....


=========================================================================
From: Guido Tent <gtent@ehv.sc.philips.com>
Subject: Re: 
Date: Tue, 30 Sep 1997 10:15:29 +0200
Source: Sound Digest Archive v01.n049

At 07:56 30-09-97 PDT, Lohse, Guenther          VIM37 wrote:
>
>Hallo Bruce thanks for response,
>
>I think pypassing electrolythic caps in power supplys is always a good idea. 
>Because of the internal inductance (which is much higher for elec. caps as 
>for film/ceramic caps) the higher frequencys are not shorted to ground 
>properly, if the frequency rises up to several 100kHz.

The inductance play a role, but the low inductance of film caps is usually
thrown away due to wrong wiring techniques

>The self resonance frequency on elec. caps is in the order of 100kHz 
>(depends on size). Ceramic caps have a  self resonance frequency in the 
>order of 10MHz (depends also on size).

I have a lot of experience with (mostly Philps, but yes others too)
Electrolytics. Depending on voltage and capacitance, the resonances can be
up to some 10 MHz and more (not too bad). The Q is low, due to resistive
losses at high frequencies

>I parallel the BG caps in the cathode bypass circuitry. There may some 
>resonance effects due to the two caps in parallel or the extented bandwith 
>cause problems?

That may cause a problem, I think we should consider having two tuned
filters parallel !

I think the audibility of capacitors is nmot within the frequency versus
impedance ratio, but within something else

Guido

>Guenther Lohse
>
>
"to be EMC or not to be EMC, that's the question"

Guido Tent
Engineer
Electro Magnetic Compatibility
Philips Semiconductors Systems Laboratory Eindhoven  (PS-SLE)
Building BE303, (Hurksestraat 19)
P.O.Box 218,  5600MD Eindhoven, The Netherlands
Phone: +31-40-27 24553
fax  : +31-40-27 22764

E-mail: guido.tent@ehv.sc.philips.com
Seri  : gtent@nlsce1

- - Let's make things better ! -


=========================================================================
From: davidbarnett@aristotle.net (David N. Barnett)
Subject: Re: 
Date: Fri, 19 Dec 1997 22:27:46 GMT
Source: Sound Digest Archive v01.n138

On 19 Dec 1997 12:43:40 -0700, An-shyang Chu <achu@sandia.gov> wrote:

>have anyone try to use CORIAN as
>the raw material for cabinet?

Wilson Audio has used Corian, and Unity Audio used Fountainhead (a
similar product).

I think that these ceramic-loaded acrylics are rather high-Q materials
and might make for a harsh sound unless they're well-damped.

- --dnb


=========================================================================
From: William Eckle <wmeckle@primenet.com>
Subject: Re: 
Date: Sun, 15 Mar 1998 22:47:49 -0700
Source: Sound Digest Archive v01.n218

At 12:00 AM 3/16/97 -0500, Jonathan Morrison wrote:

>Hi Y'all-

>I've got a chance to get a pair of MINT Altec 604E's. Any interest, and any

>idea what they are worth? The woofer part looks a whole lot like a 515B. JDM


Hi Jonathan:

     A guy at a hifi swap meet here last year had a 604A & a 604C, he wanted $750

for the pair, they both had torn cones (he didn't come down, or sell them).


     I'd pay $500 for a pair of 604Es if you want to sell them.


 

       <bold><underline>-=<color><param>ffff,0000,0000</param>Bill
Eckle</color>=-

</underline></bold>wmeckle@primenet.com

<italic><color><param>0000,0000,ffff</param> Phoenix, Arizona 
USA</color></italic>


=========================================================================
From: Roscoe Primrose <roscoe@aiko.com>
Subject: Re: 
Date: Mon, 16 Mar 1998 18:55:44 -0500
Source: Sound Digest Archive v01.n219

Jonathan Morrison wrote:

> Hi Y'all-
> I've got a chance to get a pair of MINT Altec 604E's. Any interest, and any
> idea what they are worth? The woofer part looks a whole lot like a 515B. JDM

 Mint, with xovers, probably about 750US....   And fix your clock, it's not 1997
anymore!

- --
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


=========================================================================
From: Yip Hin Fai Johari <hfyip@pacific.net.sg>
Subject: Re: 
Date: Fri, 17 Apr 1998 07:36:21 +0800
Source: Sound Digest Archive v01.n254

At 11:14 AM 4/16/98 +0000, Jim Dudley wrote:
>As soon as my new SET amp (VV30B)  gets built in about a week or so, I'll
be looking for a good line stage to compliment this jewel.   Can anyone
recommend a 
>good piece?   I could build from scratch but  prefer a kit.  Does anyone
have any experience with the Welborne Compleat Hybrid Linestage or the
Audio Note M1 
>kit?   These kits are in line with my budget.   Something with a decent
low end to compliment my Lowthers would be helpful.
>
>Thank you,
>Jim Dudley 

Jim

I 've very good result with Ron's hybrid linestage. Worked best with 5692
redbases.


=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: Re: 
Date: Sat, 27 Jun 1998 18:03:53 PDT
Source: Sound Digest Archive v01.n325

Hi there,

>a. pin 1 & 8 of 2 X EL34 are connected to another other & 
>"grounded"

Screen-Grid (Pin 1) and Cathode....

>b. pin 2 & 7 is the "filament heater"
>c. pin 3 is connected to a "5 Ohm resistor" at the output trans.

That is the Anode (or Plate for anyone on the other side of the 
Pond...). The 5 Ohm Resistor may be there to improve Stability....

It is also usefull to determine the Bias of the Valve.... I'd expect 
about 0.25V - 0.3V over that Resistor right now.... Or in simple terms, 
0.05V for every 10mA current....

>d. pin 4 is connected to a "460 Ohm resistor" at the output trans.

That is the Grid 2 and it will be the Ultra-Linear tap on the 
Transformer...

>e. pin 5 & 6 is connected to a small adjustable switch(has 3 pins) that
>reads "22K 734M" and last of the switch pin is "grounded".

Pin 5 is the Control-Grid and the "Switch" is actually a Pot. It is 
highly likely that this controls the Bias. 22k would mean 22 kOhm, which 
seems rather low.... Are you sure there is no further resistor around 
there....?

To convert the Amp into Triode Operation simply connect Grid 2 (pin 4 ) 
to the Anode (pin 3) via a 100 Ohm 2 Watt Resistor.... Switch back on 
and monitor the Voltage on the 5 Ohm Resistors....

With 450 V +B (PSU Voltage), the Current should be no more than 55mA 
(0.275V across the 5 Ohm Resistor) to be on the safe side for the Output 
Valves....

With lower Voltages in the PSU, more Current is possible....

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: "Robert Clark" <rclark@insightinc.com>
Subject: RE: 
Date: Sun, 28 Jun 1998 08:23:58 -0400
Source: Sound Digest Archive v01.n325

Hey since we are on the subject of converting pentodes to triodes. Is there
an equally simple way of converting, say an el-34 to "enhanced triode" mode
ala Tim de Paravicini?

Bob

- -----Original Message-----
From: owner-sound@lists.io.com [mailto:owner-sound@lists.io.com]On
Behalf Of T. Loesch
Sent: Saturday, June 27, 1998 9:04 PM
To: sound@deliverator.io.com; shamsul.BK@innosabah.com.my
Subject: Re:


Hi there,

>a. pin 1 & 8 of 2 X EL34 are connected to another other &
>"grounded"

Screen-Grid (Pin 1) and Cathode....

>b. pin 2 & 7 is the "filament heater"
>c. pin 3 is connected to a "5 Ohm resistor" at the output trans.

That is the Anode (or Plate for anyone on the other side of the
Pond...). The 5 Ohm Resistor may be there to improve Stability....

It is also usefull to determine the Bias of the Valve.... I'd expect
about 0.25V - 0.3V over that Resistor right now.... Or in simple terms,
0.05V for every 10mA current....

>d. pin 4 is connected to a "460 Ohm resistor" at the output trans.

That is the Grid 2 and it will be the Ultra-Linear tap on the
Transformer...

>e. pin 5 & 6 is connected to a small adjustable switch(has 3 pins) that
>reads "22K 734M" and last of the switch pin is "grounded".

Pin 5 is the Control-Grid and the "Switch" is actually a Pot. It is
highly likely that this controls the Bias. 22k would mean 22 kOhm, which
seems rather low.... Are you sure there is no further resistor around
there....?

To convert the Amp into Triode Operation simply connect Grid 2 (pin 4 )
to the Anode (pin 3) via a 100 Ohm 2 Watt Resistor.... Switch back on
and monitor the Voltage on the 5 Ohm Resistors....

With 450 V +B (PSU Voltage), the Current should be no more than 55mA
(0.275V across the 5 Ohm Resistor) to be on the safe side for the Output
Valves....

With lower Voltages in the PSU, more Current is possible....

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: "william gaw." <whg@tiac.net>
Subject: Re: 
Date: Sun, 28 Jun 1998 09:01:12 -0400
Source: Sound Digest Archive v01.n325

God, 42 messages, and only one on topic. Bill
- -----Original Message-----
From: T. Loesch <ezee_e@hotmail.com>
To: sound@deliverator.io.com <sound@deliverator.io.com>;
shamsul.BK@innosabah.com.my <shamsul.BK@innosabah.com.my>
Date: Saturday, June 27, 1998 9:34 PM
Subject: Re:


>Hi there,
>
>>a. pin 1 & 8 of 2 X EL34 are connected to another other &
>>"grounded"
>
>Screen-Grid (Pin 1) and Cathode....
>
>>b. pin 2 & 7 is the "filament heater"
>>c. pin 3 is connected to a "5 Ohm resistor" at the output trans.
>
>That is the Anode (or Plate for anyone on the other side of the
>Pond...). The 5 Ohm Resistor may be there to improve Stability....
>
>It is also usefull to determine the Bias of the Valve.... I'd expect
>about 0.25V - 0.3V over that Resistor right now.... Or in simple terms,
>0.05V for every 10mA current....
>
>>d. pin 4 is connected to a "460 Ohm resistor" at the output trans.
>
>That is the Grid 2 and it will be the Ultra-Linear tap on the
>Transformer...
>
>>e. pin 5 & 6 is connected to a small adjustable switch(has 3 pins) that
>>reads "22K 734M" and last of the switch pin is "grounded".
>
>Pin 5 is the Control-Grid and the "Switch" is actually a Pot. It is
>highly likely that this controls the Bias. 22k would mean 22 kOhm, which
>seems rather low.... Are you sure there is no further resistor around
>there....?
>
>To convert the Amp into Triode Operation simply connect Grid 2 (pin 4 )
>to the Anode (pin 3) via a 100 Ohm 2 Watt Resistor.... Switch back on
>and monitor the Voltage on the 5 Ohm Resistors....
>
>With 450 V +B (PSU Voltage), the Current should be no more than 55mA
>(0.275V across the 5 Ohm Resistor) to be on the safe side for the Output
>Valves....
>
>With lower Voltages in the PSU, more Current is possible....
>
>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: SHAMSUL Bahrin Kamarudin <shamsul.BK@innosabah.com.my>
Subject: Ref:>Re:
Date: Mon, 29 Jun 1998 10:44:02 +0800
Source: Sound Digest Archive v01.n326

*** william gaw. on 28/06/1998 around 9:01 AM -0400 wrote ..........
- ->God, 42 messages, and only one on topic. Bill
- ->Notred.

Thanks for the "concern".

Regards.

::-)



              \\\///
             / _  _ \
           (| (.)(.) |)
|--------.OOOo--()--oOOO.-- mailto:shamsul.BK@innosabah.com.my -|
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_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/


=========================================================================
From: SHAMSUL Bahrin Kamarudin <shamsul.BK@innosabah.com.my>
Subject: Ref:>Re:
Date: Mon, 29 Jun 1998 10:58:45 +0800
Source: Sound Digest Archive v01.n326

*** T. Loesch on 27/06/1998 around 6:03 PM -0700 wrote ..........
- ->[snipped to save bandwith]
- ->
Noted the answers etc. Thanks.

- ->
- ->>e. pin 5 & 6 is connected to a small adjustable switch(has 3 pins) that
- ->>reads "22K 734M" and last of the switch pin is "grounded".
- ->
- ->Pin 5 is the Control-Grid and the "Switch" is actually a Pot. It is
- ->highly likely that this controls the Bias. 22k would mean 22 kOhm, which
- ->seems rather low.... Are you sure there is no further resistor around
- ->there....?
- ->
Actually there is but I can't get an accurate reading but its a very small
resistor connected around there.

Before I convert to "triode" mode as per below, how do or where do I check
the "bias" for this PP,UL amp ?


- ->To convert the Amp into Triode Operation simply connect Grid 2 (pin 4 )
- ->to the Anode (pin 3) via a 100 Ohm 2 Watt Resistor.... Switch back on
- ->and monitor the Voltage on the 5 Ohm Resistors....
- ->
- ->With 450 V +B (PSU Voltage), the Current should be no more than 55mA
- ->(0.275V across the 5 Ohm Resistor) to be on the safe side for the Output
- ->Valves....
- ->
- ->With lower Voltages in the PSU, more Current is possible....
- ->
Noted.

BTW, how do you calculate the triode values above and is the  a 100 Ohm 2
Watt resistor better than a 1 Watt type ?

Thanks for the INFO & explanations. Much appreciate them.


- ->Kind regards Thorsten.
- ->
Regards.


