thu, 27 Jan 2000 22:26:13 -0700 (MST)
Source: Sound Digest Archive v02.n420
On Thu, 27 Jan 2000, Carter Hendricks wrote:
> >Yes, but having indicated your need...
>
> Let's not get in to Purl's needs. But:
>
> I think the first time I replied to Purl about this, my
> little Anna was just five or six. It still doesn't matter
> what some think about the right or wrong of fast
> bass. Anna [now 8] can tell whether a speaker
> has fast, or slow bass. The language makes sense.
> If you want to talk about some special use of the language, then choose a
> different description, like maybe "green" bass.
Let us assume that you are right. What speaker parameters does one
measure to determine quickness? What engineering efforts can one
undertake either to design this quality into a speaker or enhance it? Or
are there some physical phenomena entailed that are immeasurable?
Doug Purl
=========================================================================
From: "jhlane" <jhlane@email.msn.com>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 01:27:11 -0800
Source: Sound Digest Archive v02.n421
From: <TubeGarden@aol.com>
Subject: Re: [JN] Bass horn drivers?
> >dcp@selway.umt.edu writes:
> >
> > What engineering efforts can one undertake either to design
this quality
> > into a speaker or enhance it?
> It is good practice for the engineer to listen to music on the
speaker. Once
> it is up to the engineer's standard, it is further a good idea
to have
> others, selected by the engineer as being capable of providing
useful input,
> listen to the speaker in their homes for an extended period.
First articles,
> not prototypes, and to listen to comments from the others and
address their
> concerns.
>
> Happy Ears!
> Al B^}
An indictment of today's current crop of audio engineers that
this is so...revolutionary a concept to them, wouldn't you say?
Jon Lane
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 01:55:44 EST
Source: Sound Digest Archive v02.n421
In a message dated 1/27/00 11:06:16 PM US Mountain Standard Time,
dcp@selway.umt.edu writes:
> What engineering efforts can one undertake either to design this quality
into a speaker or enhance it?
Greets Jeets Neets,
It is good practice for the engineer to listen to music on the speaker. Once
it is up to the engineer's standard, it is further a good idea to have
others, selected by the engineer as being capable of providing useful input,
listen to the speaker in their homes for an extended period. First articles,
not prototypes, and to listen to comments from the others and address their
concerns.
The alternative is to try and reduce the musical experience to a set of
repeatable measurements conducted in some "known accurate* environment.
It depends, if the engineer's personal needs are for total engineering
control or brisk sales.
Anecdotal evidence is this is an either/or situation.
Some engineers really would rather be right than rich.
Happy Ears!
Al B^}
=========================================================================
From: WBamb83392@aol.com
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 02:37:20 EST
Source: Sound Digest Archive v02.n421
In a message dated 1/28/00 1:06:16 AM Eastern Standard Time,
dcp@selway.umt.edu writes:
> Let us assume that you are right. What speaker parameters does one
> measure to determine quickness? What engineering efforts can one
> undertake either to design this quality into a speaker or enhance it? Or
> are there some physical phenomena entailed that are immeasurable?
>
> Doug Purl
In my humble opinion, the goals are these:
1. Stiff cone/VC former/glue joint- if the cone distorts, the transients will
also
2. flat impedence, low inductance- negative feedback does not work perfectly
with reactive loads.
3. minimum time delay or phase shift. When harmonics line up in time, pitch
is apparently discerned more quickly. Not pitch as in Do Re Mi, but which
octave instead.
4. Mask design imperfections. for instance, put the time delay from
enclosure resonance below the range of percussive instruments.
- -Eric Bamberg
=========================================================================
From: "jhlane" <jhlane@email.msn.com>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 02:43:43 -0800
Source: Sound Digest Archive v02.n421
- ----- Original Message -----
From: Douglas Purl <dcp@selway.umt.edu>
Subject: Re: [JN] Bass horn drivers?
> Let us assume that you are right.
- -No more an assumption required than say, if any particular
measurement is "right."
> What speaker parameters does one
> measure to determine quickness?
- -With one's ears, one measures the very sound of the system.
Insufficient for the audio scientist but then the scientist (or
at least he who prefers to be thought of thusly) tends to not
actually possess the necessary tools to fully assess the
musicality of the approach, IME.
> What engineering efforts can one
> undertake either to design this quality into a speaker or
enhance it?
- -One can apply subjective experience and then, eventually, the
preference for the more musically honest of any group of
competing technologies to the problem.
> Or are there some physical phenomena entailed that are
immeasurable?
Perhaps. Probably. Or at least, without clear knowledge of
their relative importance.
Not to be glib, DP, but fleshing out the realities of, in this
case, bass quality, tends to get verbose in a hurry. The
Subjectivist is not offended, but the Scientist demands more,
sigh. Carrying on regardless, I'd sound something like this is I
were to at least try:
For some unknown reason, some would prefer to consider only the
effect of the environment on already-reproduced bass energy as
the sole determinant of it's quality. Like referring to the
track as the only influence on my lap time even when my pistons
are scuffed, my bearings spun, and my tires blown. As if the
hardware were already assumed perfect (and why audio
objectivists, in this regard, consider themselves objective, I
don't know), and the environment irreversibly hostile. The real
world not being anechoic and all.
Yet an only slightly more insightful investigation reveals the
sins further upstream in the system. Let's contrast, albeit
subjectively:
Here, we have our theoretic, single cubic foot,
triple-kilowatt-powered "subwoofer". With response to - get
this - below 20Hz. In the other corner, Leviathan. Our splendid
imaginary horn, originating at the receiving end with an 18",
98dB, precision jewel of a woofer device and terminated at the
business end, some yards away, by the entire ROOM. And probably
limited to start its acoustic task one full octave higher in
frequency.
First, Commercial Wonder. Our Tupperware-coned,
consumer-accepted, designed-by-a-scientist "sub" throws POUNDS of
force at a half-foot disc of plastic terminated in a shoe-leather
surround of equivalent area, tossing both some number of INCHES,
their contorted sonic boom of a wavefront shredding around the
tiny corners of this tiny device placed, naked and alone, in it's
cavernous environment, where it must immediately transfer this
mere puck of quasi-acoustic coupling directly to any number of
cubic meters of air. It's motor nonlinearly dissipates literally
hundreds of thermal watts, inexpensive ceramic magnetics driving
Grand Canyon sized gaps within which (more or less, depending on
drive level) reside half-pound, multi-layer voice coils,
three-fourths of their length flailing around in mid air at any
one time. The ceramic buckles, the motor-stuff presumably
collapses and fails, and distortion components rise toward the
sky. Acoustic compression, thermal instability, mechanical
deformation, frequency contour wildly variable with level.
Somehow, this is considered hifi by those generally impressed
with observing thermoplastic jerking around spastically, some
sort of proof of sheer acoustic cubic inches, if not fidelity,
the mistuned, barking monster truck motor of the speaker world.
Applying a strobe - in our mind's eye - to our sorry little cone
and its surround while they attempt to keep up during this
sordid, twenty five hundred watt torture of ordinary materials
and assemblies reveals just how traumatic and less than linear
this whole affair must certainly be. Good thing, at least, that
we arranged a few pounds of solid cast aluminum to hold the whole
thing together.
On the other hand, our horn woofer, forever doomed to endure our
derision for nothing more than its ungainly size, requests a far
more predictable and graceful set of electromechanical overtures
be applied against the problem at hand. First, its relatively
tiny coil fits rather precisely in a relatively tiny gap,
energizing same with a motor breathtakingly superior to
Bass-In-A-Box's plastic fantastic, both in terms of it's magnetic
resiliency and focus. We tickle it with a hundred milliwatts,
and at no time need any portion of the coil leave the field's
firm embrace, the excursions some 100 times less, by comparison,
even when played at the same level as our Commercial Wonder. Our
horn's woofer also is endowed with a cone of geometrically
un-challenged select cellulose, a vast real estate of thin,
reinforced wood, that most elegant of all Mother Nature's
engineering materials and blessed with exceptional strength and
stiffness, one caressed here by soft surrounds and linear
suspensions, which, when gently motivated mere hundredths of an
inch, gleefully replies with nearly perfect behavior, the
resulting noble pressurizations swooping gracefully down our by
now fully influential horn contour, its effect to carefully and
lovingly prepare the energy to emerge happily into the
anticipating room, a technical tour de force of acoustic
leverage, unstressed, unaffected, merrily impressing virtually
distortionless bass energy throughout the home, where...
Hard not to get carried away. Quite unscientific of me.
Seriously, how do you really qualify this? Does anybody really
care? Does NASA have an audio budget?
And is it really any wonder why subjectivist audio artists
(shudder) have so much fun? Without a "scientific" yardstick,
you can't really say why you prefer a Monet to a Klee. Just if.
Jon Lane
=========================================================================
From: Douglas Purl <dcp@selway.umt.edu>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 04:23:10 -0700 (MST)
Source: Sound Digest Archive v02.n421
On Fri, 28 Jan 2000, jhlane wrote:
> > What speaker parameters does one
> > measure to determine quickness?
>
> -With one's ears, one measures the very sound of the system.
> Insufficient for the audio scientist but then the scientist (or
> at least he who prefers to be thought of thusly) tends to not
> actually possess the necessary tools to fully assess the
> musicality of the approach, IME.
How do you know what I hear?
> > What engineering efforts can one
> > undertake either to design this quality into a speaker or
> enhance it?
>
> -One can apply subjective experience and then, eventually, the
> preference for the more musically honest of any group of
> competing technologies to the problem.
I much enjoyed Jon's rhetorical fulsomeness, and I am pleased that I
inspired him to such loquaciousness. Moreover, I calculate that getting
this off his chest will lengthen his life by 4.2 years and decrease his
need for the normal male's healthy 3.5 hours of nightly penile erections
by 27%. Indeed, he ought to send me a respectable honorarium. (On the
other hand, he may resent having deprived himself. . . .)
But, I must report that I have received eight private responses on this
topic in addition to those posted to the list. Let me point the question
so that you all can help the original questioner.
Most of you are stating what he should aim for sonically. But that does
not help him discover the means of achieving those results. It's means he
seeks, not ends. Every time we have gotten down to nuts and bolts on bass
horns, some ingenious and effective designs have been described. Is it
Bert who built the impressive floor horns? Not only an elegant
application of engineering, but a practical and smart solution.
Doug Purl
=========================================================================
From: StepHydro@aol.com
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 06:33:26 EST
Source: Sound Digest Archive v02.n421
In a message dated 01/28/2000 1:<BR06:<BR16 AM
Eastern Standard , dcp@selway.umt.edu writes:
> Let us assume that you are right. What speaker parameters does one
> measure to determine quickness? What engineering efforts can one
> undertake either to design this quality into a speaker or enhance it? Or
> are there some physical phenomena entailed that are immeasurable?
Doug,
Isn't it incumbent upon the *engineer* do determine if (and prove that) his
technology is capable of resolving these issues, rather than upon the
listener to prove that his perceptive system is so capable?
It seems to me proper that science continue to proceed from observed
phenomena to postulates to testing and thence to models.
Since it seems that most human perceptive systems can understand and perceive
"fast" bass, you should be working your little hiney off trying to help your
models catch up with reality.
Remember...all this engineering and science is just about modelling
nature...it *does not* define reality. If the models fall short of reality,
it is not the reality that is lacking. And yes, some things are as yet
immeasurable, because you have not discovered how to model them.
Cheers/Carron
=========================================================================
From: StepHydro@aol.com
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 06:39:04 EST
Source: Sound Digest Archive v02.n421
In a message dated 01/28/2000 5:<BR49:<BR26 AM
Eastern Standard , jhlane@email.msn.com writes:
<really large snip>
> And is it really any wonder why subjectivist audio artists
> (shudder) have so much fun? Without a "scientific" yardstick,
> you can't really say why you prefer a Monet to a Klee. Just if.
Magnificent!!!
Carron
=========================================================================
From: StepHydro@aol.com
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 06:49:22 EST
Source: Sound Digest Archive v02.n421
In a message dated 01/28/2000 5:<BR55:<BR00 AM
Eastern Standard , dcp@selway.umt.edu writes:
> You miss the point. But most others have too.
>
> The issue is how do you instruct this fellow to achieve his goals? You
> tell him what to listen for, but how do you save him from iterating every
> variation before he becomes the proverbial monkey in the British Museum?
> What kind of a woofer does he mate with his Lowthers? A lot of issues
here.
>
> The issue is how, not what.
Dear Doug,
It is unfortunately, not we who miss the point. We are perfectly capable of
instructing him, but your "science" is utterly bereft.
We will tell him what we have found through experience and then tell him
"friend, this is not all science. We have achieved some measure of success
with these approaches. However, you are dealing with *your* preferences, and
*your* room, and *your* equipment, so you'll have to do what we did; listen,
experiment, and finally, discover what sort of compromises you are willing to
live with."
Doug, more power to you and systematic investigation. I hope that approach
someday provides the answers. But, for now, the ears rule.
Cheers/Don
=========================================================================
From: Kurt Steffensen <kurt-steffensen@teliamail.dk>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 12:06:03 +0300
Source: Sound Digest Archive v02.n421
Douglas Purl wrote:
> Let us assume that you are right. What speaker parameters does one
> measure to determine quickness? What engineering efforts can one
> undertake either to design this quality into a speaker or enhance it? Or
> are there some physical phenomena entailed that are immeasurable?
Hi Doug and other Joes.
I think I can offer you the explanation you want :-)
But first , I think you misunderstands the meaning of the phrase ?
It is just a subjective way we use to describe what we experience regarding
sound.
Our language lacks precise words in this matter.
It is supposed to be understood in the same manner as
"hard-cold-warm-soft-agressive-romantic" etc. etc.
I believe you are thinking of cycles per second ?
40 Hz is 40 Hz , and that can not be either fast or slow.
But , that is not what people means by the expression.
And no music signals are pure sine waves anyway.
Not even a single struck on the deep E-string describes a pure sine tone.
And imagine how that looks , when the big drum , follows the pick of the bass..
Now , imagine a heavy bass speaker , say a 22" or a IMF transmission line or a
tweaked over coated DIY, with lots of over weight.
This will have a long attack time , and a long "ripple".
It might reproduce 100's of degrees out of phase , and the sines may looks a
little like crossover distortion or triangular signals , and needs a couple of
hours to die out :-)
( Still 40 Hz but no longer sine ward)
That's easy to measure and to understand.
Do you agree ?
Have you ever heard a speaker system , that plays lost of bass , and the floor
keeps vibrating all the time during a certain tune ?
Then another speaker , playing the same tune , but with much more detailed and
precise bass , makes the floor vibrate in countless small series of
vibrations..
That's what I call fast bass.
One can experience a similar situation , when comparing two different
amplifiers on the same speaker.
The one that runs out of steam , may still play deep bass , but it is now a
little "loose" , "without clear articulations" , it "sums and hums" and the
floor is constantly vibrating...
That's what I call slow bass ;-)
Imagine a 40 Hz note , in which the negative amplitude is removed.
Then we are left with 40 times a positive going pulse.(Not 20 Hz or 80 Hz )
Or imagine a beginning 40 Hz note , then suddenly the signal stops or goes
negative , with a certain pulse.
Such is the behavior of natural music. - These signals MUST be reproduced by
the bass speaker , whether it likes it or not.
(And whether the crossovers likes it or not )
Such signals are not reproduced by the midrange , though that is often the
theorie.
We need to think in other paths , that the usual sinetones and La'Placa
theorems. The speakers knows nothing of these.
This way "fast and slow bass" , certainly makes sense to me. Even in the
scientific and mathematic meaning.
(I never refer it to the sine cycle , though )
Good bass speakers stops and starts fast..
And has low harmonics attached to the reproduction.
Do you know , what I mean , Doug ?
When you come to the summer meeting , I shall play fast bass for you.
Both on my Fender bass (as fast as I can ) , and my stereo ;-)
Now , Doug , I would like you to explain slow treble....;-)
- - Kurt
=========================================================================
From: Thomas Dunker <dunker@invalid.ed.ntnu.no>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 12:38:23 +0100 (CET)
Source: Sound Digest Archive v02.n421
On Thu, 27 Jan 2000, Douglas Purl wrote:
> Let us assume that you are right. What speaker parameters does one
> measure to determine quickness? What engineering efforts can one
> undertake either to design this quality into a speaker or enhance it? Or
> are there some physical phenomena entailed that are immeasurable?
I'd suggest that we start by looking at transient response and power
compression or other compression effects along with the couple dozen or so
level-dependent types of nonlinear distortion. Now I mean transient
response in terms of damping/ringing or absence thereof, perhaps transient
distortion is a better term.
Some clever academics often argue that according to Fourier, the only
important criterium for good transient response is wide bandwidth/hf
extension, and seek to base evaluations of transient response on steady
state frequency response measurements. Which, sadly, DO NOT describe the
dynamic behavior of a speaker under transient conditions.
So we'd want to look phase, damping and dynamic nonlinearities and
compression effects. Now try to argue in favor of the low efficiency
vented bass box..."optimally tuned" as it may be, but with nasty transient
behavior.
My speaker wiz friend, the veteran speaker designer Ragnar Lian has a
sort of proverb that he likes to repeat every time he gets a chance:
Sound can fundamentally be described in terms of time and air pressure.
So what we are looking at in terms of "fast" is pressure change as a
function of time. In a paper dealing with "time distortion in
loudspeakers", Lian emphasizes another aspect of bas quality: The
speaker's ability to hold a positive air pressure for the prescribed time
interval. It literally has to be "slow enough" in order to pull that off.
In vented bass enclosures, there is typically a rapid pressure increase
(as response to a unit step function) immediately followed by a similarly
rapid pressure drop, in turn followed by a succession of damped
oscillations. It is possible to compare speakers in terms of the length of
the time interval in which the speaker produces a net positive pressure
when responding to a step function. It may be argued that a CD step or
pulse is unrealistically demanding (impossible) to reproduce, but the
time/pressure aspect is interesting regardless of this, and can be
similarly studied if the step fuction is replaced with a sin^2-pulse or
similar aperiodic pulse.
It would also be interesting to study transient response in this manner
at different amplitudes/power levels to observe deterioration of transient
response with increasing signal amplitudes. I have a few papers that
show clearly how transient response is level dependent in real world
speakers, due to momentary changes in the Q/damping characteristics of the
system under conditions of heavy modulation. That itself is a transient
response/"speed" problem.
Next, how are phase relationships and other "linear distortion" problems
affected by amplitude changes?
Sure, this is a complex subject, but it's not that mysterious either.
Cut right to the bone, study time/pressure under actual transient
conditions, and PLEASE don't give us any more of that "it's all a matter
of frequency response", because there's infinitely more to it. Otherwise
one would have to prove that two speakers with the same frequency response
would have to be equally "fast" under all transient conditions and sound
the same in terms of subjective "speed". In doing so, one would
erroneously be trying to prove that all kinds of dynamic and distortion
problems in speakers could be analyzed by looking at the frequency
response. That'll be the day!
Tom
- ------------------------------------------------------------------------
_/\_ Thomas Dunker \ The Horn Speaker Home Page:
/ \ P.O.Box 2811 \ http://invalid.ed.ntnu.no/~dunker/horns.html
| | 7002 Trondheim \
| | NORWAY \--\ "Those with head above water
\____/ dunker@omegav.ntnu.no \ see only the tip of the iceberg"
|||| phone: (+47)73911068 \ (Gene Dalby)
- ------------------------------------------------------------------------
=========================================================================
From: "jhlane" <jhlane@email.msn.com>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 07:14:01 -0700
Source: Sound Digest Archive v02.n422
From: Douglas Purl <dcp@selway.umt.edu>
Subject: Re: [JN] Bass horn drivers?
> How do you know what I hear?
Or, more importantly, what you enjoy as the sound of lifelike
music reproduction? I guess you'll just have to tell us.
Sometime.
> I much enjoyed Jon's rhetorical fulsomeness, and I am pleased
that I
> inspired him to such loquaciousness.
Actually, it was the sound, but whose counting?
> Moreover, I calculate that getting
> this off his chest will lengthen his life by 4.2 years and
decrease his
> need for the normal male's healthy 3.5 hours of nightly penile
erections
> by 27%. Indeed, he ought to send me a respectable honorarium.
(On the
> other hand, he may resent having deprived himself. . . .)
Numerically true to form, Doug. You are becoming so
predictable - should I provide documentation by mail or wire? We
do so want to ensure accuracy in our...A/B testing.
> But, I must report that I have received eight private responses
on this
> topic in addition to those posted to the list. Let me point
the question
> so that you all can help the original questioner.
...earning your glee, no doubt. Music secondary?
> Most of you are stating what he should aim for sonically. But
that does
> not help him discover the means of achieving those results.
What? buying a horn woofer doesn't qualify?
> It's means he seeks, not ends.
It means he has every opportunity of finding.
> Every time we have gotten down to nuts and bolts on bass
> horns, some ingenious and effective designs have been
described. Is it
> Bert who built the impressive floor horns? Not only an elegant
> application of engineering, but a practical and smart solution.
Ingenious, effective, impressive, elegant, practical, and smart.
Ah, the subjective opinion. But one failing scientific proof,
Doug.
Jon Lane
=========================================================================
From: "jhlane" <jhlane@email.msn.com>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 07:15:31 -0700
Source: Sound Digest Archive v02.n422
- ----- Original Message -----
From: <StepHydro@aol.com>
To: <sound@deliverator.io.com>
Sent: Friday, January 28, 2000 4:33 AM
Subject: Re: [JN] Bass horn drivers?
> Since it seems that most human perceptive systems can
understand and perceive
> "fast" bass, you should be working your little hiney off trying
to help your
> models catch up with reality.
And actually DO audio???
=========================================================================
From: "jhlane" <jhlane@email.msn.com>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 07:37:25 -0700
Source: Sound Digest Archive v02.n422
"As fast as I can." <Laughing very hard, now>
Ah Kurt, this is SO beautiful! And to think JoeNet costs
nothing...more! more!
Sincerest thanks, friend.
Jon Lane
- ----- Original Message -----
From: Kurt Steffensen <kurt-steffensen@teliamail.dk>
To: Douglas Purl <dcp@selway.umt.edu>
Cc: <sound@deliverator.io.com>
Sent: Friday, January 28, 2000 2:06 AM
Subject: Re: [JN] Bass horn drivers?
> Imagine a 40 Hz note , in which the negative amplitude is
removed.
> Then we are left with 40 times a positive going pulse.(Not 20
Hz or 80 Hz )
> Or imagine a beginning 40 Hz note , then suddenly the signal
stops or goes
> negative , with a certain pulse.
>
> Such is the behavior of natural music. - These signals MUST be
reproduced by
> the bass speaker , whether it likes it or not.
> (And whether the crossovers likes it or not )
> Such signals are not reproduced by the midrange , though that
is often the
> theorie.
> We need to think in other paths , that the usual sinetones and
La'Placa
> theorems. The speakers knows nothing of these.
>
> This way "fast and slow bass" , certainly makes sense to me.
Even in the
> scientific and mathematic meaning.
> (I never refer it to the sine cycle , though )
>
> Good bass speakers stops and starts fast..
> And has low harmonics attached to the reproduction.
>
> Do you know , what I mean , Doug ?
>
> When you come to the summer meeting , I shall play fast bass
for you.
> Both on my Fender bass (as fast as I can ) , and my stereo ;-)
>
> Now , Doug , I would like you to explain slow treble....;-)
>
> - Kurt
=========================================================================
From: David Dlugos <planet10@pinc.com>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 11:24:35 -0800
Source: Sound Digest Archive v02.n422
>A follow-up plea for more information on bass drivers for horns.
Don't forget Nick McKinney's Lambda Drivers. He can build some of his VERY
low distortion bass drivers with parameters ideally suited to your needs.
http://www.lambdacoustics.com/
__________________
Transmission Line Speaker Page
http://www.t-linespeakers.org/
=========================================================================
From: James Melhuish <james@melhuish.org>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 12:43:45 -0500
Source: Sound Digest Archive v02.n422
Hi All,
Thanks for the responses!
Thanks to Doug who started a nice discussion on fast bass, measurements,
and subjectivity.
Thanks Jon, for your elegant tirade against commercial subwoofers, and
the wonderful quote on Monet and Klee.
Big thanks Craig, Bill, Grant, and Bert, who actually answered my
question!
I have heard generally of problems some people have experienced trying
to mate front horn Lowthers to separate bass speakers. A "normal"
subwoofer won't cut it, that was the reason for my original post.
A follow-up plea for more information on bass drivers for horns. I
checked out the EV12L, which seems to have the right "specs" for a horn
driver, and of course Bruce Edgar recommends it. But a question, could
I get good results with only one of these drivers per side? Why use
two, three, or more drivers per horn? Does it make much of a
difference?
Are there any drivers suitable for bass horns that are smaller in
diameter? The Lowther driver is 8 inches and simply for space packaging
reasons I might like a smaller bass driver than the 12 inch
ElectroVoice. 8 inches would be fine, maybe 10 inches. But I could
make 12 inches fit if I needed it.
Bert,
I was hoping that with the efficiency of this system, I could use just
one amplifier, my little triode-wired SV 83. I am looking into building
or purchasing a 2A3 or 45 amp at some point. Do I really need an amp
with a high damping factor for the horns? That would mean biamping as I
think it is hard to get high damping factors into SE triode amps. Now
we are talking electronic crossovers and so on!
Thanks again to everybody!
James
- --
James Melhuish & Jennifer Shearman
82 Harvard Street, Newtonville MA 02460, USA
tel: 617 965 8859
fax: 617 964 3249
mailto:jjms@melhuish.org
http://melhuish.org
=========================================================================
From: Roscoe Primrose <roscoe@aiko.com>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 14:37:58 -0500
Source: Sound Digest Archive v02.n422
James Melhuish wrote:
Snip...
>
> A follow-up plea for more information on bass drivers for horns. I
> checked out the EV12L, which seems to have the right "specs" for a horn
> driver, and of course Bruce Edgar recommends it. But a question, could
> I get good results with only one of these drivers per side? Why use
> two, three, or more drivers per horn? Does it make much of a
> difference?
>
> Are there any drivers suitable for bass horns that are smaller in
> diameter? The Lowther driver is 8 inches and simply for space packaging
> reasons I might like a smaller bass driver than the 12 inch
> ElectroVoice. 8 inches would be fine, maybe 10 inches. But I could
> make 12 inches fit if I needed it.
You might also check the specs on the EVM-10M... See
http://www.electrovoice.com/assets/prod_pdf/evm10m-eds.pdf for specs...
