Sound Practices Mailing List Files - Volume 1
=========================================================================
From: "P.A. & M. Almeflo" <sd@ljusdal.se>
Subject: 500 Hz from an 800 Hz JBL horn?
Date: Sun, 7 Jun 1998 13:52:35 +0200
Source: Sound Digest Archive v01.n304
Hello,
I was looking through an old JBL leaflet and was surprised by the info
about the JBL S7 studio monitor system. It had the LE15A woofer, the LE85
driver, the HL91 Horn and the LX5 crossover.
The horn was specified for 800 Hz cutoff and the crossing over was at 500
Hz.
This appears to be a strange way to use a compression driver.
Have any of you evaluated this system?
What are your comments?
Was this system marketed for an extended time?
Best regards,
Per Arne Almeflo
=========================================================================
From: Christian Rintelen <rintelen@datacomm.ch>
Subject: Re: 500 Hz from an 800 Hz JBL horn?
Date: Sun, 07 Jun 1998 15:00:06 +0200
Source: Sound Digest Archive v01.n304
P.A. & M. Almeflo wrote:
> The horn was specified for 800 Hz cutoff and the crossing over was at 500
> Hz.
>
> This appears to be a strange way to use a compression driver.
The 500 Hz is probably the - 3 dB point and the horn was flat from 800 Hz
upwards.
Christian
=========================================================================
From: "=?ISO-8859-1?Q?Torbj=F8rn_Lien?=" <mdrivekl@online.no>
Subject: Re: 500 Hz from an 800 Hz JBL horn?
Date: Sun, 7 Jun 1998 21:43:05 +0200
Source: Sound Digest Archive v01.n304
> P.A. & M. Almeflo wrote:
>
> > The horn was specified for 800 Hz cutoff and the crossing over was
at 500
> > Hz.
> >
> > This appears to be a strange way to use a compression driver.
>
>Christian Rintelen wrote:
>
> The 500 Hz is probably the - 3 dB point and the horn was flat from
800 Hz
> upwards.
>
Using a horn all the way down to cutoff is dubious practice
nonetheless, as all horns have a somewhat "lumpy" responce approaching
cutoff, caused by both the decrease of,- and "ripple" in loading. Iwata
(and Hiraga) recommend to cross over around 2,5 times the horn cutoff
frequency for the very best results....IMVHO, this is a bit excessive
but nonetheless...My experiences so far with the 1"Iwata (400Hz
hypex-like horn) shows that it could be used from around 700 Hz without
problems,-.
I guess that JBL got away with the 500 Hz crossover due to
the encreased output (directivity) of the LE15 in this region?
TL.
=========================================================================
From: RALPH POWER <POWER.RALPH@epamail.epa.gov>
Subject: Re: 500 Hz from an 800 Hz JBL horn? -Reply
Date: Mon, 08 Jun 1998 09:36:34 -0400
Source: Sound Digest Archive v01.n305
Hi P.A. & M. Almeflo,
Christian said :
> I guess that JBL got away with the 500 Hz crossover due to
>the encreased output (directivity) of the LE15 in this region?
I owned an older version of the JBL L200 Studiomasters that used an LE15 cloth
surround woofer that crossed over at 1200 hz to an LE85 compression driver.
In later versions, they changed the woofer to foam surround and moved the
crossover down to 800 hz....I think the LE15 could go kinda high if needed.
FWIW,
- Ralph
=========================================================================
From: alfia mak <alfiamak@hkstar.com>
Subject: RE: 500 Hz from an 800 Hz JBL horn? -Reply
Date: Tue, 9 Jun 1998 00:39:02 +0800
Source: Sound Digest Archive v01.n305
Hi Ralph,
I just purchased a pair JBL L300 which use the LE15A, LA85 and the 077, I wanted to modify the cross
over so that I can push it to 98+db if possible, can you or someone share their experience ? I order
ed a special pair of coil from SOLO and AlphaCORE. I also purchased a few of the Rel-cap(1uF, 0.47),
MIT RTX (.01) and Solen cap(4uF) to replace the existing one today. Should I use any paper in Oil c
opper foil cap ? DO they make any difference in crossover network ?
ALfia
- -----Original Message-----
From: RALPH POWER [SMTP:POWER.RALPH@epamail.epa.gov]
Sent: Monday, June 08, 1998 9:37 PM
To: rintelen@datacomm.ch; sound@deliverator.io.com
Cc: mdrivekl@online.no
Subject: Re: 500 Hz from an 800 Hz JBL horn? -Reply
Hi P.A. & M. Almeflo,
Christian said :
> I guess that JBL got away with the 500 Hz crossover due to
>the encreased output (directivity) of the LE15 in this region?
I owned an older version of the JBL L200 Studiomasters that used an LE15 cloth
surround woofer that crossed over at 1200 hz to an LE85 compression driver.
In later versions, they changed the woofer to foam surround and moved the
crossover down to 800 hz....I think the LE15 could go kinda high if needed.
FWIW,
- Ralph
=========================================================================
From: =?ISO-2022-JP?B?GyRCPGNOUyEhOV1GcxsoQg==?= <CXL01514@niftyserve.or.jp>
Subject: 50W-2 and AE-2
Date: Thu, 04 Sep 1997 02:44:00 +0900
Source: Sound Digest Archive v01.n010
Hi!
I am looking for MAC 50W-2 power amps --very old vintage and AE-2
preamp.
Send private e-mail to CXL01514@niftyserve.or.jp if you have for sale.
Best Regards Koji/EIFL
=========================================================================
From: "Mark Donen" <soledadd@worldnet.att.net>
Subject: 511B/806A FS in NYC
Date: Thu, 18 Jun 1998 13:43:39 -0400
Source: Sound Digest Archive v01.n314
This is a multi-part message in MIME format.
- ------=_NextPart_000_002D_01BD9ABF.199D1D40
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Selling my pair of :
511Bs w/ 806As=20
The drivers have brand new 8ohm diaphrams. Otherwise both are stock (bug =
screens not removed, webs not cut). However I have Dynamatted the =
outside lips and on the webs.=20
NYC pick up only.
Mark
- ------=_NextPart_000_002D_01BD9ABF.199D1D40
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 4.72.2106.6"' name=3DGENERATOR>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#000000 size=3D2>Selling my pair of :</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>511Bs w/ 806As </FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>The drivers have brand new 8ohm =
diaphrams.=20
Otherwise both are stock (bug screens not removed, webs not cut). =
However I=20
have Dynamatted the outside lips and on the webs. </FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>NYC pick up only.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Mark</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV></BODY></HTML>
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From: "Mark Donen" <soledadd@worldnet.att.net>
Subject: 511B/damping
Date: Thu, 16 Apr 1998 10:21:29 -0400
Source: Sound Digest Archive v01.n253
Hi all,
Well I damped the 511s last night with dynamat -- on the front inside
sufaces and the vertical sections, on one side as well as what was left of
the dynamat on the rear part of the horns. Well, what an incredible
improvement! Strings sound pretty decent.
However, the horns still ring when tapped although much less. I wonder what
they might sound like if all the resonances were eliminated -- wouldn't
that eliminate the advantage of wooden horns? Grego says he has made his
511s completely dead (also cut through the vertical sections).
Best,
Mark
=========================================================================
From: Ron Steinberg <ca789@freenet.toronto.on.ca>
Subject: Re: 511B/damping
Date: Thu, 16 Apr 1998 11:22:39 -0400 (EDT)
Source: Sound Digest Archive v01.n253
Mark, when I had a pair of 811 horns, I was able to get them almost
completely dead by using a thin 1/4" wide strip of constrained layer
dampening material from 3M. I placed the strip on the OUTSIDE of the
horn, along the front edge, top and bottom. I wouldn't put anything on
the inside of the horn, it should be as smooth as possible. Anyhow, this
stuff really worked, made it almost completely dead. If I had applied a
few more small strips, I'm sure it would have been totally dead. 3M told
me that you only need a small amount to stop the resonance, and to apply
it to edges, where most of the resonance will occure.
Ron
On Thu, 16 Apr 1998, Mark Donen wrote:
> Hi all,
>
> Well I damped the 511s last night with dynamat -- on the front inside
> sufaces and the vertical sections, on one side as well as what was left of
> the dynamat on the rear part of the horns. Well, what an incredible
> improvement! Strings sound pretty decent.
>
>
> However, the horns still ring when tapped although much less. I wonder what
> they might sound like if all the resonances were eliminated -- wouldn't
> that eliminate the advantage of wooden horns? Grego says he has made his
> 511s completely dead (also cut through the vertical sections).
>
> Best,
>
>
> Mark
>
======================================================================
Ron Steinberg Photographer <ca789@torfree.net>
Though self employed, my opinions do not reflect those of my employer.
======================================================================
=========================================================================
From: Dale.Simon@ps.net
Subject: Re: 511B/damping
Date: Thu, 16 Apr 1998 11:51:00 -0500
Source: Sound Digest Archive v01.n253
Mind if I jump in?
The main mechanical advantage of a horn is the way it couples
the diaphram to the _air_. The _air_ in the horn resonates.
Assuming you can never remove all the ringing from the horn
itself, there may be different signatures (distortions) with
different horn materials. Some materials may produce more
pleasant distortions than others; i.e. damped aluminum sounds
different than wood. Some of these may be pleasant sounding,
and others unpleasant. Damping may alter this characteristic
slightly, but most of its influence is to the decay. Even
highly damped aluminum will still sound different than highly
damped wood.
My 2pe',
Dale
Hi all,
Well I damped the 511s last night with dynamat -- on the front inside
sufaces and the vertical sections, on one side as well as what was left of
the dynamat on the rear part of the horns. Well, what an incredible
improvement! Strings sound pretty decent.
However, the horns still ring when tapped although much less. I wonder what
they might sound like if all the resonances were eliminated -- wouldn't
that eliminate the advantage of wooden horns? Grego says he has made his
511s completely dead (also cut through the vertical sections).
Best,
Mark
=========================================================================
From: "Mark Donen" <soledadd@worldnet.att.net>
Subject: Re: 511B/damping
Date: Thu, 16 Apr 1998 12:06:15 -0400
Source: Sound Digest Archive v01.n253
Thanks Ron,
>Ron wrote:
>
> I wouldn't put anything on
> the inside of the horn, it should be as smooth as possible.
>
I realize what I posted is a little unclear. I did not put any material on
the "inside" of the horn, just on the concave part outside (as you rightly
put it) part of the outer edges of the horn. Not dynamat is on the horn
acoustic surface itself.
I think I asked this before, what is the 3M material called and where is it
availible?
Best,
Mark
- ----------
> ======================================================================
> Ron Steinberg Photographer <ca789@torfree.net>
> Though self employed, my opinions do not reflect those of my employer.
> ======================================================================
=========================================================================
From: Ron Steinberg <ca789@freenet.toronto.on.ca>
Subject: Re: 511B/damping
Date: Thu, 16 Apr 1998 12:15:24 -0400 (EDT)
Source: Sound Digest Archive v01.n253
On Thu, 16 Apr 1998, Mark Donen wrote:
> I think I asked this before, what is the 3M material called and where is it
> availible?
Hi Mark, I got a sample from 3M directly. Can't remember the model #,
I'll have to look it up at home. Have no idea where you will find it.
I'll get back to you with the info.
Regards,
Ron
======================================================================
Ron Steinberg Photographer <ca789@torfree.net>
Though self employed, my opinions do not reflect those of my employer.
======================================================================
=========================================================================
From: Roscoe Primrose <roscoe@aiko.com>
Subject: Re: 511B/damping
Date: Thu, 16 Apr 1998 12:22:16 -0400
Source: Sound Digest Archive v01.n253
Ron Steinberg wrote:
> Mark, when I had a pair of 811 horns, I was able to get them almost
> completely dead by using a thin 1/4" wide strip of constrained layer
> dampening material from 3M. I placed the strip on the OUTSIDE of the
> horn, along the front edge, top and bottom. I wouldn't put anything on
> the inside of the horn, it should be as smooth as possible. Anyhow, this
> stuff really worked, made it almost completely dead. If I had applied a
> few more small strips, I'm sure it would have been totally dead. 3M told
> me that you only need a small amount to stop the resonance, and to apply
> it to edges, where most of the resonance will occure.
> Ron
>
>
Snip...
The 811 is an order of magnitude easier to dampen than the 511... I've had both,
and you're right, the 811 can be damped with a few square inches... The 511
still rings noticably when completely covered in DynaMat (but much much less than
undamped, undamped you can easily get a 5-7 sec ring from a 511 vs a <1 sec ring
from an 811). By far the most important part of the 511 is the outside of the
front of the bell (where it would hold water if you put it out in the rain...)
then the large flat surfaces behind the mounting flange..
Peace
- --
Roscoe Primrose -- mailto:roscoe@aiko.com -- http://www.aiko.com/roscoe
"Once in a while you get shown the light
In the strangest of places if you look at it right." Robert Hunter
"640K ought to be enough for anybody" , Bill Gates, 1981
=========================================================================
From: Plaato <Plaato@aol.com>
Subject: Re: Re: 511B/damping
Date: Thu, 16 Apr 1998 17:37:15 EDT
Source: Sound Digest Archive v01.n254
In a message dated 4/16/98 2:10:11 PM, roscoe@aiko.com wrote:
<< By far the most important part of the 511 is the outside of the
front of the bell (where it would hold water if you put it out in the rain...)
>>
Fill this part with sand. It almost completely deadens the horn.
That's all I did, and I'm very happy with the sound.
Henry
=========================================================================
From: Roscoe Primrose <roscoe@aiko.com>
Subject: Re: 511B/damping
Date: Thu, 16 Apr 1998 18:07:44 -0400
Source: Sound Digest Archive v01.n254
Dale.Simon@ps.net wrote:
> Mind if I jump in?
>
Of course not! heck, if we didn't want people jumping in, we'd have done this
somewhere else!
> The main mechanical advantage of a horn is the way it couples
> the diaphram to the _air_. The _air_ in the horn resonates.
I don't know if resonates is the proper term. The air moves in response to the
diaphragm, but things don't generally resonate over a 5 octave frequency
spread....
