Sound Practices Mailing List Files - Volume 1
=========================================================================
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 -|
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
_/ 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:
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 _/
_/ 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: "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 _/
_/ 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: "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
- ------=_NextPart_000_0063_01BDC87C.6EF21260
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
<HTML>
<HEAD>
<META content=3Dtext/html;charset=3Diso-8859-1 =
http-equiv=3DContent-Type>
<META content=3D'"MSHTML 4.72.3110.7"' name=3DGENERATOR>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#000000 size=3D2>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.
>
>
Tim Reese