::-)



              \\\///
             / _  _ \
           (| (.)(.) |)
|--------.OOOo--()--oOOO.-- mailto:shamsul.BK@innosabah.com.my -|
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
_/    H/P: 019-8107360   TEL: 6088-244185   FAX: 6088-251679    _/
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_/   ========================================================   _/
_/    TO BECOME A LEADING HI-TECH, PEOPLE ORIENTED FINANCIAL    _/
_/         SERVICES COMPANY WHICH OFFERS WORLD CLASS            _/
_/              INNOVATIVE PRODUCTS AND SERVICES                _/
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
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_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/


=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: Re: Ref:-Re:
Date: Mon, 29 Jun 1998 04:16:23 PDT
Source: Sound Digest Archive v01.n327

Hi there,

>->Pin 5 is the Control-Grid and the "Switch" is actually a Pot. It is
>->highly likely that this controls the Bias. 22k would mean 22 kOhm, 
>->which seems rather low.... Are you sure there is no further 
>->resistor around there....?
>->
>Actually there is but I can't get an accurate reading but its a very 
>small resistor connected around there.

Check the Colour Code....

>Before I convert to "triode" mode as per below, how do or where do I 
>check the "bias" for this PP,UL amp ?

As detailed in my original Answer.... Measure the Voltage across the 
5-Ohm Resistor connected to Pin 3 (Anode). 0.05V = 10mA current through 
the valve.....

>BTW, how do you calculate the triode values 

25 Watt Anode dissipation.

450V +B. 

There is little Voltage Drop in the OPT and no Cathode Bias Voltage (as 
it is fixed bias).

So the Maximum allowable standing/quiescent Current is: 

25VA/450V=0.055A or 55mA. This is a very conservative rating and will 
probably take a Watt or Two of the Output Power.... But it will be easy 
on the Output Valves....

>is the  a 100 Ohm 2 Watt resistor better than a 1 Watt type ?

Not really, it is just "safer".... I have a big tendency to over-rate 
any component....

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: SHAMSUL Bahrin Kamarudin <shamsul.BK@innosabah.com.my>
Subject: Ref:>Re: Ref:-Re:
Date: Tue, 30 Jun 1998 09:50:36 +0800
Source: Sound Digest Archive v01.n328

*** T. Loesch on 29/06/1998 around 4:16 AM -0700 wrote ..........
- ->
- ->>Actually there is but I can't get an accurate reading but its a very
- ->>small resistor connected around there.
- ->
- ->Check the Colour Code....
- ->
Noted.

I would like to firstly thank you and others for all the help and
information etc on this "pentode to triode" conversions.

Will do so on tonight to check the colour codes. Didn't wrote it down as
last night I was busy & had finally successfully converted my current UL,PP
amp to "triode" mode. No problems encountered. Got it running from around
2.00am till 8.00am morning over here.

- ->
- ->As detailed in my original Answer.... Measure the Voltage across the
- ->5-Ohm Resistor connected to Pin 3 (Anode). 0.05V = 10mA current through
- ->the valve.....
- ->
Noted.

Thanks for the "clarification". Will bear this in mind when I convert it
back to its original UL,PP mode but I don't see the point as it works &
sound "superbly" in "triode" mode.


- ->>BTW, how do you calculate the triode values
- ->
- ->[snipped to save bandwith]
- ->
Noted.

Thanks again for the "clarification".

Just for your info, after the "triode" mode conversions, before I re-bias
the tubes, the voltage across all the 5 Ohm resistors was around 170mV, so
I reduced all to around 50-55mV. I'm using a digital multimeter for this
purpose.


- ->
- ->>is the  a 100 Ohm 2 Watt resistor better than a 1 Watt type ?
- ->
- ->Not really, it is just "safer".... I have a big tendency to over-rate
- ->any component....
- ->
Cool. I bought & use 100 Ohm 2 Watt resistors for all the output taps. The
resistors were reasonable priced and affordable by my end.


Regards.

::-)



              \\\///
             / _  _ \
           (| (.)(.) |)
|--------.OOOo--()--oOOO.-- mailto:shamsul.BK@innosabah.com.my -|
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
_/    H/P: 019-8107360   TEL: 6088-244185   FAX: 6088-251679    _/
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_/   ========================================================   _/
_/    TO BECOME A LEADING HI-TECH, PEOPLE ORIENTED FINANCIAL    _/
_/         SERVICES COMPANY WHICH OFFERS WORLD CLASS            _/
_/              INNOVATIVE PRODUCTS AND SERVICES                _/
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
_/ THIS IS A          | INNOSABAH SECURITIES SDN BHD (194990-K) _/
_/ COMPUTER GENERATED | 11 EQUITY HOUSE, BLOCK K,               _/
_/ ELECTRONIC MAIL    | SADONG JAYA, KARAMUNSING,               _/
_/ AND IS DEEMED TO   | 88100 KOTA KINABALU, SABAH,             _/
_/ HAVE BEEN SIGNED   | M   A   L   A   Y   S   I   A           _/
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/


=========================================================================
From: "Bert Doppenberg" <lowther@wxs.nl>
Subject: ........
Date: Sat, 15 Aug 1998 18:42:19 +0200
Source: Sound Digest Archive v01.n391

This is a multi-part message in MIME format.

- ------=_NextPart_000_0063_01BDC87C.6EF21260
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

Test

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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>
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<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#000000 size=3D2>Test</FONT></DIV></BODY></HTML>

- ------=_NextPart_000_0063_01BDC87C.6EF21260--


=========================================================================
From: "Riesz, Ted - PETFISH" <Ted.Riesz@mailhost.dpie.gov.au>
Subject: RE: 
Date: Wed, 26 Aug 1998 18:18:01 +1000
Source: Sound Digest Archive v01.n402

	 Yves Le Gal > Some, who have listened to a J.C. Verdier rebuilt
124 (a complete feature
> was published in l'Audiophile eons ago), believe that this version is
> as
> good - in a different way - as the 301. As I've not listened to it, I
> can't be more specific.
> 
> 
	 I have a TD124 II which I use with a Rega RB300 arm.  I would
be very interested in knowing more about the JC Verdier rebuild.

	Could anyone on the list enlighten us.  In particular, what are
the pros and cons of removing the top platter?

	Regards

	Ted Riesz 


=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: 
Date: Wed, 16 Sep 1998 10:46:10 -0500
Source: Sound Digest Archive v01.n423

At 7:40 AM -0400 9/16/98, Larry D. Moore wrote:
>oes:
>
>Last weekend I had a very nice conversation with Steve Berger of
>AprilSound.  We discussed at some length the Bronze 50 amplifier that
>appeared on the cover of a past issue of SP.  There is a schematic on
>Steve's web page.  You see, I generally live with a breadboard, clip lead
>nightmare amplifier in the intest of persuing the art of amplifier design.
>Recently, I began law school.  Yep, hung up my RF research and development
>engineering career at Lucent Technologies and decide to try my hand at law.
> Patent law, hopefully, when I'm done.  But, I degress in a way.  What I'm
>getting at is in moving to attend law school and taking a step down in
>space, I needed to rid myself of the clip leads, not to mention the safety
>of having this contraption in my living room.  So, the image you see is
>what I came up with.  I call it the "Montford".  This iis the signal
>chassis.  It was aptly named by my buddy Rimmer de Vries, since I moved on
>to Montford Avenue.  The idea of the chassis is make it through law school
>in an astetically acceptable fashion while still allowing experimentation
>and development.  So, take a peek at the image.  The input and ouput stages
>are built on seperate modules/subchassis which allowing swapping to
>different combinations/stages.  There is a seperate power supply chassis,
>no image here yet, which will allow various configurations as well.  But,
>back to Steve.  One of the configurations which I tried and am currently
>using is quite similar to the Bronze 50.  I just had to see where Steve and
>the NY triode boys were at on this stuff.  I'm using Nature Sound NS-70s
>with Valve Art 5300B output tubes.  The audiophile deluxe version from
>Angela with ceramic bases and gold pins.  TRY permalloy!!  Use it the way
>it is intended and forget about all that noise about saturating the core.
>I'm running 70-75mA.  I find no difference between 60 and 100mA.  For an
>interstage, I went with Steve's suggestion of the Nature Sound NC-14, the
>poor man's NC-20 as some call it?!  Ha, ha, I know why!  What a deal!  What
>a value.  Worth its weight in gold.  It is killer and used correctly has
>tons of bandwidth.  I'm using the 7119 Amperex gold pin in place of the
>5687.  You can directly substitue it.  It tends to be a bit smoother to my
>ear.  I'm also using all Panasonic TSHAs per jc's suggestion, with some
>oils here and there for the small values.  They are killer too.  A couple
>of points: 1) Get some good magnetics, don't screw around.  You're going to
>all this effort, make it worth while.  Buy something your great grand kids
>will inherit.  Don't play transformer of the month.  You're whole design
>will be compromised.  Call Steve.  He's great. 2)  Think real hard about
>three stages.  It allows low mu tubes and increases the sensitivity of the
>amplifer.  The dymanics associated with this approach can bring an increase
>in jump factor as great as switching to horn speakers on top of horn
>speakers, which I already use.  A side getter here is the direct coupling
>of the first two stages.  It is almost like two amplifiers, if you will.  I
>changed some things in the power supply.  The output stage B+ rectifier is
>diode dampeners.  The input/driver stage choke is a low inductance, low
>DCR. 2H, 50 ohms.  Also, I tried all the rectifier tubes and diode dampener
>and still will stick with HEXFREDS.  Both these were better to me.  The
>requirements of the input stage and ouput stage are quite different.  My
>personal philosophy.  Use DC on the input/driver filaments, I though it
>made the background blacker.  All in all, this is a superb place to start
>if you aren't confortable designing yourself.  And even if you are, try
>this.  Do not under estimate this design.  IMHO, it is the best thing in
>the public domain and I've built them all with the exception of Greggo's
>amp in the last SP.  Steve really did everyone a service by throwing this
>up on his webpage.

Great post, LD.  I too find the 7119 better in many ways than the 5687,
though there are some debatable points.  I must say that the 5687 has a lot
of warmth and air, but compared to the 7119 they are much "dirtier" on
top--depends on what sound you want.  The 7119s are leaner but much
cleaner.  You are probably doing a direct-coupled 7119 cascade, no?  This
probably complicates things too much, but I have to add that the 7119 in
parallel is a really sweet proposition--extra focus and clarity without any
smudging or darkness.  Whereas a parallel 5687 can get overly detailed and
a bit fierce, a parallel 7119 actually seems to "lighten up"...

Regarding rectifiers, are you saying that you prefer hexfreds to the damper
diodes and tube rectifiers?  I recently was encouraged to try some good
sand diodes and was pleasantly surprised by the results.  I lost some of
the immediacy of a tube rectifier, but also lost a lot of distortion and
sag in the PS, leaving a sense of much more apparent power than I thought I
had.  It took a few days for the "veiling" to burn away.  I'm not sure this
would please the 2A3/Lowther crowd, where you want more delicacy and
liquidity, but my ProAcs seem ever so much happier with the diode supply.
Plus you can go to town and back with capacitance on the output tube, and
the bass just snaps to nicely.  A friend of mine has a neat trick wherein
he uses hexfreds on the output stages and a 5Y3 to supply the input stages,
where you're not swinging the current around--a great compromise IMO.

Regarding more input stages, I couldn't agree more.  Again, when you are
driving a less efficient system with SE, it's not so much the lack of power
as the lack of dynamcis which can kill you.  God knows I've struggled with
getting the gain I want over the past year, and it isn't easy to find the
right tube compliment.  An interstage obviously would be a boon, wherein
you can use more stages, but still get a little step-up with the tranny and
lose a coupling cap.

And finally, yes yes, if you haven't taken those expensive BGs and screechy
Cerafines out of your amps and repaced them with a good stock electrolytic
like the Panasonics, please try it.  It removes a whole layer of coloration
and distortion from the sound.  Sure, you'll find you have to go back and
clean up some things that were masked by the caps, but you'll really start
to hear the tubes more and the caps less...:-)

What do you think of the 5300?

On a different but related note, I posted some chokes for sale the other
day and the hungry responses where legion.  So take a look at Nebraska
Surplus (www.surplussales.com) where they have a good stock of mil-spec,
potted high current chokes.  They aren't cheap, but they are reasonable,
and nothing sounds better than a good potted Freed or other mil type IMHO.
I have ordered stuff from Nebraska and was sent some beautiful things, no
fuss no muss.  They also have some NICE power trannies.


Grover Gardner
groverg@postoffice.att.net


=========================================================================
From: "Larry D. Moore" <l-moore@onu.edu>
Subject: Re: 
Date: Wed, 16 Sep 1998 14:28:38 -0400
Source: Sound Digest Archive v01.n424

SNIP OLLA
>
>Great post, LD.  I too find the 7119 better in many ways than the 5687,
>though there are some debatable points.  I must say that the 5687 has a lot
>of warmth and air, but compared to the 7119 they are much "dirtier" on
>top--depends on what sound you want.  The 7119s are leaner but much
>cleaner.  You are probably doing a direct-coupled 7119 cascade, no?  

I didn't really find them leaner in this application, but cleaner, yes.
You hit my taste.  I want to extract as much information out of the
recording(s) as possible so as to recreate the performance.  Notice I said
recordings which means I need to listen to all my material, not just a few
select one which make my system sound good.  I sent you another email with
the topology of the input/driver stage that is on Steve's web site.

This
>probably complicates things too much, but I have to add that the 7119 in
>parallel is a really sweet proposition--extra focus and clarity without any
>smudging or darkness.  Whereas a parallel 5687 can get overly detailed and
>a bit fierce, a parallel 7119 actually seems to "lighten up"...

Yea, I'm doing some of that in another design right now.  You're on point
here too.

>
>Regarding rectifiers, are you saying that you prefer hexfreds to the damper
>diodes and tube rectifiers?  

Yes, for the input stage.  Although, I'm not sure I cound hear the
difference between HEXFREDs and diode dampeners.  I tried both naturally.
For the output stage, I used diode dampeners which I prefer to typical
rectifiers, GZ37, 5AR4, 5V4, etc.  I like the 83 in the right circumstances
though.