> Assuming you can never remove all the ringing from the horn
> itself, there may be different signatures (distortions) with
> different horn materials. Some materials may produce more
> pleasant distortions than others; i.e. damped aluminum sounds
> different than wood. Some of these may be pleasant sounding,
> and others unpleasant. Damping may alter this characteristic
> slightly, but most of its influence is to the decay. Even
> highly damped aluminum will still sound different than highly
> damped wood.
> My 2pe',
>
I agree, but the more effective your damping, the smaller the difference will
be... I think that with equally well damped horns, the difference in sound
between wood/metal/plastic can generally be attributed to the
hardness/reflectivity of the inner surface of the horn.
Peace
- --
Roscoe Primrose
- -- mailto:roscoe@aiko.com -- http://www.aiko.com/roscoe --
"Once in a while you get shown the light
In the strangest of places if you look at it right." Robert Hunter
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: 511B unexpected results
Date: Tue, 19 May 1998 22:10:53 -0500
Source: Sound Digest Archive v01.n285
Hi all
I had to measure a subwoofer I'm working on the other day and I figured
as long as I had the TDS system setup out side I would also measure the
511B horn.
I will post the plots somewhere and go into more detail but I can say
several things (all re 2 meters on axis).
The horn appears to provide an acoustic load from about 400 HZ up
however the mouth conditions effect the response up to about 2KHZ where
there is a dip (from 1Khz to 3 KHZ). The physical surroundings of the
mouth have a substancial effect on the response from 400 to 1 KHZ and I
will try to make more baffle board measurements soon.
From about 3 KHZ to 10 KHZ it is very good and flat. Above 10Khz is a
roll off and at 20 KHZ is a resonance (not likely audible).
The range from 400 to 1000HZ is also up about 4-5 dB from the above 3 K
region.
When driving the system thru a 16 ohm resistor, the mouth effects are
reduced some and the difference between the 400-1K and above 3KHZ is
reduced 2 to 3 DB, overall the response is a little flatter.
Placing a 1 mfd polyproplyene cap across the 16 ohm resistor brought up
the above 10K roll off to essentially flat to 20KHZ.
I also grabbed a JBL Le85t horn/lens set up and measured that,
interestingly the 511B was flatter on axis.
Does anyone have the schematic and values for typical crossovers
dedicated to the 511? I would like to model them and see how they
correspond to the 511's amplitude and phase response.
Best Regards,
Thomas Danley
ITC
=========================================================================
From: Joseph Lowe <jlowe@cdc.net>
Subject: Re: 511B unexpected results
Date: Wed, 20 May 1998 00:33:51 -0400 (EDT)
Source: Sound Digest Archive v01.n285
On Tue, 19 May 1998, Thomas Danley wrote:
> Placing a 1 mfd polyproplyene cap across the 16 ohm resistor brought up
> the above 10K roll off to essentially flat to 20KHZ.
This describes the crossover that I use with the addition of a series 30Uf
cap to rolloff LF. It took a lot of listening to arrive at the right
values with no test gear...
=========================================================================
From: "Daniel J. Marshall" <danmarshall@worldnet.att.net>
Subject: 515Bs
Date: Wed, 04 Feb 1998 15:38:39 -0800
Source: Sound Digest Archive v01.n182
Hi All,
Well, I just received the pair of 515Bs from the chap in Las Vegas, for
whom I posted the Altec Stuff a few days ago, Tony Marra. Boy are ever
nice, pristine would be the proper term, I believe, and packed extremely
well in Altec boxes strapped to 3/8 plywood packed in larger boxes with
peanuts on all sides. If you haven't bought any of his stuff and he
still has anything of interest, you ought to jump on it right away.
(No, I am not getting a commission).
I am very pleased with them and for $250/pair, what is to complain
about. I have seen them advertised for twice this amount. This was a
very refreshing experience in contrast to the previous 515B debacle.
(This chap still has not responded to my two emails). Tony said had
used the 416-8As in his system originally and later upgraded to the
515s, and he stated that they were substantial improvement over the
416s. I had originally inquired about the 416s and casually commented,
that, if I had my druthers, I'd druther have the 515s for more money.
And he agreed to break down the systems and sell the components
separately. What A guy. I so happ-ee.
I also got a pair of JBL 2405 slot super tweeters from him (104 W/m
sens). They go from 7 kHz on up to whatever and look like a good thing,
though I have not played with them yet. I had never used these before,
but they sounded like such a good thang I couldn't resist, especially
after taking a look at the JBL literature. Anyone used them?
Anyway, thought I would just put in another plug for Tony based on my
good experience in dealing with him.
My homebrew TS spreadsheet program keeps coming up with refrigerator
sized enclosures to get good low-bass response and even then requires
taking measures to increase the Qts. Maybe driving them with good UL PP
EL-34 or 6550 amps w/o feedback, or maybe with just enough feedback to
get the proper Zo to attain the desired Qts, hmmm. Sounds like a good
use for the humongous Allen amps.
Dan Marshall
=========================================================================
From: William Eckle <wmeckle@primenet.com>
Subject: Re: 515Bs
Date: Wed, 04 Feb 1998 17:13:52 -0700
Source: Sound Digest Archive v01.n182
At 03:38 PM 2/4/98 -0800, Daniel J. Marshall wrote:
>I also got a pair of JBL 2405 slot super tweeters from him (104 W/m
>sens). They go from 7 kHz on up to whatever and look like a good thing,
>though I have not played with them yet. I had never used these before,
>but they sounded like such a good thang I couldn't resist, especially
>after taking a look at the JBL literature. Anyone used them?
Hi Daniel:
I've used a pair to augment my A7s, fed by an active Xover at 8K Hz. One caution:
Don't test with test tones at high levels (especially square waves), or you'll have a bill
from the JBL repair dept. Other than that it'll depend on your HF hearing. Mine isn't
so great at 103 yrs. old <<g>.
<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: "Daniel J. Marshall" <danmarshall@worldnet.att.net>
Subject: 515Bs
Date: Wed, 13 May 1998 16:29:25 -0700
Source: Sound Digest Archive v01.n278
Hi All,
Say, there is a pair of 515Bs, described as 99 percent perfect, for sale
over on ebay. I am in no way related to, or acquainted with, the
seller, just thought someone on the list might be looking for a pair.
They just came up today and the bid is currently at $300. It is a three
day auction. If interested, you can view the listing at:
http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=13950822
Dan Marshall
=========================================================================
From: Roscoe Primrose <roscoe@aiko.com>
Subject: 5670/2C51...
Date: Tue, 20 Oct 1998 10:40:46 -0400
Source: Sound Digest Archive v01.n462
Picked up a bunch of these (about 35) as part of a larger lot at a
hamfest ($5 for the whole lot, anybody need a bunch of 5xxx "special
6AK5"s?). All but 5 tested good... Anyone used these? How do they
sound? They look like they might work well for a MM phono stage...
Peace
- --
Roscoe Primrose -- mailto:roscoe@aiko.com --
http://www.aiko.com/roscoe
"Once in a while you get shown the light
In the strangest of places if you look at it right." Robert Hunter
"640K ought to be enough for anybody" , Bill Gates, 1981
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: 5670/2C51...
Date: Tue, 20 Oct 1998 13:05:02 -0500
Source: Sound Digest Archive v01.n462
At 10:40 AM -0400 10/20/98, Roscoe Primrose wrote:
>Picked up a bunch of these (about 35) as part of a larger lot at a
>hamfest ($5 for the whole lot, anybody need a bunch of 5xxx "special
>6AK5"s?). All but 5 tested good... Anyone used these? How do they
>sound? They look like they might work well for a MM phono stage...
Very hot and punchy, not bad, didn't play around with them too much--my
four samples were monstrously microphonic...
Grover Gardner
groverg@postoffice.att.net
=========================================================================
From: tubesguy@mail.execpc.com (Patrick Currie)
Subject: Re: 5670/2C51...
Date: Tue, 20 Oct 1998 21:45:48 -0500
Source: Sound Digest Archive v01.n462
>Picked up a bunch of these (about 35) as part of a larger lot at a
>hamfest ($5 for the whole lot, anybody need a bunch of 5xxx "special
>6AK5"s?). All but 5 tested good... Anyone used these? How do they
>sound? They look like they might work well for a MM phono stage...
>
>Peace
>--
>Roscoe Primrose
Hey Roscoe -
Doc and the eXtreme boys are doing line stages with the 5670. Heard one at
VSAC, and it was eXtremely good. See the Soul Sister schematic in a recent
VALVE for one idea. - Pat
Pat Currie (tubesguy@execpc.com)
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: 5670 dual triode
Date: Fri, 28 Aug 1998 13:34:02 -0500
Source: Sound Digest Archive v01.n407
Hi all
Would any of you guys tried, or have curves for 5670, a small dual triode?
Tom Danley
=========================================================================
From: "Jeff Brouwer"<jeff_brouwer_at_crc-tmd@mail.crc.com>
Subject: Re: 5670 dual triode
Date: Fri, 28 Aug 98 17:34:18 -0500
Source: Sound Digest Archive v01.n407
Hey Tom,
I found the curves at:
http://www.duncanamps.simplenet.com/cgi-bin/miva?/tubedata/sheetshere.
mv
I built the VALVE "soul sister" preamp and tried out 5670's and
2C51's. Only have had one night to listen so far, but the 2C51's
sounded nicer to both me and and a friend. (The 2C51 is supposed to
be an equivalent.) We both noticed a striking difference between two
NOS 5670's, one sounded good, one sounded very bad. The nice sounding
tube was a GE "5 Star", the bad a JAN GE. Neither of us had ever
heard such a wide variation between two supposedly identical tubes
before. The two samples of 2C51's sounded similar to the good 5670,
but a little clearer and with more, better defined bass. (BTW, the
"soul sister" is a para-feed single stage preamp with a
dual-transistor current-source plate load. I used the Freed 15k:500
trannys Joe mentioned a couple weeks back.)
-jeff
______________________________ Reply Separator _________________________________
Subject: 5670 dual triode
Author: <Tom@ppci.com> at Internet
Date: 8/28/98 1:34 PM
Hi all
Would any of you guys tried, or have curves for 5670, a small dual triode?
Tom Danley
=========================================================================
From: Paul Joppa <pdj@ISDNseattle.net>
Subject: Re: 5670 dual triode
Date: Sat, 29 Aug 1998 00:02:02 -0700
Source: Sound Digest Archive v01.n408
I got the following list from Tim Lollar (who put on the preamp tube
tasting at VSAC 98):
a 396A is a WE 2C51 just another variant.
this cool pamphlet lists the following:
2C51
6CC42
396A
1219
6185
5670
6386
CV2831
CV2866
CV5894
CV8247
tim
Somebody recently posted some curves ...<looking around>... Ah! Here
it is, http://machmat.student.utwente.nl/sheet/2c51.gif from the
www.avvt.com pages (Mattijs de Vries).
- -Paul Joppa
Thomas Danley wrote:
>
> Hi all
> Would any of you guys tried, or have curves for 5670, a small dual triode?
>
> Tom Danley
=========================================================================
From: Joseph Lowe <jlowe@cdc.net>
Subject: Re: 5670 dual triode
Date: Sat, 29 Aug 1998 08:27:14 -0400 (EDT)
Source: Sound Digest Archive v01.n408
On Sat, 29 Aug 1998, Paul Joppa wrote:
> I got the following list from Tim Lollar (who put on the preamp tube
> tasting at VSAC 98):
>
> a 396A is a WE 2C51 just another variant.
> this cool pamphlet lists the following:
> 6386
This one is variable Mu. It is the tube used in the famous Fairchild
670 limiter.
=========================================================================
From: tubesguy@execpc.com (Patrick Currie)
Subject: 56, 76, etc?
Date: Sun, 24 Aug 1997 12:05:16 -0500
Source: Sound Digest Archive v01.n001
Hi all -
I'll try again with a question that I asked last week. Anyone have
experience comparing the 56 with the 76? I understand that they're
"identical" except for the filaments, but any suggestions or preferences?
This tube, choke loaded, will drive a 71A. I am planning on using AC on
the heater of the driver, whichever I end up using.
I also have available the "legendary" Tungsol VT-231 version of the 6SN7.
Thoughts on sharing both channels in one tube envelope? TIA - Pat
Pat Currie, Lowther Club of America Upper Midwest Representative
(608)233-8956, 266-9290 (Madison, WI)
=========================================================================
From: Steve Van Osdell <svanos@toast.net>
Subject: 5687 and 5781 tubes
Date: Sat, 03 Jan 1998 22:57:46 -0600
Source: Sound Digest Archive v01.n149
I've been hearing that these tubes (especially in black plate versions) are
far far superior to 6SN7's for driver tubes. Any thoughts anyone? And
where can I find some? And Joe, that was 5687 not 5686 - not sure if that
was a typo, or if you were looking in your book for 5686.
Thanks, Steve
=========================================================================
From: "Hugh R. Dean" <aspen@alphalink.com.au>
Subject: Re: 5687 and 5781 tubes
Date: Sun, 04 Jan 1998 20:25:02 +1100
Source: Sound Digest Archive v01.n149
Hi Steve, you wrote:
>I've been hearing that these tubes (especially in black plate versions) are
>far far superior to 6SN7's for driver tubes. Any thoughts anyone?
Yes, I'd have to agree. But, they are not really the same; while their mu
is similar the Rp is 5K for 6SN7s and 2K for 5687s. Furthermore, the 5687
will pass 18mA without sweating per section while the 6SN7 is balls to the
wall at about 12mA.
One caution, however. The 5687 does not like cathode/heater voltages over
100V while the 6SN7 seems indestructible in this area. And the 5687 is
thermally very stressed, with a much more powerful filament and plate
dissipation, and gets very hot. Consequently its life is far shorter than
a 6SN7. And it's not the neutral sounding tube the 6SN7 is, either.
Cheers,
Hugh R. Dean
Melbourne, Australia
=========================================================================
From: Ron Bales <rbales@gte.net>
Subject: Re: 5687 and 5781 tubes
Date: Sun, 04 Jan 1998 09:54:13 -0500
Source: Sound Digest Archive v01.n150
Hi Steve, In this triodialist's opinion, it is really tough to beat the
SN7. It distorts less than any other amplification device invented by
man (okay, the 26 may have a claim, but brings its own problems. It is
reliable enough for spaceflight, available at low cost and high quality
anywhere tubes are sold and is capable of delivering good drive to
difficult loads with a 50+ year history of sounding good in use.