Peace
- --
Roscoe Primrose -- mailto:roscoe@aiko.com --
http://www.aiko.com/roscoe
"Once in a while you get shown the light
In the strangest of places if you look at it right." Robert Hunter
"640K ought to be enough for anybody" , Bill Gates, 1981
=========================================================================
From: DocGaw@cs.com
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 15:03:40 EST
Source: Sound Digest Archive v02.n422
Image communication at 800-552-1639 is having a sale on EVM-12L drivers for
$100 each. They are great bass horn drivers with qes of 0.2 and Fs of 55 Hz
Bill Gaw
=========================================================================
From: "Bert Doppenberg" <LCH@lowther.nl>
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 19:15:08 -0000
Source: Sound Digest Archive v02.n422
Hi James,
>A follow-up plea for more information on bass drivers for horns. I
>checked out the EV12L, which seems to have the right "specs" for a horn
>driver, and of course Bruce Edgar recommends it. But a question, could
>I get good results with only one of these drivers per side? Why use
>two, three, or more drivers per horn? Does it make much of a
>difference?
The only advantage is that the horn will be shorter with a larger starting surface...the
acoustical power from one driver in a horn is more then enough!
>Are there any drivers suitable for bass horns that are smaller in
>diameter? The Lowther driver is 8 inches and simply for space packaging
>reasons I might like a smaller bass driver than the 12 inch
>ElectroVoice. 8 inches would be fine, maybe 10 inches. But I could
>make 12 inches fit if I needed it.
Yes, there are but mostly limited due the small top-top excursion ( - less acoustical
power). The choice depends on the level you want to play, the size (volume) of the
listening room, the high crossover frequency, the size of the horn, etc.
>I was hoping that with the efficiency of this system, I could use just
>one amplifier, my little triode-wired SV 83. I am looking into building
>or purchasing a 2A3 or 45 amp at some point. Do I really need an amp
>with a high damping factor for the horns? That would mean biamping as I
>think it is hard to get high damping factors into SE triode amps. Now
>we are talking electronic crossovers and so on!
It depends on what you are looking for. The rather large surface of a horn needs control
if you want to have true accurate, short (fast) and "kicking" bass. I experimented with
several amps and found out that using an amp with a higher dampening factor gives a better
detailed, more dynamic, more ease and kicking bass coming from my horns or other large
coned systems. The only "bottleneck" is that the sound often is very dry, not musical,
clean, etc....
BUT, the solution for this is to use the output of the tube amp (which bass sound
qualities are much more reveiling) and connect this (lowering the gain with resistors) to
the input of this amp. This way you'll have both advantages, nice sounding bass WITH
control!
Crossing over isn't a big problem either, I am only using 1 resistor of 220k and one
capacitor of 68nF for the filter!
The acoustical crossover of the sub horn deals with the rest of the higher spectrum and
the Lowthers are playing fullrange (also acoustical filtered - my front horn doesn't go
deeper in frequency then 150Hz).
Bert,
- ------
E-mail:
BD-Design : Sales@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Oris 150 : http://www.lowther.nl/wwwpages/opinions.html
Phone/Fax : +31 341 254500 Mobile: +31 6 51242990
=========================================================================
From: "Sellek, Grant (TSA)" <Grant.Sellek@transport.sa.gov.au>
Subject: RE: [JN] Bass horn drivers?
Date: Sat, 29 Jan 2000 00:42:05 +1030
Source: Sound Digest Archive v02.n422
OK, you want to build bass horns. If I read your original message correctly
(enclosed below), James, you didn't want a dissertation on bass itself so
much as a few clear recommendations on *drive units* for use in bass horns?
If I'm right, this is my take. Get a low-Q driver. Look for a big motor and
a light cone. This will give you a driver with the rising frequency response
(on a baffle) that you require for a horn. For example, my 15" JBL 2220J
fits the bill with a Qes of 0.18. The driver's resonant fundamental
frequency is not so important because a horn (a proper horn) can effectively
control the driver below Fs.
But I see from your post that you only need 250Hz. This widens your choice
somewhat. As a rule your bass horn's upper frequency rolloff will be
F=2Fs/Qes where Fs is driver resonance. So you could pick a driver of
Fs=50Hz and Qes=0.4 and get your bandwidth (just).
Pick your driver before your horn, so you can correctly design the horn
throat and get correct flare.
Here are some candidate 12" drivers with suitable parameters ; EVM12L, FORCE
12, JBL 2202, JBL E-120, Eminence 12699.
15" drivers ; JBL 2220, Altec 515-8G and 8GHP, Gauss 3540, 3580, 3581, 4562,
4581 and 4582, Polydax PR38LXT250, RCF Lab L15/554, TOA HLS 3806-8 and
3812-8, Beyma 15G-400, 15GF-200 and 15GI-100, Eminence 15588.
Remember that some of these drivers won't go much over 250Hz; if you wanted
350Hz most of them would not be on the list.
Am I helping?
Grant
> -----Original Message-----
> From: James Melhuish [mailto:james@melhuish.org]
> Sent: Friday, 28 January 2000 8:17 am
> To: JoeNet A
> Subject: [JN] Bass horn drivers?
> Importance: Low
>
>
> Hi All,
>
> I am considering building a separate bass horn for approx 50 Hz to 250
> Hz to mate with Lowther DX3s in small front horns. I have reasonable
> knowledge of horn design, but would like some advice as to what are
> considered some of the good bass horn drivers. I would prefer one
> driver per horn, and something "quick" to match the Lowther's
> responsiveness. Price isn't much of an issue, unless we talk silly
> money (I'd like to keep the bass driver costs under 3 or 4 hundred
> dollars for the pair, preferably less). Any ideas? Thanks.
>
> James
>
> --
> James Melhuish & Jennifer Shearman
> 82 Harvard Street, Newtonville MA 02460, USA
> tel: 617 965 8859
> fax: 617 964 3249
> mailto:jjms@melhuish.org
> http://melhuish.org
>
>
=========================================================================
From: StepHydro@aol.com
Subject: Re: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 18:21:43 EST
Source: Sound Digest Archive v02.n423
In a message dated 01/28/2000 12:<BR50:<BR32 PM
Eastern Standard, james@melhuish.org writes:>
> A follow-up plea for more information on bass drivers for horns. I
> checked out the EV12L, which seems to have the right "specs" for a horn
> driver, and of course Bruce Edgar recommends it.
I looked at it and thought it had far too high an Fs for a basshorn. What am
I missing?
> That would mean biamping as I
> think it is hard to get high damping factors into SE triode amps. Now
> we are talking electronic crossovers and so on!
James,
Your amp has all the "electronics" you need for xovers. Why not just install
filters at the inputs. You could have two pairs of input jacks and run them
FR or LP/HP, depending on which jacks you choose.
Cheers/Carron
=========================================================================
From: Greg Berchin <76145.2455@compuserve.com>
Subject: [JN] Bass horn drivers?
Date: Fri, 28 Jan 2000 23:55:08 -0500
Source: Sound Digest Archive v02.n424
My first post. Hope I'm sending this to the right place; embarrassed
otherwise.
There seems to be need for a simple tutorial on drivers for horns. I
recommend "Low Frequency Horn Design Using Thiele/Small Driver Parameters",
by D.B. Keele, Jr.; 57th Convention of the Audio Engineering Society, May
10-13, 1977.
A few points from that paper:
"The driver related corner frequencies which indicate the bounds of
resistance controlled operation can be shown as:
fHS = (fS)/(QTS) [19]
and
fLS = (QTS)(fS) [20]
These bounds roughly indicate the range over which a driver will be
suitable for use as a horn driver ...
It is instructive to form the ratio of these two expressions, ie
(fHS)/(fLS) = 1/(QTS^2)
which indicates that a low value of QTS (high motor strength, large
magnets, etc.) is desirable for loudspeakers used as horn drivers if the
widest operating bandwidth is desired."
Also (me writing again now, not Don Keele), the paper shows a derivation of
the frequency above which the response starts to roll-off because of the
moving mass of the driver:
fHM = 2(fS)/(QTS) [23]
So, to summarize, from equations [19] and [23] it can be seen that a HIGH
value of fS, the driver free-air resonance, is desirable for high frequency
extension of the horn. And, from all three equations it can be seen that a
LOW value of QTS is desirable, both for extended high frequency operation
AND for extended low frequency operation. The greater the bandwidth that
the horn must cover, the higher fS must be and the lower QTS must be.
In other words, the high mass, low fS drivers popular for conventional
enclosures are NOT good candidates for horn loading.
Some other interesting equations from that paper:
optimal throat area (optimized for efficiency):
ST = 2(PI)(fS)(QTS)(VAS)/c (c = speed of sound)
back cavity volume:
VB = (VAS)/{(fC)/[(fS)(QTS)] - 1}
Someone mentioned the EVM-12L as a good horn candidate. Some other good
candidates are the DL12X (12"), the EVM-10M (10"), and the DL10X (10").
The last two are good for midrange applications, each offering fHM values
near 800 Hz. Both of the 12" drivers have fHM in the neighborhood of 470
Hz.
Greg Berchin
Lead Signal Processing Engineer
Telex Pro Audio (aka Electro-Voice)
=========================================================================
From: Nicholas McKinney <nick@lambdacoustics.com>
Subject: Re: [JN] Bass horn drivers?
Date: Sat, 29 Jan 2000 15:46:06 -0500
Source: Sound Digest Archive v02.n424
At 11:55 PM 1/28/00 -0500, Greg Berchin wrote:
>So, to summarize, from equations [19] and [23] it can be seen that a HIGH
>value of fS, the driver free-air resonance, is desirable for high frequency
>extension of the horn. And, from all three equations it can be seen that a
>LOW value of QTS is desirable, both for extended high frequency operation
>AND for extended low frequency operation. The greater the bandwidth that
>the horn must cover, the higher fS must be and the lower QTS must be.
Hi Greg, do you know if there has been any work done on this that uses the real
driver parameters like Bl, Re, Sd, Mms instead of the derived like Fs and Qts?
I ask this because increasing the Fs by way of lowering compliance very rarely
helps anything when voltage simulations are run instead of the T/S "normalized"
style. The mentioned equations seem to not take into account the stiffness of
the suspension. It would seem the cone area and mass vs the motor strength is
the issue, and that is found with only the 4 parameters I posted (Bl, Re, Sd,
Mms)
Best regards
Nick
Nicholas McKinney
Lambda Acoustics Inc.
www.lambdacoustics.com
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: Re: [JN] Bass horn drivers?
Date: Sat, 29 Jan 2000 17:52:25 -0500
Source: Sound Digest Archive v02.n425
Nicholas McKinney wrote:
> At 11:55 PM 1/28/00 -0500, Greg Berchin wrote:
>
> >So, to summarize, from equations [19] and [23] it can be seen that a HIGH
> >value of fS, the driver free-air resonance, is desirable for high frequency
> >extension of the horn. And, from all three equations it can be seen that a
> >LOW value of QTS is desirable, both for extended high frequency operation
> >AND for extended low frequency operation. The greater the bandwidth that
> >the horn must cover, the higher fS must be and the lower QTS must be.
>
> Hi Greg, do you know if there has been any work done on this that uses the real
> driver parameters like Bl, Re, Sd, Mms instead of the derived like Fs and Qts?
> I ask this because increasing the Fs by way of lowering compliance very rarely
> helps anything when voltage simulations are run instead of the T/S "normalized"
> style. The mentioned equations seem to not take into account the stiffness of
> the suspension. It would seem the cone area and mass vs the motor strength is
> the issue, and that is found with only the 4 parameters I posted (Bl, Re, Sd,
> Mms)
>
> Best regards
>
> Nick
>
> Nicholas McKinney
> Lambda Acoustics Inc.
> www.lambdacoustics.com
Hi Nick, all
I'm back (and you didn't know I was gone)
Nick I don't know of anything "modern" on horns that deals in real world
parameters (like Mms, BL, Re etc) and not derived ones (as in M. Leach's paper)
however the way the properties effect what happens are easier to visualize with
real physical properties so it would make sense to do so..
Its like this, near as I can tell.
Picture a parallel R, L and C, a tank circuit. This circuit has a "Q" and this "Q"
is set by the magnitude of the reactance's (the size of the L and C) compared to
the size of the R (the higher the R, the higher the Q).
If this were a speaker, the higher the Q would mean narrower bandwidth.
In an efficient horn, you (usually) have a driver in a sealed box who's volume and
suspension puts the Fb at about 1/3 up from the desired low cutoff and high
cutoff. (in other words a bit below the middle of operation).
This gives you a big impedance peak (produced by the speakers "tank circuit").
Then the driver is coupled to a horn suitable for the low frequency cutoff and this
applies damping to the curve spreading out the bandwidth (-3 dB points) as it
lowers the Q. The damping is increased to attain the desired bandwidth, often it
is necessary to make the radiator area considerably larger than the throat area to
get sufficient damping or BW.
At the high end of the response, one reaches the point where the impedance is
falling and that dictates the high cutoff....except that if one attaches an
appropriate air cavity between the horn and radiator, one can extend the hf
response significantly in exchange for making the final roll off slope 18 dB /oct
instead of 12 (the same way a vented box extends the cutoff down in exchange for a
steeper final roll off)
Assuming one is between the compliance and mass controlled corners, the drivers
unloaded impedance would be much higher than Rdc, when loaded by the horn, this
lowers it, in the case of a horn/driver which is %50 efficient, the impedance is
resistive at 2X Rdc (half the power into electrical/mechanical losses, half into
sound).
In this case also, the drivers reactance's are completely dominated by the acoustic
load and you have one of those rare situations where the acoustic phase is Zero
degrees and the driver can actually reproduce a complex waveshape.
Seems to me, those drivers you are making probably would be good for this kind of
thing as the radiator has to operate as a velocity source, series L is a killer of
hf response and most other big speakers have a good bit "O" L.
A perfect horn would have a flat impedance through out the entire bandwidth (some
day maybe I'll find one) but usually horns have some minor or not so minor or even
major "up and down stuff" in there responses.
Often, at least with efficient horns, this can be significantly reduced by driving
the horn from an equal impedance rather than a voltage source. In this case as the
ripples in the impedance have a smaller effect on how much current is drawn and so
how much sound is produced. A damping factor of 1 is desired so to speak.
Some generalities (assuming a decent horn size for frequency of interest)
Take any driver and horn and measure out what it does.
Increasing the motor size alone (BL / sqr rt of Rdc) mainly increases efficiency
but also BW to a lesser degree.
Increasing the compression ratio, increases the BW ( increases the acoustic load
on driver), lowering the resistive impedance, lowering the efficiency. (makes the
Rdc larger with respect to R load).
Increasing the compression ratio, keeping the BW and efficiency the same requires a
heavier driver, smaller back volume, smaller front volume.
Increasing compression ratio, increases (rapidly) acoustic power produced at Xmax
Increasing compression ratio concentrates increasing acoustic pressure in smaller
areas which increases air produced distortion.
For a given sound level, raising horn flare cutoff frequency reduces mid/high
distortion produced by air non linearity.
Making the horn have a lower frequency cutoff makes the throat area increase and
often increases total efficiency.
Making both cutoff's higher in frequency horn with the same driver/throat area's
requires a driver that is lighter but has smaller motor strength. (rapidly requires
unobtainium).
Making both cutoffs lower requires a much heavier driver and somewhat stronger
motor
Part of what makes horns so much fun is that one can take a driver and horn that do
not belong together and while no increase in efficiency is gained, there is
apparent gain due to controlling directivity.
Nick I saw and saved the post on the Lowther driver numbers and now that I have a
"big meeting" I've been sweating out of the way I will run those through the
'puter, I know there were a couple people that were interested.. One thing I did
see was they run out of excursion but quick and the back loaded horn helped a
bunch.
Makes me think of your "low series L" woofers umm.
Tom
=========================================================================
From: Greg Berchin <76145.2455@compuserve.com>
Subject: [JN] Bass horn drivers?
Date: Sun, 30 Jan 2000 10:06:07 -0500
Source: Sound Digest Archive v02.n425
Nicholas McKinney wrote:
>do you know if there has been any work done on this that uses the real
driver parameters like Bl, Re, Sd, Mms instead of the derived like Fs and
Qts?<
That same Keele paper does a fair amount of that. For example, from the
paper:
ST = [(rho0)(c)(RE)(SD^2)]/[(B^2)(l^2)] [eq 1]
fHS = [(B^2)(l^2)]/[(2PI)(RE)(MMS)] [eq 2]
fLS = (RE)/[(2PI)(B^2)(l^2)(CMS)] [eq 3]
fLC = (RE)/[(4PI)(B^2)(l^2)(CMS)] [eq 4]
fHM = [(B^2)(l^2)]/[(PI)(RE)(MMD)] [eq 7]
VB = [(rho0)(c^2)(RE)(SD^2)]/[(2PI)(fC)(B^2)(l^2)] [eq 13]
(Apologies if there are any typographical errors in the placement of the
parentheses and brackets, it would probably be best to contact AES and get
a copy of the paper.)
I must admit at this point that loudspeaker design is not really my gig;
signal processing is. But I do dabble in speaker design as a hobby, and
working for a company that manufactures loudspeakers really makes that a
lot easier!
Greg Berchin
Lead Signal Processing Engineer
Telex Pro Audio
=========================================================================
From: Craig Preston <cpreston@mediaone.net>
Subject: Re: [JN] Bass horn drivers?
Date: Sun, 30 Jan 2000 16:46:00 -0500
Source: Sound Digest Archive v02.n426
Hi, Joes,
The Keele, Leach, and Small papers on using low-frequency drivers in
horns can be ordered on the AES Web site
(http://www.aes.org/publications/preprints/search.html). I looked up the
preprint numbers, which might make ordering easier:
D.B. Keele, Jr., "Low-Frequency Horn Design Using Thiele/Small Driver
Parameters": Preprint 1250
Richard H. Small, "Suitability of Low-Frequency Drivers for Horn-Loaded
Loudspeaker Systems": Preprint 1251
W. Marshall Leach, Jr., "On the Specification of Moving-Coil Drivers for
Low-Frequency Horn-Loaded Loudspeakers": Preprint 1405. Also reprinted
in the AES anthology: "Loudspeakers Volume 2."
There must be something terribly wrong with me since I'm looking up
stuff on the AES Web site instead of attending a Super Bowl party. Oh
well...
Craig Preston
Greg Berchin wrote:
>
>
> Nicholas McKinney wrote:
>
> >do you know if there has been any work done on this that uses the real
> driver parameters like Bl, Re, Sd, Mms instead of the derived like Fs and
> Qts?<
>
> That same Keele paper does a fair amount of that. For example, from the
> paper:
>
> ST = [(rho0)(c)(RE)(SD^2)]/[(B^2)(l^2)] [eq 1]
>
> fHS = [(B^2)(l^2)]/[(2PI)(RE)(MMS)] [eq 2]
>
> fLS = (RE)/[(2PI)(B^2)(l^2)(CMS)] [eq 3]
>
> fLC = (RE)/[(4PI)(B^2)(l^2)(CMS)] [eq 4]
>
> fHM = [(B^2)(l^2)]/[(PI)(RE)(MMD)] [eq 7]
>
> VB = [(rho0)(c^2)(RE)(SD^2)]/[(2PI)(fC)(B^2)(l^2)] [eq 13]
>
> (Apologies if there are any typographical errors in the placement of the
> parentheses and brackets, it would probably be best to contact AES and get
> a copy of the paper.)
>
> I must admit at this point that loudspeaker design is not really my gig;
> signal processing is. But I do dabble in speaker design as a hobby, and
> working for a company that manufactures loudspeakers really makes that a
> lot easier!
>
> Greg Berchin
> Lead Signal Processing Engineer
> Telex Pro Audio
=========================================================================
From: Greg Berchin <76145.2455@compuserve.com>
Subject: [JN] Bass horn drivers? & Keele's equations
Date: Sat, 29 Jan 2000 09:48:03 -0500
Source: Sound Digest Archive v02.n424
Grant Sellek wrote:
>The JBL paper gives different equations (while quoting Keele as the
source)
>to those Greg quoted. For example,
>
>From Greg:
> fHS = (fS)/(QTS) [19]
>and
> fLS = (QTS)(fS) [20]
>
>From JBL:
> fHM = 2(fS)/(QTS)
>and
> fLC = (QTS)(fS)/2
Actually, JBL's are the same; it's just a matter of "creeping subscripts".
Further down in my post I show equation [23]:
>the paper shows a derivation of
>the frequency above which the response starts to roll-off because of the
>moving mass of the driver:
> fHM = 2(fS)/(QTS) [23]
which is the same as the JBL equation. I did not include the equation for
fLC from Keele's paper in my post.
Maybe the best way to clarify the difference between the subscripts is to
quote Don Keele's paper again, this time from the glossary:
"fHM upper rolloff corner (-3 dB) frequency due to the effects
of driver moving mass acting alone"
"fHS upper frequency bound fo the driver's resistance
controlled region when operated in free air"
"fLC lower rolloff corner (-3 dB) frequency due to driver
suspension compliance alone when driving infinite tube"
"fLS lower frequency bound of the driver's resistance
controlled region when operated in free air"
So, fLS and fHS define the approximate band over which the driver will be
resistance controlled in the horn -- essentially the region over which the
horn will act like a "horn".
And fHM defines the frequency at which the response is -3 dB, and above
which the response of the driver begins to roll-off due to the mass of its
own cone. From equations [19] and [23], this is seen to occur one octave
above fHS.
And fLC defines the frequency at which the response is -3 dB, and below
which the response of the driver begins to roll-off due to suspension
compliance in an infinite tube. From the equations, this is seen to occur
one octave below fLS.
>JBL makes no mention of fHS and fLS, but claims that "the region of flat
>power response will be bounded by fHM and fLC",
True, and largely a matter of interpretation. The resistance controlled
region spans fLS to fHS, and one octave above and below these frequencies
the power response is -3 dB. Using conventional notation, the power
response is "flat +0/-3 dB between fLC and fHM".
>JBL go on to say (still quoting Keele) that above fHM there are two
>further frequencies fHVC and fHC at which the rolloff slopes increase
>to 12dB and 18dB respectively.
Also true, but in the portion of Keele's paper that I did not quote.
>But I think the general guide of low-Q, big magnet and
>stiff cone will lead you to a good driver.
That was really the point that I wanted to make.
Thanks for your response,
Greg Berchin
=========================================================================
From: "Sellek, Grant (TSA)" <Grant.Sellek@transport.sa.gov.au>
Subject: RE: [JN] Bass horn drivers? & Keele's equations
Date: Sat, 29 Jan 2000 17:28:43 +1030
Source: Sound Digest Archive v02.n424
This is quite coincidental (thanks Greg), because I was just yesterday
trying to apply Keele's equations to my 8" low-mid driver the JBL M209.
Without much success. I was using Keele's equations as quoted in JBL's
publication "JBLs New Maximum Output Midrange-Low Frequency Transducers" at
http://www.jblpro.com/pub/technote/tn_v1n24.pdf
The JBL paper gives different equations (while quoting Keele as the source)
to those Greg quoted. For example,
From Greg:
fHS = (fS)/(QTS) [19]
and
fLS = (QTS)(fS) [20]
From JBL:
fHM = 2(fS)/(QTS)
and
fLC = (QTS)(fS)/2
JBL makes no mention of fHS and fLS, but claims that "the region of flat
power response will be bounded by fHM and fLC", and show an indcative graph
of flat response between those limits and 6dB slopes beyond each bound. JBL
go on to say (still quoting Keele) that above fHM there are two further
frequencies fHVC and fHC at which the rolloff slopes increase to 12dB and
18dB respectively.
When I plugged my JBL M209 parameters into these 4 formulae I got fLC=18Hz,
fHM=467Hz, fHVC=5800Hz and fHC=315Hz respectively. Well that can't be right.
Using Greg's version of Keele on my M209's I get fLS=35Hz, fHS=233Hz, and
fHM=467Hz. that probably isn't right either, because Tom Danley once
modelled a flat response to 1000+Hz for my M209 driver using Marshall
Leach's paper. Also JBL use this driver in a low-mid horn and publish a flat
measured response from 220-1200Hz.
You can also see from the JBL-quoted Keele formulae that the frequency
ratios of the region of flat power response is 4/(QTS^2), which is 4 times
the operating bandwidth that Greg quoted.
My only usable conclusions from all this: (1) I need a personal copy of
Keele's paper, and (2) Amateurs like me need to take care in using
theoretical papers. But I think the general guide of low-Q, big magnet and
stiff cone will lead you to a good driver.
Grant
- -----Original Message-----
From: Greg Berchin [mailto:76145.2455@compuserve.com]
Sent: Saturday, 29 January 2000 3:25 PM
To: JoeNet sound digest
Subject: [JN] Bass horn drivers?
My first post. Hope I'm sending this to the right place; embarrassed
otherwise.
There seems to be need for a simple tutorial on drivers for horns. I
recommend "Low Frequency Horn Design Using Thiele/Small Driver Parameters",
by D.B. Keele, Jr.; 57th Convention of the Audio Engineering Society, May
10-13, 1977.
A few points from that paper:
"The driver related corner frequencies which indicate the bounds of
resistance controlled operation can be shown as:
fHS = (fS)/(QTS) [19]
and
fLS = (QTS)(fS) [20]
These bounds roughly indicate the range over which a driver will be
suitable for use as a horn driver ...
It is instructive to form the ratio of these two expressions, ie
(fHS)/(fLS) = 1/(QTS^2)
which indicates that a low value of QTS (high motor strength, large
magnets, etc.) is desirable for loudspeakers used as horn drivers if the
widest operating bandwidth is desired."
Also (me writing again now, not Don Keele), the paper shows a derivation of
the frequency above which the response starts to roll-off because of the
moving mass of the driver:
fHM = 2(fS)/(QTS) [23]
So, to summarize, from equations [19] and [23] it can be seen that a HIGH
value of fS, the driver free-air resonance, is desirable for high frequency
extension of the horn. And, from all three equations it can be seen that a
LOW value of QTS is desirable, both for extended high frequency operation
AND for extended low frequency operation. The greater the bandwidth that
the horn must cover, the higher fS must be and the lower QTS must be.
In other words, the high mass, low fS drivers popular for conventional
enclosures are NOT good candidates for horn loading.
Some other interesting equations from that paper:
optimal throat area (optimized for efficiency):
ST = 2(PI)(fS)(QTS)(VAS)/c (c = speed of sound)
back cavity volume:
VB = (VAS)/{(fC)/[(fS)(QTS)] - 1}
Someone mentioned the EVM-12L as a good horn candidate. Some other good
candidates are the DL12X (12"), the EVM-10M (10"), and the DL10X (10").
The last two are good for midrange applications, each offering fHM values
near 800 Hz. Both of the 12" drivers have fHM in the neighborhood of 470
Hz.
