Sound Practices Mailing List Files - Volume 2
=========================================================================
From: longrie@mmace.nrl.navy.mil
Subject: [JN] Re: QED
Date: Mon, 08 Feb 1999 11:19:54 +0000
Source: Sound Digest Archive v02.n033
>Date: Fri, 5 Feb 1999 15:15:11 -0500 (EST)
>From: Tim Reese <tgrmail@nmr.MGH.harvard.EDU>
>Subject: Re: [JN] QED
>QED is neat stuff; I don't remember much about it now except for the quantum
>equivalence of electricity and magnetism ... undergraduate physics was long
>ago, and since then I've had my head stuffed with neutron transport and other
>worthless topics. For thode interested, I'd recommend the spectacular
>"Feynmann Lectures in Physics" - great stuff for beefing up your physical
>intuition, and accessible.
>
>Richard Feynmann came to speak to the undergrads when I was at UCI, which
>he mentions anecdotally in one of his popular press books ("Surely you
>must be joking, Mr. Feynmann" maybe). He lectured on QCD (quantum chromo-
>dynamics) and made it seem simple, almost obvious - wow, what a guy.
>
>Also read his "The Character of Physical Law" if you come across it.
>
>cheers tr
>- ----------------------------------------------------------------------
>Tim Reese, MGH NMR Center reese@nmr.MGH.harvard.edu
>
>------------------------------
Tim, I will second that, third it and ... nth it.
Feynman was the man. He played with vacuum tubes as a kid,
taking apart and fixing radios for sport. See what can
happen when you start 'em young?
BTW, Mr. Spock took apart tricorders when he was a kid.
Did you know that spock is 'sparks' in vulcan?
gary
=========================================================================
From: Alex Megann <Alex.P.Megann@soc.soton.ac.uk>
Subject: [JN] QED (was: Capacitor Blind Test)
Date: Thu, 4 Feb 1999 11:17:07 GMT
Source: Sound Digest Archive v02.n027
Tim Reese wrote:
"At the risk of veering off topic (and not intending to insult Mr. Danley),
Tom, you couldn't be more wrong. QED has no control over our gear - QED is a
human construct conceived and intended to describe and predict how the
physical world works. The physical world operates under its own rules and
constraints, which our puny minds (well, my puny mind) struggle to
comprehend."
I don't know whether I'm agreeing or disagreeing with you, Tim,
(or maybe neither!). Just out of general interest, the theory of
Quantum Electrodynamics, which is the theory of how matter
interacts with electromagnetic fields, has probably been tested
and confirmed with greater precision than the Newtonian theory
of gravitation (it's easier since the fields are stronger). The
picture of reality which QED gives us is strikingly different from
our everyday experience of people-sized objects - the "vacuum" is
actually buzzing with energy, with particles and photons fizzing in
and out of existence, while it also explains why electrons circling
atoms don't spiral into the atomic nuclei in a fraction of a
microsecond, which is what classical electrodynamics would predict.
Alex
=========================================================================
From: Tim Reese <tgrmail@nmr.MGH.harvard.EDU>
Subject: Re: [JN] QED (was: Capacitor Blind Test)
Date: Fri, 5 Feb 1999 15:15:11 -0500 (EST)
Source: Sound Digest Archive v02.n029
Alex wrote
>Tim Reese wrote:
>
>"At the risk of veering off topic (and not intending to insult Mr. Danley),
>Tom, you couldn't be more wrong. QED has no control over our gear - QED is a
>human construct conceived and intended to describe and predict how the
>physical world works. The physical world operates under its own rules and
>constraints, which our puny minds (well, my puny mind) struggle to
>comprehend."
>
>I don't know whether I'm agreeing or disagreeing with you, Tim,
>(or maybe neither!).
Could be both, or neither, or somewhere in between... it was an off-handed
remark, and made what in hindsight seems like a semantic point.
QED is neat stuff; I don't remember much about it now except for the quantum
equivalence of electricity and magnetism ... undergraduate physics was long
ago, and since then I've had my head stuffed with neutron transport and other
worthless topics. For thode interested, I'd recommend the spectacular
"Feynmann Lectures in Physics" - great stuff for beefing up your physical
intuition, and accessible.