The 5687, is a lovely little flame thrower. When I first got some, the
first thing I did was burn my fingers pulling one out of the tube
tester! It can deliver much more current than the SN7, like twice, if
you plan on driving anything nasty (like headphones or flirting with A2)
it is a great pick. I'd think that unless you had a job that required
the extra grunt, I'd stick with the SN7.
Don't know what a 5781 is. Earlier you asked about the 5751, I can
comment on that. It is more in the high mu 12AX7 family than any thing
else. Bit less mu than an AX7, but a bit more grunt, though not quite as
much as a 12AT7. I very highly recommend it as a plug-in replacement
for the AX7 in cases where that tube is being asked to actually drive
something. The 12AX7, is a very linear device when operated as it
likes, but that doesn't leave it with much ability to drive loads. 5751
is much better, and as a driver the AT7 is about as good as it gets in a
high mu tube.
So what do you need to amplify?
ROn
Steve Van Osdell wrote:
>
> I've been hearing that these tubes (especially in black plate versions) are
> far far superior to 6SN7's for driver tubes. Any thoughts anyone? And
> where can I find some? And Joe, that was 5687 not 5686 - not sure if that
> was a typo, or if you were looking in your book for 5686.
>
> Thanks, Steve
=========================================================================
From: Grover Gardner <groverg@bellatlantic.net>
Subject: Re: 5687 and 5781 tubes
Date: Sun, 4 Jan 1998 22:16:36 -0600
Source: Sound Digest Archive v01.n150
At 10:57 PM -0600 1/3/98, Steve Van Osdell wrote:
>I've been hearing that these tubes (especially in black plate versions) are
>far far superior to 6SN7's for driver tubes. Any thoughts anyone? And
>where can I find some? And Joe, that was 5687 not 5686 - not sure if that
>was a typo, or if you were looking in your book for 5686.
>
>Thanks, Steve
Er, not sure if the numbers are right...5687 is used by a lot of people,
but not everyone would say it was superior to the 6SN7... 5871 is a special
6V6, but I don't find any 578...1
Grover Gardner
groverg@bellatlantic.net
=========================================================================
From: "Johari Yip" <hfyip@pacific.net.sg>
Subject: 5687 line stage
Date: Sat, 11 Apr 1998 09:18:33 +0800
Source: Sound Digest Archive v01.n249
Hi everyone,
As Easter weekend is here already, I've sometime in my hand and is about to
try out John Leaurealt's 5687 linestage as appeared in VALVE. Instead of
just building it "as of", I'd be making a few "modification" to the
schematic so to speak.
Firstly, I would like to regulate the HT with MJE 13007 and LT 1085 CT from
a tube rectified (5852) pi filter of 390uF 450V/30H 40mA/390uF 450V.
I would run a +6.3V/-6.3V to the heater filament to contro; the
heater/cathode leakage problem.
As it is a known fact that 5687 tends to draw grid current, how do I
control this area of the problem?
Any comments on the above undertakings are most appreciated.
Thanks in advance.
Johari Yip.
=========================================================================
From: David Home <tubehead@vcn.bc.ca>
Subject: Re: 5687 line stage
Date: Sun, 12 Apr 1998 21:18:26 -0700 (PDT)
Source: Sound Digest Archive v01.n250
> As it is a known fact that 5687 tends to draw grid current, how do I
> control this area of the problem?
What is your source for this 'fact'? Under what conditions please?
Regards, David
=========================================================================
From: "Johari Yip" <hfyip@pacific.net.sg>
Subject: Re: 5687 line stage
Date: Mon, 13 Apr 1998 15:26:49 +0800
Source: Sound Digest Archive v01.n250
I don't know whether the grid current is linked to this problem but it's
quite prominent when you turn the volume control (the volume pot is fine).
There'll be a sizzling sound coming out of your speakers. This problem was
also brought up in the SP article "WOT".
What's your thought, David?
Johari Yip.
- ----------
> From: David Home <tubehead@vcn.bc.ca>
> To: Johari Yip <hfyip@pacific.net.sg>
> Cc: sound@deliverator.io.com
> Subject: Re: 5687 line stage
> Date: Monday, April 13, 1998 12:18 PM
>
> > As it is a known fact that 5687 tends to draw grid current, how do I
> > control this area of the problem?
>
> What is your source for this 'fact'? Under what conditions please?
>
> Regards, David
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: 5687 line stage
Date: Mon, 13 Apr 1998 22:40:10 +0200
Source: Sound Digest Archive v01.n251
At 15:26 13-4-98 +0800, Johari Yip wrote:
>I don't know whether the grid current is linked to this problem but it's
>quite prominent when you turn the volume control (the volume pot is fine).
>There'll be a sizzling sound coming out of your speakers. This problem was
>also brought up in the SP article "WOT".
>What's your thought, David?
Give more headroom e.g. choose an operating oint such that you have more
grid to cathode voltage
Guido
>Johari Yip.
>----------
>> From: David Home <tubehead@vcn.bc.ca>
>> To: Johari Yip <hfyip@pacific.net.sg>
>> Cc: sound@deliverator.io.com
>> Subject: Re: 5687 line stage
>> Date: Monday, April 13, 1998 12:18 PM
>>
>> > As it is a known fact that 5687 tends to draw grid current, how do I
>> > control this area of the problem?
>>
>> What is your source for this 'fact'? Under what conditions please?
>>
>> Regards, David
>
>
=========================================================================
From: Simon Busbridge <S.C.Busbridge@bton.ac.uk>
Subject: Re: 5687 line stage
Date: Tue, 14 Apr 1998 08:14:46 +0100 (BST)
Source: Sound Digest Archive v01.n252
>As it is a known fact that 5687 tends to draw grid current, how do I
>control this area of the problem?
Any valve will draw grid current if the grid goes positive wrt the
cathode. What bias conditions are you operating under?
Regards
Simon
Dr Simon Busbridge
Department of Mechanical and Manufacturing Engineering
University of Brighton
Lewes Road
Moulsecoomb
Brighton BN2 4GJ
UNITED KINGDOM
Tel: 0044 (0)1273 642542
Fax: 0044 (0)1273 642327
e-mail: s.c.busbridge@bton.ac.uk
"..biology is what you do when you don't have the maths for real
science.." (sliders)
=========================================================================
From: Yip Hin Fai Johari <hfyip@pacific.net.sg>
Subject: Re: 5687 line stage
Date: Wed, 15 Apr 1998 07:10:07 +0800
Source: Sound Digest Archive v01.n252
At 08:14 AM 4/14/98 +0100, Simon Busbridge wrote:
>>As it is a known fact that 5687 tends to draw grid current, how do I
>>control this area of the problem?
>
>Any valve will draw grid current if the grid goes positive wrt the
>cathode. What bias conditions are you operating under?
>
>Regards
>
>Simon
Hi Simon,
The 5687 is operating at a plate voltage of 150V running at 15mA thru a
470R cathode resistor.
Regards,
Johari
=========================================================================
From: David Home <tubehead@vcn.bc.ca>
Subject: Re: 5687 line stage
Date: Thu, 16 Apr 1998 13:18:05 -0700 (PDT)
Source: Sound Digest Archive v01.n254
I have recently been listening to every tube I can get my hands on to
try in my breadboard line-stage. I tried the 5687 with two NiCds(-2.6V)
on the cathode, a 100K volume pot, a 12 K ohm WW on the plate and a
0.47 oiler out. PS supply was 290V, putting 100V on the plate.
Firstly, I did not get any grid current with these conditions using two
different tubes.
Secondly, I did not try the tube at any other operating conditions
because I did not likre the sound of the tube. My reference is a boring
old 6SN7GTB Sylvania in the above circuit which sounded clearer, more
open and dynamic. The difference was not suttle, so I gave up on the
tube.
I originally wanted a lower gain, so I though a driver tube would be
the ticket. Low Rp, high current, just the thing right? Not to my ears.
All the driver tubes I have tried as a pre-amp tube have been
dissipointing. The hands down worst was the 12B4. Keep this tube for
driving your 211 grids.
Best sound so far? ECC33, the rarest of the rare. I don't even own it,
just a loaner from a collector. I'm thinking it has got to be the round
plate that makes
it sound so good. It just shimmers with sutle detail and the treble is
SMOOTH. I am going to try some other round plate medium gain tubes
next. Any suggestions from other sceptics? I have tried the #37 but the
high plate resistance was an issue.
Regards, David
On Mon, 13 Apr 1998, Johari Yip wrote:
> I don't know whether the grid current is linked to this problem but it's
> quite prominent when you turn the volume control (the volume pot is fine).
> There'll be a sizzling sound coming out of your speakers. This problem was
> also brought up in the SP article "WOT".
> What's your thought, David?
>
> Johari Yip.
> ----------
> > From: David Home <tubehead@vcn.bc.ca>
> > To: Johari Yip <hfyip@pacific.net.sg>
> > Cc: sound@deliverator.io.com
> > Subject: Re: 5687 line stage
> > Date: Monday, April 13, 1998 12:18 PM
> >
> > > As it is a known fact that 5687 tends to draw grid current, how do I
> > > control this area of the problem?
> >
> > What is your source for this 'fact'? Under what conditions please?
> >
> > Regards, David
>
=========================================================================
From: Yip Hin Fai Johari <hfyip@pacific.net.sg>
Subject: Re: 5687 line stage
Date: Fri, 17 Apr 1998 07:33:05 +0800
Source: Sound Digest Archive v01.n254
At 01:18 PM 4/16/98 -0700, David Home wrote:
>I have recently been listening to every tube I can get my hands on to
>try in my breadboard line-stage. I tried the 5687 with two NiCds(-2.6V)
>on the cathode, a 100K volume pot, a 12 K ohm WW on the plate and a
>0.47 oiler out. PS supply was 290V, putting 100V on the plate.
>
>Firstly, I did not get any grid current with these conditions using two
>different tubes.
What's the plate current you're working the tubes.
>Secondly, I did not try the tube at any other operating conditions
>because I did not likre the sound of the tube. My reference is a boring
>old 6SN7GTB Sylvania in the above circuit which sounded clearer, more
>open and dynamic. The difference was not suttle, so I gave up on the
>tube.
I have very good results with the 5692s in my previous preamp and I
think it's a level of sound that's hard to surpass. Anyway, I like to
venture forth
and try my hand on different tubes at different operating points.
>I originally wanted a lower gain, so I though a driver tube would be
>the ticket. Low Rp, high current, just the thing right? Not to my ears.
>All the driver tubes I have tried as a pre-amp tube have been
>dissipointing. The hands down worst was the 12B4. Keep this tube for
>driving your 211 grids.
>
>Best sound so far? ECC33, the rarest of the rare. I don't even own it,
>just a loaner from a collector. I'm thinking it has got to be the round
>plate that makes
>it sound so good. It just shimmers with sutle detail and the treble is
>SMOOTH. I am going to try some other round plate medium gain tubes
>next. Any suggestions from other sceptics? I have tried the #37 but the
>high plate resistance was an issue.
Yeah, but then the thing is they are very expensive tube to own.
A preamp that sounded good because it uses a exotic tube is expected.
I prefer to work on tubes that's relatively easy to find, don't cost a bomb
and
still able to squeeze a respectable amount of performances from it.
>
>Regards, David
>
>On Mon, 13 Apr 1998, Johari Yip wrote:
>
>> I don't know whether the grid current is linked to this problem but it's
>> quite prominent when you turn the volume control (the volume pot is fine).
>> There'll be a sizzling sound coming out of your speakers. This problem was
>> also brought up in the SP article "WOT".
>> What's your thought, David?
Anyway, it's a mistake on my part. The sizzling sound is caused by wrong
plate voltages and operating point.
Apologies?
Regards,
Johari Yip.
=========================================================================
From: davidbarnett@aristotle.net (David Barnett)
Subject: Re: 5687 line stage
Date: Fri, 17 Apr 1998 22:04:01 GMT
Source: Sound Digest Archive v01.n256
On Thu, 16 Apr 1998 13:18:05 -0700 (PDT), David Home
<tubehead@vcn.bc.ca> wrote:
>Best sound so far? ECC33, the rarest of the rare.
SSssshhhhh! That tube's supposed to be my little secret. Looks
pretty useless on paper (medium mu, medium rp...), works well in
practice. I've only got three of 'em, though, Mullards with
pinch-bases, in blue boxes.
Do yours have pinch bases or button bases?
I'm curious to try the whole ECC31-32-33-34 series, has anyone messed
with these in lieu of the usual 6SN7/6SL7 types? I can't remember
which is which, but one of these is a replacement for the SN, one is
close to the SL (I think mu=65 instead of 70), and one is kinda
similar to a 6BL7 and might be very useful for a driver with some
current guts.
- --dnb
=========================================================================
From: "Jim Dudley" <jimd@polaris.net>
Subject: 5687 linestage
Date: Tue, 05 May 98 15:08:03
Source: Sound Digest Archive v01.n269
Hi all,
Looking for experiences with John Levreault's 5687 parallel anode follower line stage or similar.
Pardon me if this is old news.
Regards,
Jim Dudley
=========================================================================
From: Yip Hin Fai Johari <hfyip@pacific.net.sg>
Subject: Re: 5687 linestage
Date: Wed, 06 May 1998 07:23:05 +0800
Source: Sound Digest Archive v01.n270
At 03:08 PM 5/5/98 +0000, Jim Dudley wrote:
>Hi all,
>
>Looking for experiences with John Levreault's 5687 parallel anode follower
line stage or similar. Pardon me if this is old news.
>
>Regards,
>Jim Dudley
Jim
Just finished it with some advice from John himself. Believe me, every
thing that John said in the VALVE is truth.
This simple, straight forward but very transparent design just don't get in
the way of your system.
Did a bit of changes to the original design by implementing a SS HT
regulated PS and this really improved the airiness,
space rendition and control of the preamp.
What can I say, got to try it to experience it.
Johari
=========================================================================
From: peterca@ento.csiro.au
Subject: Re: 5687 linestage
Date: Wed, 6 May 1998 13:07:57 +1000 (EST)
Source: Sound Digest Archive v01.n270
>Hi all,
>
>Looking for experiences with John Levreault's 5687 parallel anode follower
>line stage or similar. Pardon me if this is old news.