Greg Berchin
Lead Signal Processing Engineer
Telex Pro Audio (aka Electro-Voice)
=========================================================================
From: Douglas Purl <dcp@selway.umt.edu>
Subject: [JN] Bass Horns
Date: Thu, 8 Jul 1999 13:08:22 -0600 (MDT)
Source: Sound Digest Archive v02.n199
In the thread BC alludes to on the loudspeaker list, one individual has
engaged in some correspondence with me after I outlined the problems one
faces if an ideal bass horn large enough to cover the two lowest octaves
were constructed. I don't believe the flare constant can be maintained
sufficiently to avoid the consequences of reactance irregularities if
folds are used, and certainly the mouth area + m + length requirements
make such an undertaking architectural rather than cabinet shop. No
wonder that people opt for a reasonable compromise and scale their
high-pass cutoff upwards.
The question that has arisen is just how low can people get in ordinary
homes with a true horn? I find that though I have impressions of how low
the deepest home horns are designed to go (right or wrong, ca. 80 Hz
unfolded), I cannot recall having read a discussion of what has been
accomplished. I suppose the other issue too is that I can stand being
disabused if in fact folding has been achieved without serious
consequences. After all, as resistance falls and reactance rises at a
given Hz, output does begin to become imaginary.
Doug Purl
=========================================================================
From: "Bert Doppenberg" <LCH@lowther.nl>
Subject: Re: [JN] Bass Horns
Date: Thu, 8 Jul 1999 22:45:40 +0200
Source: Sound Digest Archive v02.n199
Hi Douglas,
>In the thread BC alludes to on the loudspeaker list, one individual has
>engaged in some correspondence with me after I outlined the problems one
>faces if an ideal bass horn large enough to cover the two lowest octaves
>were constructed. I don't believe the flare constant can be maintained
>sufficiently to avoid the consequences of reactance irregularities if
>folds are used, and certainly the mouth area + m + length requirements
>make such an undertaking architectural rather than cabinet shop. No
>wonder that people opt for a reasonable compromise and scale their
>high-pass cutoff upwards.
My horns (some photo's during building at http://home.wxs.nl/~lowther/concreet.htm ) go
down to 23Hz (-6dB)....
>The question that has arisen is just how low can people get in ordinary
>homes with a true horn? I find that though I have impressions of how low
>the deepest home horns are designed to go (right or wrong, ca. 80 Hz
>unfolded), I cannot recall having read a discussion of what has been
>accomplished. I suppose the other issue too is that I can stand being
>disabused if in fact folding has been achieved without serious
>consequences. After all, as resistance falls and reactance rises at a
>given Hz, output does begin to become imaginary.
The response is smooth with a peak of 5 dB at 32Hz.... at my listening position! :-)
Bert,
- ------
E-mail:
Business : BD-Design@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Tel./Fax: (0341) 254500 Mobile: (06) 51242990
=========================================================================
From: Michel Paquette <mpaquette@lasiris.com>
Subject: Re: [JN] Re: Bass Horns
Date: Thu, 01 Jul 1999 11:53:52 -0400
Source: Sound Digest Archive v02.n200
Cool!
Michel
Thomas Danley wrote:
> For the last 8 months I have been working on a new type of horn/ multiple driver
> combination(patent applied) I am very pleased with.
> It has a 20" square mouth, about 20 inches deep,constant directivity, has a 250 HZ low cutoff
> and is + - 2,dB from 250 Hz to 20+ KHz. Sensitivity is 112 dB one watt/ one meter and the
> distortion products are VERY low and it goes very loud.. Also, not a trace of "Horn sound"
> Despite building unconventional drivers for the last bunch of years, this one uses "off the
> shelf" drivers and is the best all around sounding speaker I have heard in my living room to
> date..
> Horns obviously can work very well IF everything is right.
>
> Tom Danley
> Servodrive inc. / Sound Physics Labs
>
> You can see the first of the products using this new horn at servodrive.com
> Look for the UNITY speaker (aimed at pro sound)
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: Re: [JN] Bass Horns
Date: Fri, 9 Jul 1999 04:29:16 -0400
Source: Sound Digest Archive v02.n200
Bert suggested we look:
>>>My horns (some photo's during building at
http://home.wxs.nl/~lowther/concreet.htm ) go
down to 23Hz (-6dB)....<<<
Bert, my first thought was - WOW - what did your wife say when she got back
from visiting her mother?"
Question: how high are they, how long, and how wide overall for the pair?
Very impressed that you did them in stereo. Now when I get that country
house I'll call you...
Allen (VSE)
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: [JN] Bass Horns
Date: Fri, 9 Jul 1999 09:15:22 +0200
Source: Sound Digest Archive v02.n200
- ----------
> De : Douglas Purl <dcp@selway.umt.edu>
> A : sound@deliverator.io.com
> Objet : [JN] Bass Horns
> Date : jeudi 8 juillet 1999 21:08
> The question that has arisen is just how low can people get in ordinary
> homes with a true horn? I find that though I have impressions of how low
> the deepest home horns are designed to go (right or wrong, ca. 80 Hz
> unfolded), I cannot recall having read a discussion of what has been
> accomplished.
Hello,
Roggero'horn are visible on Thomas Dunker's "Horn Page" at
ftp://invalid.ed.unit.no/pub/pictures/audio/roggiero.jpg
The cut-off frequency of the bass horns is 18.5 Hz (-3dB) and their
effiency is 108 dB/1W/1m, .
Roggero is a kind of pioneer for French audiophiles (I have a paper written
by him in "La Revue du Son" in '64.
On Thomas Dunker's website there is 2 other concrete bass horns belonging
to Japanese audiophiles. Both of those horns possess a cut-off frequency at
20Hz (-3dB)
You can see them at:
ftp://invalid.ed.unit.no/pub/pictures/audio/takashir.jpg
(The bass horns are in the ceiling...)
ftp://invalid.ed.unit.no/pub/pictures/audio/kobayash.jpg
Those who possess the Special Issue No 1 of "La Nouvelle Revue du Son" can
see others bass horns having low cut-off frequency...
Both of those horns are in "normal" houses. ;-)
Best regards,
Jean-Michel Le Cleac'h, Paris, France
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: Re: [JN] Re: Bass Horns
Date: Fri, 09 Jul 1999 09:38:29 -0500
Source: Sound Digest Archive v02.n200
Hi all
It is true that there are relationships that must be maintained in order to make a "proper"
bass horn.
Having designed a number of commercially successful bass horns (TPL-1,2 and 3, SDL-4 and 5 and
the Bass Tech 7), I can say there is no way around some of the issues involved.
Also though, getting low bass out of a horn in a room is also not impossible.
Horns are intended to "feel" the radiation resistance of free space, when the formula's are
used which result in optimum efficiency, truly spectacular results are possible, for example
when Garth Brooks, U-2, Michael Jackson and others do tours with BT-7's, they generally only
use 12 to 16 units total, which supply the low frequency's for a 140+ box sound system. This
is possible because 16 units can produce over 3 kw of acoustic power from 28 to 100 HZ with low
distortion and this makes the BT-7 the worlds most powerful subwoofer.
While the math is quite specific about what needs to be done, putting a bass horn in a "small"
room changes everything. When a horn is operating in a room below the lowest room modes (in
the pressure mode without free space radiation resistance), it gradually reverts to a sealed
box system as the frequency is lowered. This is the "pressure mode" of operation like a woofer
in a car..
Remember that a horns efficiency ONLY comes into play when the length is 1/2 wl or greater and
begins to be an advantage (in reducing cone motion for a given output) when the length is 1/4
wl or greater.
Since most horns seem to be designed from "lore" rather than the specific electroacoustic
relationships involved, the rear enclosure volume is typically larger than is proper (putting
fb at a lower than proper frequency) and so as the frequency falls, true horn loading may be
out of the picture but the room gain combined with the sealed box's response can provide
significant low frequency output down to a very low frequency.
Horns are difficult to design partly due to the math and partly due to the difficulty in
modeling the response for a smaller than ideal horn size and that any horn and speaker
combination will produce sound.
These issues have lead to the blind acceptance of "special flares" or geometry's etc. believed
to have mystical or special properties.
Interestingly when one does have the ability to model any particular shape/size horn with any
driver, on see's they are nothing special and that the best results come from the best
relationships for the driver and frequency range..
For the last 8 months I have been working on a new type of horn/ multiple driver combination
(patent applied) I am very pleased with.
It has a 20" square mouth, about 20 inches deep,constant directivity, has a 250 HZ low cutoff
and is + - 2,dB from 250 Hz to 20+ KHz. Sensitivity is 112 dB one watt/ one meter and the
distortion products are VERY low and it goes very loud.. Also, not a trace of "Horn sound"
Despite building unconventional drivers for the last bunch of years, this one uses "off the
shelf" drivers and is the best all around sounding speaker I have heard in my living room to
date..
Horns obviously can work very well IF everything is right.
Tom Danley
Servodrive inc. / Sound Physics Labs
You can see the first of the products using this new horn at servodrive.com
Look for the UNITY speaker (aimed at pro sound)
=========================================================================
From: Ketil Parow <ketil@marketview.no>
Subject: [JN] Re: Bass Horns
Date: Fri, 09 Jul 1999 10:55:06 +0100
Source: Sound Digest Archive v02.n200
Hey everyone. Been off the list for half a year or so.
Kind of reassuring to see that the majority of personalitites I've come to know are still
around.
Kind of weird too, to notice how little the subjects have changed. The part that is really
unnerving, though, is to find that I like it that way. Truly a forum for hard-core DIY
geeks like myself.
The issue at hand:
Doug wrote:
> >In the thread BC alludes to on the loudspeaker list, one individual has
> >engaged in some correspondence with me after I outlined the problems one
> >faces if an ideal bass horn large enough to cover the two lowest octaves
> >were constructed. I don't believe the flare constant can be maintained
> >sufficiently to avoid the consequences of reactance irregularities if
> >folds are used, and certainly the mouth area + m + length requirements
> >make such an undertaking architectural rather than cabinet shop. No
> >wonder that people opt for a reasonable compromise and scale their
> >high-pass cutoff upwards.
Having been through a couple of projects where I mulled over these problems again and
again, here's my $0.02 worth:
Reaching 20Hz with a true horn system, without gross response irregularities ("black
holes") in the bottom octave involves cabinets that are way to large for most domestic
environments. No matter what die-hard horn fans claim. All the exotic systems we've seen
examples of from Japan, from France, from Holland, from wherever, must be considered
extreme and really of no interest to the average home and system owner.
Beranek (and others) has dealt thoroughly with the problems associated with foreshortening
and reduction of mouth size. Specifically, see "Acoustics", chapter 9.
In my latest project, the "All Fun" horn, I set out to test the theories and rules-of-thumb
regarding reduction of horn size. The "All Fun" horn is an attempt to construct and build a
horn of acceptable proportions and good bass reproduction down to ca. 40Hz, within above
mentioned rules. By way of confirmimg these theories, the project was a success.
The thing is, though, that acceptable deviance from "flat curve" and general tolerance in
sound reproduction has shrunk since the 50s, when most of these theories where articulated.
+/- 6db, even +/-12db in the low bass, from the ideal response was considered perfectly
acceptable. I really don't think this holds up nowadays.
For all the perceived qualities of horn systems, flat bass reproduction down to 20Hz is not
their main virtue.
An article that I've written on the "All Fun" project, slated for Speaker Builder 5/99,
deals in more detail with the specifics of these problems. For those of you that read the
article, pay attention to the measured freq. response curves. They sort of tell the whole
story.
Regards,
Ketil Parow
=========================================================================
From: "Bert Doppenberg" <LCH@lowther.nl>
Subject: Re: [JN] Bass Horns
Date: Fri, 9 Jul 1999 12:34:16 +0200
Source: Sound Digest Archive v02.n200
Hi Allen,
>Bert, my first thought was - WOW - what did your wife say when she got back
>from visiting her mother?"
I have the luxury to have a separate listening room, she doesn't mind! ;-)
>Question: how high are they, how long, and how wide overall for the pair?
The horn mouth is 410 x 67 cm (stereo) and the length is 535 cm..
I can send you the table if you like?
Bert,
- ------
E-mail:
Business : BD-Design@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Tel./Fax: (0341) 254500 Mobile: (06) 51242990
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: [JN] Re: Bass Horns
Date: Fri, 9 Jul 1999 14:06:59 +0200
Source: Sound Digest Archive v02.n200
> De : Ketil Parow <ketil@marketview.no>
> A : sound@deliverator.io.com
> Objet : [JN] Re: Bass Horns
> Date : vendredi 9 juillet 1999 11:55
> Reaching 20Hz with a true horn system, without gross response
irregularities ("black
> holes") in the bottom octave involves cabinets that are way to large for
most domestic
> environments. No matter what die-hard horn fans claim. All the exotic
systems we've seen
> examples of from Japan, from France, from Holland, from wherever, must
be considered
> extreme and really of no interest to the average home and system owner.
Hello,
I disagree heartfully with your last sentence.
Your opinion is related to marketing (commercial) and such an "average
system owner" should not be considered in a forum the goal of which is DIY
and top quality sound reproducing.
Saying "such systems are extreme and of no interest"... is, IMHO, a really
bad thing to say on the Joenet as it certainly freezes some DIYers in their
decision to study such projects...
> Beranek (and others) has dealt thoroughly with the problems associated
with foreshortening
> and reduction of mouth size. Specifically, see "Acoustics", chapter 9.
Most of those works and more recent ones on reducing the dimensions,
folding...find their justifications in commercial products not in DIY
projects (a concrete bass horn cannot be a commercial product). Folded
horns (and/or rear horn loaded loudspeakers) generally are taking a hudge
volume in a living room. That's not the case with concrete bass horns that
can be build "outdoor" of the living room.
Just see the picture of the systems I mentionned that use concrete bass
horns: they are less invading visually in a living room than folded horns.
The best example is the Takashiri system, it is difficult to locate the
bass horns and the low-mid and mid horns are nearly invisible.
In the Kobayashi system, the wall in which the horns mouths are can be
masked by a curtain.
Such horns systems possess a better WAF than bass-reflex and folded horns.
I, for one don't consider concrete bass horns as extreme, BTW they are
generally cheap and fun to build as cement and plaster allow some last
minute modifications that cannot be done using wood or resin...
Best regards,
Jean-Michel Le Cleac'h, Paris, France
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: Re: [JN] Bass Horns
Date: Fri, 9 Jul 1999 14:08:15 -0400
Source: Sound Digest Archive v02.n200
Bert offered:
>>>The horn mouth is 410 x 67 cm (stereo) and the length is 535 cm..
I can send you the table if you like?<<<
Nein Danke - or at least not untill I have that house in the country
anyway...
Allen (VSE)
But I'd sure like to visit some time and hear it all running!
=========================================================================
From: Ketil Parow <ketil@marketview.no>
Subject: [JN] Re: Bass Horns
Date: Fri, 09 Jul 1999 16:38:34 +0100
Source: Sound Digest Archive v02.n200
"Le Cleac'h J.-M." wrote:
> > De : Ketil Parow <ketil@marketview.no>
> > Reaching 20Hz with a true horn system, without gross response
> irregularities ("black
> > holes") in the bottom octave involves cabinets that are way to large for
> most domestic
> > environments. No matter what die-hard horn fans claim. All the exotic
> systems we've seen
> > examples of from Japan, from France, from Holland, from wherever, must
> be considered
> > extreme and really of no interest to the average home and system owner.
>
> Hello,
>
> I disagree heartfully with your last sentence.
> Your opinion is related to marketing (commercial) and such an "average
> system owner" should not be considered in a forum the goal of which is DIY
> and top quality sound reproducing.
I sort of expected that argument, and I sort of agree with your point on the
"average *system* owner" bit. Most of us, though, own
houses/condos/apartments/what have you, and must as such be considered average
*home* owners, with the limitations that apply.
I still think that there's a lack of perspective here. My opinions are NOT
based in any commercial interests whatsoever. But, seriously, as we pursue our
goals of audio bliss, many of us reach a point where the whole thing blows out
of proportion and becomes extreme. Do not get me wrong, I stand in absolute
awe of some of the most extreme projects I've seen. BUT, in all fairness, they
still deserve to be called extreme. In some cases, the extreme itself is a
goal. And why not?
> Saying "such systems are extreme and of no interest"... is, IMHO, a really
> bad thing to say on the Joenet as it certainly freezes some DIYers in their
> decision to study such projects...
See the above. I am sorry if this came across as an attempt to debase the
efforts of extreme DIYers. If it did, it was not intended. What I'm trying to
say here, is that given the limitations that most of us live under, a lot of
these systems are of no practical interest. They are definitely worth looking
into, though, for the sake of reference, and (flame me to Hell) curiosa.
Honestly, who has a backyard to spare, to hold bass horns and compression
chambers? Who has a spare room adjoining the living room, to house bass horns?
Who has an unused floor in their house? For those of us who didn't think of
embedding bass horns in the ground under the house (terrific idea, btw, Bert),
who wants to rip up their flooring and dig out funnels for their horns?
And so on... The point is that these ideas simply will not fly for the majority
of us.
> Beranek (and others) has dealt thoroughly with the problems
>associated with foreshortening and reduction of mouth size.
>Specifically, see "Acoustics", chapter 9.
> Most of those works and more recent ones on reducing the dimensions,
> folding...find their justifications in commercial products not in DIY
> projects (a concrete bass horn cannot be a commercial product).
Allow me to rephrase your remark to get my point across:
"Most of those works and more recent ones on reducing the dimensions,
folding...find their justifications in the practical situations and the
limitations set forth by our dwelling places, not in no-compromise DIY
projects (a concrete bass horn will not fit into an apartment)."
As a matter of fact, a lot of the material presented over the years (articles
and theories now considered reference) were written for DIYers, and in some
cases, even *by* knowledgeable DIYers.
> Folded
> horns (and/or rear horn loaded loudspeakers) generally are taking a hudge
> volume in a living room. That's not the case with concrete bass horns that
> can be build "outdoor" of the living room.
>
> Just see the picture of the systems I mentionned that use concrete bass
> horns: they are less invading visually in a living room than folded horns.
> The best example is the Takashiri system, it is difficult to locate the
> bass horns and the low-mid and mid horns are nearly invisible.
> In the Kobayashi system, the wall in which the horns mouths are can be
> masked by a curtain.
>
> Such horns systems possess a better WAF than bass-reflex and folded horns.
All of this is granted. The systems you mention are fine examples of creative
DIY designs. Unfortunately, All of them also qualify as extreme systems, based
on the fact that 99.99% of us simply do not have any means of accommodating
systems of these dimensions. Not indoors, not outdoors, not anywhere.
> I, for one don't consider concrete bass horns as extreme,
Well, then you are lucky. Although my house is larger than average (that would
be the average here in Norway), I wish I could say the same...
> BTW they are
> generally cheap and fun to build as cement and plaster allow some last
> minute modifications that cannot be done using wood or resin...
Yes, I've reached the same conclusions. Maybe there's a way I can persuade my
wife to let me cut those mouth holes in our living room floor after all...
=========================================================================
From: Ketil Parow <ketil@marketview.no>
Subject: Re: [JN] Re: Bass Horns
Date: Fri, 09 Jul 1999 16:43:12 +0100
Source: Sound Digest Archive v02.n200
bobcx@prodigy.net wrote:
> > Hey everyone. Been off the list for half a year or so.
>
> Welcome back.
> >
> > An article that I've written on the "All Fun" project, slated for Speaker
> Builder 5/99.....
> Can you please tell a bit more about it. Lowther, I hope
Yes, it is yet another backloaded horn.
> ... How big is it?
footprint apx. 30cm by 60cm, height 110cm
> How hard to build?
Easier than the "BigFun".
More info will eventually (after publication) follow.
=========================================================================
From: Douglas Purl <dcp@selway.umt.edu>
Subject: Re: [JN] Re: Bass Horns
Date: Fri, 9 Jul 1999 13:31:16 -0600 (MDT)
Source: Sound Digest Archive v02.n201
A terrific and informative discussion. I'll bet Bert's wife was floored
by his horns. Those who haven't peeked owe themselves the url.
A few questions.
1. Has anyone involved with these monumental horns thought out loud about
the rationale for going horn rather than, say, electing a multi-woofer
equivalent-sensitivity direct radiator woofer?
2. Why not a single bass woofer? Tom Nousaine seems to be making a good
case on behalf of a summed <80 Hz sub with corner location. Since the
horn probably needs the corner anyway . . . Anybody ratiocinated on that?
3. I presume most of these systems described or alluded to are in-room.
But with folded horns and those originating outside the room boundaries,
how is acoustic phasing achieved?
4. Probably a corollary of #1. Was the rationale for choosing the horn
woofer/subwoofer theoretic or practical? (As Jean Michel argues, there is
something to be admired in the pioneering spirit of dreamers who act out.)
Doug Purl
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: Re: [JN] Re: Bass Horns
Date: Sat, 10 Jul 1999 02:34:31 -0400
Source: Sound Digest Archive v02.n201
>1. Has anyone involved with these monumental horns thought out loud about
>the rationale for going horn rather than, say, electing a multi-woofer
>equivalent-sensitivity direct radiator woofer?
yes... power... high power amps suck... even high power tube amps... it is
much easier to control a single driver than a multiple... look at the specs
of jc's speaks at ny noize... 100+ db... yet they still ate 300B amps for
lunch...you might gain in one area but you give it back up in another...
i'm not saying a high power amp with multi drivers will sound bad... its
just harder to make them sound right. i fully believe a properly
implamented multi amped low power system (blue thunder arthur loeschs for
reference) can deliver amazing sound... hell the top half of jc's 3way make
my toes tap...
>2. Why not a single bass woofer? Tom Nousaine seems to be making a good
>case on behalf of a summed <80 Hz sub with corner location. Since the
>horn probably needs the corner anyway . . . Anybody ratiocinated on that?
what does ratiocinated mean??? is it dangerous?
from multi drivers to a single corner driver? are you covering all bases?
given your references disdain for tubes in general... that just covers
another of your trolls... we all know bass below 80 hz is omnidirectional
so why worry??? how does he suggest you power this single driver... not to
mention the rest of the drivers... get some cinder block and join the big
leagues... or ar u wipped?
>3. I presume most of these systems described or alluded to are in-room.
>But with folded horns and those originating outside the room boundaries,
>how is acoustic phasing achieved?
define room boundry
define folded horn
define ratiocinated
please define phase of a 20 hz signal??? or should your chest compress in
instead of out??? move the alotted footage an it will reverse...i'll take
the sound factory approach to this one... ya just gotta feel it.
>4. Probably a corollary of #1. Was the rationale for choosing the horn
>woofer/subwoofer theoretic or practical? (As Jean Michel argues, there is
>something to be admired in the pioneering spirit of dreamers who act out.)
i dunno... but berts bass horns seem well thought out for the joelist
mentality... the made perfect sense to me (size and all) i learned from his
thought process ..
be it theoretic or practical.. again i dunno... but it was real...(did you
see the pictures?) and with a little thought you can see what his thoughts
were... and i suspect the bulk of the people here will agree with his
thinking on one level or another... now using a 1000W solid state amp in a
single driver corner bass box... well that thinking belongs here too... we
need laughs too... since it has a far better chance of being a commercial
product than anything we talk about... ironis isn't it.
ok now some questions for those that remain....
1. where is your music playback system can any of us hear it given proper
notice?
2. if you open your house up to fellow list members will you:
A) hide your jewels
b) hide your tubes
c) hide your celine deion cd
d) hide your krell amp
e) none of the above... since we will understand and maybe learn something new
3. do you own and refer to a scrabble dictionary to humiliate your friends
4. which might be a coronary to #1... if a fellow list member dropped you a
private note would you invite them over thesaurus and all??
my doors are always open... how about yours?
dave
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: Re: [JN] Re: Bass Horns
Date: Sat, 10 Jul 1999 11:59:10 -0600
Source: Sound Digest Archive v02.n201
Thomas Danley wrote:
>
SNIP
> when Garth Brooks, U-2, Michael Jackson and others do tours with BT-7's,
> they generally only
> use 12 to 16 units total, which supply the low frequency's for a 140+ box
> sound system. This
> is possible because 16 units can produce over 3 kw of acoustic power from
> 28 to 100 HZ with low
> distortion and this makes the BT-7 the worlds most powerful subwoofer.
- -------------------
Hi Tom:
3 KILL-o-watts of ACOUSTIC power ? ! ? ! ? Is that a typo? At 10%
efficency, that's 30kW of drive or nearly 2kW per unit? Can this be?
Bill - PEARL, Inc.
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: Re: [JN] Re: Bass Horns
Date: Sat, 10 Jul 1999 16:55:41 -0500
Source: Sound Digest Archive v02.n201
PEARL Cust Serv wrote:
> Thomas Danley wrote:
> >
> SNIP
> > when Garth Brooks, U-2, Michael Jackson and others do tours with BT-7's,
> > they generally only
> > use 12 to 16 units total, which supply the low frequency's for a 140+ box
> > sound system. This
> > is possible because 16 units can produce over 3 kw of acoustic power from
> > 28 to 100 HZ with low
> > distortion and this makes the BT-7 the worlds most powerful subwoofer.
>
> -------------------
> Hi Tom:
> 3 KILL-o-watts of ACOUSTIC power ? ! ? ! ? Is that a typo? At 10%
> efficency, that's 30kW of drive or nearly 2kW per unit? Can this be?
>
> Bill - PEARL, Inc.
Hi Bill
No its not a type O, both the mathcad model for a multiple box system and
independent lab test measurements put the efficiency (for 6 close coupled
units) at 46% (avg.) from 28 to 125 HZ.
They are horn loaded low frequency compression drivers after all.
Each BT-7 handles 400 Watts RMS with about 1 dB of power compression and will
handle 800 Watts for 15 seconds or less.
When we made one of the first cut sheets, we had the idea to blow out the
candles on a birthday cake
with a "pulse" signal. It will do this easily up to a couple feet away from a
single unit but the camera was blurred too much by the vibration to make a good
picture.
These are fun boxes but too big and too much for the home, a pair of
ContraBass's (much smaller) are about right for a very loud stereo.
Best Regards
Tom
There is more "poop" on them at Servodrive.com if interested
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: [JN] Bass Horns
Date: Mon, 12 Jul 1999 17:03:51 +0200
Source: Sound Digest Archive v02.n203
> De : Douglas Purl <dcp@selway.umt.edu>
> A : sound@deliverator.io.com
> Objet : Re: [JN] Re: Bass Horns
> Date : vendredi 9 juillet 1999 21:31
> 3. I presume most of these systems described or alluded to are in-room.
> But with folded horns and those originating outside the room boundaries,
> how is acoustic phasing achieved?
Hello,
Here in France, many multiways systems are now using digital crossover like
the BSS FDS388. Such devices possess delay lines (digital allows it nearly
for free...) that can be used for the purpose of time alignnment even with
large delays between drivers...