I recently was encouraged to try some good
>sand diodes and was pleasantly surprised by the results.  I lost some of
>the immediacy of a tube rectifier, but also lost a lot of distortion and
>sag in the PS, leaving a sense of much more apparent power than I thought I
>had.  It took a few days for the "veiling" to burn away.  I'm not sure this
>would please the 2A3/Lowther crowd, where you want more delicacy and
>liquidity, but my ProAcs seem ever so much happier with the diode supply.
>Plus you can go to town and back with capacitance on the output tube, and
>the bass just snaps to nicely.  A friend of mine has a neat trick wherein
>he uses hexfreds on the output stages and a 5Y3 to supply the input stages,
>where you're not swinging the current around--a great compromise IMO.

Hum, food for thought.

>
>Regarding more input stages, I couldn't agree more.  Again, when you are
>driving a less efficient system with SE, it's not so much the lack of power
>as the lack of dynamcis which can kill you.  

Amen, brother.

God knows I've struggled with
>getting the gain I want over the past year, and it isn't easy to find the
>right tube compliment.  An interstage obviously would be a boon, wherein
>you can use more stages, but still get a little step-up with the tranny and
>lose a coupling cap.
>
>And finally, yes yes, if you haven't taken those expensive BGs and screechy
>Cerafines out of your amps and repaced them with a good stock electrolytic
>like the Panasonics, please try it.  It removes a whole layer of coloration
>and distortion from the sound.  

Exactly what I heard too.

Sure, you'll find you have to go back and
>clean up some things that were masked by the caps, but you'll really start
>to hear the tubes more and the caps less...:-)

Yea, it might actually show just how awful those SCRs can be.  I swear I
can pick them out a mile away now.

>
>What do you think of the 5300?

I guess I kinda like it.  People really miss the point on the 300B to me
just like jc says.  They characterize the sound of the 300B with the sound
of the lack luster driver stage.  What a mistake/lack of understanding.

>
>On a different but related note, I posted some chokes for sale the other
>day and the hungry responses where legion.  So take a look at Nebraska
>Surplus (www.surplussales.com) where they have a good stock of mil-spec,
>potted high current chokes.  They aren't cheap, but they are reasonable,
>and nothing sounds better than a good potted Freed or other mil type IMHO.
>I have ordered stuff from Nebraska and was sent some beautiful things, no
>fuss no muss.  They also have some NICE power trannies.

Thanks for the tip.  I searched for over three years for the power tx and
chokes which I am using for these amps.  Grover, please measure the DCR of
the secondary of your power tx with a VOM.  I find that this relates just
like the DCR of the choke to the sound.  The lower the better.

>
>
>Grover Gardner
>groverg@postoffice.att.net
>
Take care and thanks for responding,
LDM


=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re:
Date: Wed, 16 Sep 1998 16:36:08 -0500
Source: Sound Digest Archive v01.n425

At 2:28 PM -0400 9/16/98, Larry D. Moore wrote:

>Grover, please measure the DCR of
>the secondary of your power tx with a VOM.  I find that this relates just
>like the DCR of the choke to the sound.  The lower the better.

A good tip in return.  Again, one finds that the milpspec stuff almost
always has shockingly low DCR in the windings.  I guess we *all* paid
billions for these things many years ago, but now we can pick them up for a
fraction of their original cost and take advantage of the detritus of the
old military-industrial complex!


Grover Gardner
groverg@postoffice.att.net


=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: 
Date: Thu, 10 Dec 1998 22:40:24 +0100
Source: Sound Digest Archive v01.n533

At 13:06 10-12-98 -0000, you wrote:
>Dear Guido,

Hi Pascal,

>I read your post (on JoeList) on the Jolida CD player and noted you own a
TEAC VRDS10. I too, am very fond of TEAC players, and would like to ask you
a few questions.
>
>I have located a used TEAC P-10 with its matching DAC. This used to be
very upmarket combination in the TEAC range, but is now quite out of date
technically, at least for the DAC (at least that's what it SOUNDED like). I
can have the pair for quite cheap (the price of a new VRDS 8). My questions
are:
>
>- Could you tell me if you know if the VRDS mechanics have much evolved
since the P-10 drive ?

Not really, they are made producable

>- The sound of the P-10 with the DAC of the VRDS 25X was very detailed,
but also *very* hard and dry.

Correct, as is the VRDS 10

>Could you recommend a DAC that would retain the details but tame the
harshness in the sound (the DAC which is sold with the P-10 drive
considerably softens the sound, but *a lot* of detail is lost compared to
the VRDS25X DAC) ?

I am thinking on the Audio Note DAC-3

Recently we found out that you need a very good DAC to get rid of the sound
of the TEAC. Even through a "decent" DAC, te TEAC harshness can be heard.
Our own DAC is very insensitive for incoming jitter and therefor makes the
TEAC sound analogue

The DAC-3 will be a good match, but not good enough

Again, I bought my TEAC for mechanical stability, knowing that I had to
invest a lot to make it sound properly as a drive

>- Do you think/know whether the P-10 is far behind more modern designs
from TEAC in terms of quality/jitter/detail ... ?

The jitter of all TEAC's I measured is not outstanding, some others are
worse, some are better

>(All in all, would you recommend buying it ;-> )

You have two options:

1-buy a very good drive, and a DAC with average performance w.r.t. jitter
2-buy an average drive, but a very good DAC
(our DAC has  intensive re-clocking, a local oscillator with less than 1 ps
jitter, and a PLL loop at less than 1 Hz)

It is like amplifier versus speaker: power versus efficiency. I prefer low
power and high efficiency. I prefer a rock solid regeneration of the clock
in a DAC

>Thank you very much for your help.

Does it help :-)

Succes

Guido

>Best regards,
>Pascal.
>
>


0000


=========================================================================
From: Rick Francis <rfranci@uoft03.UTOLEDO.EDU>
Subject: Re: 0 - 60 V, 10 A DC powersupply
Date: Wed, 22 Oct 1997 17:05:30 -0400 (EDT)
Source: Sound Digest Archive v01.n080

On Wed, 22 Oct 1997, Finn Hammer wrote:

> For this, I am in need of a DC supply, that will cover from 0-60 Volts,
> and deliver max. 10 Ampere.
> 
I'd use a variac as AC source for a stepdown transformer and SS 
rectification.  Turn a 110:220 transformer the other way (you have 220, 
right?) and you should be able to do this quickly. Too bad you're far 
away, I've got a 10 amp 150 volt supply...

Rick


=========================================================================
From: Finn Hammer <f-hammer@post5.tele.dk>
Subject: 0 - 60 V, 10 A DC powersupply
Date: Wed, 22 Oct 1997 21:57:21 +0200
Source: Sound Digest Archive v01.n080

I am soon going to do a comprehensive range of measurements on a new,
and hopefully more succesfull fieldcoil loudspeaker magnet.

For this, I am in need of a DC supply, that will cover from 0-60 Volts,
and deliver max. 10 Ampere.

The supplies that I have are limited to 30 Volts, 3 Ampere, and although
Weller has a 10 amp. supply, it is limited to 30 V.

What to do?

I need a schematic, so that I can whip one up in a hurry. It doesn`t
have to deliver 10A @ 1 volts, It will work into 7 Ohms.

If you know anyplace where I can get a schematic, pleace point me in
that direction, if you are able to construct one for me, I am willing
pay you for the effort.

Kindest, Finn
- -- 
                    HOME OF
            Tractrix Horns, Tube Amps,
    Fieldcoil Loudspeakers and Computer Graphics

       http://home5.inet.tele.dk/f-hammer/


1111


=========================================================================
From: "Mark Donen" <soledadd@worldnet.att.net>
Subject: 1000 watts per channel?
Date: Thu, 30 Apr 1998 12:28:19 -0400
Source: Sound Digest Archive v01.n265

Another anecdote for you:

My college roomate came to visit last night from out of town. He is also
into his hifi in his own, very different, way. He has his huge SS McIntoshs
and Big JBL studio monitors plus Sunfire sub (biamped 500 per channel on
the bass and 250 on the mid/highend) I played him my "little" Altec system
with jc's little 10 watt amps with some Hendrix and Marley, stuff with a
lot of bass, and I asked him "how many watts does it sound like?" He
doesn't know nothin' from tubes or Altec. "500 watts a channel?", he said.
"no" I said. "are they really 1000 watts?" he asked, straight faced....


=========================================================================
From: Kalman Rubinson <kr4@is2.nyu.edu>
Subject: Re: 1000 watts per channel?
Date: Thu, 30 Apr 1998 14:23:11 -0400 (EDT)
Source: Sound Digest Archive v01.n265

On Thu, 30 Apr 1998, Mark Donen wrote:
> My college roomate came to visit last night from out of town. He is also
> into his hifi in his own, very different, way. He has his huge SS McIntoshs
> and Big JBL studio monitors plus Sunfire sub (biamped 500 per channel on
> the bass and 250 on the mid/highend) I played him my "little" Altec system
> with jc's little 10 watt amps with some Hendrix and Marley, stuff with a
> lot of bass, and I asked him "how many watts does it sound like?" He
> doesn't know nothin' from tubes or Altec. "500 watts a channel?", he said.
> "no" I said. "are they really 1000 watts?" he asked, straight faced....

I think that reflects on his esthetics as much as on yours.

Kal
> 
> 

Nota Bene:  New address is kr4@is2.nyu.edu


=========================================================================
From: "Mark Donen" <soledadd@worldnet.att.net>
Subject: Re: 1000 watts per channel?
Date: Thu, 30 Apr 1998 16:58:43 -0400
Source: Sound Digest Archive v01.n265

Hey Kal,

Only trying to point out that 10 watts can sound really powerful. My
friends aesthetics of course are not mine. He wants power and bass that is
all he is into. The point of getting together a system like mine was not
just bass. That just came as a bonus with the package. But it has to be
said for some music you just gotta have it. For bass alone and more and
better bass than I have, I could have just gone to Canal St and bought
myself 2 pairs of JBL 2226 and a Crown switching amp and saved myself time
and trouble! 

Regards,

Mark

- ----------
> From: Kalman Rubinson <kr4@is2.nyu.edu>
> To: Mark Donen <soledadd@worldnet.att.net>
> Cc: joelist <sound@deliverator.io.com>
> Subject: Re: 1000 watts per channel?
> Date: Thursday, April 30, 1998 2:23 PM
> 
> On Thu, 30 Apr 1998, Mark Donen wrote:
> > My college roomate came to visit last night from out of town. He is
also
> > into his hifi in his own, very different, way. He has his huge SS
McIntoshs
> > and Big JBL studio monitors plus Sunfire sub (biamped 500 per channel
on
> > the bass and 250 on the mid/highend) I played him my "little" Altec
system
> > with jc's little 10 watt amps with some Hendrix and Marley, stuff with
a
> > lot of bass, and I asked him "how many watts does it sound like?" He
> > doesn't know nothin' from tubes or Altec. "500 watts a channel?", he
said.
> > "no" I said. "are they really 1000 watts?" he asked, straight faced....
> 
> I think that reflects on his esthetics as much as on yours.
> 
> Kal
> > 
> > 
> 
> Nota Bene:  New address is kr4@is2.nyu.edu
> 


=========================================================================
From: Kalman Rubinson <kr4@is2.nyu.edu>
Subject: Re: 1000 watts per channel?
Date: Thu, 30 Apr 1998 17:08:24 -0400 (EDT)
Source: Sound Digest Archive v01.n265

On Thu, 30 Apr 1998, Mark Donen wrote:

> Only trying to point out that 10 watts can sound really powerful.

I understand. 

> My friends aesthetics of course are not mine.

Yes, and it was his that I was critical of.

Kal


=========================================================================
From: "Mark Donen" <soledadd@worldnet.att.net>
Subject: Re: 1000 watts per channel?
Date: Thu, 30 Apr 1998 21:27:58 -0400
Source: Sound Digest Archive v01.n265

Oh well,

I wasn't sure. But how do they get all that power and be so small and light
and cool running?

Best,

Mark

- ----------
> From: David Barnett <davidbarnett@aristotle.net>
> To: sound@deliverator.io.com
> Subject: Re: 1000 watts per channel?
> Date: Thursday, April 30, 1998 8:19 PM
> 
> On Thu, 30 Apr 1998 16:58:43 -0400, "Mark Donen"
> <soledadd@worldnet.att.net> wrote:
> 
> >I could have just gone to Canal St and bought
> >myself 2 pairs of JBL 2226 and a Crown switching amp and saved myself
time
> >and trouble! 
> 
> Sorry to nitpick, but I think Crown amps are still analog.  At least
> the five I have at work are.
> 
> --dnb


=========================================================================
From: davidbarnett@aristotle.net (David Barnett)
Subject: Re: 1000 watts per channel?
Date: Fri, 01 May 1998 00:19:49 GMT
Source: Sound Digest Archive v01.n265

On Thu, 30 Apr 1998 16:58:43 -0400, "Mark Donen"
<soledadd@worldnet.att.net> wrote:

>I could have just gone to Canal St and bought
>myself 2 pairs of JBL 2226 and a Crown switching amp and saved myself time
>and trouble! 

Sorry to nitpick, but I think Crown amps are still analog.  At least
the five I have at work are.

- --dnb


=========================================================================
From: davidbarnett@aristotle.net (David Barnett)
Subject: Re: 1000 watts per channel?
Date: Fri, 01 May 1998 02:00:12 GMT
Source: Sound Digest Archive v01.n265

On Thu, 30 Apr 1998 21:27:58 -0400, "Mark Donen"
<soledadd@worldnet.att.net> wrote:

>I wasn't sure. But how do they get all that power and be so small and light
>and cool running?

Good question.  I think there's some power supply jiggery-pokery in
the MA3600VZ and MA5000VZ, but (1) they ain't all that light (I've had
to carry them up a ladder to mount them in a rack...), and (2) the
audio bits are all analog.