>
>Regards,
>Jim Dudley
I have just finish an amp in which one half of a 5687 is used RC coupled to
a VV32B single-ended output stage. I'm very pleased. I use the half 5687
at ~15mA, ~8V bias (cathode resistor with 1000uF Oscon electrolytic bypass)
resulting in about 180V plate voltage. The supply is 420V and the load
resistor is ~14K. The following grid resistor is 100K and the coupling cap
is a 0.22uF MIT film and foil type. ±6V peak input gives about ±90V peak
out which is sufficient to drive the VV32B for full power. In these
conditions the load line looks pretty good for linearity but could be even
better with a higher load impedance.
I think the tube should be an excellent preamp valve. Its 2Kohm output
impedance means it should have no trouble with the capacitance of cables.
Completely over the top would be to use it in an SRPP type of stage with a
some fet constant current sources instead of an upper cathode resistor. I
havn't tried that, only with a 12AU7 and a single fet which I think it
works very well. Perhaps a choke wound with enough very fine wire to get
the required resistance for bias and very high inductance?
Dr. Peter Campbell (peterca@ento.csiro.au)
Div. Entomology, C.S.I.R.O. Ph.61-2-62464053 or -62464158 (w)
Box 1700 Canberra A.C.T. 2601 61-2-62516213 (h)
Australia 61-2-62464173 (fax)
=========================================================================
From: RALPH POWER <POWER.RALPH@epamail.epa.gov>
Subject: 5687 linestage hacking
Date: Tue, 24 Nov 1998 11:33:21 -0500
Source: Sound Digest Archive v01.n502
Hi ,
More changes last weekend on the 5687 linestage....
I tried putting the 6BQ5 PP line trannies on the outputs, the sound quality was
VERY good, but I just could not get the hum out. So I converted back to cap
output and the hum is gone. Must have had something to do with the output
trannies. I will contact Jack and order me a real pair of custom 5687 SE line
output trannies and try again as it is definitely a place where I want to go.
When I went back to cap coupling, I used the 1 uf Angela paper in oil caps for
outputs. Compared to the Hovland 1.5ufs, the sound is less etched and more
musical, but the SS rectification probably plays a part here. If I were going to stay
with cap coupling, I would use the Angela copper foil in oil caps with their new low
prices or even the new Procap silver foil in oil caps as a most musical bet here.
I installed the new 150V PS trannie and changed the plate resistor to 10K to
compensate and the sound is at least as good, maybe even better in the bass.
Still keeping to that low 85v @ 8ma point preferred by Randy. Looking at the
operating points on the tube data sheet for the 5687, the transconductance should
be higher and the plate resistance lower at this low operating point.
BTW, I'm running with the SS rectified power supply (!) from the original Welborne
linestage as I don't have room for a tube rectifier in the linestage cabinet.
Getting great sound from it. I'll report on any more changes later.
- Ralph
=========================================================================
From: "Chris Beck" <cbeck@brewercompany.com>
Subject: Re: 5687 linestage hacking
Date: Tue, 24 Nov 1998 12:11:52 -0600
Source: Sound Digest Archive v01.n502
Amen to that. I can pick up a Weller soldering gun 15 feet away if it's
pointed the right way. I can have the preamp quite close to the power amps
without hum induction, but the power supply for the preamp, with it's soon
to be discarded Utah power tranny (VERY old) puts out quite the magnetic
field. Any closer than 2 feet I start getting hum.
Solution: Put everything in steel cans. I am having Jack wind me a power
tranny for the preamp right now, and soon I will have him supply me with
cans to put everything in so I can get the whole preamp on one chassis. He
has his setup that way and the hum level is extremely low, even with 100dB
efficient horns. He's also fooling around with mu-metal and other types of
shielding.
Chris Beck
See my web page at: http://www.execpc.com/~n9zes/index.htm
- ----------
> From: Simon Busbridge <S.C.Busbridge@bton.ac.uk>
> To: RALPH POWER <POWER.RALPH@epamail.epa.gov>
> Cc: sound@deliverator.io.com
> Subject: Re: 5687 linestage hacking
> Date: Tuesday, November 24, 1998 11:02 AM
>
> Ralph,
>
> Direct magnetic pick-up by line-stage transformers is a real problem,
> particularly if you have sensitive power amps.
>
> Simon
>
> Dr Simon Busbridge
> School of Engineering
> University of Brighton
> Lewes Road
> Moulsecoomb
> Brighton BN2 4GJ
> UNITED KINGDOM
>
> Tel: 0044 (0)1273 642542
> Fax: 0044 (0)1273 642327/642301
> e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com
>
>
>
>
=========================================================================
From: Simon Busbridge <S.C.Busbridge@bton.ac.uk>
Subject: Re: 5687 linestage hacking
Date: Tue, 24 Nov 1998 17:02:10 +0000 (GMT)
Source: Sound Digest Archive v01.n502
Ralph,
Direct magnetic pick-up by line-stage transformers is a real problem,
particularly if you have sensitive power amps.
Simon
Dr Simon Busbridge
School of Engineering
University of Brighton
Lewes Road
Moulsecoomb
Brighton BN2 4GJ
UNITED KINGDOM
Tel: 0044 (0)1273 642542
Fax: 0044 (0)1273 642327/642301
e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: 5687 linestage hacking
Date: Sun, 29 Nov 1998 12:39:33 +0100
Source: Sound Digest Archive v01.n508
At 11:33 24-11-98 -0500, RALPH POWER wrote:
>
>Hi ,
>
>More changes last weekend on the 5687 linestage....
>
>I tried putting the 6BQ5 PP line trannies on the outputs, the sound
quality was
>VERY good, but I just could not get the hum out. So I converted back to cap
>output and the hum is gone.
Sound like induced hum by magnetical coupling. Try orientation !
Guido
Must have had something to do with the output
>trannies. I will contact Jack and order me a real pair of custom 5687 SE
line
>output trannies and try again as it is definitely a place where I want to go.
>
>When I went back to cap coupling, I used the 1 uf Angela paper in oil caps
for
>outputs. Compared to the Hovland 1.5ufs, the sound is less etched and more
>musical, but the SS rectification probably plays a part here. If I were
going to stay
>with cap coupling, I would use the Angela copper foil in oil caps with
their new low
>prices or even the new Procap silver foil in oil caps as a most musical
bet here.
>
>I installed the new 150V PS trannie and changed the plate resistor to 10K to
>compensate and the sound is at least as good, maybe even better in the
bass.
>Still keeping to that low 85v @ 8ma point preferred by Randy. Looking at the
>operating points on the tube data sheet for the 5687, the transconductance
should
>be higher and the plate resistance lower at this low operating point.
>BTW, I'm running with the SS rectified power supply (!) from the original
Welborne
>linestage as I don't have room for a tube rectifier in the linestage cabinet.
>
>Getting great sound from it. I'll report on any more changes later.
>
> - Ralph
>
>
>
>
>
>
>
=========================================================================
From: RALPH POWER <POWER.RALPH@epamail.epa.gov>
Subject: 5687 linestage - now WOT
Date: Thu, 17 Dec 1998 11:09:23 -0500
Source: Sound Digest Archive v01.n542
Hi All,
I'm reporting back now after converting and tweaking my 5687 linestage to
the new Electraprint 3500 line output transformers. Much thanks goes
to Achnan Arduman and his "Fluence" preamp for ideas and inspiration here.
I basically did a rebuild of my cap coupled 5687 linestage to convert it to an
outboard 5Y3 power supply in order to minimize hum pickup by the OTs.
I used a 5" x 5" x 3" (?) Radio Shack project box ($6.99) for the outboard PS
and had to mount the 5Y3 in a horizontal position to get it all in the box. I
recommend using a bigger box if I had to do it over again.
It has an LCLC B+ supply and a CLC filament supply, similar to the Ultrastage
preamp.
After converting to the tube power supply I noticed a definite "relaxing" in the sound
of the linestage with some increase in sound stage. Initially I only had an LC power
supply because I ran out of room in the PS box and as a result, had some ~120hz
hum problems. But after I took Chris's suggestion of adding and additional LC
stage in the linestage box, it eliminated all the hum. Now it's as quite as a church
mouse.
The sound is simply stunning with more detail than I have ever had before, but
integrated in a most natural way, without hype or unnatural balance. In hindsight,
I would say that output cap coupling seems to have "holes or gaps" in frequency
response versus the response of the line output transformers. This is probably
not verifiable on a scope, but that is the way it sounds to my ears. There is a
"wholeness" to the sound now that is just not there with the caps.
Well recorded music is mind boggling in it's reproduction of space and air,
while multi track stuff comes across as much less real sounding. But
everything is totally revealed in either case. Another level of sound
reproduction in my experience. It will force you to confront the "music"
and not the "sound" coming from your speakers.
With a pair of good caps costing $40 and more, these output transformers at
$150 per pair are definitely worth the difference for the difference in sound
quality I say.
In addition, the Electraprint OTs I received had a 30 ohm tap for driving
headphones which I installed and tried. Wow, a great headphone amp
to boot ! Now I just have to get some good headphones to mate with
my preamp. Maybe some cheaper Grados .....
I have made up a schematic of this linestage and offer it freely by email to
anyone upon request.
- - Ralph
=========================================================================
From: Adnan Arduman <adnana@turk.net>
Subject: Re: 5687 linestage - now WOT
Date: Fri, 18 Dec 1998 17:58:13 +0200
Source: Sound Digest Archive v01.n543
Hi Ralph,
I'm very glad to hear that my FLUENCE project gave you a positive
inspiration. Many thanks for reporting it.
I'd be interested to receive your schematic.
Sincerely,
Adnan
>Hi All,
>
>I'm reporting back now after converting and tweaking my 5687 linestage to
>the new Electraprint 3500 line output transformers. Much thanks goes
>to Achnan Arduman and his "Fluence" preamp for ideas and inspiration here.
Please visit my personal "NUANCE & FLUENCE" web site:
http://www.arduman.com/aa
tel: +90-216-310 44 70 (w)
fax: +90-216-343 42 01
e-mail: adnana@turk.net
=========================================================================
From: "Johari Yip" <hfyip@pacific.net.sg>
Subject: Re: 5687 linestage - now WOT
Date: Sat, 19 Dec 1998 10:47:09 +0800
Source: Sound Digest Archive v01.n544
Hi guys,
Now, I know a lot of talk has been said about coupling the linestage with a
OPTX but what other benefit do we get other than better "drive". Don't get
me wrong here, I'm all for sonic bliss but don't you think we are adding
"flavors" to the sound. There's also the added complication of
shielding/directional orientation of the OPTX to content with. Correct me
here if I'm wrong but isn't the job of a pre-amp be just matching the
impedance of the source to the power amps and, at the same time provides a
slight gain to that signal. I would prefer to use an IT in the power amps
for additional drive to the output tubes.
I apologize if this has been brought up before.
Regards,
Johari
- ----------
> From: Adnan Arduman <adnana@turk.net>
> To: RALPH POWER <POWER.RALPH@epamail.epa.gov>
> Cc: sound@deliverator.io.com
> Subject: Re: 5687 linestage - now WOT
> Date: Friday, December 18, 1998 11:58 PM
>
>
> Hi Ralph,
>
> I'm very glad to hear that my FLUENCE project gave you a positive
> inspiration. Many thanks for reporting it.
> I'd be interested to receive your schematic.
>
> Sincerely,
>
> Adnan
>
>
>
> >Hi All,
> >
> >I'm reporting back now after converting and tweaking my 5687 linestage
to
> >the new Electraprint 3500 line output transformers. Much thanks goes
> >to Achnan Arduman and his "Fluence" preamp for ideas and inspiration
here.
>
>
>
> Please visit my personal "NUANCE & FLUENCE" web site:
> http://www.arduman.com/aa
>
> tel: +90-216-310 44 70 (w)
> fax: +90-216-343 42 01
> e-mail: adnana@turk.net
=========================================================================
From: Adnan Arduman <adnana@turk.net>
Subject: Re: 5687 linestage - now WOT
Date: Sun, 20 Dec 1998 19:28:23 +0300
Source: Sound Digest Archive v01.n546
Hi Johari,
>Correct me
>here if I'm wrong but isn't the job of a pre-amp be just matching the
>impedance of the source to the power amps and, at the same time provides a
>slight gain to that signal.
The OPT is exactly doing that: matching the impedence of the preamp to the
power amp and helping to drive the next stage and an interconnect cable. If
you don't like this solution you would have to put a cathode follower tube
and a capacitor. It's either the transformer or other components which in
their case add their own flavour. At this point it becomes a personal
choice. I can sincerely tell you that I'm happy with mine.
I hope this helps.
Sincerely,
Adnan
Visit my "NUANCE & FLUENCE" web site:
http://www.arduman.com/aa
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: 5687 linestage - now WOT
Date: Sat, 02 Jan 1999 23:15:24 +0100
Source: Sound Digest Archive v01.n555
Joes,
Since I heard my first IT coupled amp I never want R-C coupling anymore:
The technical reasons and advantages of iron
1-no series coupling cap
2-no secondary load of the IT necessary so:
3-no current through the driving tube
4-no current through the supply (except dc)
5-no waste of audio energy since transformers do not absorb
6-ease of fixed biasing to next stage, eliminating another (cathode)cap
7-lower supply voltages, or:
8-more voltage swing at even lower than original supply (remember, no waste)
9-less distortion (I have 90 Vrms with only 0,2% thd)
You need a good IT though
regards,
=
Guido
At 10:47 19-12-98 +0800, Johari Yip wrote:
>Hi guys,
>
>Now, I know a lot of talk has been said about coupling the linestage with a
>OPTX but what other benefit do we get other than better "drive". Don't get
>me wrong here, I'm all for sonic bliss but don't you think we are adding
>"flavors" to the sound. There's also the added complication of
>shielding/directional orientation of the OPTX to content with. Correct me
>here if I'm wrong but isn't the job of a pre-amp be just matching the
>impedance of the source to the power amps and, at the same time provides a
>slight gain to that signal. I would prefer to use an IT in the power amps
>for additional drive to the output tubes.
>I apologize if this has been brought up before.