Best regards,
Jean-Michel Le Cleac'h, Paris, France
=========================================================================
From: "John" <str8aro@purdue.edu>
Subject: [JN] Bass Horns
Date: Mon, 20 Mar 2000 17:27:49 -0500
Source: Sound Digest Archive v02.n488
Hi everyone,
I was wondering if anyone here has built a large bass horn with a curve
in it. I've been thinking about building something like this - maybe a 40
hz horn that curved 360 degrees (like a snail) to make it a little more
compact (well, not stretching out forever anyway...). More specifically,
does the volume of the horn matter? When I drew up a side view of a horn
like this, it came out having a smaller contained volume of air than the
same expansion built as a straight horn would have. I sized this design by
drawing a center line of the curve at the length I wanted. Anyone have any
insights one this? Or is this not something to worry about?
John
=========================================================================
From: Owen Young <oyoung@clear.net.nz>
Subject: Re: [JN] Bass Horns
Date: Tue, 21 Mar 2000 20:05:21 +1200
Source: Sound Digest Archive v02.n488
John,
A quick calc:
A Hyperbolic-Exponential flare bass horn of 40Hz design cutoff freq
would need to be 3 sq m mouth size(32 sq ft)/3.75m long(12.3ft) for
floor location; or 0.75 sq m mouth(8 sq ft)/2.8m long(9ft) if corner
loaded.
Irrespective of whether it is curved, folded or straight.
Owen
John wrote:
>
> Hi everyone,
> I was wondering if anyone here has built a large bass horn with a curve
> in it. I've been thinking about building something like this - maybe a 40
> hz horn that curved 360 degrees (like a snail) to make it a little more
> compact (well, not stretching out forever anyway...). More specifically,
> does the volume of the horn matter? When I drew up a side view of a horn
> like this, it came out having a smaller contained volume of air than the
> same expansion built as a straight horn would have. I sized this design by
> drawing a center line of the curve at the length I wanted. Anyone have any
> insights one this? Or is this not something to worry about?
>
> John
=========================================================================
From: Timo Christ <carnivor@uni-bremen.de>
Subject: [JN] Basshorns
Date: Sat, 03 Mar 2001 21:58:14 +0100
Source: Sound Digest Archive v02.n825
Hi All,
finally i have uploaded some photos and descriptions of my basshorns to
my website. The horn uses a Eminence Kappa 15 LF drive unit and covers
approximately 50-500 Hz (maybe 400), low-freq cutoff is 26 Hz with
corners. Box dimension is 50x60 face and 80 cm long.
Yes, a plan is included on the webpage.
URL:
http://www-user.uni-bremen.de/~carnivor/basshorn/basshorn.html
I hope this is interesting to some of you.
Regards,
Timo
- --
/ /--' Timo Christ carnivore@uni-bremen.de
/ /<-. EE Student University of Bremen, Germany
__/ /__/ Horns 'r more fun:
' http://www-user.uni-bremen.de/~carnivor/
=========================================================================
From: Ketil Parow <ketil@marketview.no>
Subject: [JN] Bass Horns & flame wars
Date: Mon, 12 Jul 1999 13:08:46 +0100
Source: Sound Digest Archive v02.n203
Hi everyone. I guess this one'll get me flamed right out of my asbestos suit, but
I think this needs saying.
Listen carefully, I will say this only once:
dave slagle wrote:
> >horn probably needs the corner anyway . . . Anybody ratiocinated on that?
>
> what does ratiocinated mean??? is it dangerous?
>
> from multi drivers to a single corner driver? are you covering all bases?
> given your references disdain for tubes in general... that just covers
> another of your trolls... we all know bass below 80 hz is omnidirectional
> so why worry??? how does he suggest you power this single driver... not to
> mention the rest of the drivers... get some cinder block and join the big
> leagues... or ar u wipped?
>
> define room boundry
>
> define folded horn
>
> define ratiocinated
>
> please define phase of a 20 hz signal??? or should your chest compress in
> instead of out??? move the alotted footage an it will reverse...i'll take
> the sound factory approach to this one... ya just gotta feel it.
>
> now using a 1000W solid state amp in a
> single driver corner bass box... well that thinking belongs here too... we
> need laughs too...
> 1. where is your music playback system can any of us hear it given proper
> notice?
>
> 2. if you open your house up to fellow list members will you:
>
> A) hide your jewels
> b) hide your tubes
> c) hide your celine deion cd
> d) hide your krell amp
> e) none of the above... since we will understand and maybe learn something new
>
> 3. do you own and refer to a scrabble dictionary to humiliate your friends
What's the point of all this, Dave? Is there something personal here, that we
don't know about?
I guess this discussion might be heading in the wrong direction now, but anyway, I
for one believe the points that Doug makes are of relevance.
The reasons why people get into audiophile DIY as a hobby, may of course vary from
individual to in-duh-vidual. But, I firmly believe that we need to agree on a
couple of issues as a foundation on which to build our discussions:
o Subjective (and, to the extent that it's possible, objective) perception of
sound reproduction quality is the goal.
o Technology is a vehicle to reaching that goal, and nothing more.
o Diversity is important. Different technologies mean different solutions to the
(basically) same problem.
o My own opinions and beliefs should be questioned, and I should be able to
question other's.
o Everything in audio reproduction involves a huge compromise. If you had the
opportunity to abx your "ultimate no-expenses-spared only-way-to-go dream system"
to live performance, there would still be gigantic differences between the real
thing and the reproduction. This should be the basis for perspective. A "no
compromise" design is in fact *at least* 95% compromise.
Some get started on this geek hobby :
a) For a love of music.
b) To prove to themselves and others that they're able to master complex
technologies and craftmanship.
c) To prove their own theories.
d) To prove "the establishment's" theories wrong.
e) Because they enjoy the nitty-gritty of building things.
f) For a wish to own unique, individual solutions.
g) To be able to own gear that performs better than commercially available units,
due to inherent marketing potential compromise.
h) To be able to get gear that costs less than commercially available units.
I'm sure there are a number of other good reasons, too. All of them fully
adequate. I'm a combination of the first two, possibly c), definitely e), f) and
h).
Building the "World's Best Loudspeaker" has never been my goal. For me, the beauty
of this hobby is to be able to try to get *more for less*. Simple as that. I will
never reach my goal. It will always be possible to get more for less. And that, I
think, is the essence of a good hobby. You should never tire of it, and you should
never be able to consider it "done".
I am into horn loudspeakers because I think they contribute something to my
listening experience. I am able to get that "something" with reasonable funds,
because I design and build them myself. This does not mean that I think that horns
are the final word in loudspeaker technology. In fact, I think a lot of commercial
horn systems are to expensive for their performance. And, to boot, I think a lot
of commercial direct-radiating multi-way systems are incredibly good for their
price and size. But that's beside the point.
The point is that the technology that I employ is cost efficient and convenient
for me in my situation. Tell me there's a cheaper/easier/more convenient way to
obtain the results that I want, with no obvious drawbacks, and I'm all over it. If
I have tried it and rejected it, fine. Then I can say "doesn't work because...". I
will have learned something new. If I have tried it and found it to work, that's
even better.
Which, I believe, is the gist of Doug's post.
I never thought I would be, but I am actually working on a project right now that
is a hybrid construction.
Having come to the conclusions on bass horns that I posted earlier, I decided that
to get that bottom octave (20Hz-40Hz) working properly, I need to employ some new
technology. I need a subwoofer. I want to keep the extraordinary clarity and
definition of the bass horns, but I want bass to go deeper. My current backloaded
Lowther horns have a cut-off at 40Hz, f-3 at somewhere around 45-48 Hz (The "All
Funs", see SpeakerBuilder 5/99), measured in their room positions.
For my first tries I have tested the Cyclone woofer from Phoenix Gold, built into
a closed box tuned to f-3 at 16Hz. The unit I tried was malfunctioning slightly
(misaligned bearings, apparently), but the results were nevertheless uplifting.
Using no crossover for the horns, an active 4. order crossover at around
40Hz-50Hz, and a modestly powered SS amp for the sub, I was able to obtain a good
(seemless) match between the systems. However, there were flaws. It seems that
some perspective got lost. Instruments were no longer as firmly positioned, and
deep male voices seemed to lose some definition and clarity.
The store that sold me the cyclone took it back, but refused to give me a working
one in return without getting payed more in between (!). I told them no way.
So the next try is going to be with a Vifa low-Q, low-Fs 12'' driver in a Voigt
pipe tuned in at around 22-24 Hz, and crossed over at around 45Hz.
It seems to me that I could have fixed some of the troubles I encountered by
crossing over the horns too, but the idea does not appeal to me, as I fear they
will lose some of their mid-bass and mid-range definition by introducing active
electronics in their signal path. I will try damping the driver cavity instead,
see where that gets me.
More info on this will follow when the "workshop season" starts again. Now it's
"boating & fishing season".
Go easy on me, Dave. I may break.
Regards,
Ketil Parow.
=========================================================================
From: "Franck JONCHERAY" <fjoncheray@ccf.fr>
Subject: [JN] bass list
Date: Thu, 02 Mar 2000 11:18:33 +0100
Source: Sound Digest Archive v02.n471
How can I subscribe to bass list ?
Thanks for your help.
******************************************
Ce message est strictement confidentiel. Son integrite n'est pas assuree sur Internet. Le contenu d
e ce message ne peut engager la responsabilite du Credit Commercial de France. Si vous n'etes pas de
stinataire du message, merci d'en avertir immediatement l'expediteur et de le detruire.
This message is strictly confidential. Integrity is not guaranteed through Internet. The content of
this message does not bind Credit commercial de France in any way. If you are not the intended rec
ipient of the message, please notify the sender immediately and delete it.
******************************************
******************************************
message a ete controle par antivirus.
******************************************
=========================================================================
From: David Dlugos <planet10@pinc.com>
Subject: RE: [JN] bass list
Date: Fri, 3 Mar 2000 08:07:35 -0800
Source: Sound Digest Archive v02.n473
>I was going to send Frank to http://www.diyloudspeakers.org/ but all I get
>is an empty site.
The diyloudspeakers.org domain is in limbo for now.
>Is it just me or have the BASS list guys moved?
John at Stryke.com has put together a subscription page on his site.
http://basszone.stryke.com/
The list itself is still as crazy as ever.
dave
____________________________________
Transmission Line Speaker Page
http://www.t-linespeakers.org/
=========================================================================
From: Dave Crawford <dcraw@home.com>
Subject: Re: [JN] bass list
Date: Fri, 03 Mar 2000 08:39:33 -0800
Source: Sound Digest Archive v02.n473
"Sellek, Grant (TSA)" wrote:
>
> I was going to send Frank to http://www.diyloudspeakers.org/ but all I get
> is an empty site.
>
> Is it just me or have the BASS list guys moved?
>
> Grant
>
> Grant Sellek
> Adelaide, Australia
> grant.sellek@transport.sa.gov.au
>
> -----Original Message-----
> From: Franck JONCHERAY [mailto:fjoncheray@ccf.fr]
> Sent: Thursday, 2 March 2000 8:49 PM
> To: sound@lists.io.com
> Subject: [JN] bass list
>
> How can I subscribe to bass list ?
> Thanks for your help.
>
Nobody has identified what happened to the diyloudspeakers URL, it just
disappeared. The Basslist still exists on the UT server. John Janowitz
set up a subscription form on his strykezone website:
http://basszone.stryke.com/
- --
Dave
If you can remain calm,
you just don't have all the facts.
Orange County, California
http://www.members.home.net/dcraw/
=========================================================================
From: Douglas Purl <dcp@selway.umt.edu>
Subject: RE: [JN] bass list
Date: Fri, 3 Mar 2000 18:36:01 -0700 (MST)
Source: Sound Digest Archive v02.n473
On Fri, 3 Mar 2000, Sellek, Grant (TSA) wrote:
> Is it just me or have the BASS list guys moved?
The original name lingers (an auto stereo fan started the list), but the
real name and topic is DIY loudspeakers list.
Doug Purl
=========================================================================
From: "Sellek, Grant (TSA)" <Grant.Sellek@transport.sa.gov.au>
Subject: RE: [JN] bass list
Date: Fri, 3 Mar 2000 20:55:07 +1030
Source: Sound Digest Archive v02.n473
I was going to send Frank to http://www.diyloudspeakers.org/ but all I get
is an empty site.
Is it just me or have the BASS list guys moved?
Grant
Grant Sellek
Adelaide, Australia
grant.sellek@transport.sa.gov.au
- -----Original Message-----
From: Franck JONCHERAY [mailto:fjoncheray@ccf.fr]
Sent: Thursday, 2 March 2000 8:49 PM
To: sound@lists.io.com
Subject: [JN] bass list
How can I subscribe to bass list ?
Thanks for your help.
******************************************
Ce message est strictement confidentiel. Son integrite n'est pas assuree
sur Internet. Le contenu de ce message ne peut engager la responsabilite du
Credit Commercial de France. Si vous n'etes pas destinataire du message,
merci d'en avertir immediatement l'expediteur et de le detruire.
This message is strictly confidential. Integrity is not guaranteed through
Internet. The content of this message does not bind Credit commercial de
France in any way. If you are not the intended recipient of the message,
please notify the sender immediately and delete it.
******************************************
******************************************
message a ete controle par antivirus.
******************************************
=========================================================================
From: "Murray Leshner" <multi-volti@softhouse.com>
Subject: [JN] Bass list?
Date: Mon, 19 Jun 2000 02:45:37 -0400
Source: Sound Digest Archive v02.n585
Looking for basslist subscription info.
Thanks
Murray
=========================================================================
From: Robert Schneider <bobschneiderx@mediaone.net>
Subject: Re: [JN] Bass list?
Date: Sat, 24 Jun 2000 22:54:55 -0500
Source: Sound Digest Archive v02.n591
On Mon, 19 Jun 2000 02:45:37 -0400, you wrote:
>Looking for basslist subscription info.
>
The address of the Bass List server is listproc@lists.cc.utexas.edu
To subscribe, send an email to it with the following on a single line
of text in the message body
subscribe bass <your email address> <your name>
Leave a blank line after that command. You'll get a confirmation
message within a couple of minutes, with further instructions.
The Bass List is well worth getting. Besides lots of good discussions
on speaker design (not much tube specific, though), there are a number
of parts discounts available to list subscribers.
Bob Schneider
bobschneiderx@nospam.mediaone.net
schneirr@nospam.bp.com
The views expressed are not those of my employer, my wife, or
the National Football League.
All rights reserved.
=========================================================================
From: houndman@onix.com
Subject: [JN] Bass List ??
Date: Sun, 17 Dec 2000 18:54:14 -0500
Source: Sound Digest Archive v02.n761
anyone know how to subscribe to the Bass List ??
=========================================================================
From: "Aaron Bohnen" <bohnen@unixg.ubc.ca>
Subject: Re: [JN] Bass List ??
Date: Sun, 17 Dec 2000 16:50:36 -0800
Source: Sound Digest Archive v02.n762
Hi everyone,
> anyone know how to subscribe to the Bass List ??
Yep, here you go:
http://www.hayenga.com/basslist/subscribe.html
best regards,
Aaron
___________________________________________________________
Aaron Bohnen email: bohnen@unixg.ubc.ca
- -Ph.D. Student, Civil Engineering Department, U.B.C.
- -website: http://www.civil.ubc.ca/home/bohnen
=========================================================================
From: "Larry D. Moore" <l-moore@onu.edu>
Subject: [JN] BASS List get together
Date: Fri, 21 May 1999 17:14:53 -0400
Source: Sound Digest Archive v02.n150
For those of you so inclined,
I just finished a line stage preamp for the bassslist show in California on
June 5, 1999.
Also, a pair of Iguanas will be there.....so if you are interested please
contact:
Steve Schenkel
sschenkel@juno.com
Thanks for the Bandwidth,
L.D. Moore
=========================================================================
From: sschenkel@juno.com
Subject: [JN] Bass list meeting in Southern California
Date: Tue, 4 May 1999 12:34:05 -0700
Source: Sound Digest Archive v02.n138
SoCal Joes
The Bass List is having it's semi anual get together near LAX. We would
like to invite the Joes to join us.
There are 14 people currently who plan to attend. Many are bringing
friends so I would not be surprised if the total would not top 20. Kimon
Bellas and Alain Benard from Orca will be there to show off their Raven
R-3 system. The list of speakers that are going to be available to hear
so far are:
1. Raven R-3 in a system designed by Orca
2. Raven R-2/Focal 7K4211DB
3. Raven R-2/Cabasse 21M18
4. Aria 5R
5. Aria 5A
6. Nohr 7" 2 way using the SS9700/8545
7. Contra Bass
8. The Apex "Junior"- a 6" 2 way using the TND Duo
The date is June 6th, time is 12:00 pm. Please let me know if you can
attend. We would love to hear some great tube gear and any speakers you
would care to bring. Directions will follow.
Steve Schenkel
___________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
or call Juno at (800) 654-JUNO [654-5866]
=========================================================================
From: Ed Billeci <tube@teleport.com>
Subject: [JN] Bass reflex Lowthers ??!!??
Date: Thu, 6 Apr 2000 14:59:06 -0700
Source: Sound Digest Archive v02.n511
Hey Lowther fans, check out this link. I am not affiliated with them in
any way, never bought anything, or communicated with them. However, I
though some Joes may enjoy a visit. The claims made by his website are,
uhh..unique. ;->))
(BTW, I have a pair of Medallion cabs for sale, best offer. Pick up in
Portland, OR)
http://users.fastrans.net/classicaudio/Lowther.html
=========================================================================
From: darmah@goodnet.com
Subject: Re: [JN] Bass reflex Lowthers ??!!??
Date: Thu, 6 Apr 2000 18:20:25 -0700
Source: Sound Digest Archive v02.n512
Hi Joes
Ed Wrote:
> Hey Lowther fans, check out this link. I am not affiliated with them
> in
> any way, never bought anything, or communicated with them. However, I
> though some Joes may enjoy a visit. The claims made by his website are,
> uhh..unique. ;->))
>
I recently had a inquery myself regarding this exact person and his
die-hard love for reflex loading a Lowther. Spme of the points he
brings up in favor of reflex loading are entirely valid.
Just prior to that I had a call from a guy who had actually been
there and heard them.
It appears the room he demos the reflex loaded Lowthers in has
carpet so thick it ticles the ankles. The drapes are so heavy they
need extra support.
All in all the room is acoustically dead...or even dead an
decomposed!!!
I could see where this might work. But few of us have listening
rooms that are anechoic chambers so take the claims with a grain
of salt. I know some people who bought this combo and they
ended up building horns.
I've always said that the Lowther can be reflex loaded BUT:
The less powerfull models should work better as far as tonal
balance is concerned. They will subjectively go lower than in
standard Lowther loads as well.
Also power handling and maximum volume will decrease due to
greater cone excursion relative to the more standard horn/pipe load.
Best Regards
Marc S. Wauters
darmah@goodnet.com
My Lowther Enthusiasts Page:
http://www.goodnet.com/~darmah/lowther/lowther.htm
=========================================================================
From: "Carter Hendricks" <carter@i1.net>
Subject: Re: [JN] Bass reflex Lowthers ??!!??
Date: Thu, 6 Apr 2000 21:24:40 -0500
Source: Sound Digest Archive v02.n512
Marc wrote:
> Just prior to that I had a call from a guy who
> had actually been there* and heard them.
I've heard them, too. The reflex cabinets make
caricatures of the Lowthers, like the drivers
are wearing those big long red shoes like the
clowns in the circus. All one hears are the faults.
> I've always said that the Lowther can be reflex
>loaded
I'm not so sure. I do think that the only reason
to put Lowthers in a reflex box is to sell them
cheaper.
--Carter
* Gotta take off your shoes!
=========================================================================
From: "Carter Hendricks" <carter@i1.net>
Subject: Re: [JN] Bass reflex Lowthers ??!!??
Date: Thu, 6 Apr 2000 21:25:10 -0500
Source: Sound Digest Archive v02.n512
Marc wrote:
> Just prior to that I had a call from a guy who
> had actually been there* and heard them.
I've heard them, too. The reflex cabinets make
caricatures of the Lowthers, like the drivers
are wearing those big long red shoes like the
clowns in the circus. All one hears are the faults.
> I've always said that the Lowther can be reflex
>loaded
I'm not so sure. I do think that the only reason
to put Lowthers in a reflex box is to sell them
cheaper.
--Carter
* Gotta take off your shoes!
=========================================================================
From: "schiff.chu" <schiff.chu@mciworld.com>
Subject: [JN] bass reflex Lowther speakers
Date: Wed, 24 Nov 1999 21:05:53 -0700
Source: Sound Digest Archive v02.n345
Hi Guys,
I have finally come to the conclusion a few months back that using a Meggie
1a (though @ 90dB efficiency) in a single-end application JUST do not cut
it. They do not SING well with only 3 watts and you really do not get the
benefits of SE-amp with them.
After much thoughts and looking around, even coming up with a 42 Hz version
of Carfrae horn rip-off (it was fun designing it while it lasted), then my
wife ask the critical question after she took a look at the drawing "WHAT
ARE YOU DOING? Are you going to build THAT?" I then realized this......
if I ever going to get a horn into our house, they have to be "small". No
Medallion II, No Mauhorn, No Egar, No Classic Audio, No Exemplar (you can
not get them anyway!), No Lam horn ($$), No Carfrae ($$$$$!) etc.......
They have appeal to the eyes of ..... well, you know.
I would like to get full-range (or close to it), 100dB efficiency and stick
with Lowther driver (don't ask why..... just let us say that I want to try
it). This bass-reflex design at
http://users.fastrans.net/classicaudio/lowther.html caught my eyes the
other night. Has any look into this?? Any thoughts.
hopper
=========================================================================
From: MHuber@t-online.de (Manfred Huber)
Subject: Re: [JN] bass reflex Lowther speakers
Date: Thu, 25 Nov 1999 09:56:59 +0100
Source: Sound Digest Archive v02.n345
Hopper,
>I would like to get full-range (or close to it), 100dB efficiency and stick
>with Lowther driver (don't ask why..... just let us say that I want to try
>it). This bass-reflex design at
>http://users.fastrans.net/classicaudio/lowther.html caught my eyes the
>other night. Has any look into this?? Any thoughts.
I would not try to use a Lowther in a bass-reflex design.
The Xmax of a Lowther driver is way too small for use with
anything but a horn.
One other thing is that the Lowters have a response that is rising with
frequency. A perfect match for a horn that brings up the response in the lower octaves.
You sure can get a more or less flat response by EQing but this means that you
have to attenuate the higher frequencies and this means that you loose efficiency.
Regards
Manfred
- ------------------
Manfred Huber
MHuber@t-online.de
- ------------------
=========================================================================
From: "Bert Doppenberg" <LCH@lowther.nl>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Thu, 25 Nov 1999 17:20:04 +0100
Source: Sound Digest Archive v02.n345
Hi Hopper,
>After much thoughts and looking around, even coming up with a 42 Hz version
>of Carfrae horn rip-off (it was fun designing it while it lasted), then my
>wife ask the critical question after she took a look at the drawing "WHAT
>ARE YOU DOING? Are you going to build THAT?" I then realized this......
The lady of the house... ;-)
>I would like to get full-range (or close to it), 100dB efficiency and stick
>with Lowther driver (don't ask why..... just let us say that I want to try
>it). This bass-reflex design at
>http://users.fastrans.net/classicaudio/lowther.html caught my eyes the
>other night. Has any look into this?? Any thoughts.
I have tried this design, if placed inside a corner, it will give a reasonable tonal
balance (the corner used as horn mouth). This isn't optimal, but the only way to keep the
high sensitivity without equalising with a filter!
Regards,
Bert,
- ------
E-mail:
Business : Sales@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Tel./Fax: (0341) 254500 Mobile: (06) 51242990
=========================================================================
From: "Carter Hendricks" <carter@i1.net>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Thu, 25 Nov 1999 22:36:53 -0600
Source: Sound Digest Archive v02.n345
- -----Original Message-----
From: Manfred Huber <MHuber@t-online.de>
To: sound <sound@lists.io.com>
Date: 25 November, 1999 3:51 AM
Subject: Re: [JN] bass reflex Lowther speakers
>Hopper,
>
>>I would like to get full-range (or close to it), 100dB efficiency and
stick
>>with Lowther driver (don't ask why..... just let us say that I want to try
>>it). This bass-reflex design at
>>http://users.fastrans.net/classicaudio/lowther.html caught my eyes the
>>other night. Has any look into this?? Any thoughts.
>
>I would not try to use a Lowther in a bass-reflex design.
>The Xmax of a Lowther driver is way too small for use with
>anything but a horn.
>Regards
>Manfred
I actually heard Lowthers in those reflex boxes.
They were frightening awful. Nasty.
On the other hand, I am told that the Hedlund
horns sound wonderful, and Lynn says they
look great.
Happy Thanksgiving!
--Carter
=========================================================================
From: =?iso-8859-1?q?Josef=20Aigner?= <josef_aigner@yahoo.com>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Fri, 26 Nov 1999 03:41:41 -0800 (PST)
Source: Sound Digest Archive v02.n346
Hugh,
this sound very interesting but, what kind of Mauhorn ? and what
modification ? Only the rounded corners in the horn or also a
modified chamber.
As a chepo-box I use a Fostex 164 in a bass-reflex design. 93db/W -
low cost - in 11 litres, simply great. The only thing "X-over" is a
impedance linearisation. So the 218 is interesting. Can you supply us
with some details ?
Josef
__________________________________________________
Do You Yahoo!?
Thousands of Stores. Millions of Products. All in one place.
Yahoo! Shopping: http://shopping.yahoo.com
=========================================================================
From: "Carter Hendricks" <carter@i1.net>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Fri, 26 Nov 1999 18:09:27 -0600
Source: Sound Digest Archive v02.n346
- -----Original Message-----
From: Hugh R. Dean <aspen@alphalink.com.au>
To: Carter Hendricks <carter@i1.net>; Joenet <sound@deliverator.io.com>
Date: 26 November, 1999 2:33 AM
Subject: Re: [JN] bass reflex Lowther speakers
>Carter writes:
>
>> I actually heard Lowthers in those reflex boxes.
>> They were frightening awful. Nasty.
>
>Generally, my sentiments about the Lowthers entirely.
>Hugh
No, not the Lowthers, the B O X E S!
I heard other Lowther drivers on the same
electronics, the same afternoon, but these
in "factory" horn cabinets--and they were,
well, Lowthers. For good and bad.
But those reflex boxes were mean.
--Carter
=========================================================================
From: "Hugh R. Dean" <aspen@alphalink.com.au>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Fri, 26 Nov 1999 19:33:22 +1100
Source: Sound Digest Archive v02.n346
Carter writes:
> I actually heard Lowthers in those reflex boxes.
> They were frightening awful. Nasty.
Generally, my sentiments about the Lowthers entirely.
OTOH, a couple days back I heard the Fostex 208 Sigma in a Mauhorn, modified
for fully curved profile on the bends and with all voids filled with
polystyrene beads.