Richard Feynmann came to speak to the undergrads when I was at UCI, which
he mentions anecdotally in one of his popular press books ("Surely you
must be joking, Mr. Feynmann" maybe). He lectured on QCD (quantum chromo-
dynamics) and made it seem simple, almost obvious - wow, what a guy.
Also read his "The Character of Physical Law" if you come across it.
cheers tr
- ----------------------------------------------------------------------
Tim Reese, MGH NMR Center reese@nmr.MGH.harvard.edu
=========================================================================
From: "pagebleu" <pagebleu@globetrotter.qc.ca>
Subject: [JN] Quad
Date: Sat, 29 Jan 2000 11:52:14 +0100
Source: Sound Digest Archive v02.n424
This is a multi-part message in MIME format.
- ------=_NextPart_000_0024_01BF6A4F.48BD7640
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Hi there,
In case there "could" be some interest. I have a "Quad control unit =
QCII" mono, and its mate the AM tuner, for sale.
If anybody interested, just email me at pagebleu@quebectel.com=20
Thanks
Now back to the soldering gun...
Sylvain
- ------=_NextPart_000_0024_01BF6A4F.48BD7640
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
<HTML>
<HEAD>
<META content=3Dtext/html;charset=3Diso-8859-1 =
http-equiv=3DContent-Type>
<META content=3D'"MSHTML 4.72.3110.7"' name=3DGENERATOR>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV>
<DIV>Hi there,</DIV>
<DIV> </DIV>
<DIV>In case there "could" be some interest. I have a =
"Quad=20
control unit QCII" mono, and its mate the AM tuner, for sale.</DIV>
<DIV> </DIV>
<DIV>If anybody interested, just email me at <A=20
href=3D"mailto:pagebleu@quebectel.com">pagebleu@quebectel.com</A> </DIV>
<DIV> </DIV>
<DIV>Thanks</DIV>
<DIV> </DIV>
<DIV>Now back to the soldering gun...</DIV>
<DIV> </DIV>
<DIV>Sylvain</DIV></DIV></BODY></HTML>
- ------=_NextPart_000_0024_01BF6A4F.48BD7640--
=========================================================================
From: "wmollard" <wmollard@dowco.com>
Subject: [JN] Quad ESL-57 and SE R120
Date: Sat, 23 Sep 2000 19:30:23 -0700
Source: Sound Digest Archive v02.n671
Hey Joes,
Interesting to hear a couple of recent comments on electrostatics. While
waiting for some "real" speakers I had the opportunity to grab some ESL-57s.
The amp is nothing special, a 7788 interstaged into an R120 using an FS-050
airgapped tranny. The trannies have about 25 hours on them so I tried to
stay away from any critical listening. But dang if I just don't keep finding
my self spinning one CD after another. If anyone has said ESL have no bass I
beg to differ...deep and detailed. They aren't as dynamic as Lowthers or
eXemplars (what is) and the highs are a wee bit rolled off but they have an
incredible detail, clarity and emotional presence.
Although they were only meant to be a passing experiment they have me
thinking... and my wife worrying because I have enough for a stacked pair.
Most comments about Quad ESLs and SE tube amps focus on the problems of
driving the speaker's capacitive load. What specific problems occur when an
SE tube amp is used to drive the Quad's capacitive load. It would seem the
larger transformers would provide an emf buffer for the low high frequency
reactance. Would the use of a higher primary opt, say 10K driving a 211,
resolve the issue... it would the 5W R120 power issue.
BTW, I was also play around with the Black Art 417A opt and a one tube 7788
amp. While the 7788 is a bit analytical at the operating point I was using,
these
opts are the cat's pajamas for voicing input / driver tubes... unless of
course you are
using 86 dbl speaks like the Quads.
TIA
Bill Mollard
=========================================================================
From: John Levreault <jlevro@mediaone.net>
Subject: Re: [JN] Quad ESL-57 and SE R120
Date: Sun, 24 Sep 2000 10:32:50 -0400
Source: Sound Digest Archive v02.n671
wmollard wrote:
>
>
> The amp is nothing special, a 7788 interstaged into an R120 using an FS-050
> airgapped tranny.
Sounds special enough!
JL
=========================================================================
From: "pagebleu" <pagebleu@globetrotter.qc.ca>
Subject: [JN] Quad for sale
Date: Sat, 29 Jan 2000 11:49:53 +0100
Source: Sound Digest Archive v02.n424
This is a multi-part message in MIME format.