>
>Regards,
>Johari
>
>----------
>> From: Adnan Arduman <adnana@turk.net>
>> To: RALPH POWER <POWER.RALPH@epamail.epa.gov>
>> Cc: sound@deliverator.io.com
>> Subject: Re: 5687 linestage - now WOT
>> Date: Friday, December 18, 1998 11:58 PM
>>
>>
>> Hi Ralph,
>>
>> I'm very glad to hear that my FLUENCE project gave you a positive
>> inspiration. Many thanks for reporting it.
>> I'd be interested to receive your schematic.
>>
>> Sincerely,
>>
>> Adnan
>>
>>
>>
>> >Hi All,
>> >
>> >I'm reporting back now after converting and tweaking my 5687 linestage
>to
>> >the new Electraprint 3500 line output transformers. Much thanks goes
>> >to Achnan Arduman and his "Fluence" preamp for ideas and inspiration
>here.
>>
>>
>>
>> Please visit my personal "NUANCE & FLUENCE" web site:
>> http://www.arduman.com/aa
>>
>> tel: +90-216-310 44 70 (w)
>> fax: +90-216-343 42 01
>> e-mail: adnana@turk.net
>
>
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: Re: 5687 linestage - now WOT
Date: Sun, 03 Jan 1999 00:49:57 -0700
Source: Sound Digest Archive v01.n555
€ Johari Yip wrote:
>Hi everyone,
>
>Thanks Guido, you've listed a whole list of "pros" to why IT coupling is,
>in fact, far superior to R-C coupling in amps but at a much higher cost.
>Now, having said all the advantages of IT coupling, Am I correct to say
>that there would be further improvement if the linestage is also OPTX
>coupled?
>On a different note, I know with IT coupling, we can bias the output tube
>for Class A2 operation for some transmitter tubes like the 211, 845 and the
>recent SV572 series of tubes. What's the advantage of IT coupling in Class
>A2 operation here as compared to, say, cathode follower coupled from a
>power tube like 6AS7, triode-wired EL34, 6L6 etc a la "AN Ongaku"?
>Guido or anyone?
>
>Thanks in advance,
>Johari
======================
€ Guido wrote:
>> Joes,
>>
>> Since I heard my first IT coupled amp I never want R-C coupling anymore:
>>
>> The technical reasons and advantages of iron
>>
>> 1-no series coupling cap
>> 2-no secondary load of the IT necessary so:
>> 3-no current through the driving tube
>> 4-no current through the supply (except dc)
>> 5-no waste of audio energy since transformers do not absorb
>> 6-ease of fixed biasing to next stage, eliminating another (cathode)cap
>> 7-lower supply voltages, or:
>> 8-more voltage swing at even lower than original supply (remember, no
>waste)
>> 9-less distortion (I have 90 Vrms with only 0,2% thd)
>>
>> You need a good IT though
>>
>> regards,
>> =
>> Guido
>>
===================
Dear Johari:
Taking up first the question you posed in your last paragraph: assuming
that you inquire about Class A2 single-ended operation, it's my thought that
an IT used to anode load the driver stage would not perform as well on the
test bench as a resistively loaded cathode follower. I've not yet built
either of these stages and so cannot begin to comment on sonics.
Before getting into this however it is useful to recall a few of things
about coupling transformers:
1 - For the vast majority of ITs designed for power amp use, there is no
need to
wind anything other than a 1:1 ratio. If the IT is replacing a load
resistor
and the original B+ is maintained (and the driver tube can handle
such B+/
dissipation and is very linear) then the available output rises
by 6dB nearly enough...
2 - Because a 1:1 ratio is satisfactory, it is both possible and
practical to
bifilarly wind the primary and secondary. This has several
advantages:
a - VERY tight inductive coupling
b - NO >> effective << capacitance primary-to-secondary until the
leakage
reactance begins to cause the secondary voltage to roll off.
c - easy construction, almost, there is a trick NEEDED here that
I'll leave to
your discovery
3 - 'b' above depends crucially upon adjacent ends of the pri. & sec.
being
connected "earthy" and "swinging".
Theoretically then, the matter is that with an increasingly positive
drive on the output tube's control grid, an increasing electron flow from
that grid must be "sunk" by the driving stage.
In the CF case, the cathode's voltage is VERY closely "following" (hence
the name) the increasingly positive voltage on the control grid. The driver
tube is being "turned on", so to speak, with the result that it's Rp
diminishes and this enables the tube to handle the demand that it "sink"
electron flow from the subsequent, positively driven control grid. Remember
that the CF stage is non-inverting...
The anode loaded IT stage is inverting so it's grid must be driven more
negative, turning the tube "off" and increasing it's Rp. by the action of
the transformer, this increasing Rp appears effectively in series with the
increasing conductance (decreasing resistance) of the positively driven
output control grid. The result is a decreased ability to sink electron flow
from the said grid and the outcome will be dynamic compression...
In a push-pull stage, this outcome is ideal as it fosters soft clipping,
in an SE stage, it's a mess...
The "obvious" solution might be to reverse the connection of either the
primary OR the secondary but this will completely blow off the very
agreeable condition 'b' above. I don't think I'd follow this route.
It seems more sensible to choke load a voltage amp and cap couple it
into a self-biased CF with the IT connected between the series,
bias-generating resistor and ground. With 100k or less from the CF's control
grid to the junction of the IT and resistor, it's input impedance will be
enormous so a very small Jensen, copper-foil oiler could be used and the
driver stage would run essentially constant current...
Then again, I haven't built this although I'm about to...
There are few more things I want to say, but somehow it got to be
midnight!! ...
How'd THAT happen??
Happy Trails,
Bill Perkins, PEARL Inc.
2528 19 St. S.W., Calgary, Ab.,
Canada T2T 4X3
Ph. 1 403 244 4434 Fx. 1 403 244 9026
P.S.
As I proof read this a thought occurred: it's possible to reduce the
distortion of the SE amp, end-to-end, if the last inverting-stage before the
final is loaded so as to produce a transfer curve that is the inverse of the
final. This is called Complementary Distortion Reduction and the notion has
been around for 40 years at least.
In terms of distortion reduction, it's almost feedback but without the
inevitable higher order non-linearities, the loop delay and the consequent
creation of a chaotic, low-level noise "floor".
Driving a low admittance load like a self-biased CF, a choke-loaded
voltage amplifing stage traverses a dynamic load line is the better part of
horizontal; triode heaven... So, how does one decrease its linearity?
Above any rational low frequency, enough inductive reactance becomes a
virtual current source and that HIGH impedance can be successfully
degenerated by a parallel resistance of the desired value. Stage gain will
be sacrificed but maximum output swing will not... bears thinking about...
later.
zzzzZZZZZzzzzzZZZZZzzzzzZZZZ........
=========================================================================
From: "Johari Yip" <hfyip@pacific.net.sg>
Subject: Re: 5687 linestage - now WOT
Date: Sun, 3 Jan 1999 11:22:28 +0800
Source: Sound Digest Archive v01.n555
Hi everyone,
Thanks Guido, you've listed a whole list of "pros" to why IT coupling is,
in fact, far superior to R-C coupling in amps but at a much higher cost.
Now, having said all the advantages of IT coupling, Am I correct to say
that there would be further improvement if the linestage is also OPTX
coupled?
On a different note, I know with IT coupling, we can biase the output tube
for Class A2 operation for some transmitter tubes like the 211, 845 and the
recent SV572 series of tubes. What's the advantage of IT coupling in Class
A2 operation here as compared to, say, cathode follower coupled from a
power tube like 6AS7, triode-wired EL34, 6L6 etc ala "AN Ongaku"? Guido or
anyone?
Thanks in advance,
Johari
- ----------
> From: evaguido <EvaGuido@iaehv.nl>
> To: Johari Yip <hfyip@pacific.net.sg>; RALPH POWER
<POWER.RALPH@epamail.epa.gov>; Adnan Arduman <adnana@turk.net>
> Cc: sound@deliverator.io.com
> Subject: Re: 5687 linestage - now WOT
> Date: Sunday, January 03, 1999 6:15 AM
>
> Joes,
>
> Since I heard my first IT coupled amp I never want R-C coupling anymore:
>
> The technical reasons and advantages of iron
>
> 1-no series coupling cap
> 2-no secondary load of the IT necessary so:
> 3-no current through the driving tube
> 4-no current through the supply (except dc)
> 5-no waste of audio energy since transformers do not absorb
> 6-ease of fixed biasing to next stage, eliminating another (cathode)cap
> 7-lower supply voltages, or:
> 8-more voltage swing at even lower than original supply (remember, no
waste)
> 9-less distortion (I have 90 Vrms with only 0,2% thd)
>
> You need a good IT though
>
> regards,
> =
> Guido
>
> At 10:47 19-12-98 +0800, Johari Yip wrote:
> >Hi guys,
> >
> >Now, I know a lot of talk has been said about coupling the linestage
with a
> >OPTX but what other benefit do we get other than better "drive". Don't
get
> >me wrong here, I'm all for sonic bliss but don't you think we are adding
> >"flavors" to the sound. There's also the added complication of
> >shielding/directional orientation of the OPTX to content with. Correct
me
> >here if I'm wrong but isn't the job of a pre-amp be just matching the
> >impedance of the source to the power amps and, at the same time provides
a
> >slight gain to that signal. I would prefer to use an IT in the power
amps
> >for additional drive to the output tubes.
> >I apologize if this has been brought up before.
> >
> >Regards,
> >Johari
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: 5687 linestage - now WOT
Date: Sun, 03 Jan 1999 14:21:46 +0100
Source: Sound Digest Archive v01.n555
At 11:22 3-1-99 +0800, Johari Yip wrote:
>Hi everyone,
>
>Thanks Guido, you've listed a whole list of "pros" to why IT coupling is,
>in fact, far superior to R-C coupling in amps but at a much higher cost.
>Now, having said all the advantages of IT coupling, Am I correct to say
>that there would be further improvement if the linestage is also OPTX
>coupled?
I believe that implicit advantages count everywere, also in a linestage
I would like to add as an advantage to IT coupling that in general a better
compromise can be achieved for gain versus output impedance
>On a different note, I know with IT coupling, we can biase the output tube
>for Class A2 operation for some transmitter tubes like the 211, 845 and the
>recent SV572 series of tubes. What's the advantage of IT coupling in Class
>A2 operation here as compared to, say, cathode follower coupled from a
>power tube like 6AS7, triode-wired EL34, 6L6 etc ala "AN Ongaku"? Guido or
>anyone?
Basicaly none
A CF might be DC coupled to the output tube, while the CF in turn is dc
coupled and biased through the IT
A CF makes real A2 drive possible, driving the output from an anode
(regardless of coupling mechanism) usually cannot drive the output tube in A2
>Thanks in advance,
Welcome, like everyone
Guido
>Johari
>
>----------
>> From: evaguido <EvaGuido@iaehv.nl>
>> To: Johari Yip <hfyip@pacific.net.sg>; RALPH POWER
><POWER.RALPH@epamail.epa.gov>; Adnan Arduman <adnana@turk.net>
>> Cc: sound@deliverator.io.com
>> Subject: Re: 5687 linestage - now WOT
>> Date: Sunday, January 03, 1999 6:15 AM
>>
>> Joes,
>>
>> Since I heard my first IT coupled amp I never want R-C coupling anymore:
>>
>> The technical reasons and advantages of iron
>>
>> 1-no series coupling cap
>> 2-no secondary load of the IT necessary so:
>> 3-no current through the driving tube
>> 4-no current through the supply (except dc)
>> 5-no waste of audio energy since transformers do not absorb
>> 6-ease of fixed biasing to next stage, eliminating another (cathode)cap
>> 7-lower supply voltages, or:
>> 8-more voltage swing at even lower than original supply (remember, no
>waste)
>> 9-less distortion (I have 90 Vrms with only 0,2% thd)
>>
>> You need a good IT though
>>
>> regards,
>> =
>> Guido
>>
>> At 10:47 19-12-98 +0800, Johari Yip wrote:
>> >Hi guys,
>> >
>> >Now, I know a lot of talk has been said about coupling the linestage
>with a
>> >OPTX but what other benefit do we get other than better "drive". Don't
>get
>> >me wrong here, I'm all for sonic bliss but don't you think we are adding
>> >"flavors" to the sound. There's also the added complication of
>> >shielding/directional orientation of the OPTX to content with. Correct
>me
>> >here if I'm wrong but isn't the job of a pre-amp be just matching the
>> >impedance of the source to the power amps and, at the same time provides
>a
>> >slight gain to that signal. I would prefer to use an IT in the power
>amps
>> >for additional drive to the output tubes.
>> >I apologize if this has been brought up before.
>> >
>> >Regards,
>> >Johari
>
>
=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: Re: 5687 linestage - now WOT
Date: Mon, 04 Jan 1999 03:19:12 PST
Source: Sound Digest Archive v01.n557
Hi there,
>Now, having said all the advantages of IT coupling, Am I correct
>to say that there would be further improvement if the linestage
>is also OPTX coupled?
This is hard to say. But after testing my friends Euridice Linestage
(with Bartolucci Output Transformers) in my system, we are both conviced
that for transparency there is no loss in either transparency or
low-level resolution when compared to my own (non transformer coupled)
Line-Stage or to a passive attenuator...
For this the build and part's quality has to be exceptional of course,
but this is one active preamp that DOES NOT MUCK UP THE SOUND....
The Linestage from the Artur Loesch Phono Preamp (which I used for my
own preamp Design with my own Phono-Stage) is another one....
Even (with all due respect) Allen Wrigts "Super Linear Cathode Follower"
Linestage looses some transparency when compared to the Arthur Loesch
Design....
So the good ole WOT is certainly something else.... If you can afford
the parts-quality needed to get this working properly - go for it.
>On a different note, I know with IT coupling, we can biase
>the output tube for Class A2 operation for some transmitter
>tubes like the 211, 845 and the recent SV572 series of tubes.
There is quite a range of options how to do this.... I think looking at
the Designs of Nobu Shishido (unfortunatly he has recently taken up
residence outside this miserable earthly realm) will provide
instructive.
He uses a Interstage Transformer with a Stepdown ratio (about 0.8 in the
designs I have recently seen - 805, SV572-30 or 160). He generally uses
a Triode wired 6L6 as driver.
All his designs use Cathode Feedback on the output Valve and some degree
of overall feedback.
