Sound Practices Mailing List Files - Volume 2
=========================================================================
From: "Murray Leshner" <multi-volti@softhouse.com>
Subject: [JN] 700 V amps;
Date: Thu, 15 Jun 2000 00:25:47 -0400
Source: Sound Digest Archive v02.n580
Hello:
700 V amps - I think it's for the same reason people mud race motorcycles
(or ice race...is there anyone still alive that does that?)
I have a friend who said "Forget the 700 Club, I joined the 1100 club the
other day !" (got shocked, barely, luckily).
The floating filament supplies are the most annoying part to me...
=========================================================================
From: rcjones1@mmm.com
Subject: [JN] 7119/5687 pre-amp - Looking for different operating points.
Date: Fri, 29 Jun 2001 08:06:00 -0500
Source: Sound Digest Archive v02.n916
I think I allready asked this question before, but I don't remember.
Basically I have a 5687 pre-amp with the Electra-Print output transformer.
I think it is the LC3500 or something.
I am running them at 120v, 12mA? The sound is detailed and very neutral. I
want to try something a little more "lush and romantic" sounding. Is there
another op. point to use? or should I try a 7119? Or is there another tube
to use here?
Thanks!
Richard
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] 7119/5687 pre-amp - Looking for different operating points.
Date: Fri, 29 Jun 2001 09:30:12 EDT
Source: Sound Digest Archive v02.n916
- --part1_23.db924c8.286ddce4_boundary
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In a message dated 6/29/01 6:18:35 AM US Mountain Standard Time,
rcjones1@mmm.com writes:
> The sound is detailed and very neutral. I
> want to try something a little more "lush and romantic" sounding.
Greets!
Welcome to the Monkey House!
The documentation and formulas, if found, tell us about power and distortion.
Sound is find it yourself territory :)
Try some and see. Just do not exceed plate dissipation rating!
This is called art of industrial design.
Happy Ears!
Al B^}
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Content-Type: text/html; charset="US-ASCII"
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<HTML><FONT FACE=arial,helvetica><BODY BGCOLOR="#ffffff"><FONT SIZE=2>In a message dated 6/29/01 6:
18:35 AM US Mountain Standard Time,
<BR>rcjones1@mmm.com writes:
<BR>
<BR>
<BR><BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px
; PADDING-LEFT: 5px">The sound is detailed and very neutral. I
<BR>want to try something a little more "lush and romantic" sounding.</FONT><FONT COLOR="#000000" S
IZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"></BLOCKQUOTE>
<BR></FONT><FONT COLOR="#000000" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0">
<BR>Greets!
<BR>
<BR>Welcome to the Monkey House!
<BR>
<BR>The documentation and formulas, if found, tell us about power and distortion.
<BR>
<BR>Sound is find it yourself territory :)
<BR>
<BR>Try some and see. Just do not exceed plate dissipation rating!
<BR>
<BR>This is called art of industrial design.
<BR>
<BR>Happy Ears!
<BR>Al B^}
<BR>
<BR></FONT></HTML>
- --part1_23.db924c8.286ddce4_boundary--
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: [JN] 7119/5687 pre-amp - Looking for different operating points.
Date: Fri, 29 Jun 2001 14:42:06 -0400
Source: Sound Digest Archive v02.n917
rcjones1@mmm.com wrote:
>
> I think I allready asked this question before, but I don't remember.
>
> Basically I have a 5687 pre-amp with the Electra-Print output transformer.
> I think it is the LC3500 or something.
>
> I am running them at 120v, 12mA? The sound is detailed and very neutral. I
> want to try something a little more "lush and romantic" sounding. Is there
> another op. point to use? or should I try a 7119? Or is there another tube
> to use here?
>
> Thanks!
> Richard
The 7044 is more "lush" than the 5687, I think. The 7119 is sweeter,
but leaner-sounding. Best of all is the 6900, but they are hard to find.
- --
Grover Gardner
groverg@postoffice.att.net
Visit my web site at http://home.att.net/~groverg/homepage.htm
=========================================================================
From: "Paul De Raymond Leclercq" <Pderl@btinternet.com>
Subject: Re: [JN] 7119/5687 pre-amp - Looking for different operating points.
Date: Fri, 29 Jun 2001 14:52:53 -0700
Source: Sound Digest Archive v02.n917
Hello.
I suggest the 6350. This valve, although not boasting the high gm of 5687
and 7119/E182CC, does sound good. It is also very linear. Mu is 18 and Pa
4W. It was manufactured by RCA, GE, Sylvania and Tung-Sol.
regards
Paul Leclercq
- ----- Original Message -----
From: <rcjones1@mmm.com>
To: <sound@lists.io.com>
Sent: Friday, June 29, 2001 6:06 AM
Subject: [JN] 7119/5687 pre-amp - Looking for different operating points.
> I think I allready asked this question before, but I don't remember.
>
> Basically I have a 5687 pre-amp with the Electra-Print output transformer.
> I think it is the LC3500 or something.
>
> I am running them at 120v, 12mA? The sound is detailed and very neutral.
I
> want to try something a little more "lush and romantic" sounding. Is
there
> another op. point to use? or should I try a 7119? Or is there another tube
> to use here?
>
> Thanks!
> Richard
>
=========================================================================
From: "Paul De Raymond Leclercq" <Pderl@btinternet.com>
Subject: Re: [JN] 7119/5687 pre-amp - Looking for different operating points.
Date: Fri, 29 Jun 2001 15:18:53 -0700
Source: Sound Digest Archive v02.n917
Further to my previous message, you might try 6463 (same pin-out as 6350) -
it may, perhaps be closer to what you require.
Paul
- ----- Original Message -----
From: <rcjones1@mmm.com>
To: <sound@lists.io.com>
Sent: Friday, June 29, 2001 6:06 AM
Subject: [JN] 7119/5687 pre-amp - Looking for different operating points.
> I think I allready asked this question before, but I don't remember.
>
> Basically I have a 5687 pre-amp with the Electra-Print output transformer.
> I think it is the LC3500 or something.
>
> I am running them at 120v, 12mA? The sound is detailed and very neutral.
I
> want to try something a little more "lush and romantic" sounding. Is
there
> another op. point to use? or should I try a 7119? Or is there another tube
> to use here?
>
> Thanks!
> Richard
>
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 7119/5687 pre-amp - Looking for different operating points.
Date: Fri, 29 Jun 2001 19:35:15 +0200
Source: Sound Digest Archive v02.n917
At 14:52 29-6-01 -0700, Paul De Raymond Leclercq wrote:
>Hello.
>
>I suggest the 6350. This valve, although not boasting the high gm of 5687
>and 7119/E182CC, does sound good. It is also very linear. Mu is 18 and Pa
>4W. It was manufactured by RCA, GE, Sylvania and Tung-Sol.
and often used by Japanese DIY circuits
Guido
>regards
>
>Paul Leclercq
>----- Original Message -----
>From: <rcjones1@mmm.com>
>To: <sound@lists.io.com>
>Sent: Friday, June 29, 2001 6:06 AM
>Subject: [JN] 7119/5687 pre-amp - Looking for different operating points.
>
>
>> I think I allready asked this question before, but I don't remember.
>>
>> Basically I have a 5687 pre-amp with the Electra-Print output transformer.
>> I think it is the LC3500 or something.
>>
>> I am running them at 120v, 12mA? The sound is detailed and very neutral.
>I
>> want to try something a little more "lush and romantic" sounding. Is
>there
>> another op. point to use? or should I try a 7119? Or is there another tube
>> to use here?