- --dnb


=========================================================================
From: "Le Cleac'h    J.-M." <lecleach@cgi.ensmp.fr>
Subject: 100 years of cinema loudspeakers
Date: Fri, 11 Dec 1998 19:24:33 +0100
Source: Sound Digest Archive v01.n534

Give a look at:

http://www.amps.net/newsletters/21_cine.htm

100 YEARS OF CINEMA LOUDSPEAKERS 
                                                                           
                             By John Aldred  

and

http://www.audioworld.net/Goodolddays/Beginning/beginindex.htm

Where did it all begin?

Fra Hi-Fi & Music Review 1958 

Best regards,

Jean-Michel Le Cleac'h, Paris, France


=========================================================================
From: Larry Van Wormer <lvw@bmts.com>
Subject: $10 coupon from Music Boulevard
Date: Wed, 14 Oct 1998 19:06:12 -0400
Source: Sound Digest Archive v01.n454

I've found out a bit more about the various good deals from Music
Boulevard. Seems the company offers special deals through some web
sites. The people who know more about this have a regular list of sites
they check, which I hope to get. If so will pass it along. In the
meantime here is a current coupon from the Netscape site. (Go there,
click on "Music" under Shopping, then click on the Music Boulevard ad on
the screen that comes up. Order from the page that comes up, and you
will get $10 deducted from the CD order you place. It works, I've
already ordered a CD. Don't worry about what the ad says, you can order
any CD and get the discount.)

http://www.musicblvd.com/cgi-bin/tw/2184_20_chi^S&FS=NETCENTER

Larry Van Wormer


=========================================================================
From: Allen Wright <AllenWright@compuserve.com>
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Date: Wed, 23 Dec 1998 18:32:05 -0500
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=========================================================================
From: "Ken Dangerfield" <bpyakd@mail.island.net>
Subject: Re: 10th Anniversary
Date: Wed, 4 Mar 1998 21:10:46 -0800
Source: Sound Digest Archive v01.n208

I second Paul Joppa's suggestion for a parafeed OPT for the SV-572 
series (and the matching plate load choke).

It would open up a whole new realm for the guys who like the sound of 
tungsten (me included after hearing it at VSAC) .

Regards,
Ken Dangerfield


=========================================================================
From: tubesguy@mail.execpc.com (Patrick Currie)
Subject: 10th Anniv product-845 parafeed
Date: Thu, 5 Mar 1998 18:59:13 -0500
Source: Sound Digest Archive v01.n209

Doc said:

>but some R & D has shown that 845 nickel parafeed may just flat whup
>anything else around.

Well, how about a low-power version using the 450v, 80ma point, with BACs
and 2004s?  Might be only 4 or 5 watts, but let the whupping begin. - Pat

Pat Currie (tubesguy@execpc.com)


=========================================================================
From: Paul Joppa <pdj@ISDNseattle.net>
Subject: Re: 10th Anniv product-845 parafeed
Date: Thu, 05 Mar 1998 22:18:46 -0800
Source: Sound Digest Archive v01.n209

That operating point would likely give 10-11 real watts. But having
heard Bottlehead's VV52 parafeed (it's wonderful!), I'd suggest less 
volts and more amps. For the brave, 400v and 100mA is the 300B max 
spec of 40 watts. Gives less power but less distortion. I know
Dan prefers this; maybe he will tell us what difference he hears.
Good chokes are hard to find; you want I think at least 50 henries.
Maybe four EX003's in series-parallel?! Or give up some power, run 
320v at 80 mA with the new big chokes...

- -Paul Joppa

Patrick Currie wrote:
> 
> Doc said:
> 
> >but some R & D has shown that 845 nickel parafeed may just flat whup
> >anything else around.
> 
> Well, how about a low-power version using the 450v, 80ma point, with BACs
> and 2004s?  Might be only 4 or 5 watts, but let the whupping begin. - Pat
> 
> Pat Currie (tubesguy@execpc.com)


=========================================================================
From: Paul Joppa <pdj@ISDNseattle.net>
Subject: Re: 10th Anniv product-845 parafeed
Date: Fri, 06 Mar 1998 07:23:03 -0800
Source: Sound Digest Archive v01.n209

Yip Hin Fai Johari wrote:
> 
> Hey I am working on a 845 SE amp that's running at the 450V 80mA point.
> It's fixed bias at -46V and cap. coupled to the anode of a 5691.
> Output trans is rated at 2K5 primary.
> Any thoughts about this amp.
> 
> Johari

That's the load for max. power, but distortion might be a little high. 
You'd lose very little power going to a higher load impedance - 4K to
5K 
should cut second harmonic in half. If primary inductance is not too 
small, you might try it with an 8ohm speaker on the 4ohm tap, just to 
see how it sounds.

- -Paul Joppa


=========================================================================
From: Yip Hin Fai Johari <hfyip@pacific.net.sg>
Subject: Re: 10th Anniv product-845 parafeed
Date: Fri, 06 Mar 1998 18:58:20 +0800
Source: Sound Digest Archive v01.n209

At 06:59 PM 3/5/98 -0500, you wrote:

>Well, how about a low-power version using the 450v, 80ma point, with BACs
>and 2004s?  Might be only 4 or 5 watts, but let the whupping begin. - Pat
>
>Pat Currie (tubesguy@execpc.com)

Hey I am working on a 845 SE amp that's running at the 450V 80mA point.
It's fixed bias at -46V and cap. coupled to the anode of a 5691.
Output trans is rated at 2K5 primary.
Any thoughts about this amp.

Johari 


=========================================================================
From: Yip Hin Fai Johari <hfyip@pacific.net.sg>
Subject: Re: 10th Anniv product-845 parafeed
Date: Sat, 07 Mar 1998 07:17:50 +0800
Source: Sound Digest Archive v01.n209

At 07:23 AM 3/6/98 -0800, you wrote:
>Yip Hin Fai Johari wrote:
>> 
>> Hey I am working on a 845 SE amp that's running at the 450V 80mA point.
>> It's fixed bias at -46V and cap. coupled to the anode of a 5691.
>> Output trans is rated at 2K5 primary.
>> Any thoughts about this amp.
>> 
>> Johari
>
>That's the load for max. power, but distortion might be a little high. 
>You'd lose very little power going to a higher load impedance - 4K to
>5K 
>should cut second harmonic in half. If primary inductance is not too 
>small, you might try it with an 8ohm speaker on the 4ohm tap, just to 
>see how it sounds.
>
>-Paul Joppa

Hi Paul,

Thanks for your valuable insights. I'm using a Lundahl LL1620 which is a
universal O/P trans but primary is set at 3K. I'll rewire it to 5K and give
it a try.
Thanks again for your response.

Johari 


=========================================================================
From: Joseph Lowe <jlowe@cdc.net>
Subject: Re: 10V valves
Date: Wed, 7 Oct 1998 12:11:55 -0400 (EDT)
Source: Sound Digest Archive v01.n444

On Thu, 8 Oct 1998, Sellek, Grant (TSA) wrote:

> Can anyone send a list of valves that use 10V heaters? Preferably those that
> have some audio potential. 

805, 838, 203A, 833


=========================================================================
From: "Sellek, Grant (TSA)" <Grant.Sellek@roads.sa.gov.au>
Subject: 10V valves
Date: Thu, 08 Oct 1998 00:11:04 +0930
Source: Sound Digest Archive v01.n444

Can anyone send a list of valves that use 10V heaters? Preferably those that
have some audio potential. I am looking for something that will yield at
least a watt or so in class A; maybe something a little offbeat and which,
for that reason, is not priced (prized?) very highly. I of course know about
the 211 and 845, but not much else.

Grant

Grant Sellek
Adelaide, Australia
grant.sellek@roads.sa.gov.au


=========================================================================
From: Paul Joppa <pdj@ISDNseattle.net>
Subject: Re: 10V valves
Date: Wed, 07 Oct 1998 21:30:38 -0700
Source: Sound Digest Archive v01.n445

Sellek, Grant (TSA) wrote:
> 
> Can anyone send a list of valves that use 10V heaters? Preferably those that
> have some audio potential. I am looking for something that will yield at
> least a watt or so in class A; maybe something a little offbeat and which,
> for that reason, is not priced (prized?) very highly. I of course know about
> the 211 and 845, but not much else.

I wouldn't hesitate to try any of the double-triode TV vertical
amp/osc types - 10DA7, DE, DR, EG, EM, EW, FD, FR, or GF. 
Unfortunately none seem to be DN7 types, but all are 6-10w output side
at 700-1000 ohms rp. I'd stay with the ones that have a low-mu
'driver' section myself, so you can run enough current to drive the
output grid capacitance. 

There's also a 10BQ5...

- -Paul Joppa


=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: 10V valves
Date: Wed, 07 Oct 1998 22:52:52 +0200
Source: Sound Digest Archive v01.n445

At 00:11 8-10-98 +0930, Sellek, Grant (TSA) wrote:
>Can anyone send a list of valves that use 10V heaters? Preferably those that
>have some audio potential. I am looking for something that will yield at
>least a watt or so in class A

try EL95 SE in triode (850 mW). Usual 6.3 V heater

Guido

>; maybe something a little offbeat and which,
>for that reason, is not priced (prized?) very highly. I of course know about
>the 211 and 845, but not much else.
>
>Grant
>
>Grant Sellek
>Adelaide, Australia
>grant.sellek@roads.sa.gov.au
>
>


=========================================================================
From: Andrej Deticek <andrej.deticek@siol.net>
Subject: Re: 10V valves
Date: Thu, 08 Oct 1998 00:26:01 +0100
Source: Sound Digest Archive v01.n445

> At 00:11 8-10-98 +0930, Sellek, Grant (TSA) wrote:
> >Can anyone send a list of valves that use 10V heaters? Preferably those that
> >have some audio potential. I am looking for something that will yield at
> >least a watt or so in class A; maybe something a little offbeat and which,
> >for that reason, is not priced (prized?) very highly. I of course know about
> >the 211 and 845, but not much else.
> >
> >Grant
> >
> >Grant Sellek
> >Adelaide, Australia
> >grant.sellek@roads.sa.gov.au
> >
> >

Hello Grant,

If it has to be a 10V heater and you are happy with 1 - 2W output and
should not be expensive, you can try valve type 10CW5 (=YL86).
 This is a 9-pin miniature valve (Noval), an equivalent to 6CW5(= EL86)
valve, however with a 10V heater.
The valve is quite linear (The tube was built for an output audio
amplifier amplification) and you can get about 2W of output SE, when
triode connected, at a plate voltage of 170V, plate load 1200 Ohm.
The price would certainly be right (In USA $2.5 for a NOS tube from ETE,
$3.10 from AES, for example).

There is a 10V heater equivalent of EL84 also, called 10BQ5 (=YL84),
something that many have discovered to use instead of the NOS EL84
valves, so they are harder to get and a little more expensive (In USA $
3.00 at ETE, and $ 5.00 at SND). This second valve is more linear in my
opinion, but opinions differ...
That will give you same power output of 2W at a little higher plate
voltage of 250V and a plate load of 3500 ohm. 
Maybe this would be something you had in mind.

Regards,

Andrej Deticek


=========================================================================
From: "Sellek, Grant (TSA)" <Grant.Sellek@roads.sa.gov.au>
Subject: RE: 10V valves
Date: Thu, 08 Oct 1998 10:11:23 +0930
Source: Sound Digest Archive v01.n445

Thanks to all who have helped. It has been an interesting thread. I will
look firstly into the valves with higher plate voltage, because that would
enable me to use the tube as a treble amp but run it off the same B+ (1100V)
as the main amp (845 monoblocks, just getting started) without too large a
dropper resistor. This is not essential but it would be kind of neat because
it saves building another power supply.

And no, I am not going to use the 833!!!

If you have any further thoughts, please let me know.

Grant

Grant Sellek
Adelaide, Australia
grant.sellek@roads.sa.gov.au


=========================================================================
From: "Riesz, Ted - PETFISH" <Ted.Riesz@mailhost.dpie.gov.au>
Subject: RE: 10V valves
Date: Thu, 8 Oct 1998 16:59:31 +1100
Source: Sound Digest Archive v01.n445

I have some 11BM8s ( a 11v version of 6BM8) presumably used in transformerless TV's, the bane of man
y a tech. 

Would the 1 v diff in filament voltage be a problem.  This is in recognition of the earlier discussi
on of the downsides in filament undervoltage?

Regards

Ted Riesz


=========================================================================
From: Peter Sikking <peter.sikking@amc.de>
Subject: 10(Y) curves...
Date: Thu, 23 Apr 1998 13:03:36 +0000
Source: Sound Digest Archive v01.n260

Hi Joesters,

If anybody has got platecurves and plate resistance curves for the
10 or 10Y triode, I would be most grateful if I could obtain a copy.

Also I would like to hear from people who have used it whether it
is a tricky tube to use.

Thanks,

	--Peter

music lover, ultra-fi builder, GUI designer & developer, on drums... 
from:amsterdam@ulm.germany  +49 731 505 1540 facsimile +49 731 505 1839


=========================================================================
From: Philippe <Cadique@worldnet.fr>
Subject: Re: 10(Y) curves...
Date: Sat, 25 Apr 1998 08:29:46 +0200
Source: Sound Digest Archive v01.n261

Peter Sikking wrote:
> 
> Hi Joesters,
> 
> If anybody has got platecurves and plate resistance curves for the
> 10 or 10Y triode, I would be most grateful if I could obtain a copy.

hi Peter

I'v got the 10y  RCA characteristics in an old book (P.H. Brans
Vademecum 1948).
There are no curves, only characteristics.
I you are interested, I can scan the page and send it to you.

Philippe


=========================================================================
From: Ed_Fausto@colpal.com (Ed Fausto)
Subject: Re[2]: 10 (Y) curves...
Date: Sat, 25 Apr 1998 15:57:05 -0400
Source: Sound Digest Archive v01.n261

     Philippe,
     
        Send me a copy too.  I got 2 pairs of brown base Sylvania 10Y with 
     graphite plates.  Anyone who had experience using these in SE.
     