>What's the advantage of IT coupling in Class A2 operation here
>as compared to, say, cathode follower coupled from a power tube
>like 6AS7, triode-wired EL34, 6L6 etc ala "AN Ongaku"? Guido or
>anyone?
I do not think that the IT will be technically superior.
However, I have been more than once been very vocal about my view of
Cathote Followers (simply say I don't like their sound)....
If you MUST go Class A2 You might be interested in a (still only
conceptual) Design I have come up with that I call "Super-Mu-Stage". It
should be directly coupled to the Power-Valves Grid.
This neccesitates a split PSU for which the "split" point is adjustable
to correctly bias the Valve for the appropriate Operating Point....
It will allow a Gain of > 90 with a 12AX7 as lower Valve, > 65 with a
6SL7 as lower Valve and > 43 with a 417A/5842 as lower Valve....
With a 12AX7 + 7119 or 6SL7 + 6BX7 the Voltage swing can be > 450
peak-peak (with more than 550V total PSU Voltage) and the 417A/5842 +
7119 Variant can still achieve about 250V peak-peak swing.
This approach allows anything up to a 845 to be driven by a single, low
distortion Stage that can sink up to 12ma current and source over 50mA,
so any Grid should be drivable....
And if the PSU's can be sorted a completely Capacitor AND Transformer
free Driver for any form of DHT can be realised....
In essence the "Super-Mu-Stage" is a combination of Allen Wrights "Super
Linear Cathode Follower" with a SRPP Stage using J-Fet Current-Sources.
Since I ended up (due to a number of external Fatcors) with a very nice
300B PSE Amp recently and because I think my system never sounded better
than it does now, work on this circuit is suspended at the moment.
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: RALPH POWER <POWER.RALPH@epamail.epa.gov>
Subject: Re: 5687 linestage - now WOT -Reply
Date: Mon, 21 Dec 1998 10:02:50 -0500
Source: Sound Digest Archive v01.n547
Hi Johari,
You commented :
>Now, I know a lot of talk has been said about coupling the linestage with a
>OPTX but what other benefit do we get other than better "drive". Don't get
>me wrong here, I'm all for sonic bliss but don't you think we are adding
>"flavors" to the sound. There's also the added complication of
>shielding/directional orientation of the OPTX to content with. Correct me
>here if I'm wrong but isn't the job of a pre-amp be just matching the
>impedance of the source to the power amps and, at the same time provides a
>slight gain to that signal. I would prefer to use an IT in the power amps
>for additional drive to the output tubes.
Since I started this recent thread, I felt I should make a few comments here.
As you probably well know by now, I am a very big proponent of transformers in
lieu of coupling caps, whether it be in preamps or amps. Given that you have
a good quality transformer, I believe that they just "let more music through" than
do coupling capacitors.
I have been fortunate in that most all the coupling transformers that I have had
occasion to use (Magnequest, Lundahl, and now Electraprint) have been good
enough that they did not color the sound in any manner that I can detect, and in
each instance have sounded more "whole" than the coupling caps that they
replaced. To my ears this has resulted in improvements in every aspect of
musical reproduction; more extension on both ends, larger sound stage,
better macro and micro dynamics, quieter background, and a more "relaxed"
presentation among others. Also it has the ability to decode more minute
spatial and tonal details within the recordings than it previously could.
After hearing these improvements in my system, I could not go back to
cap coupling.
Les than optimal coupling transformers can color the sound and I did detect a strident,
"zippy" coloration to the older Southeastern interstage transformers that I used
initially in my VV30B amp. That occurred when I used them without a secondary
loading resistor, but this is the only tranny that I have had any frequency response
problems with. But these are known to have HF ringing problems, which is a design
deficiency, that must be addressed.
I guess for me it was just an extension of my preference for transformer coupling
to use them in my preamplifier. I was further tempted by the enticing comments of
Robert Root, Chris Beck, and Adnan Arduman, among others, and hearing their
experiences with preamplifier transformer coupling.
After having built and debugged a transformer coupled preamp now, I can say that
they are indeed more sensitive to power supply deficiencies and that extra care
must be taken to address extra filtering requirements and transformer placement.
Given that these requirements are addressed, I believe the benefits gained are
worth the extra efforts that are required.
In addition I can say that I have benefitted from their hum and noise isolating properties
that Paul referred to, as I have noticed that the low level 60hz hum I
used to get in my subwoofer has now disappeared after converting my preamp
to transformer output.
In the final analysis I suppose it just comes down to personal preferences. I'm using
honey to sweeten my batter instead of sugar...I like the taste of honey better.
My 3 cents,
- Ralph
=========================================================================
From: "Chris Beck" <cbeck@brewercompany.com>
Subject: Re: 5687 linestage - now WOT -Reply
Date: Mon, 21 Dec 1998 10:26:53 -0600
Source: Sound Digest Archive v01.n547
Gee, Ralph, you took the words right out of my mouth. I think you've
pretty well summed up my experiences up to this point with my preamp. I
just can't stop listening to the damn thing. Everytime I walk in the door,
I wander over to the sytem, flip what seems like 25 switches, warm it up,
and listen. The wife just rolls her eyes and wonders out loud if we could
just have peace and quiet once in a while. To her, a $50 boombox is just
fine. GAG.
Here's something I found funny. We have two dogs, and never did they bark
at the music before the preamp was in the system. Now that I've really
dialed the preamp in, certain sounds in the music that they have probably
heard dozens of times before and never noticed will now start them barking
and running around the room trying to find out where it is. It's really
rather odd, and amusing. So, if our dogs noticed the improvement, it must
be good, huh? :-)
Chris Beck
See my web page at: http://www.execpc.com/~n9zes/index.htm
- ----------
> From: RALPH POWER <POWER.RALPH@epamail.epa.gov>
> To: hfyip@pacific.net.sg
> Cc: sound@deliverator.io.com
> Subject: Re: 5687 linestage - now WOT -Reply
> Date: Monday, December 21, 1998 9:02 AM
>
>
> Hi Johari,
>
> You commented :
>
> >Now, I know a lot of talk has been said about coupling the linestage
with a
> >OPTX but what other benefit do we get other than better "drive". Don't
get
> >me wrong here, I'm all for sonic bliss but don't you think we are adding
> >"flavors" to the sound. There's also the added complication of
> >shielding/directional orientation of the OPTX to content with. Correct
me
> >here if I'm wrong but isn't the job of a pre-amp be just matching the
> >impedance of the source to the power amps and, at the same time provides
a
> >slight gain to that signal. I would prefer to use an IT in the power
amps
> >for additional drive to the output tubes.
>
> Since I started this recent thread, I felt I should make a few comments
here.
>
> As you probably well know by now, I am a very big proponent of
transformers in
> lieu of coupling caps, whether it be in preamps or amps. Given that you
have
> a good quality transformer, I believe that they just "let more music
through" than
> do coupling capacitors.
>
> I have been fortunate in that most all the coupling transformers that I
have had
> occasion to use (Magnequest, Lundahl, and now Electraprint) have been
good
> enough that they did not color the sound in any manner that I can
detect, and in
> each instance have sounded more "whole" than the coupling caps that they
> replaced. To my ears this has resulted in improvements in every aspect
of
> musical reproduction; more extension on both ends, larger sound stage,
> better macro and micro dynamics, quieter background, and a more "relaxed"
> presentation among others. Also it has the ability to decode more minute
> spatial and tonal details within the recordings than it previously could.
> After hearing these improvements in my system, I could not go back to
> cap coupling.
>
> Les than optimal coupling transformers can color the sound and I did
detect a strident,
> "zippy" coloration to the older Southeastern interstage transformers
that I used
> initially in my VV30B amp. That occurred when I used them without a
secondary
> loading resistor, but this is the only tranny that I have had any
frequency response
> problems with. But these are known to have HF ringing problems, which is
a design
> deficiency, that must be addressed.
>
> I guess for me it was just an extension of my preference for transformer
coupling
> to use them in my preamplifier. I was further tempted by the enticing
comments of
> Robert Root, Chris Beck, and Adnan Arduman, among others, and hearing
their
> experiences with preamplifier transformer coupling.
>
> After having built and debugged a transformer coupled preamp now, I can
say that
> they are indeed more sensitive to power supply deficiencies and that
extra care
> must be taken to address extra filtering requirements and transformer
placement.
> Given that these requirements are addressed, I believe the benefits
gained are
> worth the extra efforts that are required.
>
> In addition I can say that I have benefitted from their hum and noise
isolating properties
> that Paul referred to, as I have noticed that the low level 60hz hum I
> used to get in my subwoofer has now disappeared after converting my
preamp
> to transformer output.
>
> In the final analysis I suppose it just comes down to personal
preferences. I'm using
> honey to sweeten my batter instead of sugar...I like the taste of honey
better.
>
> My 3 cents,
>
> - Ralph
>
>
>
=========================================================================
From: "Chris Beck" <cbeck@brewercompany.com>
Subject: Re: 5687 linestage - now WOT -Reply
Date: Tue, 22 Dec 1998 07:22:49 -0600
Source: Sound Digest Archive v01.n548
If the speakers were my little Radio Shack LX-4's with the Linaeum tweeter,
maybe!! With my big speakers, I don't think they have enough top end
response to do it.
They usually bark at specific sounds. In a Ron Carter CD I have, there is
some unusual bass playing with the bow, and it almost sounds like dogs
barking. Really gets them going. Barking in time with the music!
Chris Beck
See my web page at: http://www.execpc.com/~n9zes/index.htm
- ----------
> From: Le Cleac'h J.-M. <lecleach@cgi.ensmp.fr>
> To: sound@deliverator.io.com
> Subject: Re: 5687 linestage - now WOT -Reply
> Date: Tuesday, December 22, 1998 2:26 AM
>
>
> ----------
> > De : Chris Beck <cbeck@brewercompany.com>
> > Date : lundi 21 décembre 1998 17:26
>
>
> > Here's something I found funny. We have two dogs, and never did they
> bark
> > at the music before the preamp was in the system. Now that I've really
> > dialed the preamp in, certain sounds in the music that they have
probably
> > heard dozens of times before and never noticed will now start them
> barking
> > and running around the room trying to find out where it is. It's
really
> > rather odd, and amusing.
>
>
> Could this be ultrasounds created by your preamplifier and bothering
those
> poor dogs?
>
> :-)
>
> Best regards,
>
> Jean-Michel Le Cleac'h, Paris, France
>
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: 5687 linestage - now WOT -Reply
Date: Tue, 22 Dec 1998 09:26:29 +0100
Source: Sound Digest Archive v01.n548
- ----------
> De : Chris Beck <cbeck@brewercompany.com>
> Date : lundi 21 décembre 1998 17:26
> Here's something I found funny. We have two dogs, and never did they
bark
> at the music before the preamp was in the system. Now that I've really
> dialed the preamp in, certain sounds in the music that they have probably
> heard dozens of times before and never noticed will now start them
barking
> and running around the room trying to find out where it is. It's really
> rather odd, and amusing.
Could this be ultrasounds created by your preamplifier and bothering those
poor dogs?
:-)
Best regards,
Jean-Michel Le Cleac'h, Paris, France
=========================================================================
From: "Chris Beck" <cbeck@brewercompany.com>
Subject: Re: 5687 linestage - now WOT -Reply
Date: Tue, 22 Dec 1998 12:48:52 -0600
Source: Sound Digest Archive v01.n548
Well, that certainly makes sense, as I think both our dogs have heads as
hollow as a coconut! :-)) I'd imagine they resonate pretty good. I have
some pics of the two on my web page. They are really cool buddies.
Chris Beck
See my web page at: http://www.execpc.com/~n9zes/index.htm
- ----------
> From: David Barnett <davidbarnett@aristotle.net>
> To: Chris Beck <cbeck@brewercompany.com>; sound@lists.io.com
> Subject: Re: 5687 linestage - now WOT -Reply
> Date: Tuesday, December 22, 1998 12:45 PM
>
> On Tue, 22 Dec 1998 07:22:49 -0600, "Chris Beck"
> <cbeck@brewercompany.com> wrote:
>
> >They usually bark at specific sounds. In a Ron Carter CD I have, there
is
> >some unusual bass playing with the bow, and it almost sounds like dogs
> >barking. Really gets them going. Barking in time with the music!
>
> I saw a thing on TV recently, probably on Animal Planet, where they
> said that when dogs howl along with the music, it's to equalize
> pressure in their heads. Specific musical tones create bothersome
> resonances in their little walnut-brained skulls, and they howl until
> they find the right frequency to match the tone and null the
> resonance. I'm surely oversimplifying the story due to my extremely
> limited understanding.
>
> --dnb
>
=========================================================================
From: davidbarnett@aristotle.net (David Barnett)
Subject: Re: 5687 linestage - now WOT -Reply
Date: Tue, 22 Dec 1998 18:45:07 GMT
Source: Sound Digest Archive v01.n548
On Tue, 22 Dec 1998 07:22:49 -0600, "Chris Beck"
<cbeck@brewercompany.com> wrote:
>They usually bark at specific sounds. In a Ron Carter CD I have, there is
>some unusual bass playing with the bow, and it almost sounds like dogs
>barking. Really gets them going. Barking in time with the music!
I saw a thing on TV recently, probably on Animal Planet, where they
said that when dogs howl along with the music, it's to equalize
pressure in their heads. Specific musical tones create bothersome
resonances in their little walnut-brained skulls, and they howl until
they find the right frequency to match the tone and null the
resonance. I'm surely oversimplifying the story due to my extremely
limited understanding.
- --dnb
=========================================================================
From: Patrick Currie <tubesguy@chorus.net>
Subject: Re: 5687 linestage - now WOT -Reply
Date: Tue, 22 Dec 1998 17:52:03 -0600
Source: Sound Digest Archive v01.n549
>I saw a thing on TV recently, probably on Animal Planet, where they
>said that when dogs howl along with the music, it's to equalize
>pressure in their heads. Specific musical tones create bothersome
>resonances in their little walnut-brained skulls, and they howl until
>they find the right frequency to match the tone and null the
>resonance. I'm surely oversimplifying the story due to my extremely
>limited understanding.
>
>--dnb
I think Celine Dion does the same thing.