>>
>> Thanks!
>> Richard
>>
=========================================================================
From: arts.psychology@cwcom.net
Subject: Re: [JN] 7119/5687 pre-amp - Looking for different operating points.
Date: Fri, 29 Jun 2001 22:45:43 +0100
Source: Sound Digest Archive v02.n917
I'm just about to build a preamp with a 5687 in the circuit, and I'm keen to
try the 6N30P. I've tried it in input and phase splitter positions in my Leak
Stereo 20 and what I hear there is exquisite treble and a very clean sound,
maybe more mid-field than close up in perspective, but I find it seductive.
Andy
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: [JN] 7119/5687 pre-amp - Looking for different operating points.
Date: Fri, 29 Jun 2001 23:11:45 -0400
Source: Sound Digest Archive v02.n917
arts.psychology@cwcom.net wrote:
>
> I'm just about to build a preamp with a 5687 in the circuit, and I'm keen to
> try the 6N30P. I've tried it in input and phase splitter positions in my Leak
> Stereo 20 and what I hear there is exquisite treble and a very clean sound,
> maybe more mid-field than close up in perspective, but I find it seductive.
> Andy
Dave McGown of our local group built a simple preamp using this tube.
It's quite nice, better than any of the DIY 5687 preamps I've heard.
- --
Grover Gardner
groverg@postoffice.att.net
Visit my web site at http://home.att.net/~groverg/homepage.htm
=========================================================================
From: "P. de R. L." <triode@bow-tie.org.uk>
Subject: [JN] 7150
Date: Mon, 8 May 2000 21:33:03 +0100
Source: Sound Digest Archive v02.n542
Hello everybody.
has anyone come across type 7150, a peculiar stubby little pentode?
Paul Leclercq
=========================================================================
From: "P. de R. L." <triode@bow-tie.org.uk>
Subject: [JN] 7150/A1600
Date: Thu, 8 Jun 2000 23:51:39 +0100
Source: Sound Digest Archive v02.n571
Apart from the few I have, this one seems to have disappeared from the
surface of the planet! Surely someone out there knows something about this
one?
Paul@13E1.com
=========================================================================
From: TubeGarden@aol.com
Subject: [JN] 7189A
Date: Thu, 15 Mar 2001 10:17:43 EST
Source: Sound Digest Archive v02.n833
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Greets!
Replaced SV83 with GE 7189A driving 6Y6GT in no R no C amp :)
Get yours!
Happy Ears!
Al B^}
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<HTML><FONT FACE=arial,helvetica><BODY BGCOLOR="#ffffff"><FONT SIZE=2>
<BR>Greets!
<BR>
<BR>Replaced SV83 with GE 7189A driving 6Y6GT in no R no C amp :)
<BR>
<BR>Get yours!
<BR>
<BR>Happy Ears!
<BR>Al B^}
<BR>
<BR></FONT></HTML>
- --part1_bb.c84d911.27e23717_boundary--
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] 7189A
Date: Thu, 15 Mar 2001 15:52:19 EST
Source: Sound Digest Archive v02.n833
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Hmmm,
Switched to 6Y6GA and now the SV83 sounds better.
Fickle is as fickle does :)
Al B^}
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<HTML><FONT FACE=arial,helvetica><BODY BGCOLOR="#ffffff"><FONT SIZE=2>
<BR>Hmmm,
<BR>
<BR>Switched to 6Y6GA and now the SV83 sounds better.
<BR>
<BR>Fickle is as fickle does :)
<BR>
<BR>Al B^}
<BR>
<BR></FONT></HTML>
- --part1_9a.1170623b.27e28583_boundary--
=========================================================================
From: Paul Mouritsen <mourip@erols.com>
Subject: [JN] 71a IT Coupled amp is done....sort of.
Date: Mon, 24 May 1999 22:46:55 -0400
Source: Sound Digest Archive v02.n151
Hi,
I finished the wiring for my 417A/IT/371A amp today. The sound has great
promise. It has more life and light in it than I could have imagined. I am
sure that it has a bit to break in but after a half hour I was tapping my
feet and feeling very happy. The only real problem is that I seem to have
put all of the most microphonic and humm producing components known to man
in a single chassis. I do not care about the microphnics because I use this
as a dedicated headphone amp so there is really no accoustic feedback to
bother with. Good thing because you could probably use this thing as a
Karaoke machine...just sing along and it would dub in to your program. The
hard part is the humm.
I swear..honest ;-} ...I am not trying to start another humm thread...but I
am guessing that to use 71A's\371A in a headphone amp I will probably have
to cave in to DC filaments. I am using a LCRC filter so that I can use my
600VCT mains to get 220v. I am also guessing that if I went to CLC with a
lower voltage mains I could get better humm levels. The humm is at the same
level regardless of the volume level and I have humm pots on both the 5 and
6v circuits. This helped a lot. I will go to the Joenet Vault and seach on
"humm", that should hold me for a while.
Thanks to all of you who contributed the "Need help using an IT..." thread.
I learned a lot.
Best,
Paul
Please remove the xxx's in my email address to reply.. Thanks
*****************************************************************************
Paul Mouritsen.....mourip@erols.com
If you want to make God laugh, tell him your plans...
La luce che tu dai
*****************************************************************************
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: [JN] 71a IT Coupled amp is done....sort of.
Date: Mon, 24 May 1999 23:58:53 -0400
Source: Sound Digest Archive v02.n151
For headphones? Wow. Yeah, you will need DC filaments. Also, the first L in
an LCRC filter doesn't do much for the ripple, I believe. Try replacing the R
with an L if you can, that should help. The 71A and 417A are, in my
experience, both highly prone to microphony.
- --
Grover Gardner
groverg@postoffice.att.net
=========================================================================
From: Paul Mouritsen <mourip@erols.com>
Subject: Re: [JN] 71a IT Coupled amp is done....sort of.
Date: Tue, 25 May 1999 13:07:53 -0400
Source: Sound Digest Archive v02.n151
Hi Grove,
Thanks for the input. I tried patching in a choke in that spot but it did
not do the job. I only have 47mf for the first two C's so maybe I could
boost that a bit since I have a choke input. I will probably try DC just to
see. Do I need to adjust the B+ or the bias if I switch to DC. I vaguely
remember that...
Can someone help me with the math here. I need 220V at the plate of the
71A. If I replace the mains with a lower voltage one and go with CLC using
a 5AR4 what VCT should I go for? The 5AR4 drops about 25v. I am thinking
that I need around 325VCT. I figure 1.4 * 325/2 = ~275v then -25v =250v.
That gives me a little to burn off with a bleeder.
Oh, yeah. While I have everyone on the line. Is it acceptable practice to
drop B+ a little by putting a resistor to ground from the center tap of the
secondary? I saw this in a GA article. The author felt that there was no
sonic penalty.
Thanks,
Paul
At 11:58 PM 05/24/1999 -0400, you wrote:
>For headphones? Wow. Yeah, you will need DC filaments. Also, the first
L in
>an LCRC filter doesn't do much for the ripple, I believe. Try replacing
the R
>with an L if you can, that should help. The 71A and 417A are, in my
>experience, both highly prone to microphony.
>--
>Grover Gardner
>groverg@postoffice.att.net
>
Paul Mouritsen
Network Analyst
Holy Cross Hospital
Silver Spring, Maryland
mourip @ holycrosshealth.org
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: Re: [JN] 71a IT Coupled amp is done....sort of.