     Ed Fausto
     Ed_Fausto@colpal.com


______________________________ Reply Separator _________________________________
Subject: Re: 10(Y) curves...
Author:  Philippe <Cadique@worldnet.fr> at INTERNET
Date:    4/25/98 8:29 AM


Peter Sikking wrote:
> 
> Hi Joesters,
> 
> If anybody has got platecurves and plate resistance curves for the
> 10 or 10Y triode, I would be most grateful if I could obtain a copy.

hi Peter

I'v got the 10y  RCA characteristics in an old book (P.H. Brans
Vademecum 1948).
There are no curves, only characteristics.
I you are interested, I can scan the page and send it to you.

Philippe


=========================================================================
From: Rick Francis <rfranci@uoft03.UTOLEDO.EDU>
Subject: 12.8KV transformers, anyone?
Date: Thu, 09 Apr 1998 23:05:49 -0400 (EDT)
Source: Sound Digest Archive v01.n249

I know it's a long shot, but ... in the pile of muck to be disposed of 
here at the university, I spotted a pair of new Sperry transformers, with 
secondaries of 6400-0-6400, 44ma.  There was another winding at a more 
modest 1.5kv, lower current.  I can't figure out what anyone would do 
with these, but if someone wants them they can let me know.  There seems 
to be a surplus of atomic absorption photospectrometers, too.  Or was 
that spectrophotometers?  They actually disposed of an electron 
microscope, I'm told.  I found a perfectly good 6L6GC blackplate in 
something equally unpronounceable, so you never know.

On a less exotic note, I found a cool reg. PS with digital readout, so am 
thinking I can part with an Oregon tube unit, dual supply 0-600 vdc, up 
to 500 ma, and adj. bias supply to -150.  Uses SIX 807s and more.  Pickup 
only.  Also have extra variacs. And more weird PS's.

Rick Francis, rfranci@uoft03.utoledo.edu


=========================================================================
From: Mattijs de Vries <mdevries@avvt.com>
Subject: 12A any good?
Date: Wed, 09 Sep 1998 16:54:57 +0000
Source: Sound Digest Archive v01.n417

Hello all,

I'm thinking about designing my new preap using the 12A as output tube. It
looks like a real winner to me, especially the Arcturus pair I have. The
current and plate impedance are right, the amplification is exact what I'm
looking for... As far as I know I have never seen anybody using it, also it
is never real expensive, prices look very fair. Any comments about this
tube will be most welcome! Hope to hear from you,
  _______     
 | _____ |    MachMat, Mattijs de Vries
/ |     | \   Top-Fi audio equipment, Tube sales
| | ||| | |   Distributor AVVT Benelux
| | ||| | |   ------------------------------------------------
| | ||| | |   E-mail  : MdeVries@AVVT.COM (Private)
| | ||| | |             MachMat@AVVT.COM (Business)
| |_____| |   URL     : HTTP://WWW.AVVT.COM/machmat/
 \  |||  /    Adress  : Campuslaan 41-214, 7522 NG, Enschede
  |/_|_\|     Country : The Netherlands, Europe
  |     |     Phone   : 0031-53-4895091, Fax : 0031-53-4357234
  |_____|     ------------------------------------------------
   || ||      Designing is the art of making compromises.


=========================================================================
From: SHAMSUL Bahrin Kamarudin <shamsul.BK@innosabah.com.my>
Subject: 12AX7 & 12AU7 substitutes ...
Date: Mon, 20 Jul 1998 12:06:37 +0800
Source: Sound Digest Archive v01.n349

Greetings.

Just would like to know if there's any other tubes(omit their normal subs.)
that can be plugged into a 12AX7 or 12AU7 design without any modifications ?


Regards.

::-)



              \\\///
             / _  _ \
           (| (.)(.) |)
|--------.OOOo--()--oOOO.----------------------------------------|
		mailto:shamsul.BK@innosabah.com.my
		mailto:0198107360@sms.celcom.com.my
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
_/    H/P: 019-8107360   TEL: 6088-244185   FAX: 6088-251679    _/
_/                  http://www.innosabah.com.my                 _/
_/   ========================================================   _/
_/    TO BECOME A LEADING HI-TECH, PEOPLE ORIENTED FINANCIAL    _/
_/         SERVICES COMPANY WHICH OFFERS WORLD CLASS            _/
_/              INNOVATIVE PRODUCTS AND SERVICES                _/
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
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_/ COMPUTER GENERATED | 11 EQUITY HOUSE, BLOCK K,               _/
_/ ELECTRONIC MAIL    | SADONG JAYA, KARAMUNSING,               _/
_/ AND IS DEEMED TO   | 88100 KOTA KINABALU, SABAH,             _/
_/ HAVE BEEN SIGNED   | M   A   L   A   Y   S   I   A           _/
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/


=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: 12AX7 & 12AU7 substitutes ...
Date: Mon, 20 Jul 1998 21:43:22 +0200
Source: Sound Digest Archive v01.n350

At 12:06 20-7-98 +0800, SHAMSUL Bahrin Kamarudin wrote:
>Greetings.
>
>Just would like to know if there's any other tubes(omit their normal subs.)
>that can be plugged into a 12AX7 or 12AU7 design without any modifications ?

I like E80CC instead of ECC82 (12AU7)

Guido

>
>Regards.
>
>::-)
>
>
>
>              \\\///
>             / _  _ \
>           (| (.)(.) |)
>|--------.OOOo--()--oOOO.----------------------------------------|
>		mailto:shamsul.BK@innosabah.com.my
>		mailto:0198107360@sms.celcom.com.my
>_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
>_/    H/P: 019-8107360   TEL: 6088-244185   FAX: 6088-251679    _/
>_/                  http://www.innosabah.com.my                 _/
>_/   ========================================================   _/
>_/    TO BECOME A LEADING HI-TECH, PEOPLE ORIENTED FINANCIAL    _/
>_/         SERVICES COMPANY WHICH OFFERS WORLD CLASS            _/
>_/              INNOVATIVE PRODUCTS AND SERVICES                _/
>_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
>_/ THIS IS A          | INNOSABAH SECURITIES SDN BHD (194990-K) _/
>_/ COMPUTER GENERATED | 11 EQUITY HOUSE, BLOCK K,               _/
>_/ ELECTRONIC MAIL    | SADONG JAYA, KARAMUNSING,               _/
>_/ AND IS DEEMED TO   | 88100 KOTA KINABALU, SABAH,             _/
>_/ HAVE BEEN SIGNED   | M   A   L   A   Y   S   I   A           _/
>_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
>
>
>


=========================================================================
From: "Hubert M. Bath" <bathh@theriver.com>
Subject: Re: Ref:>Re: 12AX7 & 12AU7 substitutes ...
Date: Tue, 21 Jul 1998 02:00:28 -0700
Source: Sound Digest Archive v01.n350

The way this interchange is phrased suggests that the 12AX7 and the 12AU7
are considered equivalent.  Tho the envelopes are the same size, and the
pin diagrams are identical -- and hence you can plug one into a socket
designed to hold the other without (probably) anything burning up, these
two tubes are about as different as they can be.  The 12AU7 is a low-medium
 mu (amplification factor) tube, and the 12AX7 has a mu of 100 -- about as
high as you will find.  The two tubes are anything but equivalents.  This
is *not* to say that if one is substituted for another the circuit will not
"work".

Regards,  Hu Bath
- ----------
> From: SHAMSUL Bahrin Kamarudin <shamsul.BK@innosabah.com.my>
> To: 'JOE-NET Mailist' <sound@deliverator.io.com>
> Cc: evaguido <EvaGuido@iaehv.nl>
> Subject: Ref:>Re: 12AX7 & 12AU7 substitutes ...
> Date: Monday, July 20, 1998 18:44
> 
> *** evaguido on 20/07/1998 around 9:43 PM +0200 wrote ..........
> ->At 12:06 20-7-98 +0800, SHAMSUL Bahrin Kamarudin wrote:
> ->>Greetings.
> ->>
> ->>Just would like to know if there's any other tubes(omit their normal
subs.)
> ->>that can be plugged into a 12AX7 or 12AU7 design without any
modifications ?
> ->
> ->I like E80CC instead of ECC82 (12AU7)
> ->
> Cool.
> 
> Thanks for the INFO.
> 
> Regards.
> 
> ::-)
> 
> 
> 
>               \\\///
>              / _  _ \
>            (| (.)(.) |)
> |--------.OOOo--()--oOOO.----------------------------------------|
> 		mailto:shamsul.BK@innosabah.com.my
> 		mailto:0198107360@sms.celcom.com.my
> _/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> _/    H/P: 019-8107360   TEL: 6088-244185   FAX: 6088-251679    _/
> _/                  http://www.innosabah.com.my                 _/
> _/   ========================================================   _/
> _/    TO BECOME A LEADING HI-TECH, PEOPLE ORIENTED FINANCIAL    _/
> _/         SERVICES COMPANY WHICH OFFERS WORLD CLASS            _/
> _/              INNOVATIVE PRODUCTS AND SERVICES                _/
> _/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> _/ THIS IS A          | INNOSABAH SECURITIES SDN BHD (194990-K) _/
> _/ COMPUTER GENERATED | 11 EQUITY HOUSE, BLOCK K,               _/
> _/ ELECTRONIC MAIL    | SADONG JAYA, KARAMUNSING,               _/
> _/ AND IS DEEMED TO   | 88100 KOTA KINABALU, SABAH,             _/
> _/ HAVE BEEN SIGNED   | M   A   L   A   Y   S   I   A           _/
> _/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> 
> 


=========================================================================
From: SHAMSUL Bahrin Kamarudin <shamsul.BK@innosabah.com.my>
Subject: Ref:>Re: 12AX7 & 12AU7 substitutes ...
Date: Tue, 21 Jul 1998 09:44:33 +0800
Source: Sound Digest Archive v01.n350

*** evaguido on 20/07/1998 around 9:43 PM +0200 wrote ..........
- ->At 12:06 20-7-98 +0800, SHAMSUL Bahrin Kamarudin wrote:
- ->>Greetings.
- ->>
- ->>Just would like to know if there's any other tubes(omit their normal subs.)
- ->>that can be plugged into a 12AX7 or 12AU7 design without any modifications ?
- ->
- ->I like E80CC instead of ECC82 (12AU7)
- ->
Cool.

Thanks for the INFO.

Regards.

::-)



              \\\///
             / _  _ \
           (| (.)(.) |)
|--------.OOOo--()--oOOO.----------------------------------------|
		mailto:shamsul.BK@innosabah.com.my
		mailto:0198107360@sms.celcom.com.my
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
_/    H/P: 019-8107360   TEL: 6088-244185   FAX: 6088-251679    _/
_/                  http://www.innosabah.com.my                 _/
_/   ========================================================   _/
_/    TO BECOME A LEADING HI-TECH, PEOPLE ORIENTED FINANCIAL    _/
_/         SERVICES COMPANY WHICH OFFERS WORLD CLASS            _/
_/              INNOVATIVE PRODUCTS AND SERVICES                _/
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
_/ THIS IS A          | INNOSABAH SECURITIES SDN BHD (194990-K) _/
_/ COMPUTER GENERATED | 11 EQUITY HOUSE, BLOCK K,               _/
_/ ELECTRONIC MAIL    | SADONG JAYA, KARAMUNSING,               _/
_/ AND IS DEEMED TO   | 88100 KOTA KINABALU, SABAH,             _/
_/ HAVE BEEN SIGNED   | M   A   L   A   Y   S   I   A           _/
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/


=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: 12AX7 biasing and grid current.
Date: Mon, 22 Dec 1997 19:40:38 +0100 (MET)
Source: Sound Digest Archive v01.n140

Hello everyone,

Dan Cheever (Thanks to him another time) put on his webpages 3 additionnal
pictures I gave him. The URL is:

http://web.mit.edu/cheever/www/new.html

The 3 pictures are related to the 12AX7 triod (one half).

The first graph is the same as the previously available (THD versus bias and
output level) but this one shows the domains inside which H2 or H3 are dominant.

A second picture shows the evolution of the grid to cathod bias of a 12AX7
(with automatic bias) versus the output level for different values of grid
resistor and cathod resistor (in parallel on 1000 microfarads).

The third one is more general (= more independant of measurement conditions).
 It shows the plate current and the grid current behaviour of the 12AX7.
IMHO, the graph  Iplate versus Ugrid is the most convenient to display the
grid current.

Best regards.
 


=========================================================================
From: paolo.delgiusto@studioidea.it (Paolo Del Giusto)
Subject: 12ax7 supply
Date: Tue, 28 Oct 1997 18:14:36 +0100
Source: Sound Digest Archive v01.n092

        Hello people,
I'm building a preamp where the filament supply of the valves, 12ax7, is
5V, to obtain a longer life for the tubes. Since I'm not so sure it is a
good idea to reduce the filament supply, I'd like to have the opinion of
the list (instead of wasting time, bandwidth and health in useless
discussions).

Thanks



- ----------------------------------------------------------
- ----------------Paolo Del Giusto--------------------------
- ----------------------------------------------------------
- ----------paolo.delgiusto@studioidea.it-------------------
- ----------------------------------------------------------


=========================================================================
From: Richard Jones <rcjones@students.wisc.edu>
Subject: Re: 12ax7 supply
Date: Tue, 28 Oct 1997 12:47:15 -0600
Source: Sound Digest Archive v01.n093

At 06:14 PM 10/28/97 +0100, you wrote:
>        Hello people,
>I'm building a preamp where the filament supply of the valves, 12ax7, is
>5V, to obtain a longer life for the tubes. Since I'm not so sure it is a
>good idea to reduce the filament supply, I'd like to have the opinion of
>the list (instead of wasting time, bandwidth and health in useless
>discussions).
>
>Thanks
>
>
>
>----------------------------------------------------------
>----------------Paolo Del Giusto--------------------------
>----------------------------------------------------------
>----------paolo.delgiusto@studioidea.it-------------------
>----------------------------------------------------------
>
>
>
>



Those tubes are so common and cheap that you may as well go with the full
filament supply voltage on them.. i think you'd have better consistency and
performance at the recommended filament settings.