=========================================================================
From: Joe Pledger <doodle@navicom.com>
Subject: Re: 5687 linestage - now WOT -Reply
Date: Tue, 22 Dec 1998 22:49:53 -0800
Source: Sound Digest Archive v01.n549
David Barnett wrote:
>
> On Tue, 22 Dec 1998 07:22:49 -0600, "Chris Beck"
> <cbeck@brewercompany.com> wrote:
>
> >They usually bark at specific sounds. In a Ron Carter CD I have, there is
> >some unusual bass playing with the bow, and it almost sounds like dogs
> >barking. Really gets them going. Barking in time with the music!
>
> I saw a thing on TV recently, probably on Animal Planet, where they
> said that when dogs howl along with the music, it's to equalize
> pressure in their heads. Specific musical tones create bothersome
> resonances in their little walnut-brained skulls, and they howl until
> they find the right frequency to match the tone and null the
> resonance. I'm surely oversimplifying the story due to my extremely
> limited understanding.
>
> --dnb
David,
That's no "revelation", I do that when I'm working outside, and the wife
calls me!;-)
Joe Pledger
=========================================================================
From: davidbarnett@aristotle.net (David Barnett)
Subject: Re: 5687 linestage - now WOT -Reply
Date: Wed, 23 Dec 1998 01:37:01 GMT
Source: Sound Digest Archive v01.n549
On Tue, 22 Dec 1998 17:52:03 -0600, Patrick Currie
<tubesguy@chorus.net> wrote:
>I think Celine Dion does the same thing.
That's what it sounds like, anyway.
- --dnb
=========================================================================
From: "Knutson, Paul" <Paul_Knutson@blanch.com>
Subject: RE: 5687 Linestage Options
Date: Wed, 3 Jun 1998 15:34:00 -0500
Source: Sound Digest Archive v01.n302
Jim/Others, I can offer some insight on #2 from your list below:
I bought a completed version of Randy Fay's 5687 preamp from him not
long ago. In short -- I like it a lot. It is an incredibly simple
design, and it provides plenty of gain for my system. As Randy likes to
say, it's "ultra purist -- ultra minimalist".
To put things in perspective, I sold my Audible Illusions Mod3A after
getting Randy's 5687 preamp. The cost differential was ... well, I
won't even bother with that comparison. Let's just say I saved a lot of
green, even though it was quickly spent on more music.
The preamp uses a single 5687 for the amplification and a single
12AU7/Y7 in the power supply. I, and others, have found the use of the
12AU7 as a power supply diode a "curious" choice, but I can't really
argue with the results. That choice, however, may be a good candidate
for a future mod.
Due to the minimalist design, this unit is very revealing of tube
changes (and cap changes as well -- I'm using MIT's). I've pretty much
settled on the little-known 7044 variant of the 5687 family of tubes as
the best performer in my system. The 7044 even beat out the more
heralded 7119 by a small margin, and both of these versions were
appreciably better than the normal 5687's I have on hand. I'm also
using a 6072 in the power supply, which is a beefed-up member of the
12AY7 family. It beat the pants off any 12AU7 I tried in that spot.
If Randy really will sell this as a kit for $125, it's a great deal. A
fantastic choice for a beginner and should be easy to construct too.
Maybe Doc's $99 Foreplay will give it a run for its money in that price
category, but I'm not sure when we're ever gonna find that out (Hey Doc
- -- where are those Foreplay kits?!? the natives are getting restless
out here:>).
As good as Randy's 5687 preamp is (and it's the best I've had in my
system), it's simplicity probably won't confuse anyone into thinking
it's the absolute ultimate preamp. As I finish my amp project, I'm
lucky enough to have Tom Ronan building my "ultimate" preamp for me --
his custom 26 design. I've heard it ... it's a sweetie -- I was blown
away. IMHO, Tom's 26 preamp is a whole different ballgame.
Best regards, Paul
----------
From: Jim Dudley
To: sound practices
Subject: 5687 Linestage Options
Date: Wednesday, June 03, 1998 7:59AM
On Tue, 2 Jun 1998 18:14:19 +0000, Aaron Bohnen wrote:
> <large snip>
>Alternatively I have a nice little handful of 5687's. I know that they
>can be made to sound very good indeed. Does anyone have any thoughts on
>a 5687 instead of 5692-based unit?
>
>Many thanks to all...
>
>Aaron
I've decided on building a linestage based on the 5687 tube. Below are
some of the main options I've considered.
1) John Leverault's 5687 Parrallel Anode Follower featured in the 96
Valve Dec issue. Johari on the list here has built this one.
2) Randy Fay has a very simple design that uses one 5687. He sells
everything you need to build minus chassis, jacks, and switches for
$125. Kit includes a NOS
military PT. His number is (519) 735-2462. He only runs the tube at
85V @ 8 ma. Gain is about 12. Go to deja news and do a search for his
last post in r.a.m.
2/15/98 for more detail on the design (try "5687 linestage").
3) I got another design from Sridhar Gantimahapatruni (ganti). I've
pasted his simple circuit at the bottom of this post.
4) If you want to go the way of a linestage with output xformer you can
check out Diego Nardi's WOT design in Sound Practices #10. Simple
signal path but uses
proprietary transformers ($330/pair).
I can't give personal testimony to any of the above but I'm sure there
are many on the list who can. I think I'm going to try the Randy Fay
design because I don't
need the extra gain and because it appears like an easy route for a
beginner.
Jim Dudley
Ganti's circuit.
> Hi Jim
>
> Given below is power supply and basic ckt as I have implemented it.
>
> Sorry for the delay
>
> ganti
> ----------------------------------------------------------------------
> -----------------------------------------------------
>
> Power Supply
> ------------
>
> PT ---- 5AR4 --- CH ---------- R1 ------ R2 -----> B+ to 5687's
> | | | | |
> | | | | |
> BR C1 C2 C3
> | | | | |
> | | | | |
> G G G G G
>
> PT: Power Transformer with 820 VCT and 100 mA (DC)
>
> CH: Choke 10H/100mA
>
> BR: 3 22k/2W bleeder resistors
>
> C1: 22 mF/630V SCR film cap
>
> R1: 2K 2W
>
> C2: single 220mF/500V cerafine Bypass the cerafine with a .47mF/630V
>
> R2: 1K 3W
>
> C3: dual 47mF/500V cerafine Bypass the cerafine with a .47mF/630V
>
> G: Ground
>
> Preamp Ckt
> ----------
>
> Plate current = 12.2mA
> Plate voltage = 190V
> Grid Bias = 9.2V
> B+
> |
> |
> R1
> |-------C1-- O/P
> |
> | R1 = 12K/5W
> | Each plate will be a separate chanel.
> | Each grid will have a 470 Ohm grid stopper.
> ----- ------ Feed the inpu to the grid
> ----------
> ----- C1 .47mF/500V o/p coupling cap (Hovland MusiCap)
> | R2 750 Ohm cathode resistor.
> |
> |
> R2
> |
> |
> Gnd
>
>
> Noise Reduction
> ---------------
> - Have 0.1 MicroF/20V cap from the center tap of the power
> transformer
> points that feed the filament voltage
>
> - .003 MicroF/1000V cap from pin in the diode that connects to the
> choke
> to the ground.
END
=========================================================================
From: Rhthatcher@ra.rockwell.com
Subject: Re: 5687 Linestage Options
Date: Wed, 3 Jun 1998 16:32:53 -0400
Source: Sound Digest Archive v01.n302
about 2 years ago i built a kit from randy fay. it uses a 6dj8/6922 into a
el84 CF with a 12ay7 current source.
http://k2.cwru.edu/~rht3/ls.htm has a little about it.
i have black gates, hovland coupling caps, a rubicon and axon in the ps,
and caddock resistors in mine. the only
wire is about 2 inches of silver wire, the rest of the signal goes through
the few components in the thing.
it's cheap to build, and it should stomp things like sonic frontiers,
melos, krell, etc...
Randy's a great guy, he's helped me on the phone while fixing and tweaking
and generally
put up with a lot of my newbie crap. I may build his design with the 5687
if i get around to calling him and
get it. I don't know what tranny he has for that, but i may have something
that will do. before the 5687 he
was doing a 12bh7 kit. bottom line, a little money goes a LONG way with
randy fay's designs. i say
go for it! if you don't like it you're out about the same cash as a pair
of cheap boutique interconnects.
i may breadboard a 5687 preamp and a 76 preamp and try them. anyone here
build the linestage
in SP 13? how does it sound? anyone have the iron for it? i have a spare
250-0-250, a 300V, and a
550-0-550 (quite big for a preamp, tho), but nothing too close for that
preamp. i may have a choke
or 2 from the SJS phono stage i'm tearing up soon.
I've decided to go with the EAR 834P. I can't try to find the noise for
months on end and NOT
enjoy my vinyl. i've been vinyl starved since january and i'm fed up.
projects are fun and all, but the
music is more important to me! I've been borrowing a friend's EAR, and it
is pretty nice. I figure i'll drop
a few Tele's i have into it, maybe use some hovlands in there, maybe drop
in some freds (if i can fit 'em!)
and try that. got the thing for 1/3 off as a demo... hope it shows up
soon as i have to return my friend's in the
morning!
Anyone have (2) 0.15uF or (2) 1.0uF Hovland's they'd sell me?
- -randy thatcher (not fay)
2) Randy Fay has a very simple design that uses one 5687. He sells
everything you need to build minus chassis, jacks, and switches for $125.
Kit includes a NOS
military PT. His number is (519) 735-2462. He only runs the tube at 85V
@ 8 ma. Gain is about 12. Go to deja news and do a search for his last
post in r.a.m.
2/15/98 for more detail on the design (try "5687 linestage").
=========================================================================
From: "Doc B." <bottlehead@silverlink.net>
Subject: Re: 5687 Linestage Options
Date: Wed, 3 Jun 1998 19:06:55 -0700
Source: Sound Digest Archive v01.n302
>If Randy really will sell this as a kit for $125, it's a great deal. A
>fantastic choice for a beginner and should be easy to construct too.
>Maybe Doc's $99 Foreplay will give it a run for its money in that price
>category, but I'm not sure when we're ever gonna find that out (Hey Doc
>-- where are those Foreplay kits?!? the natives are getting restless
>out here:>).
We start shipping the presold Foreplay kits Monday. They have most detailed
instructions I have done to date. If you can't build it with 30 pages of
"dot to dot" instruction, A full schematic, resistance and voltage readings
for all significant test points, a CAD drawing of the parts layout, another
of the terminal designations, and another in full scale of the completely
wired preamp, a full size color photo of the finished amp wiring and a basic
lesson in soldering, you are a lost cause.
I got a special deal on 220 mfd Nichicon caps for the C-R-C-R-C filter, and
the resistors in the amp stage are metal film. Fast recovery soft start
rectifiers, ceramic sockets, laser cut aluminum chassis plate, optional wood
base kit, dual mono controls.
The soon to come $75 Anticipation upgrade (get it? Foreplay with
Anticipation) will add four Camille Cascode Constant Current Source active
loads, and make it kick ass on the bottom (which it already does nicely),
put out like 30V at 5% THD (can you say "dynamic"?), and give our big buck
eXception parafeed preamp a run for its money in the midrange.
We only have 50 for starters, and most are promised, so get to me quick if
you want in on the first production run. After that, there may be a few
weeks delay as we get more chassis plates made.
Doc B.
=========================================================================
From: "Jim Dudley" <jimd@polaris.net>
Subject: 5687 Linestage Options
Date: Wed, 03 Jun 98 12:59:24
Source: Sound Digest Archive v01.n302
On Tue, 2 Jun 1998 18:14:19 +0000, Aaron Bohnen wrote:
> <large snip>
>Alternatively I have a nice little handful of 5687's. I know that they
>can be made to sound very good indeed. Does anyone have any thoughts on
>a 5687 instead of 5692-based unit?
>
>Many thanks to all...
>
>Aaron
I've decided on building a linestage based on the 5687 tube. Below are some of the main options I'v
e considered.
1) John Leverault's 5687 Parrallel Anode Follower featured in the 96 Valve Dec issue. Johari on th
e list here has built this one.
2) Randy Fay has a very simple design that uses one 5687. He sells everything you need to build mi
nus chassis, jacks, and switches for $125. Kit includes a NOS
military PT. His number is (519) 735-2462. He only runs the tube at 85V @ 8 ma. Gain is about 12
. Go to deja news and do a search for his last post in r.a.m.
2/15/98 for more detail on the design (try "5687 linestage").
3) I got another design from Sridhar Gantimahapatruni (ganti). I've pasted his simple circuit at th
e bottom of this post.
4) If you want to go the way of a linestage with output xformer you can check out Diego Nardi's WOT
design in Sound Practices #10. Simple signal path but uses
proprietary transformers ($330/pair).
I can't give personal testimony to any of the above but I'm sure there are many on the list who can.
I think I'm going to try the Randy Fay design because I don't
need the extra gain and because it appears like an easy route for a beginner.
Jim Dudley
Ganti's circuit.
> Hi Jim
>
> Given below is power supply and basic ckt as I have implemented it.
>
> Sorry for the delay
>
> ganti
> ----------------------------------------------------------------------
> -----------------------------------------------------
>
> Power Supply
> ------------
>
> PT ---- 5AR4 --- CH ---------- R1 ------ R2 -----> B+ to 5687's
> | | | | |
> | | | | |
> BR C1 C2 C3
> | | | | |
> | | | | |
> G G G G G
>
> PT: Power Transformer with 820 VCT and 100 mA (DC)
>
> CH: Choke 10H/100mA
>
> BR: 3 22k/2W bleeder resistors
>
> C1: 22 mF/630V SCR film cap
>
> R1: 2K 2W
>
> C2: single 220mF/500V cerafine Bypass the cerafine with a .47mF/630V
>
> R2: 1K 3W
>
> C3: dual 47mF/500V cerafine Bypass the cerafine with a .47mF/630V
>
> G: Ground
>
> Preamp Ckt
> ----------
>
> Plate current = 12.2mA
> Plate voltage = 190V
> Grid Bias = 9.2V
> B+
> |
> |
> R1
> |-------C1-- O/P
> |
> | R1 = 12K/5W
> | Each plate will be a separate chanel.
> | Each grid will have a 470 Ohm grid stopper.