Date: Wed, 26 May 1999 02:46:00 -0400
Source: Sound Digest Archive v02.n152
Grovr said:
>>> Also, the first L in an LCRC filter doesn't do much for the
ripple, I believe. Try replacing the R with an L if you can, that should
help<<<
Ya gotta be kidding, Grover. As long as that first choke has enough
inductance to "act as a choke" in the first position of such a filter then
it will be way more effective than a resistor in lowering hum. LC =
12dB/octave. RC = 6 dB/octave...
But I agree with your point regarding DC heaters, IMO there is little
chance of not hearing hum from a SE DHT with AC heaters with flat from
10Hz ear covers...
Allen (VSE)
=========================================================================
From: "Henry Platt" <hnplatt@massed.net>
Subject: Re: [JN] 7247 / 12DW7
Date: Sat, 25 Sep 1999 11:32:31 -0700
Source: Sound Digest Archive v02.n285
Hi.
Some of my favorite stock EL84/6BQ5 stereo tube amps use this tube. These
are:
Dyna ST35, Fisher SA100, Eico HF85.
I have used NOS and EI brands with slight preferance for NOS RCA. I hardly
use these amps any more since going SE about 7 years ago. Still they do
sound nice.
Regards,
Henry Platt
- ----------
>From: Christian Rintelen <rintelen@datacomm.ch>
>To: Joelist <sound@lists.io.com>
>Subject: [JN] 7247 / 12DW7
>Date: Sat, Sep 25, 1999, 6:27 AM
>
> Joes,
>
> any experiences worth sharing about the 7247 / 12dw7 ? Looks interesting
> to me, but I wonder how it sounds.
>
> Christian
>
>
=========================================================================
From: David Barnett <davidbarnett@aristotle.net>
Subject: Re: [JN] 7247 / 12DW7
Date: Sat, 25 Sep 1999 11:34:52 -0500
Source: Sound Digest Archive v02.n285
On Sat, 25 Sep 1999 11:32:31 -0700, "Henry Platt" <hnplatt@massed.net>
wrote:
>Some of my favorite stock EL84/6BQ5 stereo tube amps use this tube. These
>are: Dyna ST35, Fisher SA100, Eico HF85.
The original Quicksilver 8417 mono amps used the 7247 too. Come to
think of it, the Quicksilver's front end appeared to be lifted
straight out of the Dyna ST35 almost verbatim.
BTW, Henry, we had Skavoovie and the Epitones at the club for a
private party last month. I dropped your name when talking with your
student, the baritone player, and he mentioned that he has spoken with
you fairly recently. They were a great band, and really nice guys.
Their keyboard player was very pleased with our Hammond B3, too.
- --dnb
=========================================================================
From: Tim Reese <tgrmail@nmr.MGH.harvard.EDU>
Subject: Re: [JN] 7247 / 12DW7
Date: Sat, 25 Sep 1999 13:24:21 -0400 (EDT)
Source: Sound Digest Archive v02.n285
Henry comments
>Hi.
>Some of my favorite stock EL84/6BQ5 stereo tube amps use this tube. These
>are:
>Dyna ST35, Fisher SA100, Eico HF85.
>I have used NOS and EI brands with slight preferance for NOS RCA. I hardly
>use these amps any more since going SE about 7 years ago. Still they do
>sound nice.
>Regards,
>Henry Platt
>
>----------
>>From: Christian Rintelen <rintelen@datacomm.ch>
>>To: Joelist <sound@lists.io.com>
>>Subject: [JN] 7247 / 12DW7
>>Date: Sat, Sep 25, 1999, 6:27 AM
>>
>
>> Joes,
>>
>> any experiences worth sharing about the 7247 / 12dw7 ? Looks interesting
>> to me, but I wonder how it sounds.
>>
>> Christian
>>
>>
Expanding on what Henry said, I have a few amps that use this tube (EICO
2036, 2050s) but not much time listening to them ... some lore as I
understand it: the 7247 is half a 12AU7 and 'AX7 in the same bottle. The
EICO amps (and I presume the Dyna and Fisher) used them in lieu of the
familiar 6U8A or 7199 amp/phase splitter. I don't know whether the good
reputation of the 7247 is because of the merit of the tube or because the
amps it was used in had an all-triode signal path ... the rep of the amp
sort-of implies the tubes are good sounding. They (7247) are rather expensive
for what they are - likely due to relative scarcity - and you might do better
with a nice round plate 6AV6 with a 6C4, giving the same function in two
7-pin bottles. Both the 6AV6 and 6C4 are $2 tubes rather than (typically)
more than $20 for the 12DW7.
hth tr
- ----------------------------------------------------------------------
Tim Reese, MGH NMR Center reese@nmr.MGH.harvard.edu
=========================================================================
From: Christian Rintelen <rintelen@datacomm.ch>
Subject: [JN] 7247 / 12DW7
Date: Sat, 25 Sep 1999 15:27:42 +0200
Source: Sound Digest Archive v02.n285
Joes,
any experiences worth sharing about the 7247 / 12dw7 ? Looks interesting
to me, but I wonder how it sounds.
Christian
=========================================================================
From: Jim de Kort <sp@vt52.com>
Subject: [JN] 75/100TH
Date: Tue, 29 Aug 2000 21:28:06 +0200
Source: Sound Digest Archive v02.n645
Hi Guys,
Does anyone here have experience with the 75TH or 100TH? Any ideas,
suggestions, comments, horror stories?
Regards,
Jim de Kort
jim@vt52.com
=========================================================================
From: rcjones1@mmm.com
Subject: [JN] 76 listening impressions, questions, and new amp topology: 76->71A->6B4G
Date: Fri, 17 Aug 2001 07:44:40 -0500
Source: Sound Digest Archive v02.n948
Hi gang,
Well I put the 76 in my pre-amp. Changed the PS to a LCLCCC split then a
RC for each channel. The L are 10-15H 400ohm chokes. The first 4 caps are
47uf nd the last caps are 10uf Solens. Any ideas for a better PS topology
using what I have?
Sound is quite good. Very natural and smooth. I may have lost some detail
compared to my 5687 based. The 76 are a little noisy too.
Should I try 6SN7 or 6J5 instead?
76 are at 190v 5-6mA.
I raised my filaments on them to 50v and added small caps across each tube
at the filaments.
Next my amp...
I am thinking a 76->71A->2A3(6B4G). If I use the 6B4G I will use the steve
bench hum mod.
Or should I try and build a integrated amp? any suggestions? How about a
6SN7 -> 76 -> 71A -> 6B4G? seperate Power supplies...?
Well anyhow thats all for now.
Richard
=========================================================================
From: "John Levreault" <jlevro@mediaone.net>
Subject: Re: [JN] 76 listening impressions, questions, and new amp topology: 76->71A->6B4G
Date: Fri, 17 Aug 2001 09:15:07 -0400
Source: Sound Digest Archive v02.n948
- ----- Original Message -----
From: <rcjones1@mmm.com>
To: <sound@lists.io.com>
Sent: Friday, August 17, 2001 8:44 AM
Subject: [JN] 76 listening impressions, questions, and new amp topology:
76->71A->6B4G
> Hi gang,
>
> Well I put the 76 in my pre-amp. Changed the PS to a LCLCCC split then a
> RC for each channel. The L are 10-15H 400ohm chokes. The first 4 caps
are
> 47uf nd the last caps are 10uf Solens. Any ideas for a better PS topology
> using what I have?