- ------=_NextPart_000_000E_01BF6A4E.F470F4E0
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Hi there,
In case there "could" be some interest. I have a "Quad control unit =
QCII" mono, and its mate the AM tuner, for sale.
If anybody interested, just email me at pagebleu@quebectel.com=20
Thanks
Now back to the soldering gun...
Sylvain
- ------=_NextPart_000_000E_01BF6A4E.F470F4E0
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
<HTML>
<HEAD>
<META content=3Dtext/html;charset=3Diso-8859-1 =
http-equiv=3DContent-Type>
<META content=3D'"MSHTML 4.72.3110.7"' name=3DGENERATOR>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV>Hi there,</DIV>
<DIV> </DIV>
<DIV>In case there "could" be some interest. I have a =
"Quad=20
control unit QCII" mono, and its mate the AM tuner, for sale.</DIV>
<DIV> </DIV>
<DIV>If anybody interested, just email me at <A=20
href=3D"mailto:pagebleu@quebectel.com">pagebleu@quebectel.com</A> </DIV>
<DIV> </DIV>
<DIV>Thanks</DIV>
<DIV> </DIV>
<DIV>Now back to the soldering gun...</DIV>
<DIV> </DIV>
<DIV>Sylvain</DIV></BODY></HTML>
- ------=_NextPart_000_000E_01BF6A4E.F470F4E0--
=========================================================================
From: "Ed Coleman" <ecoleman@whidbey.net>
Subject: [JN] Quad schematic?
Date: Thu, 18 Jan 2001 12:09:51 -0800
Source: Sound Digest Archive v02.n786
- --Hi Joes, I pulled a Quad 405 outta the trash last week ,(it's solid state,
I know, I know....) and was wonderin' where I might find a schematic for it
? thanks Ed
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: Re: [JN] Quad schematic?
Date: Thu, 18 Jan 2001 13:38:16 +0000
Source: Sound Digest Archive v02.n786
Hi Ed:
> --Hi Joes, I pulled a Quad 405 outta the trash last week ,(it's solid state,
> I know, I know....) and was wonderin' where I might find a schematic for it
> ? thanks Ed
Lucky you . . about half a day's work will turn that power amp into a
*surprisingly* good unit.
While I don't have the particulars, I've forwarded this mail to a friend
who has done several of these so maybe - - Hello John - - he can provide me
with some info that I can post
Bill - PEARL, Inc.
=========================================================================
From: "David B. Klein" <dklein@microtec.net>
Subject: [JN] Re: Quad stands
Date: Wed, 29 Sep 1999 20:54:27
Source: Sound Digest Archive v02.n289
I'm looking for plans for individual stands for Quad 57s, *other* than the
Sheldon Stokes model. Anyone?
TIA,
dbk
=========================================================================
From: David Barnett <davidbarnett@aristotle.net>
Subject: Re: [JN] Re: Quad stands
Date: Thu, 30 Sep 1999 01:21:51 -0500
Source: Sound Digest Archive v02.n289
On Wed, 29 Sep 1999 20:54:27, "David B. Klein" <dklein@microtec.net>
wrote:
>I'm looking for plans for individual stands for Quad 57s, *other* than the
>Sheldon Stokes model.
I use concrete blocks to elevate mine. Three per '57.
- --dnb
=========================================================================
From: "David B. Klein" <dklein@microtec.net>
Subject: Re: [JN] Re: Quad stands
Date: Thu, 30 Sep 1999 02:42:20
Source: Sound Digest Archive v02.n289
A 01:21 AM 9/30/99 -0500, David Barnett a écrit :
>On Wed, 29 Sep 1999 20:54:27, "David B. Klein" <dklein@microtec.net>
>wrote:
>
>>I'm looking for plans for individual stands for Quad 57s, *other* than the
>>Sheldon Stokes model.
>
>I use concrete blocks to elevate mine. Three per '57.
>
>--dnb
How do you find that works out esthetically?
dk
=========================================================================
From: "STEVE CORNETT" <SCORNETT@usagroup.com>
Subject: Re: [JN] Re: Quad stands
Date: Thu, 30 Sep 1999 12:56:34 -0500
Source: Sound Digest Archive v02.n290
David asked:
"...I'm looking for plans for individual stands for Quad 57s, *other* than the Sheldon Stokes model.