Absolutely wonderful. Ethereal. No shrieking mids, no thin bass, and
smooth, clear highs. A strange combination of great detail, but without the
sharpness and shriek of the PM6A in the same box. Especially good on female
vocals.
Around 101dB/watt/metre. Overdriven, if anything, with a 15W Quad II.
Cheers,
Hugh R. Dean
Melbourne, Australia
=========================================================================
From: "J. Gordon Rankin" <waudio@cinti.net>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Mon, 29 Nov 99 09:47:15 -0500
Source: Sound Digest Archive v02.n347
Guys,
I admit that the Lowther is less than considerable in the bass in a
ported arrangement. You would be lucky to get anything below 180Hz with
the 6A/7A's that I have TS for.
I did however just finish a product for another company. We took the
Fostex 208Sigma, ported it, added a super tweeter and a sub (below 120Hz)
all in one cabinet. Man it is a killer system, we just let the 208 fly
free (no xover) the tweeter comes in at 10KHz and the sub has variable
gain, phase and xover point.
I really do not see why someone can't do the same with a Lowther. I
really don't know why nobody seems to think the Lowther could use a boost
in the top and bottom end. To me, I just don't get it. I have heard some
20 different versions, always leave with the same conclusion: Glorious
midrange with some peaking, no bass, no treble.
Gordon
=======> Wavelength Audio <=======
mailto:waudio@cinti.net
http://www.WavelengthAudio.com
ph.fx. 513-271-4186 USA
=========================================================================
From: Power.Ralph@epamail.epa.gov
Subject: Re: [JN] bass reflex Lowther speakers
Date: Mon, 29 Nov 1999 09:47:02 -0500
Source: Sound Digest Archive v02.n348
Hi Gordon,
What kind of tweeter did you use and what was the crossover for it, if I might
ask ?
- Ralph
=========================================================================
From: "Bert Doppenberg" <LCH@lowther.nl>
Subject: [JN] bass reflex Lowther speakers
Date: Mon, 29 Nov 1999 20:47:38 +0100
Source: Sound Digest Archive v02.n348
Hi Gordon,
>I really do not see why someone can't do the same with a Lowther. I
>really don't know why nobody seems to think the Lowther could use a boost
>in the top and bottom end. To me, I just don't get it. I have heard some
>20 different versions, always leave with the same conclusion: Glorious
>midrange with some peaking, no bass, no treble.
Some people go for technical sound, or looking for a certain colour with lot's of bass, or
like to have a rising response in the highest frequencies, or......
Some people prefer the purity of sound with a correct stage (in size and depth), the
"open" transparent coherence sound, clarity and proper fine details with their proper
dynamics, and......
If connected to the rigth equipment, the rigth type of cabinet and environment with the
better recordings, then the use of Lowther drivers is the only way to go. Using badly
designed enclosures, using the wrong tuning and equipment, bad recordings, then a Lowther
could screem your head of due it's capability to reproduce anything you give them!
The performance of the more expensive Lowther drivers are the best available (in
comparisation, the Fostex 208 truely sucks!), but listening to the budget drivers and dito
equipment alone isn't an objective opinion, those people are telling the world that
Lowthers suck....
Bert,
- ------
E-mail:
BD-Design : Sales@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Oris 150 : http://www.lowther.nl/wwwpages/opinions.html
Phone/Fax : +31 341 254500 Mobile: +31 6 51242990
=========================================================================
From: "Bert Doppenberg" <LCH@lowther.nl>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Mon, 29 Nov 1999 22:07:14 +0100
Source: Sound Digest Archive v02.n348
Hi Gordon,
>I have heard the Lowthers and the Reps with what I would consider better
>than average equipment. The results are still the same! poor at best,
>REPS better but still not soo good. I think the REPS could be the answer,
>I just wish someone would invest in some better backhorn designs to
>really truely get them too work.
Like the Carfrae horn? This is a very nice sounding back loaded horn! ;-)
>In regards to the Fostex, my opinion is they sound better for a simple
>reason. When you optimize for ultimate in sensitivity the bandwith tends
>to loose on both ends. This in amplifier design is called the Gain
>Bandwith Principal. Since the Fostex are far less sensitive they seem to
>prefrom better on the top and bottom.
For frequency respons they are better balanced in the low-mids, the high frequencies are
better (?).
>But in each case it aways depends on the entire system to reap the best
>from any single part of it.
That's my point! ;-))
Bert,
- ------
E-mail:
BD-Design : Sales@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Oris 150 : http://www.lowther.nl/wwwpages/opinions.html
Phone/Fax : +31 341 254500 Mobile: +31 6 51242990
=========================================================================
From: "Bert Doppenberg" <LCH@lowther.nl>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Mon, 29 Nov 1999 23:15:58 +0100
Source: Sound Digest Archive v02.n348
Yo Gordon,
>No but I have heard the Loth-X, various Acousta's & Medallions, Lamhorn
>pm2, Lamhorn REPS, Bauhorns (SP?), and a few outside combinations.
Small cabinets do not give the rigth balance to the better Lowther drivers. They are all
missing "body". Some designs do have body at the expense of low frequencies and added
colourations.
>I have contacted Carfrae, no response. So have a few of my dealers, no
>response. The look great but how do they sound?
This is one design that gives a better balance using a better driver. The used DX4 is, in
my opinion, the best Lowther driver (for back loading cabinets). The Carfrae gives "body"
and extended low frequencies, the DX4 has truely extended high frequencies (you'll be
surprised!) and is "softer" sounding compared to the PM2A and PM5A at the expense of less
extended small dynamics.
Even in the Hedlund horn (with an extended mouth for more "body") this driver kicks
without loosing balance...
All depending on the connected amplifiers (preferable tubes like 300B, 2A3, etc.) wich
changes the tonal balance also...
>As a percussionist, the highs have to be right. So far the best I have
>heard from the REPS is still lacking above 12KHz.
The problem with wide-band drivers is the dispersion (Lowther have a better dispersion due
the whizzer) up to 15k with the stronger magnetic drivers.
>>For frequency respons they are better balanced in the low-mids, the high
>>frequencies are
>>better (?).
>
>So you are agreeing with me?
No, but it is easyer to create a balanced sound with the Fostex due the higher sensitivity
in the low-mids. The high frequencies screem (due the driver) and the mids are so
slooooow...
>So what do you do to make the Lowther system work? Many out there need to
>know!
Patience, tuning, moving the seat and enclosures, save some more money to be able to buy a
more suitable driver.
- - The break in time for the Lowther takes a while (>500 hours)
- - Cables, amplifiers, the sources (CD or LP), recordings for tuning make a much bigger
difference compared to conventional systems
- - Acoustical environment makes a huge difference in the tonal balance of the sound
- - Pleasure the wife and built, buy, etc. a larger cabinet (like the Hedlund or Carfrae
horn)
- - Try different amplifiers if possible (clean sound is very important)
The problem with most people is that they are not patience. Take your time, tune the
system, replace the tubes for better sounding ones (pin-compatible), etc. You'll have to
work on the system; Lowther will sound different after every change in the chain
(resistors, C's, cables, etc.). But it will be worth wile, in the end you'll will have the
best system available!
Even the Oris 150 is very critical (even more.. ) to the connected electronics.
Bert,
- ------
E-mail:
BD-Design : Sales@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Oris 150 : http://www.lowther.nl/wwwpages/opinions.html
Phone/Fax : +31 341 254500 Mobile: +31 6 51242990
=========================================================================
From: "=?ISO-8859-1?Q?Torbj=F8rn_Lien?=" <mdrivekl@online.no>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Mon, 29 Nov 1999 23:54:40 +0100
Source: Sound Digest Archive v02.n348
Hi Bert:
> If connected to the rigth equipment, the rigth type
> of cabinet and environment with the
> better recordings, then the use of Lowther drivers
> is the only way to go...........[snip].......
> ..........due it's capability to reproduce anything
> you give them!
>
What a statement!!!
(But I do appreciate your enthusiasm...)
:)
Torbjoern, Norway
>
>
>
=========================================================================
From: "J. Gordon Rankin" <waudio@cinti.net>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Mon, 29 Nov 99 15:58:20 -0500
Source: Sound Digest Archive v02.n348
>If connected to the rigth equipment, the rigth type of cabinet and
>environment with the
>better recordings, then the use of Lowther drivers is the only way to go.
>Using badly
>designed enclosures, using the wrong tuning and equipment, bad recordings,
>then a Lowther
>could screem your head of due it's capability to reproduce anything you
>give them!
>
>The performance of the more expensive Lowther drivers are the best
>available (in
>comparisation, the Fostex 208 truely sucks!), but listening to the budget
>drivers and dito
>equipment alone isn't an objective opinion, those people are telling the
>world that
>Lowthers suck....
Bert,
I have heard the Lowthers and the Reps with what I would consider better
than average equipment. The results are still the same! poor at best,
REPS better but still not soo good. I think the REPS could be the answer,
I just wish someone would invest in some better backhorn designs to
really truely get them too work.
In regards to the Fostex, my opinion is they sound better for a simple
reason. When you optimize for ultimate in sensitivity the bandwith tends
to loose on both ends. This in amplifier design is called the Gain
Bandwith Principal. Since the Fostex are far less sensitive they seem to
prefrom better on the top and bottom.
But in each case it aways depends on the entire system to reap the best
from any single part of it.
Gordon
=======> Wavelength Audio <=======
mailto:waudio@cinti.net
http://www.WavelengthAudio.com
ph.fx. 513-271-4186 USA
=========================================================================
From: "J. Gordon Rankin" <waudio@cinti.net>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Mon, 29 Nov 99 16:47:13 -0500
Source: Sound Digest Archive v02.n348
Bert,
>Like the Carfrae horn? This is a very nice sounding back loaded horn! ;-)
No but I have heard the Loth-X, various Acousta's & Medallions, Lamhorn
pm2, Lamhorn REPS, Bauhorns (SP?), and a few outside combinations.
I have contacted Carfrae, no response. So have a few of my dealers, no
response. The look great but how do they sound?
As a percussionist, the highs have to be right. So far the best I have
heard from the REPS is still lacking above 12KHz.
>>In regards to the Fostex, my opinion is they sound better for a simple
>>reason. When you optimize for ultimate in sensitivity the bandwith tends
>>to loose on both ends. This in amplifier design is called the Gain
>>Bandwith Principal. Since the Fostex are far less sensitive they seem to
>>prefrom better on the top and bottom.
>
>For frequency respons they are better balanced in the low-mids, the high
>frequencies are
>better (?).
So you are agreeing with me?
>>But in each case it aways depends on the entire system to reap the best
>>from any single part of it.
>That's my point! ;-))
So what do you do to make the Lowther system work? Many out there need to
know!
Gordon
=======> Wavelength Audio <=======
mailto:waudio@cinti.net
http://www.WavelengthAudio.com
ph.fx. 513-271-4186 USA
=========================================================================
From: "Hugh R. Dean" <aspen@alphalink.com.au>
Subject: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 08:47:48 +1100
Source: Sound Digest Archive v02.n348
Hi Bert,
You wrote:
> The performance of the more expensive Lowther drivers are the best
available (in
> comparisation, the Fostex 208 truely sucks!), but listening to the budget
drivers and dito
> equipment alone isn't an objective opinion, those people are telling the
world that
> Lowthers suck....
With respect, and knowing your love of Lowthers, I'd like to offer this:
A friend, now into his late fifties, an Englishman living in Australia, is a
brilliant woodworker and has built loudspeaker cabinets since his youth.
This man is an innovator, and has been responsible over the years for all
sorts of interesting and labour-saving mechanical gadgets.
He heard I had a couple of Fostex 208 Sigmas in Jericho horns I was not
happy with, and asked to borrow the drivers.
For twenty years he has loved Lowthers, and has collected most of the
drivers, some twenty in all.
He fitted the Sigmas a Mauhorn he had built (they slot into the same hole
with little modification), made some detail changes to the chamber (he will
not give me the details, and at $AUD3000 for the boxes, which are very
large, I understand that), and delivered them to me for audition.
On my SE tube/mosfet hybrid amps, these speakers are stunning. The bass is
just right; not overblown, and very tight. The treble is not bright, and
exactly brings out the right balance, without any hint of screaming. The
mid-range is magnificent, bringing out blues singers superbly. A close
friend who loves jazz and blues commented unsolicited that this was the
finest speaker yet, and perhaps the best he'd ever heard. (We listened to a
Deedee Bridgewater selection of Sarah Vaughan).
I can say that this combination is far superior to the Jerichos, but I
suspect that a little chamber 'tweaking' might bring them out too. The
balance is there; the FR seems almost flat, unbelievable for a horn. There
is no trace of honkiness, although it is a different sound to a direct
radiator - it seems much more 'intimate', as though you are in a
smoke-filled jazz nightclub. The vocals are not too forward; the voice is
forward of the instruments, but entirely realistic.
The builder, who is committed to Lowther but not a religious adherent,
believes the Fostex 208 and the Mauhorn is a marriage made in heaven, and
that no Lowther can compare.
Something to think about.
Cheers,
Hugh R. Dean
Melbourne, Australia
=========================================================================
From: "Martin/Campbell family" <martincampbell@apex.net.au>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 21:18:15 +1100
Source: Sound Digest Archive v02.n348
>I really do not see why someone can't do the same with a Lowther. I
>really don't know why nobody seems to think the Lowther could use a boost
>in the top and bottom end......
>Gordon
I have some numbers and graph of the responses of the PM6A and PM2A on plain
baffles which I found helpfull to understand Lowthers a little better.
Lowthers look like approx. 90db/w/m speakers untill the whizzer kicks in
from 2KHz to 10KHz. Over that range they are about 100db/w/m. Thus it
makes sense that the bottom end needs the boost from a horn to lift it up to
somewhere approaching the efficiency of the treble. Without horn loading
the efficiency below 2KHz is nothing special. In principle one could boost
below 2KHz but then the amps would want to be more than flea-powered and
then the driver would have problems with its 1mm excursion limit. That's
another reason why it needs horn loading: to maximise output while
minimising excursion.
On the other hand an amplifier boost just for the top octave should be easy
to arrange. Let's say a triode stage somewhere with just a small cap bypass
to the cathode resistor, just enough to boost a few db for the top octave.
I have only heard PM6 and PM7 in ordinary Acousta cabinets (small rear
horn). I seriously doubt if they would work without a bass horn loading.
Perhaps, as someone suggested, a reflex box might just be adequate if the
box were place hard back into a corner to maximise the effect of the corner
bass boost. Even with a bass horn, the acoustas needed to be back hard
against a wall to get adequate bass. I realise this might not be the best
horn for them but it gave me an idea of their character.
Peter Campbell
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 08:24:36 -0500
Source: Sound Digest Archive v02.n349
"J. Gordon Rankin" wrote:
> snip>
>
> So what do you do to make the Lowther system work? Many out there need to
> know!
>
> Gordon
>
I have an excellent horn design/modeling program (developed under a NASA
contract for Acoustical Levitation sources at Intersonics) and have taken a
first look at doing Lowther a "rear horn" design for one of the Joe's.
Well a good start so far as acoustically considered horn design would be to
get the real Thiel&Small specs or the real mechanical properties would also
do, like Fs, Mms, Rdc, BL and radiator area.on there drivers, the ones
supplied by Lowther are apparently funky.
Short of designing/modeling the real properties, one is left to only cut and
try or copy those who have gone before, neither is likely to result in a
"breakthru" in performance..
Any of you folks have the real driver numbers?
Tom Danley
=========================================================================
From: James Melhuish <james@melhuish.org>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 12:34:06 -0500
Source: Sound Digest Archive v02.n349
> I have an excellent horn design/modeling program (developed under a NASA
> contract for Acoustical Levitation sources at Intersonics) and have taken a
> first look at doing Lowther a "rear horn" design for one of the Joe's.
>
I have an audio website focusing on Single Driver Loudspeakers and
Horns. I have two applets that calculate Tractrix contours and
Exponential/Hyperbolic contours. Check them out at
http://melhuish.org/audio/ Also David McBean has an excellent horn
calculating program for exponential and conical contours at
http://www.users.bigpond.com/dmcbean/ It shows Impedance and SPL
response for your horn and driver parameters.
James
- --
James Melhuish & Jennifer Shearman
82 Harvard Street, Newtonville MA 02460, USA
tel: 617 965 8859
fax: 617 964 3249
mailto:jjms@melhuish.org
http://melhuish.org
=========================================================================
From: Roscoe Primrose <roscoe@aiko.com>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 13:48:31 -0500
Source: Sound Digest Archive v02.n349
Bert Doppenberg wrote:
> That's okay with me, but think about the growing use of these drivers in
> commercial systems. I guess that if there were a lot of people who don't like them, why
> bother putting all kind of new systems with Lowther on the market? ;-)
Doesn't seem to keep people from putting transistors in amplifiers...
;-)
Peace
- --
Roscoe Primrose -- mailto:roscoe@aiko.com --
http://www.aiko.com/roscoe
"Once in a while you get shown the light
In the strangest of places if you look at it right." Robert Hunter
"640K ought to be enough for anybody" , Bill Gates, 1981
=========================================================================
From: Thomas Woodley <twoodley@freespace.net>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 15:45:31 -0500 (EST)
Source: Sound Digest Archive v02.n349
> >Have you tried the REPS driver. This kicks the living ^&^%&$%^ out of the
> >DX4. I know this is a poor test since each driver requires it own
> >tweaking. But we swapped out PM2A, DX4 and the REPS (ultralight) and the
> >REPS killed either of them. I would say it took the response an extra
Gordon or anyone else - What is the REPS "ultralight"? I saw the REPS
in an earlier SP but not the ultralight version.
Best, Thom.
=========================================================================
From: Adnan Arduman <adnana@turk.net>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 16:21:23 +0200
Source: Sound Digest Archive v02.n349
Hi,
>I have contacted Carfrae, no response. So have a few of my dealers, no
>response. The look great but how do they sound?
I have heard these speakers during the London show in September and I
totally agree with Bert, they just sound great. To me it was the best sound
of the show (BTW you may read my London show report at
<http://www.arduman.com/aa>). They are well extended in both extremes, they
have excellent inner detail but don't sound edgy, mids have body, dynamics
are very good, what can I say more, they do everything right and they look
good as a bonus.
You may contact Mr. Carfrae from <carfrae@dial.pipex.com>, he replied to me
and I'm sure you will get a response too.
Sincerely,
Adnan
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
visit my personal "NUANCE & FLUENCE" web site:
<http://www.arduman.com/aa>
tel: +90-216-310 44 70 (w)
fax: +90-216-343 42 01
e-mail: <adnana@turk.net>
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 16:35:08 -0500
Source: Sound Digest Archive v02.n349
Owen Young wrote:
> Tom
>
> A while ago, someone posted the following for a PM6A:
>
> >From Klang & Ton magazine 2/93:
> T & S parameters
>
> Re 7.8 ohm
> Le 0.36 mH
> fs 45 Hz
> Qms 2.9
> Qes 0.235
> Qts 0.22
> Sd 211 cm2
> Vas 76 litre
> Cms 1.2 mm/N
> Mmd 11 g
> B*I 9.9 N/A
> SPL 96.5dB
>
> The larger alnico magnet designs (7A, 2A, 5A, 4A), the ceramic C series
> and the new DX rare earth types, may differ a little from the above.
>
> And I can attest to the fact that Lowthers do take a LONG time to start
> sounding any good at all (min 75-150hrs, 300+hrs is better).
>
> Owen
> ps. What is the convention for measuring driver radiator area? A Lowther
> cone measures 14.5cm(5.7") diam actual cone, ie 165 cm2 (not 211 cm2).
>
Hi Owen
Thanks for the numbers, these are certainly believable.
To answer your question, the acoustic piston diameter is normally considered to be
somewhat larger than the cone body alone. This is estimated by taking the
suspension's attachment point (where the motion stops as its attached to the
frame) and to where it attaches to the cone and divide it by two. In other words,
about the half way point of the edge suspension.
Thanks again.
Tom
=========================================================================
From: "Bert Doppenberg" <LCH@lowther.nl>
Subject: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 17:12:58 +0100
Source: Sound Digest Archive v02.n349
Hi Gordon,
>Have you tried the REPS driver. This kicks the living ^&^%&$%^ out of the
>DX4. I know this is a poor test since each driver requires it own
>tweaking. But we swapped out PM2A, DX4 and the REPS (ultralight) and the
>REPS killed either of them. I would say it took the response an extra
>octave in each direction. Also the detail and nuance of the driver was
>spectacular.
No, I haven't heard the REPS (for me, too expensive to consider....). Also, the DX4 isn't
that long on the market, are you sure that they breaked in properly?
>Still too me the shimmer of a cymbal was lost as was the glow and
>resonation of a good set of vibes. Two things that I cannot live without.
>In fullrange speakers the only ones that seem to repoduce these well are
>ones without a wizzer (i.e. Diatone, Fostex 108). The rest fall hard on
>the overtones.
Are you aware that a microphone, recording electronics and the system that reproduces this
recording have a HUGH influence?
A lot of speakers are very much forgiving, some speakers are not! But hey, you do not like
the Lowther's. That's okay with me, but think about the growing use of these drivers in
commercial systems. I guess that if there were a lot of people who don't like them, why
bother putting all kind of new systems with Lowther on the market? ;-)
Bert,
- ------
E-mail:
BD-Design : Sales@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Oris 150 : http://www.lowther.nl/wwwpages/opinions.html
Phone/Fax : +31 341 254500 Mobile: +31 6 51242990
=========================================================================
From: Jim Charron <jimpcn@ionsys.com>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 19:08:33 -0500
Source: Sound Digest Archive v02.n349
Hi, I've used the Fostex 208 in my lowther Mau horn 4.5m cabinet for about
a month and sold it, mainly because it did not go as low as the lowthers and
the Fostex suffers from lack of transparancey; which was more than I could take.
> Regards, Jim Charron
> The builder, who is committed to Lowther but not a religious adherent,
> believes the Fostex 208 and the Mauhorn is a marriage made in heaven, and
> that no Lowther can compare.
>
> Something to think about.
>
> Cheers,
>
> Hugh R. Dean
> Melbourne, Australia
=========================================================================
From: Jim Charron <jimpcn@ionsys.com>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 19:09:08 -0500
Source: Sound Digest Archive v02.n349
Hi, I've used the Fostex 208 in my lowther Mau horn 4.5m cabinet for about
a month and sold it, mainly because it did not go as low as the lowthers and
the Fostex suffers from lack of transparency; which was more than I could take.
> Regards, Jim Charron
> The builder, who is committed to Lowther but not a religious adherent,
> believes the Fostex 208 and the Mauhorn is a marriage made in heaven, and
> that no Lowther can compare.
>
> Something to think about.
>
> Cheers,
>
> Hugh R. Dean
> Melbourne, Australia
=========================================================================
From: "Carter Hendricks" <carter@i1.net>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 20:32:38 -0600
Source: Sound Digest Archive v02.n349
- -----Original Message-----
From: James Melhuish <james@melhuish.org>
To: Tom@ppci.com <Tom@ppci.com>; JoeNet A <sound@lists.io.com>
Date: 30 November, 1999 4:59 PM
Subject: Re: [JN] bass reflex Lowther speakers
>I have an audio website focusing on Single Driver
>Loudspeakers and horns
http://melhuish.org/audio/
This is a very important web site with a lot
of uncommon material. Nice to have James
in the group.
--Carter
=========================================================================
From: "Bert Doppenberg" <LCH@lowther.nl>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 21:01:04 +0100
Source: Sound Digest Archive v02.n349
Hi Roscoe,
>Doesn't seem to keep people from putting transistors in amplifiers... ;-)
Ouch... ;-))
But thinking about this, lot's of people like to have it "cheap"....
Bert,
- ------
E-mail:
BD-Design : Sales@lowther.nl
Lowther Club Holland : LCH@lowther.nl
Homepage : http://www.lowther.nl
Oris 150 : http://www.lowther.nl/wwwpages/opinions.html
Phone/Fax : +31 341 254500 Mobile: +31 6 51242990
=========================================================================
From: "Ken Dangerfield" <bpyakd@mail.island.net>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 1999 23:01:07 -0800
Source: Sound Digest Archive v02.n349
On 30 Nov 99, Thomas Danley said:
> I have an excellent horn design/modeling program (developed under a NASA
> contract for Acoustical Levitation sources at Intersonics) and have taken
> a first look at doing Lowther a "rear horn" design for one of the Joe's.
> Well a good start so far as acoustically considered horn design would be
> to get the real Thiel&Small specs or the real mechanical properties would
> also do, like Fs, Mms, Rdc, BL and radiator area.on there drivers, the
> ones supplied by Lowther are apparently funky. Short of designing/modeling
> the real properties, one is left to only cut and try or copy those who
> have gone before, neither is likely to result in a "breakthru" in
> performance.. Any of you folks have the real driver numbers?
You now have the T/S parameters (measured) for a PM6A. I, for
one, would be interested in what you and your program come up
with for a back loaded horn design for this driver.
Regards,
Ken Dangerfield
=========================================================================
From: "J. Gordon Rankin" <waudio@cinti.net>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 99 10:04:06 -0500
Source: Sound Digest Archive v02.n349
Bert,
Have you tried the REPS driver. This kicks the living ^&^%&$%^ out of the
DX4. I know this is a poor test since each driver requires it own
tweaking. But we swapped out PM2A, DX4 and the REPS (ultralight) and the
REPS killed either of them. I would say it took the response an extra
octave in each direction. Also the detail and nuance of the driver was
spectacular.
Still too me the shimmer of a cymbal was lost as was the glow and
resonation of a good set of vibes. Two things that I cannot live without.
In fullrange speakers the only ones that seem to repoduce these well are
ones without a wizzer (i.e. Diatone, Fostex 108). The rest fall hard on
the overtones.
Gordon
=======> Wavelength Audio <=======
mailto:waudio@cinti.net
http://www.WavelengthAudio.com
ph.fx. 513-271-4186 USA
=========================================================================
From: "J. Gordon Rankin" <waudio@cinti.net>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Tue, 30 Nov 99 17:18:50 -0500
Source: Sound Digest Archive v02.n349
>Gordon or anyone else - What is the REPS "ultralight"? I saw the REPS
>in an earlier SP but not the ultralight version.
Thom,
The ultralight uses a lite cone and extends the range on the top as well
as increase the sensitivity. More expensive than the std...