>
> Sound is quite good. Very natural and smooth. I may have lost some
detail
> compared to my 5687 based. The 76 are a little noisy too.
>
> Should I try 6SN7 or 6J5 instead?
Of course. Welcome to the world of tube tasting.
JL
=========================================================================
From: tube@jump.net
Subject: Re: [JN] 7788
Date: Fri, 18 Aug 2000 20:03:14 -0500
Source: Sound Digest Archive v02.n633
"Michael (Mick)Maloney" wrote:
> Anybody got curves for 7788 in triode connect and plate resistance at
> approx 150V- got to get this tube into a phono front end- anybody else done
> it?
> I cant raise Duncans Tube Amps- is there a new URL?
>
> MickM
From the Mullard sheets via David Crittle, 1000 ohms @ 150 V, 33 mA (5 W),
1150 ohms @ 140 V, 25 mA (3.5 W). In theory the 7788 can handle 5.75 W
in triode mode, although I am sure the life drops accordingly. At that power
and 150 V & 38 mA, the Rp is about 900 ohms.
Phil
=========================================================================
From: SBench@aol.com
Subject: Re: [JN] 7788
Date: Fri, 18 Aug 2000 20:37:07 EDT
Source: Sound Digest Archive v02.n633
In a message dated 00-08-18 19:51:01 EDT, supra@cantech.net.au writes:
<<
Anybody got curves for 7788 in triode connect and plate resistance at
approx 150V- got to get this tube into a phono front end- anybody else done
it?
I cant raise Duncans Tube Amps- is there a new URL?
>>
Duncans site ran OK earlier today. Note that he's not
on Simplenet so the URL changes to
http://www.duncanamps.com
Best Regards,
Steve
=========================================================================
From: "Michael (Mick)Maloney" <supra@cantech.net.au>
Subject: [JN] 7788
Date: Sat, 19 Aug 2000 07:46:52 +0800
Source: Sound Digest Archive v02.n633
Anybody got curves for 7788 in triode connect and plate resistance at
approx 150V- got to get this tube into a phono front end- anybody else done
it?
I cant raise Duncans Tube Amps- is there a new URL?
MickM
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: Re: [JN] Re: 7788
Date: Mon, 21 Aug 2000 11:51:23 -0400
Source: Sound Digest Archive v02.n636
>I hesitated doing this because of predujuce pentode v triode but sounds
>every bit as good as 3A/167 allowing for zero fine tuning so far.
don't hesitate, i concur.
when swapping between the trioded 7788 and 437A's a year or so ago, i heard
differences, but they were merly subtle changes in flavor, and i never
really came up with a preference... neither one of them sounded bad, but
they both stomped all over the 417A... getting the 6c45... was just
another flavor... either one of these tubes has me convinced that i will
never use a 437a again...
if the weakest part of your system is swapping a 437 for a trioded 7788 at
1/20th the cost... you better have a pretty good system! but maybe the 42
clip leads i had in the amp at that time had something to do with it.
as a plug for the critter... a few years back he had some at a fair price....
=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: Re: [JN] Re: 7788
Date: Mon, 21 Aug 2000 16:38:53 GMT
Source: Sound Digest Archive v02.n636
Hi
>I hesitated doing this because of predujuce pentode v triode but sounds
>every bit as good as 3A/167 allowing for zero fine tuning so far.
Time for the next Level Mick. Use the E810F as Penthode.... Use the Anode
Resistor to set gain and as the first part of the RIAA EQ. Follow up with
your favourite Valve as additional gainstage and buffer.... How about 12B4A?
Later T
________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
=========================================================================
From: "Michael (Mick)Maloney" <supra@cantech.net.au>
Subject: [JN] Re: 7788
Date: Mon, 21 Aug 2000 21:00:41 +0800
Source: Sound Digest Archive v02.n636
Thanks for the info , curves for E180F ,7788.
As they looked very similiar to 3A/167(WE437) I just dropped a pair
straight into
my prototype phono set up for 3A/167- changed the cathode resistor and
ended up with approx 100V on the plate @15ma.
Good enough for a trial-I just wanted to get a feel for them and see if
there was going to be microphonic problems.
Sounded good- no microphonics , gain was a bit low for my Denon DL103 but
with an unbypassed cathode resistor- a capacitor would make gain about
right but these days I would rather use a fet than a cap (never thought I
would say that!)
I hesitated doing this because of predujuce pentode v triode but sounds
every bit as good as 3A/167 allowing for zero fine tuning so far.
MickM
http://www.cantech.net.au/~supra/
SUPRATEK TRIODE " valve amplifiers for those who demand absolute sound and
finish-worldwide "
Mick Maloney
3 Parkside Ave Mt Pleasant Western Australia 6153
Ph/Fax 61 8 93644385 supra@cantech.net.au
=========================================================================
From: David Crittle <retrovox@bigpond.com>
Subject: Re: [JN] Re: 7788
Date: Tue, 22 Aug 2000 10:22:50 +1000
Source: Sound Digest Archive v02.n638
>Date: Mon, 21 Aug 2000 11:51:23 -0400
>To: sound@deliverator.io.com
>From: dslagle@earthlink.net (dave slagle)
>Subject: Re: [JN] Re: 7788
>
>as a plug for the critter... a few years back he had some at a fair price....
>
Thanks for the plug Dave, currently nil stock 7788/E810F. Sold them last of
them out at $10 each a few months back. I still have some other pentodes in
stock from $2.50 each.
BTW, I am working on my next sale list update, should be ready soon (-er or
later). Different bits of the sky keep falling in for me, so I'm a more
than a little behind.
David Crittle
retrovox@bigpond.com
http://members.dingoblue.net.au/~retrovoxaudio
=========================================================================
From: Sridhar Gantimahapatruni <Ganti@acta.com>
Subject: [JN] 7788 as a driver
Date: Fri, 5 Feb 1999 14:36:58 -0800
Source: Sound Digest Archive v02.n029
This message is in MIME format. Since your mail reader does not understand
this format, some or all of this message may not be legible.
- ------_=_NextPart_001_01BE5158.0A213D38
Content-Type: text/plain
Hi
If you recall I had posted enquires about 7788 about a month ago. I bought a
pair from
Antique, and removed the 6072A-->5687 driver stages and replaced it with a
single
7788, and this is IT coupled to a pair of triode connected EL34's operating
in SE modes.
When I did the change [with a lot of help from Joe Lowe and John Levrault],
I found the
sound to be dry, and fatiguing, there was glare which was getting on to my
nerves after
a short period of listening. There was no body in the music and it was not
enjoyable.
Couple of things before diving into the changes I made later,
I was cathode biasing the 7788, and hence had to by-pass it with a small
electrolytic.
Two days ago, I could not stand it any longer, after reading Mike's email
about
battery biasing, I bought pair of NiCad's and used that to bais the cathode.
But, I also did another
change at the same time. I had a dual 47mF cerafine, which was providing
filtering to
6072, and 5687. Now that I have only one stage, I paralleled the 47mF [why
leave the
47mF wasting around ):], and removed the by-pass caps [solen 0.22mF].
Powered up the amp, much better, there was wamrth and body, and the glare
was gone,
but then after listening for a day, I felt, I needed a small bump in the
highs that I felt
was missing, I added 0.22mF hovlands to by-pass the parallel 47mF cerafine.
I did not really
like the sound too much, I had a pair of 0.5 Handmade Oil caps, Used them to
by-pass the
47mF, and WOW!! the sound was just right to my liking [for the time being
:)]. The highs
were there without the glare, and much better weight in the presentation.