Rich


=========================================================================
From: Michel Paquette <paqm01@GEL.USherb.CA>
Subject: Re: 12ax7 supply
Date: Tue, 28 Oct 1997 13:41:52 -0400
Source: Sound Digest Archive v01.n093

Paolo said:

>        Hello people,
>I'm building a preamp where the filament supply of the valves, 12ax7, is
>5V, to obtain a longer life for the tubes. Since I'm not so sure it is a
>good idea to reduce the filament supply, I'd like to have the opinion of
>the list (instead of wasting time, bandwidth and health in useless
>discussions).
>

The tubes will certainly last longer but think the transconductance is also
lower (not that it's very high with this tube to begin with...).

Michel


=========================================================================
From: Grover Gardner <groverg@bellatlantic.net>
Subject: Re: 12ax7 supply
Date: Tue, 28 Oct 1997 22:39:23 -0600
Source: Sound Digest Archive v01.n093

At 6:14 PM +0100 10/28/97, Paolo Del Giusto wrote:
>        Hello people,
>I'm building a preamp where the filament supply of the valves, 12ax7, is
>5V, to obtain a longer life for the tubes. Since I'm not so sure it is a
>good idea to reduce the filament supply, I'd like to have the opinion of
>the list (instead of wasting time, bandwidth and health in useless
>discussions).

Er, gee, why?  I think you might *reduce* the life of the tubes by running
them improperly and they certainly won't work as well.  There's nothing
gained by running an indirectly-heated tube below it's correct filament
voltage.  You don't want to stress a DHT filament unnecessarily, but a
12AX7 will handle 6-6.6 volts.

Grover Gardner
groverg@bellatlantic.net


=========================================================================
From: Jonathan Morrison <ppdiva@pipeline.com>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 00:10:05 -0800
Source: Sound Digest Archive v01.n093

At 06:14 PM 10/28/97 +0100, you wrote:
>        Hello people,
>I'm building a preamp where the filament supply of the valves, 12ax7, is
>5V, to obtain a longer life for the tubes. Since I'm not so sure it is a
>good idea to reduce the filament supply, I'd like to have the opinion of
>the list (instead of wasting time, bandwidth and health in useless
>discussions).
>
>Thanks
>
>
>
>----------------------------------------------------------
>----------------Paolo Del Giusto--------------------------
>----------------------------------------------------------
>----------paolo.delgiusto@studioidea.it-------------------
>----------------------------------------------------------
>
>
>
>
Somewhere, perhaps Tremayne's Audio Cyclopedia, I read that with a lower
heater voltage Gm is initially lower, but remains much more constant
through the (increased) life of the tube, while it drops steadily (but
slowly) with operation at rated voltage, so that after about 1/3 of the
tube's life, Gm is higher on the low voltage tube. I tried 7DJ8's in my
Daniel one time, but didn't leave them in long enough to learn anything
about their lifespan. JDM


=========================================================================
From: Rick Francis <rfranci@uoft03.UTOLEDO.EDU>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 01:01:37 -0500 (EST)
Source: Sound Digest Archive v01.n093

On Tue, 28 Oct 1997, Grover Gardner wrote, concerning using 5v fil voltage:

> Er, gee, why?  I think you might *reduce* the life of the tubes by running
> them improperly and they certainly won't work as well.  There's nothing
> gained by running an indirectly-heated tube below it's correct filament
> voltage.  You don't want to stress a DHT filament unnecessarily, but a
> 12AX7 will handle 6-6.6 volts.
> 
How often do you see a 12AX7, or any mini tube, with a burned out 
filament? The tubes go a long long time. Kevin Hayes of VAC says he came 
across some old literature in which studio technicians claimed that 
12AX7s sound *better* after two years of use.  Get some decent tubes to 
start with, give them 6.3 v, and move on to something else! You can buy 
pulls for a buck each.

Rick


=========================================================================
From: Scott Grammer <gesic@cdc.net>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 07:11:00 -0500
Source: Sound Digest Archive v01.n093

Hugh R. Dean wrote:
(snip)
> 
> I understand that repeaters in deep sea cables dating all the way back to
> the twenties grossly underran their filaments in the interests of life.
> When you consider how cold it must be at the ocean floor, it makes you
> wonder if there are any penalties.  I'd say carbonisation of the filament
> would be one.
> 
> Cheers,
> 
> Hugh R. Dean
> Melbourne, Australia

Wow! Tubes under the sea! OK, where's Doc Bottlehead? We ned him to
organise the first annual "Valves Under the Waves" expedition!

:-)

S.G.

- -- 
"To save every cog and wheel is the first 
precaution of intelligent tinkering." -Aldo Leopold.
Check out TubeDude's Webpage of Vacuum Tube Lore!
http://www.cdc.net/~gesic


=========================================================================
From: John Levreault <jlevro@shore.net>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 08:50:48 -0500
Source: Sound Digest Archive v01.n093

At 01:01 AM 10/29/97 -0500, Rick Francis wrote:
>

>Kevin Hayes of VAC says he came 
>across some old literature in which studio technicians claimed that 
>12AX7s sound *better* after two years of use. 

That's probably because the gm drops, dropping the open loop gain, so that
the actual amount of negative feedback drops, thus improving the sound. Or
am I being overly cynical?

JL


=========================================================================
From: "Hugh R. Dean" <aspen@alphalink.com.au>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 19:16:32
Source: Sound Digest Archive v01.n093

>On Tue, 28 Oct 1997, Grover Gardner wrote, concerning using 5v fil voltage:
>
>> Er, gee, why?  I think you might *reduce* the life of the tubes by running
>> them improperly and they certainly won't work as well.  There's nothing
>> gained by running an indirectly-heated tube below it's correct filament
>> voltage.  You don't want to stress a DHT filament unnecessarily, but a
>> 12AX7 will handle 6-6.6 volts.


I have noticed that the voltage on 12AX7 filaments does have an impact on
the sound.  Slight, but there.  I run them at around 12.1 volts DC and use
a LM317T set up for slow turn-on (10s).  I have not checked the 6.3 volt
configuration, but if the ratio holds, it would be 6.05V.

I understand the 300mA 6.3VAC filament of the 12AX7 is shared with the
12AT7 and the 12AU7.  This demonstrates that the low current tube has heaps
of heat reserve (not emission, this tube is indirectly heated);  some ten
times more perhaps than the 12AU7, which has to be sailing close to the
wind.  This would help to explain the long life of the 12AX7.

I understand that repeaters in deep sea cables dating all the way back to
the twenties grossly underran their filaments in the interests of life.
When you consider how cold it must be at the ocean floor, it makes you
wonder if there are any penalties.  I'd say carbonisation of the filament
would be one.

Cheers,

Hugh R. Dean
Melbourne, Australia


=========================================================================
From: "Bottlehead" <Bottlehead@prodigy.net>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 07:45:40 -0800
Source: Sound Digest Archive v01.n094

> 
> Wow! Tubes under the sea! OK, where's Doc Bottlehead? We ned him to
> organise the first annual "Valves Under the Waves" expedition!
> 
> :-)
> 
> S.G.
> 

Well, Dyes               jnmm nmnm 

ooops, sorry, just dripped cinnamon bun goop all over the n & m keys

Dyes inlet, which the Silverdale hotel sits by, is currently populated with
a pod of orcas, but hopefully by next VSAC we can launch our full auto
skeet tubes over the inlet, then send Currie and Ronan in to retrieve the
misses

Doc B.


=========================================================================
From: "Frank Deutschmann" <fdeutsch@bfm.com>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 10:26:58 -0500
Source: Sound Digest Archive v01.n094

Hi all,

I experienced quite a ride the last two days: first Wall St. decided to have
a 15%-off sale (hey, just like Bloomies does!), then yesterday, at the worst
possible time, my company lost all net connectivity (some phones, too).
 Thanks, Bell Atlantic (trunk cable went out).  But we're finally back, and
the e-mail is trickling in....

On Oct 28,  6:14pm, Paolo Del Giusto wrote:
> I'm building a preamp where the filament supply of the valves, 12ax7, is
> 5V, to obtain a longer life for the tubes. Since I'm not so sure it is a
> good idea to reduce the filament supply, I'd like to have the opinion of
> the list (instead of wasting time, bandwidth and health in useless
> discussions).

I'd say run them at full rated voltage.  Or, run them *hotter* if you would
like; as Rick points out in a later message, these tubes are cheap.

One thing to note about full rated voltage: probably the right way to run a
tube filament is at full rated *power*; that is, measure the voltage drop
across the filament, and the current drawn by the filament, then multiply and
compare to the tube spec.  Adjust until the power figure is on target (or
hotter if you like).  This WILL burn your tubes out (slightly) faster than
the usual approach (because with this approach, as the filament R increases
with life, you would bump the voltage to maintain the same power), but again,
these tubes are cheap.

On Oct 29, 12:10am, Jonathan Morrison wrote:
> Somewhere, perhaps Tremayne's Audio Cyclopedia, I read that with a lower
> heater voltage Gm is initially lower, but remains much more constant
> through the (increased) life of the tube, while it drops steadily (but
> slowly) with operation at rated voltage, so that after about 1/3 of the
> tube's life, Gm is higher on the low voltage tube. I tried 7DJ8's in my
> Daniel one time, but didn't leave them in long enough to learn anything
> about their lifespan. JDM

This is correct; it is a side-benefit of the reduced emission preserving the
emitting surface of the cathode.  The cathode erosion/poisoning is still
occuring, though at a slower rate, thanks to the reduced emission.  The more
stable decline in Gm is paid for, though, in reduced Gm, as compared with a
tube which is maintained at the design filament power.  When compared with a
tube where no compensation for increased filament R is made over the life of
the tube, Gm on the "starved" tube will indeed be higher through much of the
life span.

On Oct 29,  7:16pm, Hugh R. Dean wrote:
> I have noticed that the voltage on 12AX7 filaments does have an impact on
> the sound.  Slight, but there.  I run them at around 12.1 volts DC and use
> a LM317T set up for slow turn-on (10s).  I have not checked the 6.3 volt
> configuration, but if the ratio holds, it would be 6.05V.

An interesting observation!  The slow turn-on is essential to preserving tube
life, IMHO, especially when running a filament (properly) on a voltage
source.
I have found that some tubes are very sensitive to the filament power, others
less so; tubes can either want more or less filament power, too.  The
filament of a tube is surprisingly complex, and I don't fully understand it
yet, but I can relate what I do know:

o It is most important to not starve the tube by running at too low a
filament voltage.  Tube starvation will vastly shorten the life of the tube,
and will give crappy sound to boot -- when starved, the tube characteristics
are very affected, and clipping will be much harder.

o The filament power changes the size of the space charge in the vicinity of
the cathode; this changes the Gm and also impacts the tube capacitances.

o The size of the filament structure in a tube, and the impedance of the
filament power supply, determine how the cathode of the tube will respond to
sudden changes in plate current.  The time constant is surprisingly small:
10-100msec or so for small signal indirectly heated tubes.  (Yes, this does
indeed mean that bass frequencies can be very strongly impacted by the
filament supply, as Bill Hewlett first [I believe] noted in his Stanford
doctoral dissertation on the design of a low distortion sine wave oscilator
- -- the future HP200A!)

> I understand the 300mA 6.3VAC filament of the 12AX7 is shared with the
> 12AT7 and the 12AU7.  This demonstrates that the low current tube has heaps
> of heat reserve (not emission, this tube is indirectly heated);  some ten
> times more perhaps than the 12AU7, which has to be sailing close to the
> wind.  This would help to explain the long life of the 12AX7.

Right, absolutely.  It is very interesting to compare heater power to plate
current; many, many tubes share heater structures, but with different plate
current ratings.  For a given heater power, the less plate current you run,
the better the cathode emission response will be (greater "heat reserve" as
Hugh points out).   This, of course, must be traded off against the benefits
of running high but more stable current.  And the benefits of a lower heat
reserve, but a more stable emission over the life of the tube.  In any case,
all else being equal, theory says to me that a tube with more heater power
will sound better than less.

> I understand that repeaters in deep sea cables dating all the way back to
> the twenties grossly underran their filaments in the interests of life.
> When you consider how cold it must be at the ocean floor, it makes you
> wonder if there are any penalties.  I'd say carbonisation of the filament
> would be one.

I hear there are scads slightly-used 300B's just lying around down there,
waiting to be picked up...!  (Seriously, it's an interesting question of how
they designed for undersea service, but I don't know anything about it.)

- -frank


=========================================================================
From: Dave Stagner <dstagner@icarus.net>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 12:37:31 -0600 (CST)
Source: Sound Digest Archive v01.n094

When worrying about the life of your tubes, ask WHY you are worried.  If
you're trying to salvage some priceless old Telefunken "Diamond", maybe
you should consider using something CHEAP!!!

Find a good modern-production replacement 12AX7... most are just a few
bucks.  Pay extra for RAM or Golden Dragon matching if needed.  Burn 'em
wide open, and throw them away when they die.  Haul out that vintage magic
tube for special occasions.  Better yet, A/B it with the new tubes and see
how much better it really is!