.."
Why would you want to take a speaker designed to work sitting on the floor, and lift it into the air
? :-)
Really, I've heard 57's and owned 63's, and I like them best on the floor. No mid-bass cancellation
to mess things up. Why elevate them?
Steve C.
=========================================================================
From: David Barnett <davidbarnett@aristotle.net>
Subject: Re: [JN] Re: Quad stands
Date: Thu, 30 Sep 1999 13:37:49 -0500
Source: Sound Digest Archive v02.n290
On Thu, 30 Sep 1999 02:42:20, "David B. Klein" <dklein@microtec.net>
wrote:
>>I use concrete blocks to elevate mine. Three per '57.
>How do you find that works out esthetically?
1) I misspoke. I use two blocks per QUAD.
2) As for aesthetics, that all depends on how much you like the look
of unfinished construction materials in your listening room. <G>
- --dnb
=========================================================================
From: "David B. Klein" <dklein@microtec.net>
Subject: Re: [JN] Re: Quad stands
Date: Thu, 30 Sep 1999 16:28:02
Source: Sound Digest Archive v02.n290
A 12:56 PM 9/30/99 -0500, STEVE CORNETT a écrit :
>David asked:
>
>"...I'm looking for plans for individual stands for Quad 57s, *other* than
the Sheldon Stokes model..."
>
>Why would you want to take a speaker designed to work sitting on the
floor, and lift it into the air? :-)
>
>Really, I've heard 57's and owned 63's, and I like them best on the floor.
No mid-bass cancellation to mess things up. Why elevate them?
>
>Steve C.
This is a reasonable argument - but I think 57s work best slightly elevated
- - say, 8 inches - not high enough to cause major diffraction or
cancellation in the lower midrange, but high enough to get closer to ear
level. With the original feet they are really low, and angled upwards in a
way that provides poor vertical coverage for the seating in modern living
rooms - slight vertical head movement produces a huge change in tone.
Properly elevated and tilted toward the horizontal they produce a brighter
and more even sound.
Cheers,
David
=========================================================================
From: "David B. Klein" <dklein@microtec.net>
Subject: Re: [JN] Re: Quad stands
Date: Thu, 30 Sep 1999 16:29:07
Source: Sound Digest Archive v02.n290
A 01:37 PM 9/30/99 -0500, David Barnett a écrit :
>On Thu, 30 Sep 1999 02:42:20, "David B. Klein" <dklein@microtec.net>
>wrote:
>
>>>I use concrete blocks to elevate mine. Three per '57.
>
>>How do you find that works out esthetically?
>
>1) I misspoke. I use two blocks per QUAD.
>
>2) As for aesthetics, that all depends on how much you like the look
>of unfinished construction materials in your listening room. <G>
>
>--dnb
>
>
LOL!
=========================================================================
From: David Barnett <davidbarnett@aristotle.net>
Subject: Re: [JN] Re: Quad stands
Date: Thu, 30 Sep 1999 18:38:32 -0500
Source: Sound Digest Archive v02.n290
On Thu, 30 Sep 1999 12:56:34 -0500, "STEVE CORNETT"
<SCORNETT@usagroup.com> wrote:
>Why would you want to take a speaker designed to work sitting on the floor, and lift it into the ai
r? :-)
To go from a "first row balcony" perspective to an "orchestra"
perspective.
- --dnb
=========================================================================
From: Triodont@aol.com
Subject: Re: [JN] Re: Quad stands
Date: Fri, 1 Oct 1999 03:25:21 EDT
Source: Sound Digest Archive v02.n290
In a message dated 99-09-30 16:55:34 EDT, you write:
<< David asked:
>
>"...I'm looking for plans for individual stands for Quad 57s, *other* than
the Sheldon Stokes model..."