Now I am beginging
to like my 7788 driver stage.
So far, twice I have tried to remove the by-pass caps of the cerafines, and
both the times I
found the presentation in music becomes too relaxing and un-involving.. but
this is the first
time I tried oil's as by-pass.
I have learnt one thing though, if your amp is highly tweaked, and you make
a change, like I did
replacing driver stages, then you need to go thru series of fine tuning
around the change before
making a judgement on the change. Thats the reason I did not post my
judgements about 7788.
Now, I can say, this is a fantastic driver.
Furture projects, I have a quad of 6B4G's , and ordered necessary parts for
a out-board
6.3V power supply from handmade. I am building the supply using a cap -->
choke --> cap.
Once I built the 6.3V supply, I am going to replace
the EL-34's with parallel 6B4G's, to get the DHT sound I heard so much
about.
I am sure once I hookup the 6B4G's I would have to go thru a series of fine
tuning before
getting the sound right...
BUt for the time being I am going enjoy this amp for a month or two sitting
back on the new
leather recliner chair my wife purchased for me to enjoy the music..
ganti
- ------_=_NextPart_001_01BE5158.0A213D38
Content-Type: text/html
Content-Transfer-Encoding: quoted-printable
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<HTML>
<HEAD>
<META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
charset=3Dus-ascii">
<META NAME=3D"Generator" CONTENT=3D"MS Exchange Server version =
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<TITLE>7788 as a driver</TITLE>
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<BODY>
<BR>
<P><FONT SIZE=3D2 FACE=3D"Arial">Hi</FONT>
</P>
<P><FONT SIZE=3D2 FACE=3D"Arial">If you recall I had posted enquires =
about 7788 about a month ago. I bought a pair from </FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">Antique, and removed the =
6072A-->5687 driver stages and replaced it with a single</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">7788, and this is IT coupled to a =
pair of triode connected EL34's operating in SE modes.</FONT>
</P>
<P><FONT SIZE=3D2 FACE=3D"Arial">When I did the change [with a lot of =
help from Joe Lowe and John Levrault], I found the</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">sound to be dry, and fatiguing, there =
was glare which was getting on to my nerves after</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">a short period of listening. There =
was no body in the music and it was not enjoyable. </FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">Couple of things before diving into =
the changes I made later,</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">I was cathode biasing the 7788, and =
hence had to by-pass it with a small electrolytic.</FONT>
</P>
<P><FONT SIZE=3D2 FACE=3D"Arial">Two days ago, I could not stand it any =
longer, after reading Mike's email about</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">battery biasing, I bought pair of =
NiCad's and used that to bais the cathode. But, I also did =
another</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">change at the same time. I had a dual =
47mF cerafine, which was providing filtering to </FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">6072, and 5687. Now that I have only =
one stage, I paralleled the 47mF [why leave the</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">47mF wasting around ):], and removed =
the by-pass caps [solen 0.22mF]. </FONT>
</P>
<P><FONT SIZE=3D2 FACE=3D"Arial">Powered up the amp, much better, there =
was wamrth and body, and the glare was gone,</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">but then after listening for a day, I =
felt, I needed a small bump in the highs that I felt </FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">was missing, I added 0.22mF hovlands =
to by-pass the parallel 47mF cerafine. I did not really</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">like the sound too much, I had a pair =
of 0.5 Handmade Oil caps, Used them to by-pass the</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">47mF, and WOW!! the sound was just =
right to my liking [for the time being :)]. The highs</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">were there without the glare, and =
much better weight in the presentation. Now I am beginging</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">to like my 7788 driver stage.</FONT>
</P>
<P><FONT SIZE=3D2 FACE=3D"Arial">So far, twice I have tried to remove =
the by-pass caps of the cerafines, and both the times I </FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">found the presentation in music =
becomes too relaxing and un-involving.. but this is the first</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">time I tried oil's as by-pass. =
</FONT>
</P>
<P><FONT SIZE=3D2 FACE=3D"Arial">I have learnt one thing though, if =
your amp is highly tweaked, and you make a change, like I did</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">replacing driver stages, then you =
need to go thru series of fine tuning around the change before</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">making a judgement on the change. =
Thats the reason I did not post my judgements about 7788.</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">Now, I can say, this is a fantastic =
driver.</FONT>
</P>
<P><FONT SIZE=3D2 FACE=3D"Arial">Furture projects, I have a quad =
of 6B4G's , and ordered necessary parts for a out-board</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">6.3V power supply from handmade. I am =
building the supply using a cap --> choke --> cap. </FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">Once I built the 6.3V supply, I am =
going to replace</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">the EL-34's with parallel 6B4G's, to =
get the DHT sound I heard so much about.</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">I am sure once I hookup the 6B4G's I =
would have to go thru a series of fine tuning before</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">getting the sound right... </FONT>
</P>
<P><FONT SIZE=3D2 FACE=3D"Arial">BUt for the time being I am going =
enjoy this amp for a month or two sitting back on the new</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">leather recliner chair my wife =
purchased for me to enjoy the music..</FONT>
</P>
<P><FONT SIZE=3D2 FACE=3D"Arial">ganti</FONT>
</P>
</BODY>
</HTML>
- ------_=_NextPart_001_01BE5158.0A213D38--
=========================================================================
From: "Ed Coleman" <ecoleman@whidbey.net>
Subject: [JN] 7868 replacement? and......
Date: Sat, 25 Nov 2000 19:15:52 -0800
Source: Sound Digest Archive v02.n745
HI Joes, is there such a thing as a drop in replacement for a 7868? I have a
TEAC integrated amp with these .I'd like to send it to the land of ebay in
working order ,without investing $ any suggestions ? tia Ed
PS , I have a (single) Warfedale W70d 4 way speaker/cabinet (read BIG and
HEAVY) for cheap , anybody ? Ed
=========================================================================
From: StepHydro@aol.com
Subject: Re: [JN] 7868 replacement? and......
Date: Sun, 26 Nov 2000 07:47:51 EST
Source: Sound Digest Archive v02.n745
Ed,
The 7868 is a 6L6 with identity problems. Any of the 6L6 types will work in
the circuit with specific mods, but there isn't a drop-in replacement. I'm
considering modding my Fisher X100-B to use 6CK4s, so I *could* have a quad
of used ones for trade :-)
Cheers/Don Carron
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 7868 replacement? and......
Date: Sun, 26 Nov 2000 16:00:15 +0100
Source: Sound Digest Archive v02.n745
Ed
I cant'find this type in my manuals. Did you check with the search /
substitute engine on Duncans' pages ?
My AVO manual gives the following data for CT160 tester:
thumbwheels: 541 234 410
6.3V
Vg1 = -10
Va = 300
Vg2 = 300
Ia = 60
s = 10.2
base = B9D
type = Penthode
So it looks to me like a beefy EL84 / 6BQ5, in a slightly different socket
You may adapt to EL84M, the Sovtek type which is 14 watt, inexpensive,
available, and adapt the amp slightly.
I didn't know TEAC made tube amps, by the way .....
Guido
At 19:15 25/11/2000 -0800, Ed Coleman wrote:
>HI Joes, is there such a thing as a drop in replacement for a 7868? I have a
>TEAC integrated amp with these .I'd like to send it to the land of ebay in
>working order ,without investing $ any suggestions ? tia Ed
>
>PS , I have a (single) Warfedale W70d 4 way speaker/cabinet (read BIG and
>HEAVY) for cheap , anybody ? Ed
>
>
>
=========================================================================
From: analogtubeaudio@t-online.de (Analog Tube Audio)
Subject: RE: [JN] 7868 replacement? and......