Gordon
=======> Wavelength Audio <=======
mailto:waudio@cinti.net
http://www.WavelengthAudio.com
ph.fx. 513-271-4186 USA
=========================================================================
From: Owen Young <oyoung@clear.net.nz>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Wed, 01 Dec 1999 09:22:42 +1300
Source: Sound Digest Archive v02.n349
Tom
A while ago, someone posted the following for a PM6A:
From Klang & Ton magazine 2/93:
T & S parameters
Re 7.8 ohm
Le 0.36 mH
fs 45 Hz
Qms 2.9
Qes 0.235
Qts 0.22
Sd 211 cm2
Vas 76 litre
Cms 1.2 mm/N
Mmd 11 g
B*I 9.9 N/A
SPL 96.5dB
The larger alnico magnet designs (7A, 2A, 5A, 4A), the ceramic C series
and the new DX rare earth types, may differ a little from the above.
And I can attest to the fact that Lowthers do take a LONG time to start
sounding any good at all (min 75-150hrs, 300+hrs is better).
Owen
ps. What is the convention for measuring driver radiator area? A Lowther
cone measures 14.5cm(5.7") diam actual cone, ie 165 cm2 (not 211 cm2).
Thomas Danley wrote:
> I have an excellent horn design/modeling program (developed under a NASA
> contract for Acoustical Levitation sources at Intersonics) and have taken a
> first look at doing Lowther a "rear horn" design for one of the Joe's.
> Well a good start so far as acoustically considered horn design would be to
> get the real Thiel&Small specs or the real mechanical properties would also
> do, like Fs, Mms, Rdc, BL and radiator area.on there drivers, the ones
> supplied by Lowther are apparently funky.
> Any of you folks have the real driver numbers?
>
> Tom Danley
=========================================================================
From: "Martin/Campbell family" <martincampbell@apex.net.au>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Wed, 01 Dec 1999 22:34:18 +1100
Source: Sound Digest Archive v02.n349
>> A while ago, someone posted the following for a PM6A:
Yes, that was me.
>> >From Klang & Ton magazine 2/93:
>> T & S parameters
>>
>> Re 7.8 ohm
>> Le 0.36 mH
>> fs 45 Hz
>> Qms 2.9
>> Qes 0.235
>> Qts 0.22
>> Sd 211 cm2
>> Vas 76 litre
>> Cms 1.2 mm/N
>> Mmd 11 g
>> B*I 9.9 N/A
>> SPL 96.5dB
That last one appeared to be taken as the mid-point between the 2-10KHz
region at or a little above 100db and the 1Khz and down region that was
about 90db. All in all not a very usefull number without the accompanying
graph. I guess it is an honest 96±6db.
Peter Campbell
=========================================================================
From: Jim Charron <jimpcn@ionsys.com>
Subject: Re: [JN] bass reflex Lowther speakers
Date: Wed, 01 Dec 1999 20:29:51 -0500
Source: Sound Digest Archive v02.n350
J. Gordon Rankin wrote:
> Guys,
>
> I really do not see why someone can't do the same with a Lowther. I
> really don't know why nobody seems to think the Lowther could use a boost
> in the top and bottom end. To me, I just don't get it. I have heard some
> 20 different versions, always leave with the same conclusion: Glorious
> midrange with some peaking, no bass, no treble.
>
> Gordon
>
Hey Gordon, here's a suggestion, or an alternative,use a proper back horn
loaded cabinet like
my 4.5 meter Mau Horn and stick in your favorite trusty Lowther and
get some filtering ideas from my good buddy Larry Van Warmer. With
alittle fooling around with caps and coils, I
promise good bass, reduced peaks, and top end that is as good as
the lowther driver used.
Stronger the magnet, better the top end, .... which in my opinion is decent.
Regards, Jim Charron
=========================================================================
From: "J. Gordon Rankin" <waudio@cinti.net>
Subject: [JN] Bass reponse in Tuned Pipe for low Qt woffers/fullrange
Date: Mon, 30 Aug 99 11:19:19 -0400
Source: Sound Digest Archive v02.n267
Gang,
I have built many TP's before for Triangles, Diatones and some std
woofers with good results. Sometime as in the case of the Diatones, other
boxes worked better (i.e. ported).
Anyway I had a pair of Fostex 208's haning around so I designed and built
a pair of ugly but correct cabs for the units.
No bass, none what so ever. I guess I should have seen this coming or the
Lowther gang would have been on TWQP's like crazy. I tried no insulation,
max insulation and everything in between. As in all the others I have
made, no insulation in or near the throat area and max in the back
cavity. Ended up with the best response in the area of about 1/4 fill in
the rear, low compared to the others listed above.
I did build a filter and getting good bass to 40Hz now, but only 95dB
effeciency.
Any others experienced this in TP's?
=======> Wavelength Audio <=======
mailto:waudio@cinti.net
http://www.WavelengthAudio.com
ph.fx. 513-271-4186 USA
=========================================================================
From: "Ken Dangerfield" <bpyakd@mail.island.net>
Subject: [JN] Bass Short Horn Question
Date: Thu, 17 Feb 2000 15:26:50 -0800
Source: Sound Digest Archive v02.n452
On Altec 211, some Onken types and other bass short horn/reflex
combinations, the "throat" for each driver is much larger than would
be predicted by the formulae of Leach, Edgar, et al for a full length
horn.
What considerations are at work here and is there a reliable
formula or other way of determining the optimum throat size for
such a short horn with 2 drivers mounted on the horn?
Thanks and regards,
Ken Dangerfield
=========================================================================
From: Larry Van Wormer <lvw@bmts.com>
Subject: Re: [JN] Bass Short Horn Question
Date: Thu, 17 Feb 2000 20:24:18 -0500
Source: Sound Digest Archive v02.n452
I'd appreciate it if any answers were posted to the list, as I'm looking
at this area myself right now. Isn't it true that such constructions are
really more waveguides than horns? That concept is quite interesting,
since it seems to give about 6 db increase in efficiency. The questions
I have are about the tradeoffs: Does it affect output clarity? How high
in frequency does it work well? Data on the DDH site, for instance,
would seem to indicate it works fine up to more than 1 kHz. Any
practical experience anyone cares to pass along? (My thought: if the
waveguide concept works well enough at higher frequencies, I could start
with a 100 db driver, add a waveguide, and get 106 db! And, without a
complex cabinet as with a real horn! Sounds too good to be true, so
maybe someone will point out the flaw...
http://www.users.uswest.net/~ddshorns/
Larry Van Wormer
Ken Dangerfield wrote:
>
> On Altec 211, some Onken types and other bass short horn/reflex
> combinations, the "throat" for each driver is much larger than would
> be predicted by the formulae of Leach, Edgar, et al for a full length
> horn.
>
> What considerations are at work here and is there a reliable
> formula or other way of determining the optimum throat size for
> such a short horn with 2 drivers mounted on the horn?
>
> Thanks and regards,
> Ken Dangerfield
=========================================================================
From: "Ken Dangerfield" <bpyakd@mail.island.net>
Subject: Re: [JN] Bass Short Horn Question
Date: Thu, 17 Feb 2000 18:24:45 -0800
Source: Sound Digest Archive v02.n453
Larry,
I'm sure that John Tucker (of Exemplar fame) has already worked
his way through this stuff but he's virtually impossible to get ahold
of. The SP articles on the development of the Exemplar don't really
give away too many secrets :-)) Also, they were working with a
single driver and I want to use two.
I hope we get some useful responses.
Regards,
Ken Dangerfield
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: [JN] Bass Short Horn Question
Date: Fri, 18 Feb 2000 13:33:11 +0100
Source: Sound Digest Archive v02.n453
- ----------
> De : Ken Dangerfield <bpyakd@mail.island.net>
> A : sound@deliverator.io.com
> Objet : [JN] Bass Short Horn Question
> Date : vendredi 18 février 2000 00:26
>
> On Altec 211, some Onken types and other bass short horn/reflex
> combinations, the "throat" for each driver is much larger than would
> be predicted by the formulae of Leach, Edgar, et al for a full length
> horn.
Hello,
I think that due to the shape and the max aperture angle (180degrees or
nearly) of those horns, that when the wavefronts (more or less cylindrical)
come out of the horn mouth their expansion still continue on a certain
distance from the throat to follow an expansion law near of an hyperbolic
(= exponential, hypex or catenoidal) law.
So in fact the length to consider is larger than the length of the horn
itself ans so is also the mouth area.
Best regards,
Jean-Michel Le Cleac'h, Paris, France
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: Re: [JN] Bass Short Horn Question
Date: Fri, 18 Feb 2000 15:20:21 -0500
Source: Sound Digest Archive v02.n453
Ken Dangerfield wrote:
> On Altec 211, some Onken types and other bass short horn/reflex
> combinations, the "throat" for each driver is much larger than would
> be predicted by the formulae of Leach, Edgar, et al for a full length
> horn.
>
> What considerations are at work here and is there a reliable
> formula or other way of determining the optimum throat size for
> such a short horn with 2 drivers mounted on the horn?
>
> Thanks and regards,
> Ken Dangerfield
Hi Ken
I don't recall ever looking at Altec cone drivers with respect to horn
loading and I don't have T&S params for anything of there's relevant but
from what I recall, they (like everyone then) made fairly light weight
(so far as moving mass) drivers.
The real goal in horn loading is to reduce the driver excursion for a
given acoustic power and in the process reduce the drivers distortion
(primarily distance of motion related).
It is possible that given the high cutoff (was 300 or 500 HZ in most of
there stuff as I recall) and a low moving mass driver, that the "proper"
throat area was approximately equal to the driver.
Lets not forget that this was also before a direct method of predicting
response existed, these were the "cut and try" days of loudspeaker design
with slide rule math where applicable.
I have never seen a technical treatment of a vented box / horn like a VOT
or 211 either, given the phase reversal at horn to vented trade off
frequency added to the normal vented box phase shift would likely make
this "interesting" sounding as well.
A word to those with old VOT's and other similar boxes. These were made
before the idea of calculating box response based on driver parameters
existed, these were made before anyone thought about making the amplifier
a theoretically "zero impedance voltage source". As a result, driving
one of these old systems with modern amp is likely to give substantially
wimpier bass than normal. This is because the driver is now "over damped"
for the box being now driven by a low Z instead of one near its value.
For that matter most horns deliver flatter response when driven from a
matched source rather than a voltage source.
Fortunately it is easy to restore the proper source impedance, simply add
a series resistor approximately equal to the driver Rdc. This does cost a
little in sensitivity but often the horn section has "sensitivity to
burn".
Tom Danley
=========================================================================
From: John Niven <jn@cypress.com>
Subject: Re: [JN] Bass Short Horn Question
Date: Fri, 18 Feb 2000 13:12:09 -0800
Source: Sound Digest Archive v02.n454
Tom,
This is an interesting comment. I was concerned that my ss amplifier
might not sound as good if run at low watts with an efficient horn (I
think it's class B). Do you mean that I might be better putting a series
resitor between the amp and the horn? At least until I get into SE valve
amps :-)
John
Thomas Danley wrote:
> Fortunately it is easy to restore the proper source impedance, simply add
> a series resistor approximately equal to the driver Rdc. This does cost a
> little in sensitivity but often the horn section has "sensitivity to
> burn".
>
> Tom Danley
- --
_\|/
Q John Niven (jn@cypress.com)
/ \ Staff Product Engineer
/ o\ Cypress Semiconductor
( \/ 3901 North First Street
|\ San Jose,CA 95134
| \ Telephone 408-456-1868
L L
=========================================================================
From: Martin Seddon <mseddon@iinet.net.au>
Subject: [JN] Bass Unity
Date: Fri, 15 Sep 2000 18:21:11 +0800
Source: Sound Digest Archive v02.n662
>Delivered-To: mseddon@iinet.net.au
>From: "Seddon, Martin M." <Martin.Seddon@woodside.com.au>
>To: "'Martin'" <mseddon@iinet.net.au>
>Subject: Lowther-Bass Unity
>Date: Fri, 15 Sep 2000 12:57:05 +0800
>X-Mailer: Internet Mail Service (5.5.2650.21)
>
Hi,
I just had the idea (well Tom Danley's idea) of doing a Unity on a Lowther
back horn.
Here's the story. I have a front horn (or soon will have) to strap on a
PM2A seeking the usual tales of Nirvana. I can load the back with a poly
pipe to get low Fc of 160HZ and use a sub woofer. Or I can load the back
with a back horn, but bass level will be way down.
OK, so why dont I build the back horn and power it from a hole in the side
with a supplemetary bass driver? Is there a magic G spot somewhere up there
promising blessed Unity ? Or will this just stuff up what the Lowther
does?
I know Lowther dont cross paths with Physics, and probably I got to
apologise for dragging this hoary old subject up again, but any chance of
this
working, Tom?
Martin
Martin Seddon
Operations Engineer
Tel. (08) 9348 6266
Fax. (08) 9348 4853
Mobile 0403 053514
=========================================================================
From: "Franck JONCHERAY" <fjoncheray@ccf.fr>
Subject: [JN] Bass with Klangfilm
Date: Thu, 02 Mar 2000 11:57:40 +0100
Source: Sound Digest Archive v02.n471
The Klangfilm Eurodyn used a 15 ' bass loudspeaker on a big open baffle (2,3 m * 2,3 m I believe).
I suppose this system (that I have never heard) had good bass.
Is it always possible to make good bass with a 15' driver if the open baffle is really big ?
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=========================================================================
From: Andrew Brandon <ajbrandon@yahoo.com>
Subject: Re: [JN] BassZilla
Date: Sat, 26 May 2001 12:23:53 -0700 (PDT)
Source: Sound Digest Archive v02.n893
I just received my plan for it yesterday. For $20.00
its worth it I think. He offers no theory behind his
thinking, saving he feels this works very well. It
uses a 15" Audax woofer. I obviously have not built /
heard it but wonder about that big 15" keeping up with
the fullrange driver but then again its crossed over
pretty low. If you go to his site www.blackdahlia.com
and take a look around he gives a pretty good look at
it, I think tip #24 is what its called .
The woofers are not cheap but he does say just buy the
best and get over it.
Andrew
- --- Ian McPhail <i.mcphail@rmit.EDU.AU> wrote:
> JoeNetters, anyone heard Dick Olsher's BassZilla
> design?
> Lowrher DX4 or Fostex 208 open baffle coupled with
> Audax 15" bass.
> www.blackdahlia.com
> regards Ian
__________________________________________________
Do You Yahoo!?
Yahoo! Auctions - buy the things you want at great prices
http://auctions.yahoo.com/
=========================================================================
From: "Ian McPhail" <i.mcphail@rmit.EDU.AU>
Subject: [JN] BassZilla
Date: Sat, 26 May 2001 17:06:18 +1000
Source: Sound Digest Archive v02.n893
JoeNetters, anyone heard Dick Olsher's BassZilla design?
Lowrher DX4 or Fostex 208 open baffle coupled with Audax 15" bass.
www.blackdahlia.com
regards Ian
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] BassZilla
Date: Sat, 26 May 2001 19:03:28 EDT
Source: Sound Digest Archive v02.n893
- --part1_68.f3f2085.28419040_boundary
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
In a message dated 5/26/01 12:28:07 PM US Mountain Standard Time,
ajbrandon@yahoo.com writes:
> The woofers are not cheap but he does say just buy the best and get over it.
>
Greets!
Please look at Lambda:
www.lambdacoustics.com
Our guy Nick McKinney has several models of TD15... I have a TD15M mounted in
an 80 Hz edgarhorn crossed over at 3.3K , yes 3300 Hz, to a dynamic horn
tweeter.
Big tone from a triode wired EL34 SE. Very nearly 2 watts... the M can handle
300 watts, but, 2 are plenty indoors, got me to install volume attenuators :)
Happy Ears!
Al B^}
- --part1_68.f3f2085.28419040_boundary
Content-Type: text/html; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
<HTML><FONT FACE=arial,helvetica><BODY BGCOLOR="#ffffff"><FONT SIZE=2>In a message dated 5/26/01 12
:28:07 PM US Mountain Standard Time,
<BR>ajbrandon@yahoo.com writes:
<BR>
<BR>
<BR><BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px
; PADDING-LEFT: 5px">The woofers are not cheap but he does say just buy the best and get over it.
<BR></BLOCKQUOTE></FONT><FONT COLOR="#000000" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0">
<BR>
<BR>
<BR>Greets!
<BR>
<BR>Please look at Lambda:
<BR>
<BR>www.lambdacoustics.com
<BR>
<BR>Our guy Nick McKinney has several models of TD15... I have a TD15M mounted in
<BR>an 80 Hz edgarhorn crossed over at 3.3K , yes 3300 Hz, to a dynamic horn
<BR>tweeter.
<BR>
<BR>Big tone from a triode wired EL34 SE. Very nearly 2 watts... the M can handle
<BR>300 watts, but, 2 are plenty indoors, got me to install volume attenuators :)
<BR>
<BR>Happy Ears!
<BR>Al B^}
<BR></FONT></HTML>
- --part1_68.f3f2085.28419040_boundary--
=========================================================================
From: "Kurt Th. Steffensen" <kurt-steffensen@teliamail.dk>
Subject: [JN] RE BAT
Date: Wed, 4 Aug 1999 17:38:17 +0300
Source: Sound Digest Archive v02.n221
I misunderstood what the BAT amp , was all about.
If it is (As I understands it now ) a design in which sevaral ECC 88 , or that alike is parralled it
is very uninteresting to me.
It is total impossible to match these under all the conditions they will meet ,
when reproducing music signals.
A simple normal stage will allways be better , in my experience.
I haven´t yet heard a stage , being tubes , transistors or FET´s , that did not
sounded better when the parrallel-mess was reduced to a single device.
Why not go for a single high current tube instead ?
Simple is allways best , isn´t that the lection we all experience again and again ?
Only in OTL´s we have to accept the many parallel tubes.
That is one of the weak compromises in these circuits.
(If we do not want to swap to FET or SS.)
- - Sincerely Kurt
Sincerely
- - Kurt Steffensen
=========================================================================
From: Peter Sikking <peter.sikking@virgin.net>
Subject: [JN] Batteries again, how fast...
Date: Mon, 30 Apr 2001 23:00:33 +0100
Source: Sound Digest Archive v02.n876
OK,
the recent thread on battery supplies has revamped my interest in them.
now the last time I was pondering on them, somebody muttered
'chemical delay' and I imagened them to be sluggish.
Now Jim has told us already their internal resistance is in the
centiOhm ballpark, but I can imagine this to be a steady-state DC spec.
So has anybody ever measured the responce when a current change is
induced over a battery, both in frequency domain (frequency sweep,
sine, square or other wave, doesn't matter) and in time domain
(spike, step)?
Looks like great project for one of Simon's students. >^}
And are there not any low price&size 24V lead batteries?
--ps/031
=========================================================================
From: Jim de Kort <jim@vt52.com>
Subject: Re: [JN] Batteries again, how fast...
Date: Tue, 01 May 2001 01:31:22 +0200
Source: Sound Digest Archive v02.n876
Hi,
>Now Jim has told us already their internal resistance is in the
>centiOhm ballpark, but I can imagine this to be a steady-state DC spec.
Milli-ohm if you take a single battery (15-20m), but it is indeed a static
value.
>And are there not any low price&size 24V lead batteries?
If you live in the UK (lucky you) try www.steatit.co.uk. They have some
less expensive 12V SLA's compared to other brands (30-40% less). You don't
need the hefty stuff like 10-20Ah, the smaller 3-4Ah will do nicely for
even a tube like the 300B.
Regards,
Jim de Kort
jim@vt52.com
=========================================================================
From: Simon Busbridge <S.C.Busbridge@bton.ac.uk>
Subject: Re: [JN] Batteries again, how fast...
Date: Tue, 1 May 2001 09:05:27 +0100 (BST)
Source: Sound Digest Archive v02.n877
>Looks like great project for one of Simon's students. >^}
Well use of batteries in general would be a good project.
Simon
Simon Busbridge, BSc(Hons) PhD CPhys MInstP
School of Engineering
University of Brighton
Lewes Road
Moulsecoomb
Brighton BN2 4GJ
UNITED KINGDOM
Tel: 0044 (0)1273 642542
Fax: 0044 (0)1273 642327/642301
e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com
=========================================================================
From: Peter Sikking <peter.sikking@virgin.net>
Subject: Re: [JN] Batteries again, how fast...
Date: Tue, 01 May 2001 10:14:23 +0100
Source: Sound Digest Archive v02.n877
Jim wrote:
> >And are there not any low price&size 24V lead batteries?
> If you live in the UK (lucky you) try www.steatit.co.uk.
Hmmm, no such site. Can you check that name again?
--ps/031
=========================================================================
From: Simon Busbridge <S.C.Busbridge@bton.ac.uk>
Subject: Re: [JN] Batteries again, how fast...
Date: Tue, 1 May 2001 10:50:33 +0100 (BST)
Source: Sound Digest Archive v02.n877
Thanks for this Jim, they _are_ cheap! I just looked up 12 V 1.3 Ah,
3.43 UKP! This is about 1/3 of the price from RS. This definitely
makes battery supplies attractive.
Simon
Simon Busbridge, BSc(Hons) PhD CPhys MInstP
School of Engineering
University of Brighton
Lewes Road
Moulsecoomb
Brighton BN2 4GJ
UNITED KINGDOM
Tel: 0044 (0)1273 642542
Fax: 0044 (0)1273 642327/642301
e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com
On Tue, 1 May 2001, Jim de Kort wrote:
> Hi,
>
> > > >And are there not any low price&size 24V lead batteries?
> > > If you live in the UK (lucky you) try www.steatit.co.uk.
> >
> >Hmmm, no such site. Can you check that name again?
>
> oops... www.steatite.co.uk
>
>
>
>
> Jim de Kort
> jim@vt52.com
>
> http://www.vt52.com
> http://www.ux226.com
>
>
=========================================================================
From: Jim de Kort <jim@vt52.com>
Subject: Re: [JN] Batteries again, how fast...
Date: Tue, 01 May 2001 11:40:37 +0200
Source: Sound Digest Archive v02.n877
Hi,
> > >And are there not any low price&size 24V lead batteries?
> > If you live in the UK (lucky you) try www.steatit.co.uk.
>
>Hmmm, no such site. Can you check that name again?
oops... www.steatite.co.uk
Jim de Kort
jim@vt52.com
http://www.vt52.com
http://www.ux226.com
=========================================================================
From: Jim de Kort <jim@vt52.com>
Subject: Re: [JN] Batteries again, how fast...
Date: Wed, 02 May 2001 08:48:01 +0200
Source: Sound Digest Archive v02.n877
HI,
>Thanks for this Jim, they _are_ cheap! I just looked up 12 V 1.3 Ah,
>3.43 UKP! This is about 1/3 of the price from RS. This definitely
>makes battery supplies attractive.
You UK guys are lucky. If it weren´t for shipping costs I would have bought
there myself :)))
Jim de Kort
jim@vt52.com
http://www.vt52.com
http://www.ux226.com
=========================================================================
From: "Ellen Oler" <ellenoler@earthlink.net>
Subject: [JN] battery bias
Date: Wed, 08 Dec 1999 06:56:31 -0500
Source: Sound Digest Archive v02.n357
Paul Joppa asked me to forward these three postings, he is still having ISP
problems.
Number one :
Recently the subject of battery bias came up. I believe this has come up
before, though I can't find anything in my saved-items collection. As I
remember it, there are three basic setups, with somewhat different
requirements:
1) Battery replaces cathode resistor. This battery is being charged
continuously by the cathode current. The standard is Ni-Cd, which are
usually thought to be OK at charging currents of 0.02 to 0.05 times the
amp-hour capacity. Some people have expressed a preference for lead-acid
sealed batteries; I don't know the maximum continuous charging current for
those. In the recent thread, NiMH batteries were mentioned as having higher
capacity and a higher maximum continuous charging current of 0.10 times the
amp-hour capacity. (Can anybody confirm that, or provide a number for
lead-acid?) Presumably all these get warm from the charging current, and
the heat in the circuit from other components will potentially reduce the
maximum charging current. In all these cases, the fact that such batteries
slowly self-discharge is not important since they are continually recharged.
2) Battery in series with a large grid resistor (500k-1meg), connected
between cathode and grid. (Because the grid is held negative, this usually
requires an input capacitor also.) In this arrangement, the battery current
is limited by the grid resistor, so the principal requirement is for long
shelf life (there is always some risk from grid current, see below). There
is still some grid current, from the ionization current and from any
transient drive voltages that exceed the bias. Alkaline batteries are very
good, with a typical shelf life of about 5 years. Lithium batteries are now
also readily available, at least in the AA and 9-v sizes; they have a shelf
life of 10 years. They are also said to work over a wide temperature range
but it's unclear whether that includes high temperatures. Carbon-zinc
batteries do not have so long a life, so they must be checked periodically.
Rechargeable batteries are not so suitable, since they self-discharge over
a few months and would have !
to be recharged frequently. A dead battery would remove the bias, leading
to excessive tube current and possible damage.
3) Battery in series with the grid. This eliminates the need for an input
capacitor, which is a very attractive feature. However, especially with a
low-impedance source, grid current can readily flow through the battery.
Normally a battery with a long shelf life would be preferred in this
application, but at least one person on this list has reported an exploding
alkaline battery. I speculate that was most likely due to grid current
over-charging the battery, since alkaline cells are known to be intolerant
of over-charging. It is difficult to make a recommendation in this case.
=========================================================================
From: Martin Needleman <mrndlmn@bayserve.net>
Subject: Re: [JN] battery bias
Date: Wed, 8 Dec 1999 08:24:30 -0500 (EST)
Source: Sound Digest Archive v02.n357
On Wed, 8 Dec 1999, Ellen Oler wrote:
> NiMH batteries were mentioned as having higher
> capacity and a higher maximum continuous charging current of 0.10 times the
> amp-hour capacity. (Can anybody confirm that, or provide a number for
> lead-acid?)
Anecdotal "evidence" only but my home-brew VT-52 SE was destroying four NC
batteries a month - 2 C cells in series on the cathode of each
triode-wired transformer coupled 7788 driver. Switched to NIMH and haven't
had a problem in a year and a half.
=========================================================================
From: tube@jump.net
Subject: Re: [JN] battery bias
Date: Wed, 08 Dec 1999 10:55:36 -0600
Source: Sound Digest Archive v02.n357
Martin Needleman wrote:
> [snip]
> Anecdotal "evidence" only but my home-brew VT-52 SE was destroying four NC
> batteries a month - 2 C cells in series on the cathode of each
> triode-wired transformer coupled 7788 driver. Switched to NIMH and haven't
> had a problem in a year and a half.
Martin,
I have seen several people using the 7788 triode-wired, and of course the SP
article. Does it really sound that good compared to other triodes, or does the
convenience of a one-tube low output impedance stage more than make up
for any sonic problems?