> >>
i recently had the quad esl's in-house, and was scheming to build some stands
for them that would look like blackboard stands (the quads being the
blackboards), comprising of wooden columns on the sides bolted in to the
second holes on the wooden cheeks where the stock screws normally go, and a
base that would make everything stable. it would look like the stands for the
stax f-81, if you are familiar with those, and you could tilt the quads
eitherway (like the arcicis). you could stain and finish the wood similar to
the rosewood cheeks for nice aesthetics. a couple of weeks, though, made me
decide that the quads aren't for me, so i shelved the project, although i
respect them and all :)
regards,
ramon
=========================================================================
From: "David B. Klein" <dklein@microtec.net>
Subject: Re: [JN] Re: Quad stands
Date: Fri, 01 Oct 1999 03:36:05
Source: Sound Digest Archive v02.n290
A 03:25 AM 10/1/99 EDT, Triodont@aol.com a écrit :
>In a message dated 99-09-30 16:55:34 EDT, you write:
>
><< David asked:
> >
> >"...I'm looking for plans for individual stands for Quad 57s, *other* than
> the Sheldon Stokes model..."
> > >>
>
>i recently had the quad esl's in-house, and was scheming to build some
stands
>for them that would look like blackboard stands (the quads being the
>blackboards), comprising of wooden columns on the sides bolted in to the
>second holes on the wooden cheeks where the stock screws normally go, and a
>base that would make everything stable. it would look like the stands for
the
>stax f-81, if you are familiar with those, and you could tilt the quads
>eitherway (like the arcicis). you could stain and finish the wood similar to
>the rosewood cheeks for nice aesthetics. a couple of weeks, though, made me
>decide that the quads aren't for me, so i shelved the project, although i
>respect them and all :)
>
>regards,
>ramon
>
That is one idea I did have; the other is something with a base and pillars
going to the bottom of the speaker. The Quad 57s certainly aren't
everybody's cup of tea :-) I'm assembling a 3-channel array with
biamplification, subwoofers and solid state amplification, so the system
will be hitting 106+ dB in my modest living room. Not your father's Quad
system.
Best,
David Klein
=========================================================================
From: Roscoe Primrose <roscoe@aiko.com>
Subject: Re: Re : [JN] Quantum mechanics (was audio oxymoron)
Date: Wed, 03 May 2000 11:49:11 -0400
Source: Sound Digest Archive v02.n538
Martin Seddon wrote:
>
> Thanks to WMollard for the illuminating post.
> >>>(let's leave Heizenberg's "nonsense of existence" principle
> for another day)<<<
>
> I would like to recommend a great book for all those interested in getting
> a glimpse of the totally mind boggling nature of reality we are faced with
> by Quantum Mechanics.
>
> In Search of Schrodingers Cat
> John Gribben
> ISBN 0-552-12555-5
> Black Swan / Corgi
>
>
Just for reference, Barnes & Noble has isbn 0553342533 for this book,
11.96 in paperback.
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: "Jon Lane" <jhlane@email.msn.com>
Subject: RE: Re : [JN] Quantum mechanics (was audio oxymoron)
Date: Wed, 3 May 2000 12:14:48 -0600
Source: Sound Digest Archive v02.n538
> I would like to recommend a great book for all
> those interested in getting
> a glimpse of the totally mind boggling nature of
> reality we are faced with
> by Quantum Mechanics.
>
> In Search of Schrodingers Cat
> John Gribben
> ISBN 0-552-12555-5
> Black Swan / Corgi
Another: The Dancing Wu Li Masters by Gary Zukav...
Jon Lane
=========================================================================
From: Martin Seddon <mseddon@iinet.net.au>
Subject: Re : [JN] Quantum mechanics (was audio oxymoron)
Date: Wed, 03 May 2000 23:08:41 +0800
Source: Sound Digest Archive v02.n538
Thanks to WMollard for the illuminating post.
>>>(let's leave Heizenberg's "nonsense of existence" principle
for another day)<<<
I would like to recommend a great book for all those interested in getting
a glimpse of the totally mind boggling nature of reality we are faced with
by Quantum Mechanics.
In Search of Schrodingers Cat
John Gribben
ISBN 0-552-12555-5
Black Swan / Corgi
John Gribben recounts the historical development of QM and draws the
distinction between "Quantum Cookery" (practical usage - lasers, LEDs,
A-weapons - all invented by application of QM) and the desperate efforts to
make sense of it.
QM confronts us, theoretically and empirically (at military budget order
expense) with a reality that is more like tripping on LSD.
'what happens to all those ghostly quantum worlds that collapse with their
wave functions when we make a measurement of the sub atomic system? How can
an overlapping reality, no more or less real than the one we eventually
measure, simply disapear when the measurement is made?'