Date: Sun, 26 Nov 2000 16:26:29 +0100
Source: Sound Digest Archive v02.n745
Joe´s,
I think the german EL 508 is the best replacement and use the same socket !!
Best regards
Robert
Analog Tube Audio
http://www.analogtubeaudio.de
mail@analogtubeaudio.de
Tel. +49-471-9414777
Fax. +49-471-9414778
- -----Original Message-----
From: owner-sound@lists.io.com [mailto:owner-sound@lists.io.com]On
Behalf Of evaguido
Sent: Sunday, November 26, 2000 4:00 PM
To: Ed Coleman; David Dlugos; joe list
Subject: Re: [JN] 7868 replacement? and......
Ed
I cant'find this type in my manuals. Did you check with the search /
substitute engine on Duncans' pages ?
My AVO manual gives the following data for CT160 tester:
thumbwheels: 541 234 410
6.3V
Vg1 = -10
Va = 300
Vg2 = 300
Ia = 60
s = 10.2
base = B9D
type = Penthode
So it looks to me like a beefy EL84 / 6BQ5, in a slightly different socket
You may adapt to EL84M, the Sovtek type which is 14 watt, inexpensive,
available, and adapt the amp slightly.
I didn't know TEAC made tube amps, by the way .....
Guido
At 19:15 25/11/2000 -0800, Ed Coleman wrote:
>HI Joes, is there such a thing as a drop in replacement for a 7868? I have
a
>TEAC integrated amp with these .I'd like to send it to the land of ebay in
>working order ,without investing $ any suggestions ? tia Ed
>
>PS , I have a (single) Warfedale W70d 4 way speaker/cabinet (read BIG and
>HEAVY) for cheap , anybody ? Ed
>
>
>
=========================================================================
From: StepHydro@aol.com
Subject: Re: [JN] 7868 replacement? and......
Date: Sun, 26 Nov 2000 12:39:20 EST
Source: Sound Digest Archive v02.n746
In a message dated 11/26/2000 10:<BR36:<BR37 AM
Eastern Standard, analogtubeaudio@t-online.de writes:> Joe´s,
>
> I think the german EL 508 is the best replacement and use the same socket
!!
>
> Best regards
Robert,
Is that sub info based upon the earlier post saying the 7668 is similar to
the 6BQ5??? The EL/Pl508 certainly has different basing to the 7868, and the
plate dissipation isn't nearly close.
The 7868 is really a "6L6 in a different envelope". I don't expect that the
XX508 will have similar characteristics.
Cheers/Carron
=========================================================================
From: Dan Kerl <dlkerl@knology.net>
Subject: Re: [JN] 7868 replacement? and......
Date: Sun, 26 Nov 2000 12:43:27 -0600
Source: Sound Digest Archive v02.n746
Ed Coleman wrote:
>
> HI Joes, is there such a thing as a drop in replacement for a 7868? I have a
> TEAC integrated amp with these .I'd like to send it to the land of ebay in
> working order ,without investing $ any suggestions ? tia Ed
This is a 7591A with a magnoval/novar base. There are no good drop-in
replacements. 6GM5 is electrically compatible, but uses a standard
9-pin base. All three types have gotten expensive, with the 7591A being
the worst since there are so many sockets to fill. Is there any word
on a manufacturer that's willing to do a decent 7591A without wimping
out (as Svetlana did)?
- --
Dan Kerl
dlkerl@knology.net
=========================================================================
From: Ken Gilbert <ride5000@ride.ri.net>
Subject: Re: [JN] 7868 replacement? and......
Date: Sun, 26 Nov 2000 16:47:20 -0500
Source: Sound Digest Archive v02.n746
>Date: Sun, 26 Nov 2000 12:43:27 -0600
>From: Dan Kerl <dlkerl@knology.net>
>X-Mailer: Mozilla 4.73 [en] (Win95; U)
>X-Accept-Language: en
>To: joe list <sound@lists.io.com>
>Subject: Re: [JN] 7868 replacement? and......
>Sender: owner-sound@lists.io.com
>
>
>Ed Coleman wrote:
>>
>> HI Joes, is there such a thing as a drop in replacement for a 7868? I have a
>> TEAC integrated amp with these .I'd like to send it to the land of ebay in
>> working order ,without investing $ any suggestions ? tia Ed
>
>This is a 7591A with a magnoval/novar base. There are no good drop-in
>replacements. 6GM5 is electrically compatible, but uses a standard
>9-pin base. All three types have gotten expensive, with the 7591A being
>the worst since there are so many sockets to fill. Is there any word
>on a manufacturer that's willing to do a decent 7591A without wimping
>out (as Svetlana did)?
sovtek IS making one.. it's in the first few hands right now getting wrung out,
but i know it IS out there. hopefully we will see some trickle down at
reasonable prices soon.
ken
=========================================================================
From: "Ed Coleman" <ecoleman@whidbey.net>
Subject: Re: [JN] 7868 replacement? and......
Date: Sun, 26 Nov 2000 18:38:20 -0800
Source: Sound Digest Archive v02.n746
I think Lord Valve had a couple of samples a while back, his view was he
wouldn't comment 'til he had a chance to crank 'em up , spill beer on 'em
and treat 'em like a typical guitarist might (did I offend anyone?) , I
don't have his address,its somewhere on the web , a quick search will find
'im . Ed
- -----Original Message-----
From: jc@izone.com <jc@izone.com>
To: sound@lists.io.com <sound@lists.io.com>
Date: Sunday, November 26, 2000 6:20 PM
Subject: Re: [JN] 7868 replacement? and......
>hey all,
>the lurker emerges... yeah, new sensor has a kick-ass 7591A thats just out.
>unfortunately, the first 400 get parceled out in the most insane way. its
>the way mike always does it. but there are 5000 of em on a container that
>should hit mid-december. they're fairly awesome. they are built using as
>much tooling as we already have for other 6L6 type tubes, so they won't be
>ridiculously expensive. although its not a huge run... the guitar amp
>people mike prefers (ampeg repairs) will probably get first dibs (with the
>exception of kittlelson and maybe the fischer doc?) but they will be
>available and are for real.
=========================================================================
From: Dan Kerl <dlkerl@knology.net>
Subject: Re: [JN] 7868 replacement? and......
Date: Sun, 26 Nov 2000 18:42:31 -0600
Source: Sound Digest Archive v02.n746
Ken Gilbert wrote:
> sovtek IS making one.. it's in the first few hands right now getting wrung out,
> but i know it IS out there. hopefully we will see some trickle down at
> reasonable prices soon.
This is great news. I was thinking of resocketing my Fisher 500B to use 6GM5s.
I guess I won't need to do that now. Any information on price?
- --
Dan Kerl
dlkerl@knology.net
=========================================================================
From: jc@izone.com
Subject: Re: [JN] 7868 replacement? and......
Date: Sun, 26 Nov 2000 20:48:06 -0500
Source: Sound Digest Archive v02.n746
hey all,
the lurker emerges... yeah, new sensor has a kick-ass 7591A thats just out.
unfortunately, the first 400 get parceled out in the most insane way. its
the way mike always does it. but there are 5000 of em on a container that
should hit mid-december. they're fairly awesome. they are built using as
much tooling as we already have for other 6L6 type tubes, so they won't be
ridiculously expensive. although its not a huge run... the guitar amp
people mike prefers (ampeg repairs) will probably get first dibs (with the
exception of kittlelson and maybe the fischer doc?) but they will be
available and are for real.