- -dave

By "beauty," I mean that which seems complete.
Obversely, that the incomplete, or the mutilated, is the ugly. 
Venus De Milo.
To a child she is ugly.       /* dstagner@icarus.net */
   -Charles Fort              


=========================================================================
From: tronan@orion.it.luc.edu (Thomas Ronan)
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 12:44:25 -0600
Source: Sound Digest Archive v01.n094

At 9:45 AM 10/29/97, Bottlehead wrote:
>>
>> Wow! Tubes under the sea! OK, where's Doc Bottlehead? We ned him to
>> organise the first annual "Valves Under the Waves" expedition!
>>
>> :-)
>>
>> S.G.
>>
>
>Well, Dyes               jnmm nmnm
>
>ooops, sorry, just dripped cinnamon bun goop all over the n & m keys
>
>Dyes inlet, which the Silverdale hotel sits by, is currently populated with
>a pod of orcas, but hopefully by next VSAC we can launch our full auto
>skeet tubes over the inlet, then send Currie and Ronan in to retrieve the
>misses
>
>Doc B.


I like swimming!  I'll do anything you bug guys say.  Don't say my mom
didn't teach me to respect his elders.  *grin*

Tom

- ------
Thomas Ronan             tronan@orion.it.luc.edu
1045 W. Montana, Chicago, IL 60614  773.528.0882
Lowther Club of America, Chicago Representative


=========================================================================
From: tronan@orion.it.luc.edu (Thomas Ronan)
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 15:33:34 -0600
Source: Sound Digest Archive v01.n094

>When worrying about the life of your tubes, ask WHY you are worried.  If
>you're trying to salvage some priceless old Telefunken "Diamond", maybe
>you should consider using something CHEAP!!!
>
>Find a good modern-production replacement 12AX7... most are just a few
>bucks.  Pay extra for RAM or Golden Dragon matching if needed.  Burn 'em
>wide open, and throw them away when they die.  Haul out that vintage magic
>tube for special occasions.  Better yet, A/B it with the new tubes and see
>how much better it really is!


Dave,

I disagree.  Take that vintage tube, and burn them however you would like.
Use them all the time!  We only live once, and life is too short.  Use it
while you got it, and then spend some fun time at hamfests and looking
around to see if you can find some more from time to time.  What the hell
man!

Tom

- ------
Thomas Ronan             tronan@orion.it.luc.edu
1045 W. Montana, Chicago, IL 60614  773.528.0882
Lowther Club of America, Chicago Representative


=========================================================================
From: Scott Grammer <gesic@cdc.net>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 15:59:13 -0500
Source: Sound Digest Archive v01.n094

John Levreault wrote:
> 
> At 01:01 AM 10/29/97 -0500, Rick Francis wrote:
> >
> 
> >Kevin Hayes of VAC says he came
> >across some old literature in which studio technicians claimed that
> >12AX7s sound *better* after two years of use.
> 
> That's probably because the gm drops, dropping the open loop gain, so that
> the actual amount of negative feedback drops, thus improving the sound. Or
> am I being overly cynical?
> 
> JL

Cynical? no. Maybe it's because as the gm drops the tubes are pressed
into overload less often. A lot of studio types aren't happy unless they
can hear the VU meters hit the pins with the beat of the music, you
know.

S.G.

- -- 
"To save every cog and wheel is the first 
precaution of intelligent tinkering." -Aldo Leopold.
Check out TubeDude's Webpage of Vacuum Tube Lore!
http://www.cdc.net/~gesic


=========================================================================
From: Scott Grammer <gesic@cdc.net>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 17:42:53 -0500
Source: Sound Digest Archive v01.n094

Finn Hammer wrote:
> 
> Scott Grammer wrote:
> 
> >
> > Wow! Tubes under the sea! OK, where's Doc Bottlehead? We ned him to
> > organise the first annual "Valves Under the Waves" expedition!
> >
> > :-)
> >
> > S.G.
> 
> Yeah! And what will he find: "The _DAMPEST_ triodes" :-D
Just the thing for those loosey-goosey woofers that need more -DAMP-ing
factor!

S.G.

- -- 
"To save every cog and wheel is the first 
precaution of intelligent tinkering." -Aldo Leopold.
Check out TubeDude's Webpage of Vacuum Tube Lore!
http://www.cdc.net/~gesic


=========================================================================
From: "Greg Monfort" <wingracer@email.msn.com>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 17:56:25 -0500
Source: Sound Digest Archive v01.n094

No truer words spoken.

GM
- -----Original Message-----


>Dave,
>
>I disagree.  Take that vintage tube, and burn them however you would like.
>Use them all the time!  We only live once, and life is too short.  Use it
>while you got it, and then spend some fun time at hamfests and looking
>around to see if you can find some more from time to time.  What the hell
>man!
>
>Tom
>
>------
>Thomas Ronan             tronan@orion.it.luc.edu
>1045 W. Montana, Chicago, IL 60614  773.528.0882
>Lowther Club of America, Chicago Representative
>
>
>


=========================================================================
From: Finn Hammer <f-hammer@post5.tele.dk>
Subject: Re: 12ax7 supply
Date: Wed, 29 Oct 1997 22:58:28 +0100
Source: Sound Digest Archive v01.n094

Scott Grammer wrote:

> 
> Wow! Tubes under the sea! OK, where's Doc Bottlehead? We ned him to
> organise the first annual "Valves Under the Waves" expedition!
> 
> :-)
> 
> S.G.

Yeah! And what will he find: "The _DAMPEST_ triodes" :-D
- -- 
                    HOME OF
            Tractrix Horns, Tube Amps,
    Fieldcoil Loudspeakers and Computer Graphics

       http://home5.inet.tele.dk/f-hammer/


=========================================================================
From: Guido Tent <gtent@ehv.sc.philips.com>
Subject: Re: 12ax7 supply
Date: Thu, 30 Oct 1997 09:28:32 +0100
Source: Sound Digest Archive v01.n095

At 18:14 28-10-97 +0100, Paolo Del Giusto wrote:
>        Hello people,
>I'm building a preamp where the filament supply of the valves, 12ax7, is
>5V, to obtain a longer life for the tubes. Since I'm not so sure it is a
>good idea to reduce the filament supply, I'd like to have the opinion of
>the list (instead of wasting time, bandwidth and health in useless
>discussions).

NEVER deviate from 6.3 V. If you do, go to 6.2 or so, but any other will
SHORTEN the life

(I can advise a report on this subject, it is in English, reported from a
discusion that I initiated in Holland, between audio designers (tubes) and a
Philips man who is a specialist on emission

If interested I'll supply you the address were to get

Guido

>Thanks
>
>
>
>----------------------------------------------------------
>----------------Paolo Del Giusto--------------------------
>----------------------------------------------------------
>----------paolo.delgiusto@studioidea.it-------------------
>----------------------------------------------------------
>
>
>
>
>


"to be EMC or not to be EMC, that's the question"

Guido Tent
Engineer
Electro Magnetic Compatibility
Philips Semiconductors Systems Laboratory Eindhoven  (PS-SLE)
Building BE303, (Hurksestraat 19)
P.O.Box 218,  5600MD Eindhoven, The Netherlands
Phone: +31-40-27 24553
fax  : +31-40-27 22764

E-mail: guido.tent@ehv.sc.philips.com
Seri  : gtent@nlsce1

- - Let's make things better ! -


=========================================================================
From: Guido Tent <gtent@ehv.sc.philips.com>
Subject: Re: 12ax7 supply
Date: Thu, 30 Oct 1997 09:29:29 +0100
Source: Sound Digest Archive v01.n095

At 13:41 28-10-97 -0400, Michel Paquette wrote:
>Paolo said:
>
>>        Hello people,
>>I'm building a preamp where the filament supply of the valves, 12ax7, is
>>5V, to obtain a longer life for the tubes. Since I'm not so sure it is a
>>good idea to reduce the filament supply, I'd like to have the opinion of
>>the list (instead of wasting time, bandwidth and health in useless
>>discussions).
>>
>
>The tubes will certainly last longer but think the transconductance is also
>lower (not that it's very high with this tube to begin with...).

Sorry Michel, they do not last longer (think in the chemistry inside)

Guido


>Michel
>
>
>
>


=========================================================================
From: Guido Tent <gtent@ehv.sc.philips.com>
Subject: Re: 12ax7 supply
Date: Thu, 30 Oct 1997 09:53:04 +0100
Source: Sound Digest Archive v01.n095

At 19:16 29-10-97, Hugh R. Dean wrote:
>>On Tue, 28 Oct 1997, Grover Gardner wrote, concerning using 5v fil voltage:
>>
>>> Er, gee, why?  I think you might *reduce* the life of the tubes by running
>>> them improperly and they certainly won't work as well.  There's nothing
>>> gained by running an indirectly-heated tube below it's correct filament
>>> voltage.  You don't want to stress a DHT filament unnecessarily, but a
>>> 12AX7 will handle 6-6.6 volts.
>
>
>I have noticed that the voltage on 12AX7 filaments does have an impact on
>the sound.

Bingo !

>Slight, but there.  I run them at around 12.1 volts DC and use
>a LM317T set up for slow turn-on (10s).  I have not checked the 6.3 volt
>configuration, but if the ratio holds, it would be 6.05V.

Very well ! I like it around 6.2 V

>I understand that repeaters in deep sea cables dating all the way back to
>the twenties grossly underran their filaments in the interests of life.
>When you consider how cold it must be at the ocean floor, it makes you
>wonder if there are any penalties.  I'd say carbonisation of the filament
>would be one.

Mmmh. Temperature is dominated by the heater, so to say, environment is
nearly influencing the cathode temperature

Guido

>Cheers,
>
>Hugh R. Dean
>Melbourne, Australia
>
>
>


"to be EMC or not to be EMC, that's the question"

Guido Tent
Engineer
Electro Magnetic Compatibility
Philips Semiconductors Systems Laboratory Eindhoven  (PS-SLE)
Building BE303, (Hurksestraat 19)
P.O.Box 218,  5600MD Eindhoven, The Netherlands
Phone: +31-40-27 24553
fax  : +31-40-27 22764

E-mail: guido.tent@ehv.sc.philips.com
Seri  : gtent@nlsce1

- - Let's make things better ! -


=========================================================================
From: pitaro@ozemail.com.au
Subject: Re: 12ax7 supply
Date: Fri, 31 Oct 1997 00:02:09 EST
Source: Sound Digest Archive v01.n095

** Reply to note from Dave Stagner <dstagner@icarus.net> Wed, 29 Oct 1997 12:37:31 -0600 (CST) 
>   
> Find a good modern-production replacement 12AX7... most are just a few 
> bucks.  Pay extra for RAM or Golden Dragon matching if needed.  Burn 'em 
> wide open, and throw them away when they die.  Haul out that vintage magic 
> tube for special occasions.  Better yet, A/B it with the new tubes and see 
> how much better it really is! 
 
Unfair test. I've found that old used tubes are always sound warmer and 
new tubes, even after break in period, are brighter.

Regards, 
Harry Pitaro 
+-----------------------+---------------------------------------------+ 
| Melbourne,  Australia | A good discussion is like a miniskirt;      |  
|                       | Short enough to retain interest             | 
| pitaro@ozemail.com.au | and long enough to cover the subject.       | 
+-----------------------+---------------------------------------------+


=========================================================================
From: pitaro@ozemail.com.au
Subject: Re: 12ax7 supply
Date: Fri, 31 Oct 1997 18:42:21 EST
Source: Sound Digest Archive v01.n096

** Reply to note from pitaro@ozemail.com.au Fri, 31 Oct 1997 00:02:09 EST 
 
> Unfair test. I've found that old used tubes are always sound warmer and  
> new tubes, even after break in period, are brighter. 
 
I've excelled myself with the use of the English language this time!!! 

Regards, 
Harry Pitaro 
+-----------------------+---------------------------------------------+ 
| Melbourne,  Australia | A good discussion is like a miniskirt;      |  
|                       | Short enough to retain interest             | 
| pitaro@ozemail.com.au | and long enough to cover the subject.       | 
+-----------------------+---------------------------------------------+


=========================================================================
From: Rick Francis <rfranci@uoft03.UTOLEDO.EDU>
Subject: Re: 12ax7 supply--old rectifiers might cause low fil voltage
Date: Wed, 29 Oct 1997 11:44:00 -0500 (EST)
Source: Sound Digest Archive v01.n094

On Wed, 29 Oct 1997, Frank Deutschmann wrote, among many good things:

> o It is most important to not starve the tube by running at too low a
> filament voltage.  Tube starvation will vastly shorten the life of the tube,
> and will give crappy sound to boot -- when starved, the tube characteristics
> are very affected, and clipping will be much harder.
> 
Paul "Brainiac" Joppa told me something the other day: old tube preamps 
and integrateds with DC on the preamp or phono tube filaments can suffer 
from low voltage. Certain old rectifiers get more resistive with age, and 
cause a larger voltage drop.  I don't think I've ever thought to check 
that, but I will now. I forget which kind of rectifiers are prone to this.

Rick


=========================================================================
From: "Bottlehead" <Bottlehead@prodigy.net>
Subject: Re: 12ax7 supply--old rectifiers might cause low fil voltage
Date: Wed, 29 Oct 1997 12:35:34 -0800
Source: Sound Digest Archive v01.n094

"
> On Oct 29, 11:44am, Rick Francis wrote:
> > Paul "Brainiac" Joppa told me something the other day: old tube preamps
> > and integrateds with DC on the preamp or phono tube filaments can
suffer
> > from low voltage. Certain old rectifiers get more resistive with age,
and
> > cause a larger voltage drop.  I don't think I've ever thought to check
> > that, but I will now. I forget which kind of rectifiers are prone to
this.
> 
> Good point -- I'm not sure if you are talking about SS or vac rectifiers,
> but, in the case of the vac rectifiers, those tubes can become more
resitive
> with age as their filaments weaken.  (The filaments of vac rectifiers are
> probably the most abused filaments in the amp, too, as without soft-start
> circuits, they are asked to imediately deliver full plate current --
which
> they can't do, as they are not yet hot.  So, they sacrifice themselves to
> provide slo-start for the rest of the tubes....)  This is both the
filaments
> burning up, and filaments being damaged by the imediate B+ they see when
> still cold.
> 
> -frank

I'm pretty sure Paul is referring to the fact that old selenium rectifiers,
ala the PAS 3 filament supply, drop about 15% in their voltage output over
time.
Get rid of them!