Martin
=========================================================================
From: "Daniel J. Marshall" <danmarshall@worldnet.att.net>
Subject: [JN] Quasi-SE
Date: Sat, 01 Jul 2000 06:34:13 -0700
Source: Sound Digest Archive v02.n593
Hi All,
Sooner or later, most newbie-tubies want to try SE and then ask the
question "is it OK to use PP output transformers for SE", then, when
learning of the core saturation problem, come up with the idea of
loading one side of the primary with a resistor, pentode, current
source, whatever, to balance out the dc current.
As it turns out, a cathode biased PP output stage, without a cathode
bypass resistor, one grid grounded and the other grid driven, produces a
waveform and distortion spectrum remarkable similar to a SE amp, i.e., a
fairly strong second harmonic with higher order distortion products
declining at roughly 10 to 15 dB for each successively higher harmonic.
I suppose we could call it a short-tailed pair (or perhaps a poor man's
SE amp). Here the cathode of the second output tube receives some drive
from the cathode of the first tube (and also balances out the dc
component). The output Z likely would be higher than a standard PP
configuration, perhaps twice as high, but with low rp tubes might still
be acceptable. I have not made Zo measurements, but will try to do so
later today. Perhaps this has been discussed here before, but I don't
recall seeing it discussed here, or anywhere else. Has anyone
experimented with this circuit configuration before?
I quickly modified a PP amp late yesterday, an EICO HF-22 with triode
strapped EL34s, IT coupled. Maximum power output was diminised a
little, but not a great deal, perhaps 20 percent, or so. I did a
quickie listening test, but the gain was to low to get it up to a normal
listening level. When comparing it to the SE KT66 amp I mentioned
recently (6EA7 - bridged Allied IT - KT66 - Hammond 1629SE), I didn't
notice a great deal of difference. I would hasten to add, that the
listening test was quite brief and the gain was a bit low, so I have not
drawn final conclusions. Maximum power output was around 8 watts for
the EICO amp when driven by a signal generator. Some undoubtedly will
bring up the zero (magnetic) crossing aspect, which is different than a
biased SE output transformer, but then, so is parafeed, which some claim
sounds quite good.
Any thoughts on this?
Dan Marshall
=========================================================================
From: "Daniel J. Marshall" <danmarshall@worldnet.att.net>
Subject: Re: [JN] Quasi-SE
Date: Sun, 02 Jul 2000 15:04:39 -0700
Source: Sound Digest Archive v02.n594
> > I suppose we could call it a short-tailed pair (or perhaps a
> > poor man's SE amp). Here the cathode of the second output tube
> > receives some drive from the cathode of the first tube (and also
> > balances out the dc component).
>
> Actually, wouldn't separate cathode resistors work better.
No, not really. If so, you would have to make the opposite side a
current source, a pentode, or the like, and if they were cathode biased,
the one on the amplifying side would need to be bypassed with a nasty
ol' electrolytic, plus you would now be operating into a quarter of the
original impedance. This likely would be too low for many tubes.
> I don't think you really want the AC component from the driven tube
> getting into the one that's just delivering the DC current to
> balance the transformer.
Why not, its an ordinary differential amplifying stage, using a bit
lower resistor in the cathode circuit and being driven on one side to
intentionally give an output waveform and a distortion spectrum similar
to a SE amplifier, except with more power and using a more easily
scroungable PP output transformer. It would not likely blow away a
pricey output transformer and genuine DHT audio triode, but might be
more to your liking than a conventional PP amplifier, which has an
entirely different distortion spectrum.
You refer to the signal "getting into the one that's just delivering the
DC current to balance the transformer". This is not the case at all.
The "other" output tube is also providing much of the drive, nearly as
much as the first tube. Better stated, the first tube is providing
drive signal to the second tube, or, acting as a phase inverter, if you
prefer. An imperfect one, to be sure, but one that has the property of
generating a distortion spectrum similar to a SE amplifier.
The drive voltage required to the first output tube would be nearly
twice the voltage required to drive a single tube. Anyone using this
hare-brained scheme would likely be modifying a vintage PP amplifier
which would likely have pentode output tubes. Such a mod would be
relatively easy, just triode-strap the pentodes, remove the cathode
bypass resistor, lift the drive from one grid, preferably the one being
driven by the cathode, if from a cathodyne inverter, then ground the
grid of that tube and perhaps modify the phase inverter for a bit more
gain and greater maximum signal swing. Details would vary, depending on
the original phase inverter circuit.