=========================================================================
From: Phil <tube@jump.net>
Subject: Re: [JN] 7868 replacement? and......
Date: Mon, 27 Nov 2000 01:08:11 -0600
Source: Sound Digest Archive v02.n746
jc@izone.com wrote:
> [Snip]
>
> this is a perfect segue into a little tale about 7591A's/7868's: if it is
> not generally known, who among you know why they were ever made in the
> first place, and why they disappeared so quickly even after RCA did such a
> massive marketing campaign to cram em down the early american consumer
> electronics manufacturers grundgy throats (whether they wanted them or
> not)? huh?
> [Major snip]
> it all began with philips and the patent for the audio power pentode. some
> of you may be aware that no audio power pentodes could be made in this
> country without paying philips a royalty... i'm getting carried away here a
> bit, and i've
> generalized a fair amount as well, but the point is that the 7591A was
> never anything more than a desperate local replacement for a EL-34. thats a
> fact. it always drove me nuts how sacred that tube is held in some circles.
> don't they know? its just a tube! and i still think that i'd rather have an
> EL-34! in any case, the most obvious replacement for a 7591A has always
> been an EL-34, except that it doesn't fit under the cover of a fisher 400.
> but try telling that to any of the folks that have amps that used them...
> ok, thats my venting for the day. don't forget that the 6CA7 is NOT A
> PENTODE! (its a beam tetrode!) and NOT an EL-34.
>
> i hope everyone had a happy turkey-day!
Now THAT'S a cool story ... Plus some interesting info
Phil
=========================================================================
From: jc@izone.com
Subject: Re: [JN] 7868 replacement? and......
Date: Mon, 27 Nov 2000 01:09:30 -0500
Source: Sound Digest Archive v02.n746
At 06:38 PM 11/26/00 -0800, Ed Coleman wrote:
>I think Lord Valve had a couple of samples a while back, his view was he
>wouldn't comment 'til he had a chance to crank 'em up , spill beer on 'em
>and treat 'em like a typical guitarist might (did I offend anyone?) , I
>don't have his address,its somewhere on the web , a quick search will find
>'im . Ed
all respect to ed and fat willy (aka "lord valve"), but man... why does
anyone have to have approval before checking these things out? or anything
else for that matter? i have to say that my last peek at what is going on
in the joenet has me hell-bent on putting cathode followers in everything.
there is nothing quite like dumb blanket statements like "cathode followers
suck" to get me pumped up on em. hell, if so many people are up in arms,
there just HAS to be something great going on there. either that, or all
those experts who've eightysixed em out of hand, might still have a little
work to do? no couldn't be... i forgot! everything's been all figured out.
just use a transformer! or was it an op-amp?
this is a perfect segue into a little tale about 7591A's/7868's: if it is
not generally known, who among you know why they were ever made in the
first place, and why they disappeared so quickly even after RCA did such a
massive marketing campaign to cram em down the early american consumer
electronics manufacturers grundgy throats (whether they wanted them or
not)? huh?
it all began with philips and the patent for the audio power pentode. some
of you may be aware that no audio power pentodes could be made in this
country without paying philips a royalty... and thus us americaninos were
forced to live with the beam power tetrode, because shit if we gonna pay
them a dime. we won the god damned war for crying out loud! 6L6, etc. etc.
etc.... well, for the most part, us cowboys in the new country were more
than happy to do without the suppressor grid in our output stages. but
something happened in the very beginning of the sixties that sent tremors
far and wide through the halls of RCA. it was called the EL-34. and all of
a sudden, that pesky upstart goniff mashugganah, sol marantz, actually let
sid smith give up on the good ole US of A and buy euro! jeez louise. and if
that wasn't injury on top of insult, that jerk fisher, and that creep
hafler, figured sid might know what he was doing and they started making
amps with those damned skinny little fairy tubes too! it just ain't right!
so the machinery down in darkest jersey cranked itself up into a fever
pitch. "we got to get us an american vacuum tube that'll compete with those
friggin snobs over in england, holland and (gasp!) germany", they said, and
"whats more, if they (american consumer electronics manufacturers) don't
buy em, we won't sell em anything else that they want, so there!" so, they
mixed a little sweep tube scifi in with some octal audio packaging and,
VOILA', 7591. it was prone to high frequency oscillation so they rotated
the plate 15 some degrees and presto chango, 7591A. marantz was too small
and too idealistic to buy the amazing new EL-34 like beam power tetrode
made by RCA right here in the goddamned USA but fisher was talked into it,
as were others. the higher transconductance, lower impedance and lower
distortion EL-34 (and EL-84) made it easier to make simple circuits that
sounded and performed exceptionally. this was now also the case with the
7591A, which sat sort of in between the EL-34 and EL-84 for power. all
should have been fine and dandy, except that MO valve (secretly together
with tungsol) got foolishly ambitious and sick and tired of losing at
hardball with the bastards in eindhoven. they managed to sell the idea of
massive amounts of raw audio power available only with KT-88's (6550's).
and suddenly, there were too many options. it was the beginning of the
wildest marketing race in the history of modern industrialized business.
from about 1962 to 68. very similar to the car business then, or computer
hardware trade now. some pitched power, some convenience, some the latest
tech (transistors). even marantz was doubling up on EL-34's to stay in the
arms race. everyone had to have something "new" every year. the 7591A got
lost in the shuffle. it just wasn't remarkable or even better than an
EL-34. this wasn't something that only flopped for RCA. it happened to
almost everyone else in some way or another. for a short minute, it looked
like philips might actually end up with egg on their face just like
everyone else! no way. kings of the cheap but good, philips ended up buying
or putting all of their european competion out of business, including
telefunken. they eventually bought amperex, sylvania and magnavox, who got
radically over extended, and after the japanese destroyed the american
television business (and RCA with it), philips wiped out anything left
standing in the USA. only sony stands in its way to total world consumer
electronic domination today. i'm getting carried away here a bit, and i've
generalized a fair amount as well, but the point is that the 7591A was
never anything more than a desperate local replacement for a EL-34. thats a
fact. it always drove me nuts how sacred that tube is held in some circles.
don't they know? its just a tube! and i still think that i'd rather have an
EL-34! in any case, the most obvious replacement for a 7591A has always
been an EL-34, except that it doesn't fit under the cover of a fisher 400.
but try telling that to any of the folks that have amps that used them...
ok, thats my venting for the day. don't forget that the 6CA7 is NOT A
PENTODE! (its a beam tetrode!) and NOT an EL-34.
i hope everyone had a happy turkey-day!
=========================================================================
From: "ed coleman" <ecoleman@whidbey.net>
Subject: Re: [JN] 7868 replacement? and......
Date: Mon, 27 Nov 2000 07:33:48 -0800
Source: Sound Digest Archive v02.n746
- --JC, thannkks for the very informative rant ! I loved it ! please rant more
often!! Ed
=========================================================================
From: "Larry D. Moore" <l-moore@onu.edu>
Subject: Re: [JN] 7868 replacement? and......
Date: Mon, 27 Nov 2000 09:47:01 -0500
Source: Sound Digest Archive v02.n746
Nice story, or I should say history, jc. Pretty much the way I heard it
with the exception of my story was told from the military side due to its
narrator, which is now the way I re-tell it. Funny that the way one finds
out about tube history is much like the way American Indains have
perpetuted their history. Seems that we, Americans, have been almost as
sucessful in burning tube books as we were at killing Indians. But then
again, we, as a people, have had a long history of burning books.....