Doc B.


=========================================================================
From: "Frank Deutschmann" <fdeutsch@bfm.com>
Subject: Re: 12ax7 supply--old rectifiers might cause low fil voltage
Date: Wed, 29 Oct 1997 12:51:13 -0500
Source: Sound Digest Archive v01.n094

On Oct 29, 11:44am, Rick Francis wrote:
> Paul "Brainiac" Joppa told me something the other day: old tube preamps
> and integrateds with DC on the preamp or phono tube filaments can suffer
> from low voltage. Certain old rectifiers get more resistive with age, and
> cause a larger voltage drop.  I don't think I've ever thought to check
> that, but I will now. I forget which kind of rectifiers are prone to this.

Good point -- I'm not sure if you are talking about SS or vac rectifiers,
but, in the case of the vac rectifiers, those tubes can become more resitive
with age as their filaments weaken.  (The filaments of vac rectifiers are
probably the most abused filaments in the amp, too, as without soft-start
circuits, they are asked to imediately deliver full plate current -- which
they can't do, as they are not yet hot.  So, they sacrifice themselves to
provide slo-start for the rest of the tubes....)  This is both the filaments
burning up, and filaments being damaged by the imediate B+ they see when
still cold.

- -frank


=========================================================================
From: Grego Sanguinetti <grego@latticesemi.com>
Subject: Re: 12ax7 supply--old rectifiers might cause low fil voltage
Date: Wed, 29 Oct 1997 14:19:45 -0800 (PST)
Source: Sound Digest Archive v01.n094

> I'm pretty sure Paul is referring to the fact that old selenium rectifiers,
> ala the PAS 3 filament supply, drop about 15% in their voltage output over
> time.
> Get rid of them!

But be carefull, because silicon diodes have a significantly lower
Vf (forward voltage drop) than do, even healthy, selenium devices.
You will have to add series resistance to drop the voltage down to
spec for the load, which is a good idea anyway since it will current
limit the turn on surge.

- -grego


=========================================================================
From: Scott Grammer <gesic@cdc.net>
Subject: Re: 12ax7 supply--old rectifiers might cause low fil voltage
Date: Wed, 29 Oct 1997 16:11:26 -0500
Source: Sound Digest Archive v01.n094

Rick Francis wrote:

> Paul "Brainiac" Joppa told me something the other day: old tube preamps
> and integrateds with DC on the preamp or phono tube filaments can suffer
> from low voltage. Certain old rectifiers get more resistive with age, and
> cause a larger voltage drop.  I don't think I've ever thought to check
> that, but I will now. I forget which kind of rectifiers are prone to this.
> 
> Rick

Selenium. If you replace one of these, be careful not to break it. If
you do, don't touch the insides with bare hands. Selenium is plenty
poisonous, and can be absorbed through the skin. That's why they are
usually dipped in paint. (Dyna's had selenium bias rectifiers that were
unpainted.)

S.G.

S.G.

- -- 
"To save every cog and wheel is the first 
precaution of intelligent tinkering." -Aldo Leopold.
Check out TubeDude's Webpage of Vacuum Tube Lore!
http://www.cdc.net/~gesic


=========================================================================
From: "Bottlehead" <Bottlehead@prodigy.net>
Subject: Re: 12ax7 supply--old rectifiers might cause low fil voltage
Date: Wed, 29 Oct 1997 16:58:06 -0800
Source: Sound Digest Archive v01.n094

> > I'm pretty sure Paul is referring to the fact that old selenium
rectifiers,
> > ala the PAS 3 filament supply, drop about 15% in their voltage output
over
> > time.
> > Get rid of them!
> 
> But be carefull, because silicon diodes have a significantly lower
> Vf (forward voltage drop) than do, even healthy, selenium devices.
> You will have to add series resistance to drop the voltage down to
> spec for the load, which is a good idea anyway since it will current
> limit the turn on surge.
> 
> -grego

Well, the PAS runs the fils too damn low anyway, like 11V. 
So there.

Doc B.


=========================================================================
From: davidbarnett@aristotle.net (David N. Barnett)
Subject: Re: 12ax7 supply--old rectifiers might cause low fil voltage
Date: Wed, 29 Oct 1997 20:55:53 GMT
Source: Sound Digest Archive v01.n094

On Wed, 29 Oct 1997 11:44:00 -0500 (EST), Rick Francis
<rfranci@uoft03.UTOLEDO.EDU> wrote:

>Certain old rectifiers get more resistive with age, and 
>cause a larger voltage drop.  I don't think I've ever thought to check 
>that, but I will now. I forget which kind of rectifiers are prone to this.

Selenium rectifiers certainly do this.  Replacing them with silicon
devices should restore heater voltage to a healthy level.  Perhaps
shottkys would be good here?

- --dnb


=========================================================================
From: "Martin E. von Lindenberg" <mvon@pop.erols.com>
Subject: Re: 12ax7 supply--old rectifiers might cause low fil voltage
Date: Thu, 30 Oct 1997 05:54:15 -0500
Source: Sound Digest Archive v01.n095

At 12:35 PM 10/29/97 -0800, you wrote:
>> -frank
>
>I'm pretty sure Paul is referring to the fact that old selenium rectifiers,
>ala the PAS 3 filament supply, drop about 15% in their voltage output over
>time.
>Get rid of them!
>
>Doc B.
>
Yeah, and when they short out, those suckers really stink!  Much worse than
tranny meltdown, and more staying power.

Martin
mvon@erols.com


=========================================================================
From: davidbarnett@aristotle.net (David N. Barnett)
Subject: Re: 12ax7 supply--old rectifiers might cause low fil voltage
Date: Thu, 30 Oct 1997 07:01:58 GMT
Source: Sound Digest Archive v01.n095

On Wed, 29 Oct 1997 16:58:06 -0800, "Bottlehead"
<Bottlehead@prodigy.net> wrote:

>> But be carefull, because silicon diodes have a significantly lower
>> Vf (forward voltage drop) than do, even healthy, selenium devices.
>> You will have to add series resistance to drop the voltage down to
>> spec for the load, which is a good idea anyway since it will current
>> limit the turn on surge.
>> 
>> -grego
>
>Well, the PAS runs the fils too damn low anyway, like 11V. 
>So there.

I wuz gonna say the same thing.  Ditto for Marantz 7, Mac preamps, and
most others from that era.  Even if your line voltage is at 121V like
mine, instead of the nominal 115V that most old pieces were made for.

- --dnb


=========================================================================
From: ROBERT ROSENTHAL <RBTR@mail.rkd.snds.com>
Subject: Re: 12ax7 supply--old rectifiers might cause low fil voltage -Reply
Date: Wed, 29 Oct 1997 12:39:10 -0600
Source: Sound Digest Archive v01.n094

>Certain old rectifiers get more resistive with age, and 
cause a larger voltage drop.  I don't think I've ever thought
to check 
that, but I will now. I forget which kind of rectifiers are
>prone to this.

Selenium ones with the fins ! Bingo !


=========================================================================
From: Richard C Nevill <rnevill@is.dal.ca>
Subject: Re: 12ax7 supply--old rectifiers might cause low fil voltage -Reply
Date: Wed, 29 Oct 1997 17:39:18 -0400 (AST)
Source: Sound Digest Archive v01.n094

On Wed, 29 Oct 1997, ROBERT ROSENTHAL wrote:

> >Certain old rectifiers get more resistive with age, and 
> cause a larger voltage drop.  I don't think I've ever thought
> to check 
> that, but I will now. I forget which kind of rectifiers are
> >prone to this.
> 
> Selenium ones with the fins ! Bingo !


These of course were made by Cadillac in the late fifties and early
sixties


=========================================================================
From: "Bottlehead" <Bottlehead@prodigy.net>
Subject: Re: * 12ax7 supply - orcas
Date: Thu, 30 Oct 1997 08:13:23 -0800
Source: Sound Digest Archive v01.n095

> Could we schedule the next VSAC when orcas are in residence? Please?  Out
> here we only have cows. - Pat
> 
This is a super rare occurence, they show up in Dyes inlet about as often
as Sakuma. And we know what *that* did to our schedule, huh.
Actually those poor whales are probably looking for a good body guard.
Every goober (baby we got more than our share) in Kitsap county was out in
his boat, (they estimated 150 boats at one point) chasing the poor whales
everytime they'd move to follow the salmon. I imagine they have been
handily driven away by now. People are so effing smart.

Doc B., remembering when you could share your own private Puget Sound beach
with the seals and oysters, instead of the highway noise and the septic
tank seepage.


=========================================================================
From: tubesguy@execpc.com (Patrick Currie)
Subject: * 12ax7 supply - orcas
Date: Thu, 30 Oct 1997 09:29:11 -0500
Source: Sound Digest Archive v01.n095

>Dyes inlet, which the Silverdale hotel sits by, is currently populated with
>a pod of orcas, but hopefully by next VSAC we can launch our full auto
>skeet tubes over the inlet, then send Currie and Ronan in to retrieve the
>misses
>
>Doc B.

Could we schedule the next VSAC when orcas are in residence? Please?  Out
here we only have cows. - Pat

Pat Currie (tubesguy@execpc.com)
(608)233-8956, 266-9290 (Madison, WI)


=========================================================================
From: "Alfia Mak" <alfiamak@hkstar.com>
Subject: 12AY7/6072A
Date: Thu, 1 Oct 1998 09:47:40 +0800
Source: Sound Digest Archive v01.n436

This is a multi-part message in MIME format.

- ------=_NextPart_000_003B_01BDED20.8759FD40
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	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

Hi all,
Can anyone tell me how makes the best 12AY7 or 6072A ?

Thanks

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	charset="iso-8859-1"
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<!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 4.72.3007.2"' name=3DGENERATOR>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#000000 size=3D2>Hi all,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>Can anyone tell me how makes the =
best 12AY7 or=20
6072A ?</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT color=3D#000000 size=3D2>Thanks</FONT></DIV></BODY></HTML>

- ------=_NextPart_000_003B_01BDED20.8759FD40--


=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: 12AY7/6072A
Date: Fri, 2 Oct 1998 23:10:45 -0500
Source: Sound Digest Archive v01.n439

At 9:47 AM +0800 10/1/98, Alfia Mak wrote:
>     Hi all, Can anyone tell me how makes the best 12AY7 or  6072A ?   Thanks

I can't tell you that, but I can tell you that I haven't worked with this
tube yet.  It's used in Gordon's Juniors I think and the Ongaku.  Steve
Bench, who posts regurlarly on RAT, has a really swell web page with some
interesting circuits.  He has a 12AY7-based phono stage that I downloaded
but haven't looked at yet.  he also has a line stage with a feedback volume
control.  A friend of mine builds preamps using this method for volume and
I've always been interested to see how it works.

Grover Gardner
groverg@postoffice.att.net


=========================================================================
From: "Alfia Mak" <alfiamak@hkstar.com>
Subject: 12AY7A/6072A
Date: Sat, 26 Sep 1998 11:03:52 +0800
Source: Sound Digest Archive v01.n430

This is a multi-part message in MIME format.

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	charset="iso-8859-1"
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Does anyone has graph for 12AY7A or 6072A ?

Thanks

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	charset="iso-8859-1"
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<!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 4.72.3007.2"' name=3DGENERATOR>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#000000 size=3D2>Does anyone has graph for 12AY7A or =
6072A=20
?</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT color=3D#000000 size=3D2>Thanks</FONT></DIV></BODY></HTML>

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=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: Re: 12AY7A/6072A
Date: Sat, 26 Sep 1998 08:58:50 PDT
Source: Sound Digest Archive v01.n431

Hi all,

>Does anyone has graph for 12AY7A or 6072A ?

Looking for any kind of Valve-Data? Try:

http://www.duncanamps.simplenet.com/tubedata/tubesearch.html

Pretty much ANY Valve is on the Net.

Numerous 12AY7 Data-sheet Sources are listed there:

http://www.duncanamps.simplenet.com/cgi-bin/miva?/tubedata/search.mv+12AY7

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: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: 12B4A Data-sheets & curves
Date: Thu, 14 Jan 1999 17:10:10 -0700
Source: Sound Digest Archive v01.n576

    Dear Thorsten:
    I have data along with about 800 of the critters. Their linearity is
RATHER variable so I curve trace every one before they go out the door.
    +800V is over-spec, they'll withstand a kV and the book says max
operating B+ is 500V. But..... if you're not pulling much current......
well, they're cheap.

   
    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:  "T. Loesch" <ezee_e@hotmail.com>
>To:  sound@deliverator.io.com
>Subject: 12B4A Data-shhets or curves anyone?
>Date: Thu, Jan 14, 1999, 2:11 PM
>

>Hi all,
>
>Now the basic Data (limits and one operating are available on the net 
>easily. But has anyone got a set of curves?
>
>I have a particulary nutty project in my drawer that reqires at least 
>800V Peak-Peak Swing from the Driver.... Not much current though. And 
>with 500V+B the 12B4A from the basic Data looks like it qualifies if 
>Choke/IT Loaded....
>
>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: "Johari Yip" <hfyip@pacific.net.sg>
Subject: Re: 12B4A Data-sheets & curves
Date: Fri, 15 Jan 1999 11:42:00 +0800
Source: Sound Digest Archive v01.n576

- ----------
> From: PEARL Cust Serv <custserv@pearl-hifi.com>
> To: sound@lists.io.com
> Subject: 12B4A Data-sheets & curves
> Date: Friday, January 15, 1999 8:10 AM
> 
>     Dear Thorsten:
>     I have data along with about 800 of the critters. Their linearity is
> RATHER variable so I curve trace every one before they go out the door.
>     +800V is over-spec,