> Separate resistors would be more like the normal SE situation.
You get a lot more power in the Quasi-SE than you would from totally
separated tubes using a PP transformer while retaining the electrical
characteristics of an SE amp. I breadboarded the thing and made
spectrum analyzer measurements and noted the waveform on the scope, and
both look very similar to a SE amplifier with about 80 percent of the
maximum power of a PP amplifier. I am not speculating as to how I
surmise it might work, I am stating that I implemented it, took
measurements, and concluded that that is how it does work. I also
compared it with a fairly decent SE amp and found that they sounded
remarkably similar, both sounding better than PP amps. I previously had
the driver stage of this amp configured in the same manner and it also
sounded quite nice, better than conventional PP amps I had available at
the time. It used a 6CG7 driver tube and a UTC A-18 IT. Its distortion
spectrum also closely mimicked a SE amplifier.
On thing I have yet to do is to quantify the effect on the output
impedance, which will no doubt be a bit higher than a SE amp, since the
second tube is essentially being driven as a common grid stage and the
first tube has a finite value of cathode circuit impedance. I'll do
that a bit later.
Dan Marshall
>
> Dazz
>
=========================================================================
From: "Daniel J. Marshall" <danmarshall@worldnet.att.net>
Subject: Re: [JN] Quasi-SE
Date: Sun, 02 Jul 2000 17:21:45 -0700
Source: Sound Digest Archive v02.n594
> Another interesting post, Dan ... pardon my ignorance - maybe "cathode
> bypass resistor" refers to the cathode bias resistor?
Yeaaaah, that's what I meant to say. Having a senior moment, I
suppose. Or perhaps my entire right lobe was bypassed.
> Sounds like you're suggesting a shared cathode
> resistor with one driven and one grounded grid.
Yes.
>
> >On thing I have yet to do is to quantify the effect on the output
> >impedance, which will no doubt be a bit higher than a SE amp, since the
> >second tube is essentially being driven as a common grid stage and the
> >first tube has a finite value of cathode circuit impedance. I'll do
> >that a bit later.
>
> But still lower output Z than a pentode amp sans feedback?
Oh yes.
> Perhaps it'd make sense to keep a fraction of the
> original feedback to keep the Z acceptably low?
Hopefully, it would be low enough to not have to do that. If a fairly
high Z load were used, it might be OK.
> I presume you mean a typical DHT SE amp with no global
> feedback.
Yes.
Thanks for pointing out my incorrect terminology.
DM
=========================================================================
From: "Darryl Lock" <dklock@ieee.org>
Subject: RE: [JN] Quasi-SE
Date: Sun, 2 Jul 2000 18:23:14 +1000
Source: Sound Digest Archive v02.n594
> I suppose we could call it a short-tailed pair (or perhaps a poor man's
> SE amp). Here the cathode of the second output tube receives some drive
> from the cathode of the first tube (and also balances out the dc
> component).
>
Actually, wouldn't separate cathode resistors work better. I don't think
you really want the AC component from the driven tube getting into the one
that's just delivering the DC current to balance the transformer. Separate
resistors would be more like the normal SE situation.
Dazz
=========================================================================
From: Tim Reese <tgrmail@nmr.MGH.harvard.EDU>
Subject: Re: [JN] Quasi-SE
Date: Sun, 2 Jul 2000 20:12:09 -0400 (EDT)
Source: Sound Digest Archive v02.n594
Another interesting post, Dan ... pardon my ignorance - maybe "cathode
bypass resistor" refers to the cathode bias resistor? Sounds like you're
suggesting a shared cathode resistor with one driven and one grounded
grid.
>On thing I have yet to do is to quantify the effect on the output
>impedance, which will no doubt be a bit higher than a SE amp, since the
>second tube is essentially being driven as a common grid stage and the
>first tube has a finite value of cathode circuit impedance. I'll do
>that a bit later.