I remember when I first got access to the design library at Bell Labs. I
can remember going down there thinkin' boy am I gonna score so good old
tube info now! I ask the schmuck at the desk where the tube info was. In
his wisdom he barked back at me, "Where the hell you been boy? I threw
that shit out years ago. Ain't nobody seem a tube in years around here. I
tossed that shit when we went to micro-fiche." I couldn't resist, plus I
was so disappointed, "You watch the game this weekend?" His reply, "Hell
yea." "Then if we wipe out all the tubes, you could watch the next game on
a transistor?", as I walked away with my head hung.
Thank God I'm entering a profession were there is at least the concept of
stare decisis...all be it dogma at times. I guess this brings me to the
point at hand, which jc so cleverly alluded to, as well as points out.
That being:
I'm concerned that in the web, or discussion group, age, we are too quick
to just type a question in a forum such as this. We need an answer. Our
society demands that quick gratification......Give it to me! I deserve
it!! Fix it for me because I can't!!! Or haven't even bothered to try....
Face it, the US is "transitioning" from an industrial nation to a service
oriented nation.....we need it to survive,...to maintain our growth! Now,
go back and read that word in the quotes. Sound familiar?
More often than not, an answer comes forward. The requestor takes it to
heart and is happy. Mission accomplished. But, is he really happy? Has
the mission really been accomplished? Perhaps we even have the wrong
mission??
I say no. I feel that most currently lack the interpretive capability to
digest and comprehend the answers at the rate at which they come back or
worse yet phrase the question. I can give you thousands of examples. Go
look at www.audioasylum.com SET. "The hiraga crossover was built for the
onken originally." To paraphrase. When I posted about testing the Altec
Model 19, you're crazy. The model 19 is the best Altec I've ever
heard.....although the poster had never tried any of the things I
suggested. Do I care? No....but, think about the person that asked. It
even exists on this forum. People ask questions that are answered right
there in black and white in the pages of Sound Practices. Amazing. While
we may have the ability to comprehend the written word, and I doubt this
based on my pervious cites, I doubt we have the same ability with respect
to this forum. But, perhaps this proves too much and points out human
frality once again.
You've got to be careful about superimposing interpretations and/or beliefs
on others when they are taken out of context or are unapplicable. On the
other hand, when you're asking a question you've got to comprehend the
answer in its application and then perhaps infer to your situation or problem.
Too often this is compromised. Then we often have a pissing contest. Both
sides are whizzin' trying to put the flames out, yet they are pissing on
different fires....
Food for thought, thanks jc!
So, what about ny noise 2001????
See what happens when you emerge from the darkness.....
Now my coffee is cold,
L.D. Moore
=========================================================================
From: Dan Kerl <dlkerl@knology.net>
Subject: Re: [JN] 7868 replacement? and......
Date: Mon, 27 Nov 2000 10:50:58 -0600
Source: Sound Digest Archive v02.n746
> and thus us americaninos were
> forced to live with the beam power tetrode, because shit if we gonna pay
> them a dime.
This has Sarnoff written all over it.
Nobody can illuminate something like jc can illuminate it.
- --
Dan Kerl
dlkerl@knology.net
=========================================================================
From: Tim Reese <tgrmail@nmr.MGH.harvard.EDU>
Subject: Re: [JN] 7868 replacement? and......
Date: Tue, 28 Nov 2000 09:38:18 -0500 (EST)
Source: Sound Digest Archive v02.n747
>so the machinery down in darkest jersey cranked itself up into a fever
>pitch. "we got to get us an american vacuum tube that'll compete with those
>friggin snobs over in england, holland and (gasp!) germany", they said, and
>"whats more, if they (american consumer electronics manufacturers) don't
>buy em, we won't sell em anything else that they want, so there!"
Huh. I heard somewhere that 7591 was driven by the "low profile" craze of
the early 60s ... perfect for built-ins. Not true?
>i hope everyone had a happy turkey-day!
You too jc - and to all the Joes.
best regards tr
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] 7868 replacement? and......EL34, E34L, and 6CA7
Date: Mon, 27 Nov 2000 06:32:00 EST
Source: Sound Digest Archive v02.n746
- --part1_14.c1e678b.2753a030_boundary
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
In a message dated 11/26/00 11:22:07 PM US Mountain Standard Time,
jc@izone.com writes:
> doesn't fit under the cover of a fisher 400.
>
Greets!
Ah, another legit argument for open chassis Audio.
Thanks for a fine riff on the way it went down.
Nice to know it has always been so close to the edge :)
Happy Ears!
Al B^}
- --part1_14.c1e678b.2753a030_boundary
Content-Type: text/html; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
<HTML><BODY BGCOLOR="#ffffff"><FONT SIZE=2>In a message dated 11/26/00 11:22:07 PM US Mountain Stan
dard Time, <BR>jc@izone.com writes:
<BR>
<BR>
<BR><BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px
; PADDING-LEFT: 5px">doesn't fit under the cover of a fisher 400.
<BR></BLOCKQUOTE>
<BR>
<BR>Greets!
<BR>
<BR>Ah, another legit argument for open chassis Audio.
<BR>
<BR>Thanks for a fine riff on the way it went down.
<BR>
<BR>Nice to know it has always been so close to the edge :)
<BR>
<BR>Happy Ears!
<BR>Al B^}
<BR>
<BR></FONT></HTML>
- --part1_14.c1e678b.2753a030_boundary--
=========================================================================
From: "Ed Coleman" <ecoleman@whidbey.net>
Subject: [JN] Re: 7868 replacement? and......the saga continues ...
Date: Sun, 26 Nov 2000 16:54:35 -0800
Source: Sound Digest Archive v02.n746
Well joes I pulled one of these tubes out again , and on the side right
below "Toshiba Japan HIFi " is stamped "6L" so I think whoever said it
was a camoflaged 6L6 may be right . Well, I guess I'll send it to ebay ,
output tubes guarenteed dead ! remember, you heard it hear first ! thanks
for all the replies , Ed
- -----Original Message-----
From: Ed Coleman <ecoleman@whidbey.net>
To: David Dlugos <planet10@pinc.com>; joe list <sound@lists.io.com>
Date: Saturday, November 25, 2000 7:15 PM
Subject: 7868 replacement? and......
>HI Joes, is there such a thing as a drop in replacement for a 7868? I have
a
>TEAC integrated amp with these .I'd like to send it to the land of ebay in
>working order ,without investing $ any suggestions ? tia Ed
>
>PS , I have a (single) Warfedale W70d 4 way speaker/cabinet (read BIG and
>HEAVY) for cheap , anybody ? Ed
>
=========================================================================
From: StepHydro@aol.com
Subject: [JN] 7 copies so far of DIY OPT!!!
Date: Mon, 22 Mar 1999 19:06:22 EST
Source: Sound Digest Archive v02.n086
Is there any way to stop this madness?? <VBG>
Cheers/Carron
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 7 copies so far of DIY OPT!!!
Date: Tue, 23 Mar 1999 23:03:54 +0100
Source: Sound Digest Archive v02.n088
With 7 copies DIY OPT you have 3 and a half stereo amplifier
Keep it comming :-)
Guido
At 19:06 22-3-99 EST, StepHydro@aol.com wrote:
>Is there any way to stop this madness?? <VBG>
>
>Cheers/Carron
>
>
Tim Reese