> ----- ------ Feed the inpu to the grid
> ----------
> ----- C1 .47mF/500V o/p coupling cap (Hovland MusiCap)
> | R2 750 Ohm cathode resistor.
> |
> |
> R2
> |
> |
> Gnd
>
>
> Noise Reduction
> ---------------
> - Have 0.1 MicroF/20V cap from the center tap of the power
> transformer
> points that feed the filament voltage
>
> - .003 MicroF/1000V cap from pin in the diode that connects to the
> choke
> to the ground.
END
=========================================================================
From: RALPH POWER <POWER.RALPH@epamail.epa.gov>
Subject: 5687 linestage schematic
Date: Tue, 17 Nov 1998 16:05:51 -0500
Source: Sound Digest Archive v01.n494
Hi All,
If you are looking for an simple, good sounding linestage, I have a jpeg schematic
for one that has been built by alot of people, including myself. It is generally adapted
from the latest Randy Faye preamp design. I am working on converting it to an
output trannie at the present time.
It is a single 5687 or 7044 or 7119 that runs at around 85v and 8 ma, so you
might have to dicker with the dropping resistor (1.2k) to match your power
supply (~250v).
Please let me know if you would like to get an email copy.
- Ralph
=========================================================================
From: RALPH POWER <POWER.RALPH@epamail.epa.gov>
Subject: Re: 5687 linestage schematic
Date: Wed, 18 Nov 1998 10:51:56 -0500
Source: Sound Digest Archive v01.n495
Hi again,
OK guys, regarding the 5687 linestage schematic I sent out, I want to let
everyone know that I just threw it together as indicated and do not claim that it is
a done deal by any means. One could experiment endlessly with this 5687
linestage concept and I hope that everyone that is interested will try alot of
different things with it.
Here are some suggestions :
Different operating points for the 5687. I tried ~150v briefly, but need to take
some time there and listen.
Adding a cathode bypass caps for more gain if needed. I think that 220uf @ 16v
should do the trick.
Single triode versus parallel triode per channel. I know John Leverault did a
parallel version a couple of years ago in Valve magazine that was quite good
I hear.
Different B+ and filament power supply configs. I'd like to try a voltage doubler
filament supply (12v) to see what that does for hum. Also maybe AC filaments
(might not be possible).
Different plate resistor values and maybe choke loading this puppy instead
of the plate resistor. This could possibly be a real breakthrough I think, but
I don't have a clue how to do it.
And lastly, I'm working putting the 6BQ5 PP line trannies on the outputs.
I've got them hacked in now, but the B+ is too high and I'm using a dropping
resistor to get it down. I've ordered a new 150V PS trannie to take it down
and it should be here by the weekend I hope. Hum is still a problem and
I'll address that when I redo the power supply. But the sound is otherwise
quite good and it did beat out my parallel 12AU7 Welborne linestage in the
detail department, so I'm going with it. I'll report later when I get the
new PS trannie installed.
So please report any findings as I will be interested in hearing about
them myself.
FWIW,
- Ralph
=========================================================================
From: RALPH POWER <POWER.RALPH@epamail.epa.gov>
Subject: 5687 linestage - sound report
Date: Mon, 07 Dec 1998 13:39:45 -0500
Source: Sound Digest Archive v01.n524
Hi All,
After living with an interim version of the 5687 linestage (ss power supply and cap
output) for a couple of weeks, I can now say that it is definitely an improvement
over my Welborne Labs hybrid 12AU7 linestage in my system.
It is decidedly more transparent and can resolve more detail and spatial cues
than the WL preamp. It also can drive my amps with more authority and without
strain. Surprisingly I found the AN paper and oil output caps more to my liking
than the Hovlands. As David Home says, I guess I'm just an oiler, carbon comp
kind of guy.
Another unforeseen benefit has been the improvement in the sound of my
phono preamp when played through this linestage. It has really clarified and
cleaned up peaks and fleshed out the dynamics of my phono stage. In hindsight
it makes me wonder if my old linestage had clipping or slewing problems. This
linestage also has more gain to give in the final reaches of the volume control
than the WL, which is a real benefit to my gain challenged AVA PAS derived
phono board.
I have settled on the 7119 as my tube of choice over the Phillips, Tungsol, and
RCA 5687s and the 7044, but each type has good things of it's own.
While I'm waiting for the Electraprint line output trannies to arrive, I've been
building a 5Y3 rectified outboard power supply to get the PS out of the
linestage cabinet, as I've determined this is a must to avoid hum. I finally got
it stuffed into a small Rat Shack project box (ventilated, $6.99) over the weekend
and will build a connecting cable tonight. I'm using five pin DIN sockets and
connectors to make the cable, it seems OK so far.
I'll try out the new outboard PS first to see what improvements I can garner there,
and then add the output trannies later when they arrive.
I'll keep everyone posted on new developments,
- Ralph
=========================================================================
From: "Chris Beck" <cbeck@brewercompany.com>
Subject: Re: 5687 linestage - sound report
Date: Mon, 7 Dec 1998 13:47:56 -0600
Source: Sound Digest Archive v01.n525
Hi, Ralph.
For what it's worth, I'm still chasing a little hum in my preamp. I have a
new power tranny coming, as the one I'm using is marginal. I have some 120
Hz ripple coming in from somewhere, and it could be ground related. I
think it's the filament supply, as the hum is there even with the rectifier
pulled before the caps drain down. I have plenty of filtering, so it's a
weird one. The hum is rather slight, but enough to be a problem when I go
to horns. It just might even me magnetic coupling onto the ground buss
within the power supply chassis. This particular preamp is a test bed
until I get a phono stage that I like, etc.
I'm curious, are you getting potted OPT's from Jack? That's my next
avenue. Get the power and OPT's potted to get everything on one chassis.
It works well.
Chris Beck
See my web page at: http://www.execpc.com/~n9zes/index.htm
- ----------
> From: RALPH POWER <POWER.RALPH@epamail.epa.gov>
> To: sound@deliverator.io.com
> Subject: 5687 linestage - sound report
> Date: Monday, December 07, 1998 12:39 PM
>
>
> Hi All,
>
> After living with an interim version of the 5687 linestage (ss power
supply and cap
> output) for a couple of weeks, I can now say that it is definitely an
improvement
> over my Welborne Labs hybrid 12AU7 linestage in my system.
>
> It is decidedly more transparent and can resolve more detail and spatial
cues
> than the WL preamp. It also can drive my amps with more authority and
without
> strain. Surprisingly I found the AN paper and oil output caps more to my
liking
> than the Hovlands. As David Home says, I guess I'm just an oiler, carbon
comp
> kind of guy.
>
> Another unforeseen benefit has been the improvement in the sound of my
> phono preamp when played through this linestage. It has really clarified
and
> cleaned up peaks and fleshed out the dynamics of my phono stage. In
hindsight
> it makes me wonder if my old linestage had clipping or slewing problems.
This
> linestage also has more gain to give in the final reaches of the volume
control
> than the WL, which is a real benefit to my gain challenged AVA PAS
derived
> phono board.
>
> I have settled on the 7119 as my tube of choice over the Phillips,
Tungsol, and
> RCA 5687s and the 7044, but each type has good things of it's own.
>
> While I'm waiting for the Electraprint line output trannies to arrive,
I've been
> building a 5Y3 rectified outboard power supply to get the PS out of the
> linestage cabinet, as I've determined this is a must to avoid hum. I
finally got
> it stuffed into a small Rat Shack project box (ventilated, $6.99) over
the weekend
> and will build a connecting cable tonight. I'm using five pin DIN
sockets and
> connectors to make the cable, it seems OK so far.
>
> I'll try out the new outboard PS first to see what improvements I can
garner there,
> and then add the output trannies later when they arrive.
>
> I'll keep everyone posted on new developments,
>
> - Ralph
>
>
=========================================================================
From: "Chris Beck" <cbeck@brewercompany.com>
Subject: Re: 5687 linestage - sound report
Date: Mon, 7 Dec 1998 14:55:39 -0600
Source: Sound Digest Archive v01.n525
The heaters are rectified with a bridge and 30,000uF of filtering, with a
little resistance to drop voltage to 6.3V. This DC uses a separtate lead
AND ground return from the preamp chassis to the power supply, and is in no
way connected to the preamp chassis itself.
The heater ground and B+ ground are connected only at the star ground on
the power supply chassis, which is the B+ center tap. The signal grounds,
cathode grounds, and B+ grounds are all tied at a star point in the preamp.
Then this runs via separate ground wire to the power supply chassis, where
it is tied to the aforementioned star at the B+ center tap.
I did have the filament supply completely floating at one point, but that
gave a lot of phono stage hum. I don't remember whether that helped the
linestage, though. I'm probably getting some big ground loop running here,
huh? I'll try a few things tonight and see what happens. The phono stage
itself is about to get a rebuild, so I'll take the opportunity to really
dive into the grounding scheme I want to use. The thing sounds so damn
good I don't want to take it out of the system.
Maybe float the filament grounds, but tie a cap to earth ground to suppress
noise?
CHris
- ----------
> From: evaguido <EvaGuido@iaehv.nl>
> To: Chris Beck <cbeck@brewercompany.com>; RALPH POWER
<POWER.RALPH@epamail.epa.gov>; sound@deliverator.io.com
> Subject: Re: 5687 linestage - sound report
> Date: Monday, December 07, 1998 2:22 PM
>
> Chris,
>
> Do you rectify the heaters ? If so, how is the heater circuit related
with
> the line circuit ?
>
> Do you have AC heater wiring runing in the neighbourhood of the circuit ?
> Does the heater take part in the ground wiring ?
>
> Guido
>
> At 13:47 7-12-98 -0600, Chris Beck wrote:
> >Hi, Ralph.
> >
> >For what it's worth, I'm still chasing a little hum in my preamp. I
have a
> >new power tranny coming, as the one I'm using is marginal. I have some
120
> >Hz ripple coming in from somewhere, and it could be ground related. I
> >think it's the filament supply, as the hum is there even with the
rectifier
> >pulled before the caps drain down. I have plenty of filtering, so it's
a
> >weird one. The hum is rather slight, but enough to be a problem when I
go
> >to horns. It just might even me magnetic coupling onto the ground buss
> >within the power supply chassis. This particular preamp is a test bed
> >until I get a phono stage that I like, etc.
> >
> >I'm curious, are you getting potted OPT's from Jack? That's my next
> >avenue. Get the power and OPT's potted to get everything on one
chassis.
> >It works well.
> >
> >Chris Beck
=========================================================================
From: "Chris Beck" <cbeck@brewercompany.com>
Subject: Re: 5687 linestage - sound report
Date: Mon, 7 Dec 1998 16:33:12 -0600
Source: Sound Digest Archive v01.n525
Torbjørn,
Yes, you've mentioned this before to me. Just call me stubborn! :-) The
issue I have is that the hum is there whether there is B+ being rectified
or not. That is, even when the preamp is running on nothing but the stored
energy in the B+ capacitors when I pull the rectifier tube, it has the hum.
The hum stops when I turn off the power supply, which kills the filament
supply as well as main power tranny. The filament supply runs off a
separate transformer. The main power tranny only does B+ and rectifier
heating.
That tells me (I think) that the noise is coming in from somewhere else.
Poor ground layout, poor heater supply, etc.) I KNOW this preamp can be
quiet, as I've heard it on 100dB horns. There was only the slightest faint
hum. Entirely acceptable. Mine is a bit worse, on 90dB speakers. So,
that leads me to believe I have a problem. I've mentioned this before here
on the list, and really haven't done much since then. Like I said, I have
a new power tranny coming to replace the current one, and have been waiting
upon that to really dig into the thing again. I'm going to fire up the
soldering iron tonight and fiddle around.
Chris Beck
See my web page at: http://www.execpc.com/~n9zes/index.htm
- ----------
> From: Torbjørn Lien <mdrivekl@online.no>
> Dear Christopher.
>
> I guess I've posted on these troubles before,- the single loner
> shouting nooo! You cannot do this!!
> I'll try a different approach: The small hum you're experiencing
> is a part of your circuit's design virtues!
>
> Assuming you have builded It all correct with respect to wire-
> layout, shielding etc, the reason is this:
> Your grid is *not* referenced to the same point as your kathode.
> Between your grid ref.point and cathode, there is a tiny noise
> signal, that gets amplified,-
>
> The mechanism is this one:
>
> 1. You have a real tiny amount of ripple on your B+ point. This
> ripple cannot exist over the *last* cap, near the tube. So the noise
> signal is found, divided, some of it across the B+ feed resistor,
> and some across the "B- feed", or should we say kathode resistor....
>
> First one is harmless,-but the noise across your kathode-resistor,
> is *between* your grid and cathode,-same place you put your music
> signal...
>
> Regards,
> Torbjoern Lien
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: 5687 linestage - sound report
Date: Mon, 07 Dec 1998 21:22:22 +0100
Source: Sound Digest Archive v01.n525
Chris,
Do you rectify the heaters ? If so, how is the heater circuit related with
the line circuit ?
Do you have AC heater wiring runing in the neighbourhood of the circuit ?
Does the heater take part in the ground wiring ?
Guido
At 13:47 7-12-98 -0600, Chris Beck wrote:
>Hi, Ralph.
>
>For what it's worth, I'm still chasing a little hum in my preamp. I have a
>new power tranny coming, as the one I'm using is marginal. I have some 120
>Hz ripple coming in from somewhere, and it could be ground related. I
>think it's the filament supply, as the hum is there even with the rectifier
>pulled before the caps drain down. I have plenty of filtering, so it's a
>weird one. The hum is rather slight, but enough to be a problem when I go
>to horns. It just might even me magnetic coupling onto the ground buss
>within the power supply chassis. This particular preamp is a test bed
>until I get a phono stage that I like, etc.
>
>I'm curious, are you getting potted OPT's from Jack? That's my next
>avenue. Get the power and OPT's potted to get everything on one chassis.
>It works well.
>
>Chris Beck
>
>See my web page at: http://www.execpc.com/~n9zes/index.htm
>
>----------
>> From: RALPH POWER <POWER.RALPH@epamail.epa.gov>
>> To: sound@deliverator.io.com
>> Subject: 5687 linestage - sound report
>> Date: Monday, December 07, 1998 12:39 PM
>>
>>
>> Hi All,
>>
>> After living with an interim version of the 5