Phil
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: Re: [JN] battery bias
Date: Wed, 8 Dec 1999 11:07:20 -0500
Source: Sound Digest Archive v02.n357
> at least one person on this list has reported an exploding
>alkaline battery. I speculate that was most likely due to grid current
>over-charging the battery, since alkaline cells are known to be intolerant
>of over-charging.
that might be me, but the batteries i sploded were doing a fixed bias
through the secondary of an IT to the grid of an output...
in this situation a nicad/lead acid/nimh will easily stay
charged...alkaline, carbon zinc... has a good chance of sploding....
dave
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] battery bias
Date: Wed, 8 Dec 1999 11:07:29 EST
Source: Sound Digest Archive v02.n357
In a message dated 12/8/99 6:28:33 AM US Mountain Standard Time,
mrndlmn@bayserve.net writes:
> home-brew VT-52 SE was destroying four NC batteries a month
Greets Jeets Neets,
My inline AA grid bias has been flawless for months. It IS a Radio Shack
alkaline.
WE 396A driving triode-strapped Philco 6U6GT SE.
Happy Ears!
Al B^}
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: Re: [JN] battery bias
Date: Wed, 8 Dec 1999 11:09:46 -0500
Source: Sound Digest Archive v02.n357
>Anecdotal "evidence" only but my home-brew VT-52 SE was destroying four NC
>batteries a month - 2 C cells in series on the cathode of each
>triode-wired transformer coupled 7788 driver. Switched to NIMH and haven't
>had a problem in a year and a half.
hmm... I have been running 2- 4.0AH Dcells for well over a year problem
free... what kind of C-cells were they???
what size nimh batteries are you using???
dave
=========================================================================
From: Martin Needleman <mrndlmn@bayserve.net>
Subject: Re: [JN] battery bias
Date: Wed, 8 Dec 1999 14:12:26 -0500 (EST)
Source: Sound Digest Archive v02.n358
Phil,
I haven't really compared it to other triodes but, to my ear, it sounds
remarkably good. I'm running it right on the hairy edge - 30+ milliamps
with 185 raw volts on the plate and two NIMH AA cells on the cathode.
It's coupled to one of Lucas Cant's interstage transformers which Lucas
claims can take 35 mA before saturation.
To answer your second question - I chose this configuration because it was
so simple that even I couldn't mess it up 8*)
Martin
On Wed, 8 Dec 1999 tube@jump.net wrote:
> Martin,
>
> I have seen several people using the 7788 triode-wired, and of course the SP
> article. Does it really sound that good compared to other triodes, or does the
> convenience of a one-tube low output impedance stage more than make up
> for any sonic problems?
>
> Phil
>
=========================================================================
From: StepHydro@aol.com
Subject: [JN] Battery bias question
Date: Fri, 5 Feb 1999 20:30:01 EST
Source: Sound Digest Archive v02.n030
I've been reading about others' experiments in battery bias. I am converting a
PP 6L6 mono amp to fixed bias. I have a ton of 180mA ni-cd cells around the
house from little cars (I stole the motors for free-flight model airplanes
:-).
If I were to stack these to get the -22.5VDC that I need, would I have to add
a charger circuit to keep them up?
Finally, in the design I'm copying, there are 270K grid resistors to each tube
(junction of coupling cap and stopper) from the bias suply. In order to use
one cell stack for both tubes, I think I'd have to have a resistor like this
sitting above the Ni-Cds. Would its value need to be that high?
If someone knows of a schematic using battery bias of this voltage magnitude,
please send me the URL.
TIA and cheers/Carron
Cheers/Carron
=========================================================================
From: Joseph Lowe <jlowe@cdc.net>
Subject: Re: [JN] Battery bias question
Date: Sat, 6 Feb 1999 22:37:34 -0500 (EST)
Source: Sound Digest Archive v02.n031
On Fri, 5 Feb 1999 StepHydro@aol.com wrote:
> If I were to stack these to get the -22.5VDC that I need, would I have to add
> a charger circuit to keep them up?
Yes, they would go flat after a while. You do not really need to use
nicads for grid bias. If you are looking for -22.5 V, then Radio Shack
sells a small 22.5 volt battery that is perfect for this. There is no
current drawn from the battery when it is in the grid circuit. In fact
what you will find is that the voltage will rise slightly on the battery
from grid leakage, a very low level charging current will flow.
>
> Finally, in the design I'm copying, there are 270K grid resistors to each tube
> (junction of coupling cap and stopper) from the bias suply. In order to use
> one cell stack for both tubes, I think I'd have to have a resistor like this
> sitting above the Ni-Cds. Would its value need to be that high?
Not really, but if you go too low it will load the driver stage. You still
must not violate the maximum grid resistance stated in the data for the
tube, even with battery bias.
A final point... If you put the batteries in the cathode circuit, then you
MUST use nicads. They will have to take the full cathode current, which
for power tubes will most likely be way too much. This is better left for
low level circuits.
=========================================================================
From: "Epstein, Jeremy" <JEpstein@ndbcap.com>
Subject: [JN] Battery charger
Date: Fri, 20 Apr 2001 12:10:36 -0400
Source: Sound Digest Archive v02.n871
The current discussion of battery supplies is fantastic - it is just the
kind of thing I read Joenet for - total fringe activity, completely away
from mainstream audio thought. Special thanks to Jim DeKort for his
contributions, I know he is way far down this road of battery supplies so it
is good to get his experience.
I know I am reading this discussion with great interest. As you know I am
running that Free Lunch 2A3 amp and this battery idea looks like a fantastic
way to get a split, bypassed DC supply of arbitrary (with 12V quanta I
guess) values. Very interesting to me, obviously there are practical
problems but who cares? This might be a way to get rid of bypass caps AND PS
caps, holy moly!
- -j
=========================================
Jeremy Epstein........jepstein@ndbcap.com
=========================================
=========================================================================
From: "Epstein, Jeremy" <JEpstein@ndbcap.com>
Subject: [JN] Battery charger
Date: Fri, 20 Apr 2001 12:27:35 -0400
Source: Sound Digest Archive v02.n871
He is probably launching a satellite or something, but any time now Danielak
will chime in and tell us how to run all this stuff from a solar panel.
(Won't help Siimon in rainy Oxford, but for the rest of us . . . .)
- -j
=========================================
Jeremy Epstein........jepstein@ndbcap.com
=========================================
=========================================================================
From: Jim de Kort <jim@vt52.com>
Subject: Re: [JN] Battery charger
Date: Fri, 20 Apr 2001 20:01:36 +0200
Source: Sound Digest Archive v02.n871
Hi,
>He is probably launching a satellite or something, but any time now Danielak
>will chime in and tell us how to run all this stuff from a solar panel.
I've actually contemplated this idea, but the cost of a good panel (3 amps
continuous) is just a bit too high unless I can find one or two at a
surplus store.
Regards,
Jim de Kort
jim@vt52.com
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] Battery charger
Date: Mon, 23 Apr 2001 10:40:24 -0400
Source: Sound Digest Archive v02.n873
hi guys,
jeremy is about right.
i have been terrible busy lately.
but since he called me out, i oughta get up to date.
1. i use LEAD-filled solder.
2. i use a crappy $10 soldering iron. (got a weller station in a box
somewhere, but never got around to it...)
3. i use the interconnects that came with my CD player.
4. can't afford a SACD player, yet.
5. i don't have any "audiophile" recording (that i know of...)
there.
i think i'm up to date thru april... ;)
this whole battery power and charging thing was discussed in detail
a few months back.
jim de kort is the MAN.
in the end, his approach is the safest, and most economical way of
handling many series SLA batteries.
this is because each cell is charged individually, according to the
manufacturers' recommendations for long service life.
the SLA chargers themselves are very cheap and simple.
with a little more overhead, could be tweaked for more feature
like temp sensing/compensation, timed operation, etc.
but i doubt these features are required in this case...
other battery choices might change matters, significantly.
but i'm not sure that nicads, nimh, li ion, etc, would be a better choice.
the adjustable zener shunt has been done before.
it was scheduled to fly on the mars 01 lander Li Ion battery
(sister mission to recently launched "mars oddessy" orbitter).
there are some drawbacks to this approach.
namely the dissipation of the shunt elements -especially if a reasonably
high charge rate is used.
my bretheren in california patented (?!?) this approach
along with a neat solution (complication) to the dissipation
problem.
the shunt element was made up of a darlington power transistor
with a small value resistor in the emmitter.
the voltage across this resistor was read differentially
(for each cell/shunt combination) and fed back to the main
constant-current source. when the current shunted in any cell
became excessive, the constant-current supply would be cut back,
proportionately.
this approach, however, assumes all cells have reasonably
equal charge/voltage characteristics/charge demands....
i don't want to get into this...
there are pros and cons for any of these systems,
but in the end, it is much easier to take the batteries off-line
and charge them individually.
the relays, then, are just a neat tool to do the change-over
for you...
bob.d.
> ----------
> From: Epstein, Jeremy[SMTP:JEpstein@ndbcap.com]
> Sent: Friday, April 20, 2001 12:27 PM
> To: Joenet (E-mail)
> Subject: [JN] Battery charger
>
> He is probably launching a satellite or something, but any time now
> Danielak
> will chime in and tell us how to run all this stuff from a solar panel.
> (Won't help Siimon in rainy Oxford, but for the rest of us . . . .)
>
> -j
> =========================================
> Jeremy Epstein........jepstein@ndbcap.com
> =========================================
>
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] Battery charger
Date: Mon, 23 Apr 2001 10:49:33 -0400
Source: Sound Digest Archive v02.n873
i haven't drawn this out in my mind, again,
but it seems to me that the dual-stacked supply (a la slagle)
is the way to go for this type of arrangement.
this way the two current loops are essentially isolated.
you don't have to worry about imbalanced loading above and below
the tap point.
then again, perhaps the free-lunch, 2a3 cathode battery will
be constantly charging.
perhaps a plus (use NiCd based upon charge rate of <C/10).
how about picking up a few honda insight 144V battery packs.
they're only 6.5Ah, since the electric motor only supplements
the gas engine.
they are NiMh, so i'll bet they are $$$!!!
> ----------
> From: Epstein, Jeremy[SMTP:JEpstein@ndbcap.com]
> Sent: Friday, April 20, 2001 12:10 PM
> To: Joenet (E-mail)
> Subject: [JN] Battery charger
>
> The current discussion of battery supplies is fantastic - it is just the
> kind of thing I read Joenet for - total fringe activity, completely away
> from mainstream audio thought. Special thanks to Jim DeKort for his
> contributions, I know he is way far down this road of battery supplies so
> it
> is good to get his experience.
>
> I know I am reading this discussion with great interest. As you know I am
> running that Free Lunch 2A3 amp and this battery idea looks like a
> fantastic
> way to get a split, bypassed DC supply of arbitrary (with 12V quanta I
> guess) values. Very interesting to me, obviously there are practical
> problems but who cares? This might be a way to get rid of bypass caps AND
> PS
> caps, holy moly!
>
> -j
> =========================================
> Jeremy Epstein........jepstein@ndbcap.com
> =========================================
>
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] Battery charger
Date: Mon, 23 Apr 2001 10:55:28 -0400
Source: Sound Digest Archive v02.n873
yes, solar power is still NOT CHEAP.... ;(
and the overhead to do anything other than (semi)constant
current charging, or to use the array as efficiently
as possible (peak-power tracking) would make the supply
nastier than the ac mains....
i'd imagine there would be a fair amount of HF noise
(RF and UV/solar flare induced) picked up by these things...
although i have not looked into it myself... ;)
> ----------
> From: Jim de Kort[SMTP:jim@vt52.com]
> Sent: Friday, April 20, 2001 2:01 PM
> To: Epstein, Jeremy; Joenet (E-mail)
> Subject: Re: [JN] Battery charger
>
> Hi,
>
> >He is probably launching a satellite or something, but any time now
> Danielak
> >will chime in and tell us how to run all this stuff from a solar panel.
>
> I've actually contemplated this idea, but the cost of a good panel (3 amps
>
> continuous) is just a bit too high unless I can find one or two at a
> surplus store.
>
>
>
> Regards,
>
>
> Jim de Kort
> jim@vt52.com
>
=========================================================================
From: Peter Boser <pboser@yahoo.com>
Subject: [JN] Battery filaments
Date: Sat, 9 Dec 2000 11:53:15 -0800 (PST)
Source: Sound Digest Archive v02.n756
I've been reading the thread about using batteries on
filaments, and spied the 6volt (9.5aH) batteries from
my daughter's Power Wheels Barbie Jeep. The warnings
say they contain lead and acid, so I guess they're
lead acid batteries. I charged them up a month or
more ago, but it got cold and they never went back
into the Jeep. (No heater on the Jeep.) So, I put the
volt meter on them and found that they didn't need
recharging -- they were at a bit less than 6.5 volts.
I took one and hooked it up to the filaments on my
breadboard 5842 spud amp, and it ran at 6.28 volts
(pretty close!). (Still using a lab power supply --
haven't gotten around to building a proper power
supply, enclosure, etc.) Wow, that's really quiet!
The power transformer's physical hum on my Bottlehead
Foreplay preamp is much louder than anything I can
hear through the speakers! I haven't been using this
amp for a while, since I finished my 2A3 amps
(Bottlehead Afterglows), so I guess I'll try switching
back and forth to see what I think. What do the
anti-battery forces say will be the downside?
As was suggested in the thread, this type of
setupbrings the likelihood of anyone else in the
family being able to use such an amp virtually down to
zero (especially in light of sophisticated clip-lead
connection scheme). I know the discussion includes
innuendo of relays and automatic chargers, etc., all
of which are beyond my experience (and maybe my
comprehension.) I know Bob D. mentioned using an
LM317 chip -- instead of asking one of you to hold my
hand, could you tell me who manufactures the chip so I
can look at the data sheets? (I know even less about
solid state stuff than tubes!)
Also, on the Teres DIY turntable list someone
mentioned using a model train transformer for running
the TT at 78rpm. I just set up the little train under
the Christmas tree, so I'm thinking after the new year
(millenium) maybe I'll appropriate the transformer
too! What other stuff do my kids have that I can use
for the hifi?
Pete
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=========================================================================
From: "Phil Sieg" <psieg@nxs.net>
Subject: Re: [JN] Battery filaments
Date: Sat, 9 Dec 2000 18:43:40 -0500
Source: Sound Digest Archive v02.n756
Hi Pete, Joes,
>
> I've been reading the thread about using batteries on
> filaments, and spied the 6volt (9.5aH) batteries from
> my daughter's Power Wheels Barbie Jeep. The warnings
> say they contain lead and acid, so I guess they're
> lead acid batteries. I charged them up a month or
> more ago, but it got cold and they never went back
> into the Jeep. (No heater on the Jeep.)
You obviously missed the '20s Bentley with real leather bonnet straps,
working headlights and a heater. From Hammacher Schlemmer for a mere $11K -
for a pedal car!
So, I put the
> volt meter on them and found that they didn't need
> recharging -- they were at a bit less than 6.5 volts.
> I took one and hooked it up to the filaments on my
> breadboard 5842 spud amp, and it ran at 6.28 volts
> (pretty close!). (Still using a lab power supply --
> haven't gotten around to building a proper power
> supply, enclosure, etc.) Wow, that's really quiet!
> The power transformer's physical hum on my Bottlehead
> Foreplay preamp is much louder than anything I can
> hear through the speakers! I haven't been using this
> amp for a while, since I finished my 2A3 amps
> (Bottlehead Afterglows), so I guess I'll try switching
> back and forth to see what I think. What do the
> anti-battery forces say will be the downside?
Well, since I was the one asking all the questions, I won't qualify as an
expert. But I use DC current-regulated filaments exclusively (which I very
much like - quiet and good sounding). I expect battery-fed filaments to
take pride of place.
> As was suggested in the thread, this type of
> setupbrings the likelihood of anyone else in the
> family being able to use such an amp virtually down to
> zero (especially in light of sophisticated clip-lead
> connection scheme).
It doesn't have to be clip leads. Get a good locking connector (e.g.
Amphenol ) with the requisite number of pins. If you follow the scheme I
last outlined, you will do a charger per amp (but that's not absolutely
necessary). For a two-stage amp like the Afterglows, you'll need a four-pin
connector to feed the regulators in parallel. Hardwire the umbilical to
your charger (just a tranny and filter caps), mount the regs in the AG
chassis and the panel-mount portion on the back of the amp (drill out the
base) or on the top plate, whichever is easier. Keep it connected and power
it up when you aren't listening. No problem with inquisitive little
fingers.
I know the discussion includes
> innuendo of relays and automatic chargers, etc., all
> of which are beyond my experience (and maybe my
> comprehension.)
You will have to use either a relay or a switch, otherwise the filaments are
"always on". As Jim de Kort pointed out, DPDT relays are fairly cheap. The
low tech way is to put a toggle switch at each tube and turn the filaments
off when not listening. Then activate the charger.
I know Bob D. mentioned using an
> LM317 chip -- instead of asking one of you to hold my
> hand, could you tell me who manufactures the chip so I
> can look at the data sheets? (I know even less about
> solid state stuff than tubes!)
Srearch for National Semiconductor, Motorola, Genral Semiconductor, etc.
You'll find the data sheet or the manufacturers equipment.
> Also, on the Teres DIY turntable list someone
> mentioned using a model train transformer for running
> the TT at 78rpm. I just set up the little train under
> the Christmas tree, so I'm thinking after the new year
> (millenium) maybe I'll appropriate the transformer
> too! What other stuff do my kids have that I can use
> for the hifi?
Their ears. They are absolutely without preconceived notions. If your
child tells you it doesn't sound good, it doesn't. ;-)
Phil
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] Battery filaments
Date: Mon, 11 Dec 2000 09:33:56 -0500
Source: Sound Digest Archive v02.n757
> What other stuff do my kids have that I can use
> for the hifi?
> Pete
>
>
>
i just nabbed a can of play-dough to put under the feet of
an amp (to isolate vibrations)...
and i am "still-fixing" my daughter's "gymnast-barbie"
since it is now part of a little coil-winder in the garage... ;)
bob.d.
=========================================================================
From: "Phil Sieg" <psieg@nxs.net>
Subject: Re: [JN] Battery filaments
Date: Mon, 11 Dec 2000 10:21:12 -0500
Source: Sound Digest Archive v02.n757
Oooh, kinky! Fetish DIY ;-).
Phil
- ----- Original Message -----
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
To: <sound@deliverator.io.com>
Sent: Monday, 11 December, 2000 09.33
Subject: RE: [JN] Battery filaments
>
> > What other stuff do my kids have that I can use
> > for the hifi?
> > Pete
> >
> >
> >
> i just nabbed a can of play-dough to put under the feet of
> an amp (to isolate vibrations)...
>
> and i am "still-fixing" my daughter's "gymnast-barbie"
> since it is now part of a little coil-winder in the garage... ;)
>
> bob.d.
>
=========================================================================
From: rcjones1@mmm.com
Subject: [JN] Battery Filaments maybe... ideas?
Date: Wed, 17 Oct 2001 08:13:51 -0500
Source: Sound Digest Archive v02.n994
Ok,
I narrowed my hum down to 12mV per channel... not too bad really.
How about battery powered filaments?
Any sources for a 6v and a 5v battery?
5v will pull about 500mA and the 6v 3A. Any circuits out there for a 5v /
6v charger? (simple)
I assume just lead/acid batteries are the best?
Thanks!!!
Richard
=========================================================================
From: S.C.Busbridge@bton.ac.uk
Subject: RE: [JN] Battery Filaments maybe... ideas?
Date: Thu, 18 Oct 2001 07:53:53 +0100
Source: Sound Digest Archive v02.n994
Hi Richard,
12 mV is still quite high. I managed to achieve about 1/10th of this in my
833 amp, but only by using a DC supply on the filament. At 10 A it is not
battery run....
6 V is easy, use sealed lead acids. The right voltage and a sensible
capacity. 5 V may be more difficult and you might have to use a dropper
resistor. For a charger all I use is an LM317 circuit (with heatsink) set
to 2.2 V charge per cell (I trickle charge) and a big resistor in the output
to limit the s/c current to something sensible (e.g. 0.5 A for a 5 Ah cell).
As the cell voltage comes up the current drops, which is fine. You can
charge more aggressively than this but the life of the battery will be
shorter. In my case I have so little time these days that the odd hour or
two per week I listen is at full charge. You will need a large battery for
6 V. Can you use a 12 V car battery and connect heaters in series?
Batteries and valves - what a winning combination!!
Simon
Simon Busbridge, BSc(Hons) PhD CPhys MInstP
School of Engineering
University of Brighton
Lewes Road
Moulsecoomb
Brighton BN2 4GJ
UNITED KINGDOM
Tel: 0044 (0)1273 642542
Fax: 0044 (0)1273 642327/642301
e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com
Audio www site: http://audio.eng.bton.ac.uk
> ----------
> From: rcjones1@mmm.com[SMTP:rcjones1@mmm.com]
> Sent: 17 October 2001 14:13
> To: sound@lists.io.com
> Subject: [JN] Battery Filaments maybe... ideas?
>
> Ok,
>
> I narrowed my hum down to 12mV per channel... not too bad really.
>
> How about battery powered filaments?
>
> Any sources for a 6v and a 5v battery?
>
> 5v will pull about 500mA and the 6v 3A. Any circuits out there for a 5v /
> 6v charger? (simple)
>
> I assume just lead/acid batteries are the best?
>
> Thanks!!!
>
> Richard
>
=========================================================================
From: Neil Jendon <neil@newcontrol.com>
Subject: [JN] Battery life
Date: Mon, 06 Nov 2000 10:32:10 -0800
Source: Sound Digest Archive v02.n723
Hi,
I'm still in the math and parts requisition phase of my 01A linestage. I
want to run the filaments with batteries. How do I estimate battery life.
(5V filament drawing .25 amp). I see batteries listed by amp hours; does
that figure represent the number of hours the battery can provide 1 amp of
current, or am I misunderstanding amp hours?
Thanks again, Joes!
- -Neil
=========================================================================
From: Neil Jendon <neil@newcontrol.com>
Subject: Re: [JN] Battery life
Date: Mon, 06 Nov 2000 11:21:19 -0800
Source: Sound Digest Archive v02.n723
Hi,
Thanks to Carron and Pierre. Onward to my next threshold of understanding.
- -neil
=========================================================================
From: Phil <tube@jump.net>
Subject: Re: [JN] Battery life
Date: Mon, 06 Nov 2000 11:29:21 -0600
Source: Sound Digest Archive v02.n723
Yep, you're right. A 12V battery with a 1 A/Hr life is twice as big as a
6V with 1 A/Hr.
Phil
Neil Jendon wrote:
> Hi,
>
> I'm still in the math and parts requisition phase of my 01A linestage. I
> want to run the filaments with batteries. How do I estimate battery life.
> (5V filament drawing .25 amp). I see batteries listed by amp hours; does
> that figure represent the number of hours the battery can provide 1 amp of
> current, or am I misunderstanding amp hours?
>
> Thanks again, Joes!
>
> -Neil
=========================================================================
From: Owen Young <oyoung@clear.net.nz>
Subject: [JN] Battery power TT?
Date: Tue, 11 Apr 2000 20:58:54 +1200
Source: Sound Digest Archive v02.n517
Guys & Gals,
Can any Joes offer a lead into trickle charger cct design for say a
battery powered 12vdc TT?
TIA
Owen
=========================================================================
From: "J. Gordon Rankin" <waudio@cinti.net>
Subject: Re: [JN] Battery power TT?
Date: Tue, 11 Apr 00 09:43:03 -0400
Source: Sound Digest Archive v02.n517
>Can any Joes offer a lead into trickle charger cct design for say a
>battery powered 12vdc TT?
Owen,
Find a copy of the National Semiconductor analog applications book. Also
there are many great designs at battery websites. Better yet, just buy
one from Mouser.com
Gordon
=====> Wavelength Audio <=====
mailto:waudio@cinti.net
http://www.WavelengthAudio.com
ph.fx. 513-271-4186 USA
=========================================================================
From: SBench@aol.com
Subject: [JN] Battery Preamp
Date: Fri, 12 May 2000 23:31:42 EDT
Source: Sound Digest Archive v02.n544
Hi Joes,
As I promised, part 2 is up on my web pages. This has the phono preamp
schematic on it as well as overall topology and selection schematics.
Next issue will cover the line stages.
Driect access to part 2 is at
http://members.aol.com/sbench/6088pre2.html
or via "front door" as usual (http://members.aol.com/sbench101)
Best Regards,
Steve
=========================================================================
From: "Hugh R Dean" <aspen@alphalink.com.au>
Subject: Re: [JN] Battery Preamp
Date: Sat, 13 May 2000 18:15:05 +1000
Source: Sound Digest Archive v02.n544
Hi Steve,
> Driect access to part 2 is at
> http://members.aol.com/sbench/6088pre2.html
>
> or via "front door" as usual (http://members.aol.com/sbench101)
Brilliant work, Steve. It takes me months to get stuff sorted out, it takes
you days.
I seem to spend my time designing trick pcbs; you just get on with it.
Congratulations on marvellous work. I would be really interested to hear
how this sounds compared to a straight triode preamp, say like the Andy
Grove or Arthur Loesch.
Cheers,
Hugh R. Dean
Melbourne, Australia
=========================================================================
From: SBench@aol.com
Subject: Re: [JN] Battery Preamp
Date: Sat, 13 May 2000 13:55:45 EDT
Source: Sound Digest Archive v02.n545
In a message dated 00-05-13 04:17:09 EDT, aspen@alphalink.com.au writes:
<< I would be really interested to hear
how this sounds compared to a straight triode preamp, say like the Andy
Grove or Arthur Loesch.
Cheers,
Hugh R. Dean
Melbourne, Australia >>
Hi Hugh,
Sound is not too bad. Good at both ends frequency wise, and upper mid
is quite smooth and accurate. Lower mid has a *slight* predominance that
doesn't show up on frequency response sweeps.
Overall sound is slightly analytic, but not cold nor "lifeless". As I
mentioned, it *does* sound like a pentode.
If you get a chance to get to Kurt's summer outing, you'll be able to
hear it first hand.
Best Regards,
Steve
=========================================================================
From: "Andy Evans" <arts.psychology@cwcom.net>
Subject: Re: [JN] batterysounds
Date: Tue, 20 Mar 2001 10:46:05 -0000
Source: Sound Digest Archive v02.n837
Good question. The rechargeable batteries are Lead Acid, NiCad or Nickel
Metal Hydride. I was wondering myself which to use for a MC phono circuit
using good quality op amps.
Andy Evans: andy@artsandmedia.com
Visit our website: http://www.artsandmedia.com
- ----- Original Message -----
From: Jörg Buschmann <bmann@nexgo.de>
To: <sound@lists.io.com>
Sent: Tuesday, March 20, 2001 7:10 PM
Subject: [JN] batterysounds
> hi fellow solder-slingers,
>
>
> i am playing around with a transformer pre.
> tube is 76 and the opt is 20k/600 ohm.
> last experiment was puting a 9v battery under
> the cathode (instead of 2.2k and 220 uf bg).
> seems to be some kind of window-opening - but
> i am not shure if i like everything i see (hear).
>
> so the battery is a plain battery - do sound
> nicads different. are there any differences in
> batteris? do i really have to compare batteries
> from now on??
>
> schönen tach
> jörg
>
=========================================================================
From: J=?ISO-8859-1?B?9g==?=rg Buschmann <bmann@nexgo.de>
Subject: [JN] batterysounds
Date: Tue, 20 Mar 2001 11:10:09 -0800
Source: Sound Digest Archive v02.n837
hi fellow solder-slingers,
i am playing around with a transformer pre.
tube is 76 and the opt is 20k/600 ohm.
last experiment was puting a 9v battery under
the cathode (instead of 2.2k and 220 uf bg).
seems to be some kind of window-opening - but
i am not shure if i like everything i see (hear).
so the battery is a plain battery - do sound
nicads different. are there any differences in
batteris? do i really have to compare batteries
from now on??
schönen tach
jörg
=========================================================================
From: Eric Kingsbury <ekingsbu@hawaii.edu>
Subject: Re: [JN] batterysounds
Date: Tue, 20 Mar 2001 08:17:50 -1000 (HST)
Source: Sound Digest Archive v02.n838
Jepstein did some experimentation with this on a 6C45pi spud amp: seemed
(to him) that the best sound was indeed with a 'normal' type battery, as
opposed to alkalines, nicads, etc.
Poinz
On Tue, 20 Mar 2001, Andy Evans wrote:
> Good question. The rechargeable batteries are Lead Acid, NiCad or Nickel
> Metal Hydride. I was wondering myself which to use for a MC phono circuit
> using good quality op amps.
>
> Andy Evans: andy@artsandmedia.com
> Visit our website: http://www.artsandmedia.com
> ----- Original Message -----
> From: Jörg Buschmann <bmann@nexgo.de>
> To: <sound@lists.io.com>
> Sent: Tuesday, March 20, 2001 7:10 PM
> Subject: [JN] batterysounds
>
>
> > hi fellow solder-slingers,
> >
> >
> > i am playing around with a transformer pre.
> > tube is 76 and the opt is 20k/600 ohm.
> > last experiment was puting a 9v battery under
> > the cathode (instead of 2.2k and 220 uf bg).
> > seems to be some kind of window-opening - but
> > i am not shure if i like everything i see (hear).
> >
> > so the battery is a plain battery - do sound
> > nicads different. are there any differences in
> > batteris? do i really have to compare batteries
> > from now on??
> >
> > schönen tach
> > jörg
> >
>
>
>
=========================================================================
From: Paul Joppa <pj@bottlehead.com>
Subject: Re: [JN] batterysounds
Date: Tue, 20 Mar 2001 10:39:06 -0800
Source: Sound Digest Archive v02.n838
Alkaline and carbon-zinc will often explode when overcharged, as
they eventually will be under the cathode. NiCd batteries can
take a continuous charging rate, usually as high as 1/20 of the
mA-hr capacity. Under continuous charge, they will run as high
as 1.5v/cell, so a 9-v rechargeable (which is usually 7.2v
discharge, 6 cells) will hold nearly 9v in this application.
=========================================================================
From: Eric Kingsbury <ekingsbu@hawaii.edu>
Subject: Re: [JN] Batterysounds
Date: Thu, 22 Mar 2001 08:21:51 -1000 (HST)
Source: Sound Digest Archive v02.n839
Sorry, Jep; I was working from memory. It was in one of the AA forums, I
thought it was you . . .
Just call me Al.
Poinz
On Thu, 22 Mar 2001, Epstein, Jeremy wrote:
> Eric Kingsbury <ekingsbu@hawaii.edu> wrote:
>
> >Jepstein did some experimentation with this on a 6C45pi spud amp:
> >seemed (to him) that the best sound was indeed with a 'normal' type
> >battery, as
> >opposed to alkalines, nicads, etc.
>
> Poinzy, I think you may have me mixed in with someone else - I do use
> battery bias on a 6C45Pi (it is a convertible, spud power amp/line stage)
> but I did not really compare battery types. The only thing close to this is
> that I found that a conventional alkaline (go Tigers!) battery would not
> survive the constant charging current. A NiCad is the only type of
> rechargeable I have tried and I find it sounds !!very!! good compared to R/C
> bias and somewhat better than LED bias.
>
> I am sure there are others who have done battery comparisons, but I must
> confess it wasn't me.
>
> -j
>
> Poinz
>
> On Tue, 20 Mar 2001, Andy Evans wrote:
>
> > Good question. The rechargeable batteries are Lead Acid, NiCad or Nickel
> > Metal Hydride. I was wondering myself which to use for a MC phono circuit
> > using good quality op amps.
>
> =========================================
> Jeremy Epstein........jepstein@ndbcap.com
> =========================================
>
=========================================================================
From: "Epstein, Jeremy" <JEpstein@ndbcap.com>
Subject: [JN] Batterysounds
Date: Thu, 22 Mar 2001 09:47:59 -0500
Source: Sound Digest Archive v02.n839
Eric Kingsbury <ekingsbu@hawaii.edu> wrote:
>Jepstein did some experimentation with this on a 6C45pi spud amp:
>seemed (to him) that the best sound was indeed with a 'normal' type
>battery, as
>opposed to alkalines, nicads, etc.
Poinzy, I think you may have me mixed in with someone else - I do use
battery bias on a 6C45Pi (it is a convertible, spud power amp/line stage)
but I did not really compare battery types. The only thing close to this is
that I found that a conventional alkaline (go Tigers!) battery would not
survive the constant charging current. A NiCad is the only type of
rechargeable I have tried and I find it sounds !!very!! good compared to R/C
bias and somewhat better than LED bias.
I am sure there are others who have done battery comparisons, but I must
confess it wasn't me.
- -j
Poinz
On Tue, 20 Mar 2001, Andy Evans wrote:
> Good question. The rechargeable batteries are Lead Acid, NiCad or Nickel
> Metal Hydride. I was wondering myself which to use for a MC phono circuit
> using good quality op amps.
=========================================
Jeremy Epstein........jepstein@ndbcap.com
=========================================
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: RE: [JN] Batterysounds
Date: Thu, 22 Mar 2001 11:38:50 -0500
Source: Sound Digest Archive v02.n839
>I would just like to air my humble decenting opinion on this issue.
>Firstly, I only think NiCd batteries sounds good on high
>gain/transconductance tubes. I tried stacking a bunch to get ~9V to bias a
>#26 and did not like the result. For biasing a 417A or 6C45Pi, it is a great
>cheap method.
to add some more quick experiences to this...
my first stage of the noise mess... um i mean amp is an eimac 15E (DHT gain
of 25 Rp of say 12K)
for ease sake i tossed a 100 ohm resistor black gate bypass to net me 6V
bias... got everything tuned in operating point headroom wise and all was
well.
i tossed a 6V lead acid cell in for kicks and gave it a listen for a day or
two... not the sound i like... i put the R/C combo back in, and thats more
like it... next i went to a pair of nimh batteries (1/2 the bias) and the
sound got even better... but alas i needed 4 of them and didn't have them
on hand... tried 4 D-cell nicads for the 6V and still wasn't impressed. i
finally got 4 of the nimh cells in there and still something seems to be
lacking, and i still prefer the R/C combo for music... if i could get away
with the two cells i would do that, but i need the 6V of bias to get the
full 25W out of the amp so as it stands the R/C stays.
i think the problem is with the seriesing of the cells and not the Gm of
the tube, one is ideal, two in series is OK but as you get more, problems
start to happen. and remember a 9V is just a bunch of the 1.2V cells in
series. the high gm tubes just happen to bias up at the 1-2 cell point.
i want to go back to the 4 nimh cells again, and try paralleling individual
cells and then series them to see if that helps... if you look at it as a
chain... its only as good as the weakest link... the longer the chain the
more chance for a problem?
dave
=========================================================================
From: "Epstein, Jeremy" <JEpstein@ndbcap.com>
Subject: RE: [JN] Batterysounds
Date: Thu, 22 Mar 2001 13:29:42 -0500
Source: Sound Digest Archive v02.n839
No worries mate. I don't doubt that SOMEBODY posted on this, just wasn't me.
- -j
=========================================
Jeremy Epstein........jepstein@ndbcap.com
800 435 1240..........NDB Capital Markets
=========================================
> -----Original Message-----
> From: Eric Kingsbury [mailto:ekingsbu@hawaii.edu]
> Sorry, Jep; I was working from memory.
=========================================================================
From: David Home <David_Home@creoscitex.com>
Subject: RE: [JN] Batterysounds
Date: Thu, 22 Mar 2001 16:07:34 +0100
Source: Sound Digest Archive v02.n839
I would just like to air my humble decenting opinion on this issue.
Firstly, I only think NiCd batteries sounds good on high
gain/transconductance tubes. I tried stacking a bunch to get ~9V to bias a
#26 and did not like the result. For biasing a 417A or 6C45Pi, it is a great
cheap method.
I got much better results with the #26 by using a method pointed out to me
by Manfred Huber. That is putting a alkiline battery bypassed with a
resistor/small cap between the grid and the wiper of my volume pot,
referenced to ground through the pot itself. Produced an amazingly
transparent sound. Unfortunately, it had an edge tha drove me screaming from
the room after an hour. I went back to my trusty RC bias using a Blackgate.
Maybe not the same level of transparency, but a nice balanced agreeable
sound hour after hour.
Regards, David
- -----Original Message-----
From: Epstein, Jeremy [mailto:JEpstein@ndbcap.com]
Sent: Thursday, March 22, 2001 3:48 PM
To: Joenet (E-mail)
Subject: [JN] Batterysounds
Eric Kingsbury <ekingsbu@hawaii.edu> wrote:
>Jepstein did some experimentation with this on a 6C45pi spud amp:
>seemed (to him) that the best sound was indeed with a 'normal' type
>battery, as
>opposed to alkalines, nicads, etc.
Poinzy, I think you may have me mixed in with someone else - I do use
battery bias on a 6C45Pi (it is a convertible, spud power amp/line stage)
but I did not really compare battery types. The only thing close to this is
that I found that a conventional alkaline (go Tigers!) battery would not
survive the constant charging current. A NiCad is the only type of
rechargeable I have tried and I find it sounds !!very!! good compared to R/C
bias and somewhat better than LED bias.
I am sure there are others who have done battery comparisons, but I must
confess it wasn't me.
- -j
Poinz
On Tue, 20 Mar 2001, Andy Evans wrote:
> Good question. The rechargeable batteries are Lead Acid, NiCad or Nickel
> Metal Hydride. I was wondering myself which to use for a MC phono circuit
> using good quality op amps.
=========================================
Jeremy Epstein........jepstein@ndbcap.com
=========================================
=========================================================================
From: "Remco Stoutjesdijk" <remco@ultranalog.com>
Subject: RE: [JN] Batterysounds
Date: Thu, 22 Mar 2001 16:59:09 +0100
Source: Sound Digest Archive v02.n839
...
> putting a alkiline battery bypassed with a
> resistor/small cap between the grid and the wiper of my volume pot,
> referenced to ground through the pot itself. Produced an amazingly
> transparent sound. Unfortunately, it had an edge tha drove me
> screaming from
> the room after an hour.
I was thinking of something similar... the 'edge' I think occurs when Vg
nears or crosses zero. Then weird stuff happens. The grid wants to draw
current in the direction opposite to what the battery likes, and I can't
even figure out how it would be supplied at all...
Remco
- --
http://www.ultranalog.com
=========================================================================
From: rcjones1@mmm.com
Subject: [JN] Battery supply for pentodes.... ?
Date: Wed, 17 Oct 2001 13:14:27 -0500
Source: Sound Digest Archive v02.n994
Hehe.. how about this...
A pentode CF with a choke in the cathode. Battery supply for the plate and
screen. How would they be wired?
Maybe a EL509 at 140v plate and 140v screen? thats essentially 12 12v
batteries in series. Need some 4Ah or so.
A 1H, 200mA choke in the cathode (low DCR).
Any sources for surplus batteries... cheap.
Richard
=========================================================================
From: "Michael (Mick)Maloney" <supra@cantech.net.au>
Subject: [JN] Battery tubes
Date: Tue, 19 Jun 2001 07:33:42 +0800
Source: Sound Digest Archive v02.n913
- --=======458A7FBD=======
Content-Type: text/plain; x-avg-checked=avg-ok-44C84953; charset=us-ascii
>Date: Mon, 18 Jun 2001 11:35:27 +0100 (BST)
>From: Simon Busbridge <S.C.Busbridge@bton.ac.uk>
>Subject: RE: [JN] Listening experiences with UX226
>
>Hi,
>
>>I also have the 46 which I'd love to try.
>
>The 31 looks interesting to me - anyone tried it?
>
Yes and the 33 is also a great sounding tube when transformer coupled and
triode connected in a preamp.
Much prefered it to the 26 which I never liked.
Some of the "1" series of battery tubes are also very good.(and cheap)
Interesting to see Manfred using the 3A/110B- I found it a bit bass shy but
silky treble-it really impressed the "detail" freaks.
MickM
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=========================================================================
From: MHuber@t-online.de (Manfred Huber)
Subject: Re: [JN] Battery tubes
Date: Tue, 19 Jun 2001 15:20:04 +0200
Source: Sound Digest Archive v02.n913
Mick,
>Interesting to see Manfred using the 3A/110B- I found it a bit bass shy but
>silky treble-it really impressed the "detail" freaks.
In my preamp it is not at all bass shy and the Transformers take
care that I don't get too much detail. ;-)
But a preamp is more then just a tube...
Regards
Manfred
- ------------------
Manfred Huber
MHuber@t-online.de
- ------------------
=========================================================================
From: Simon Busbridge <S.C.Busbridge@bton.ac.uk>
Subject: [JN] Battery valve tuner
Date: Mon, 12 Mar 2001 08:00:50 +0000 (GMT)
Source: Sound Digest Archive v02.n830
I have recently designed a DF96 based TRF radio tuner for LW. The
purpose is to bring in Radio 4 and Radio France to reasonable quality.
It also brings in other waker French stations and the pirate station. It
runs at about 5 mA from 8 PP3 batteries + 100 mA from a D cell. It is a
bandpass design. If anyone is interested (unlikely!) let me know and I
will send it across the aether.
Best,
Simon
Simon Busbridge, BSc(Hons) PhD CPhys MInstP
School of Engineering
University of Brighton
Lewes Road
Moulsecoomb
Brighton BN2 4GJ
UNITED KINGDOM
Tel: 0044 (0)1273 642542
Fax: 0044 (0)1273 642327/642301
e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com
=========================================================================
From: "Carter Hendricks" <carter@i1.net>
Subject: [JN] BB 2604
Date: Wed, 2 Aug 2000 22:04:20 -0500
Source: Sound Digest Archive v02.n616
Might anyone have one
spare 2604 they could
mail to me and I'll send
a fiver? Not enough for
a digidog order...
--Carter
=========================================================================
From: torisawa <torisawa@crc.co.jp>
Subject: [JN] BBS in JAPAN
Date: Thu, 23 Mar 2000 15:06:35 +0900
Source: Sound Digest Archive v02.n491
Hi,
Homemade Amplifiers Club started BBS.
Homemade Amplifiers Club is located in Japan and try to build
amplifiers of many different schematics.
Please click below.
http://www.kwjpn.com/6bm8/bbs2/bbs.cgi
Everbody can submit any message related to audio, music, etc.
Also can ask questions about Super Triode Connection (STC) ampifiers.
We have a lot of experience to build STC amplifiers and can help you with building them.
Please visit us.
Thank you,
Yuichi Torisawa
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] BBS in JAPAN
Date: Thu, 23 Mar 2000 12:47:21 +0100
Source: Sound Digest Archive v02.n492
dear Yuichi-san,
Thank you for pointing us in the direction of your site. I am going to have
a look immediately as I already enjoyed lots of the Japanese audio sites.
Besides that I want to take the oppertunity to welcome all the Japanese
Joenet members among us; I am very happy to meet you here as I am sure it
will widen and extend the disussions and finally result in better sound !
many regards,
=
Guido
At 15:06 23/03/2000 +0900, torisawa wrote:
>Hi,
>
>Homemade Amplifiers Club started BBS.
>Homemade Amplifiers Club is located in Japan and try to build
>amplifiers of many different schematics.
>
>Please click below.
>
>http://www.kwjpn.com/6bm8/bbs2/bbs.cgi
>
>Everbody can submit any message related to audio, music, etc.
>Also can ask questions about Super Triode Connection (STC) ampifiers.
>We have a lot of experience to build STC amplifiers and can help you with
building them.
>
>Please visit us.
>
>
>Thank you,
>
>
>Yuichi Torisawa
>
>
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: [JN] BBS in JAPAN
Date: Thu, 23 Mar 2000 13:47:30 +0100
Source: Sound Digest Archive v02.n492
- ----------
> De : evaguido <EvaGuido@iaehv.nl>
> A : torisawa <torisawa@crc.co.jp>; JoeList <sound@lists.io.com>
> Objet : Re: [JN] BBS in JAPAN
> Date : jeudi 23 mars 2000 12:47
>
> dear Yuichi-san,
>
> Thank you for pointing us in the direction of your site. I am going to
have
> a look immediately as I already enjoyed lots of the Japanese audio sites.
>
> Besides that I want to take the oppertunity to welcome all the Japanese
> Joenet members among us; I am very happy to meet you here as I am sure it
> will widen and extend the disussions and finally result in better sound !
>
> many regards,
> =
> Guido
Hello,
I dislike oneline messages but have to add my voice to Guido: thanks and
welcome to our Japanese friends.
Best regards,
Jean-Michel Le Cleac'h
=========================================================================
From: torisawa <torisawa@crc.co.jp>
Subject: Re: [JN] BBS in JAPAN
Date: Fri, 24 Mar 2000 17:19:59 +0900
Source: Sound Digest Archive v02.n494
Hi All,
We (Homemade Amplifiers Club) think that the BBS
would become a kind of FAQ or data base after many people
submit many messages.
Especially, messages about audio, schematics, etc. in Japan will be appreciated.
Off course, another messages will be appreciated, too.
I hope Joelist and our BBS exchange ideas and have a good relation.
Homemade Amplifiers BBS
http://www.kwjpn.com/6bm8/bbs2/bbs.cgi
Homemade Amplifiers Index page
http://plaza28.mbn.or.jp/~6bm8/englith/index.htm
Thank you
Yuichi Torisawa
=========================================================================
From: "Daniel J. Marshall" <danmarshall@worldnet.att.net>
Subject: Re: [JN] B & D on the Joe List....
Date: Sat, 06 Feb 1999 22:51:35 -0800
Source: Sound Digest Archive v02.n031
PEARL Cust Serv wrote:
>
> Joes:
> Now that I have your attention, I was going thru some "Sent Mail" and
> noticed that was sent privately rather than as a Joe List post:
>
> B(lack) & D(ecker) make a series of drill bits that are IDEAL for
> drilling sheet metal. Called the "Power Points" they are commonly available
> from B&D resellers in a 1/16" to 1/4" index with larger sizes available on
> special order.
> They are a split point grind BUT the points are ground to a much smaller
> "pilot" diameter, .121" in the case of a .25" bit.
> This is hard to explain: imagine a two flute, 1/4" spiral, end-mill with
> a .121" fluteless drill axially protruding about .080" from the cutting end
> of the end mill and you pretty much have it.
> The only difference is that the faces of the "flutes" are ground so that
> they cut though on the .25" diameter BEFORE the bit cuts through anywhere
> else, with the exceptioan of the pilot. So, when drilling sheet metal you
> get beautufully ROUND, burr-free holes, on center (these bits don't "walk")
> and the bits won't climb into the hole as they break through.
>
> *********>>>>>>>>>> HIGHLY RECOMMENDED <<<<<<<<<<************
>
> Bill - PEARL
Yes, I have used them, they are quite nice. Take care to avoid dulling
them though, as they are a bitch to sharpen. There are similar wood
bits called "brad point" bits which are much better suited for drilling
wood than are regular metal cutting bits. They are constructed like a
regular twist drill, but sharpened differently. They have a sharp
center point, square and pointy, I guess you could say, and the outer
flutes touch the work before the remainder of the bit. They don't walk
about like a regular metal-cutting bit, so are expecially useful for
dowelling, plus they make a much cleaner cut with little, or no
splintering. But then dowel joinery is a bit of a joke anymore with the
superior biscuit joiners that are commonly available.
Dan Marshall
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: [JN] B & D on the Joe List....
Date: Sat, 06 Feb 1999 23:02:33 -0700
Source: Sound Digest Archive v02.n031
Joes:
Now that I have your attention, I was going thru some "Sent Mail" and
noticed that was sent privately rather than as a Joe List post:
B(lack) & D(ecker) make a series of drill bits that are IDEAL for
drilling sheet metal. Called the "Power Points" they are commonly available
from B&D resellers in a 1/16" to 1/4" index with larger sizes available on
special order.
They are a split point grind BUT the points are ground to a much smaller
"pilot" diameter, .121" in the case of a .25" bit.
This is hard to explain: imagine a two flute, 1/4" spiral, end-mill with
a .121" fluteless drill axially protruding about .080" from the cutting end
of the end mill and you pretty much have it.
The only difference is that the faces of the "flutes" are ground so that
they cut though on the .25" diameter BEFORE the bit cuts through anywhere
else, with the exceptioan of the pilot. So, when drilling sheet metal you
get beautufully ROUND, burr-free holes, on center (these bits don't "walk")
and the bits won't climb into the hole as they break through.
*********>>>>>>>>>> HIGHLY RECOMMENDED <<<<<<<<<<************
Bill - PEARL
=========================================================================
From: Scott Grammer <tubedude@cdc.net>
Subject: Re: [JN] B & D on the Joe List....
Date: Sun, 07 Feb 1999 09:55:44 -0500
Source: Sound Digest Archive v02.n032
PEARL Cust Serv wrote:
> Joes:
> Now that I have your attention, I was going thru some "Sent Mail" and
> noticed that was sent privately rather than as a Joe List post:
>
> B(lack) & D(ecker) make a series of drill bits that are IDEAL for
> drilling sheet metal. (snip)
I second the reccomendation. I used to work for B&D for a while, and these bits
are quite studly. As I remember, they also have a no-breakage warranty. If one
breaks, you take it to a B&D retailer and they give you a new one. Pretty cool.
Cheers!
S.G.
- --
TubeDude's Webpage of Vacuum Tube Lore! http://www.cdc.net/~tubedude/
Smoke Free Youth! http://www.cdc.net/~tubedude/smokefreeyouth.html
The hardest thing in the world to understand is the income tax.
Albert Einstein
=========================================================================
From: Scott Grammer <tubedude@cdc.net>
Subject: Re: [JN] B & D on the Joe List....
Date: Sun, 07 Feb 1999 12:15:57 -0500
Source: Sound Digest Archive v02.n032
evaguido wrote:(snip)
>
> wat is the "trade name" of these bits ?
>
> Guido
(snip)
They're called "Bullets".
S.G.
- --
TubeDude's Webpage of Vacuum Tube Lore! http://www.cdc.net/~tubedude/
Smoke Free Youth! http://www.cdc.net/~tubedude/smokefreeyouth.html
The hardest thing in the world to understand is the income tax.
Albert Einstein
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] B & D on the Joe List....
Date: Sun, 07 Feb 1999 16:47:42 +0100
Source: Sound Digest Archive v02.n032
At 09:55 7-2-99 -0500, Scott Grammer wrote:
>
>
>PEARL Cust Serv wrote:
>
>> Joes:
>> Now that I have your attention, I was going thru some "Sent Mail" and
>> noticed that was sent privately rather than as a Joe List post:
>>
>> B(lack) & D(ecker) make a series of drill bits that are IDEAL for
>> drilling sheet metal. (snip)
>
>I second the reccomendation. I used to work for B&D for a while, and these
bits
>are quite studly. As I remember, they also have a no-breakage warranty. If
one
>breaks, you take it to a B&D retailer and they give you a new one. Pretty
cool.
wat is the "trade name" of these bits ?
Guido
>Cheers!
>S.G.
>
>
>--
>TubeDude's Webpage of Vacuum Tube Lore! http://www.cdc.net/~tubedude/
>Smoke Free Youth! http://www.cdc.net/~tubedude/smokefreeyouth.html
>The hardest thing in the world to understand is the income tax.
> Albert Einstein
>
>
>
=========================================================================
From: Andrej Deticek <andrej.deticek@siol.net>
Subject: Re: [JN] B & D on the Joe List....
Date: Sun, 07 Feb 1999 17:31:10 +0100
Source: Sound Digest Archive v02.n032
evaguido wrote:
>
> >PEARL Cust Serv wrote:
>
> >> B(lack) & D(ecker) make a series of drill bits that are IDEAL for
> >> drilling sheet metal. (snip)
> >
>
> wat is the "trade name" of these bits ?
>
> Guido
>
Hello,
I think these are sold under the name of "Bullet" drill bits. At least
this is what B&D is selling here in Slovenia. Those that we get here
are made in Germany by Bayrische Bohrerwerke (BBW). I have been using
them for a couple of years and like them a lot.
Andrej Deticek
=========================================================================
From: Michael Kerster <mkerster@sympatico.ca>
Subject: Re: [JN] B & D on the Joe List....
Date: Sun, 07 Feb 1999 23:17:16 -0500
Source: Sound Digest Archive v02.n032
Hi Joes,
That's great and everything, but for my money, the Unibit step drills are
where it's at...start with a
small (1/8) pilot hole and drill any hole size from 1/8 to 1/2" with ONE
bit. Other sizes are available
and these blow the snot out of anything I've seen anywhere. These give
PERFECT round holes with almost zero
effort. Amazing.
At 11:02 PM 2/6/99 -0700, PEARL Cust Serv wrote:
> Joes:
> Now that I have your attention, I was going thru some "Sent Mail" and
>noticed that was sent privately rather than as a Joe List post:
>
> B(lack) & D(ecker) make a series of drill bits that are IDEAL for
>drilling sheet metal. Called the "Power Points" they are commonly available
>from B&D resellers in a 1/16" to 1/4" index with larger sizes available on
>special order.
> They are a split point grind BUT the points are ground to a much smaller
>"pilot" diameter, .121" in the case of a .25" bit.
> This is hard to explain: imagine a two flute, 1/4" spiral, end-mill with
>a .121" fluteless drill axially protruding about .080" from the cutting end
>of the end mill and you pretty much have it.
> The only difference is that the faces of the "flutes" are ground so that
>they cut though on the .25" diameter BEFORE the bit cuts through anywhere
>else, with the exceptioan of the pilot. So, when drilling sheet metal you
>get beautufully ROUND, burr-free holes, on center (these bits don't "walk")
>and the bits won't climb into the hole as they break thr