But still lower output Z than a pentode amp sans feedback? Perhaps it'd
make sense to keep a fraction of the original feedback to keep the Z
acceptably low? I presume you mean a typical DHT SE amp with no global
feedback.
tia tr
- ----------------------------------------------------------------------
Visit http://www.nmr.MGH.harvard.edu/~reese MRI, tube audio, reptiles
Tim Reese, MGH NMR Center reese@nmr.MGH.harvard.edu
=========================================================================
From: Dan Marshall <mdaniel7@uswest.net>
Subject: [JN] Quasi-SE Zo Measurements
Date: Wed, 12 Jul 2000 16:31:32 -0700
Source: Sound Digest Archive v02.n602
Hi All,
Someone inquired as to whether I had made the Zo measurements for the
Quasi-SE amp, which I had previously promised to do. Well, I just did a
quickie and thought perhaps others may be interested. In review,
Quasi-SE is the name I coined (as far as I know) to a modified PP
amplifier in cathode bias, no cathode bypass capacitor, one grid
grounded, the other grid driven.
The amp was a modified EICO HF22 (6,600 ohms primary) with a pair of
triode-strapped Sveltana Gold top EL34s. The amp was transformer
coupled to the output stage and one grid had been disconnected from the
IT and connected to ground. The input signal was connected directly
from a HP 200CD oscillator to the output grid so there was no other
mechanism for distortion to have to consider.
With the no-load output voltage set to 3 volts on the 8 ohm tap, an 8
ohm load resistor was connected to the 16 ohm tap (same as a 4 ohm to
the 8 ohm tap). The output voltage on the 8 ohm tap dropped from 3.0
volts to 1.61 volts. I then reconnected the grid that had been grounded
to the IT and repeated the measurement, i.e., on a normal PP circuit.
When the same load was applied, the 3 volt no-load voltage dropped to
1.59 volts, or essentially the same as for the Quasi-SE connection. I
fully expected the Quasi-SE to have a poorer damping factor (higher
output impedance) than normal PP, but, within experimental error, it
turned out to be the same. Hmmmm. I don't have a plausible explanation
for this at the moment, and, as I said, it was a quickie, as I had to
break off to attend to other matters.
I also recorded some distortion measurements. I previously stated that
the distortion spectrum looked quite similar to a conventional SE amp.
Here are the measurements. I was drive-voltage limited so they only go
up to 2.78 watts. Perhaps a more thorough measurement later.
Vo(V) Po(W) 2nd 3rd 4th 5th 6th 7th
1 0.125 -42 -66 >-80
2 0.50 -35 -60 >-80
2.83 1.00 -32 -53 -75 >-80
4 2.00 -28 -46 -65 -76 >-80
4.72 2.78 -26 -42 -54 -68 >-80
These figures seem somewhat higher than the initial measurements, but I
did not spend time to investigate why, or make any special effort to
optimize the bias current, so perhaps they could be improved. I did
have reason to suspect one of the output tubes. Though they checked OK,
they did exhibit more 2nd order distortion in PP than they should have,
so these measurements may not be the last word, but should give you the
general idea.
Anyway, here you see a sizable 2nd order harmonic with a declining
distortion spectrum similar to a SE amp, and it pretty much sounds like
a SE amp. Perhaps not the way to start a new design, but perhaps worth
considering when you feel the uncontrollable urge to scrounge PP output
trannys from the scrap heap to use in SE amps for the office, or
whatever. It certainly is a far superior approach than using PP trannys
as a conventional SE output, with dc bias on the core. The bass
response would not be compromised, as would it be with dc bias on the
core, plus they should easily outperform the little cheapie SE output
transformers. I will do more tweaking and listening later. Have been
busy playing with speakers lately.
Dan Marshall
=========================================================================
From: Cuno Snoeren <c.snoeren@tip.nl>
Subject: Re: [JN] question 2: CD-R
Date: Thu, 27 May 1999 00:01:05 +0200
Source: Sound Digest Archive v02.n152
Hi Murray
> how one can record analog input audio to CD.
You can copy it with your soundcard, and the software belonging to that
or a soundcard, for example Creative Sound LE or another program.
Select it at PCM mode, 44.100Hz;16-bits;Stereo 172kB/s.
This is the language CD's are recorded with.
Copy it first to your harddrive and then to your CD-R or CD-RW.
(Most Philips audio CD-mechanisms will also play CD-RW!!)
> I'm wondering if the 'full version' of the Adaptec software or some > other software allows the sa
ving of files as .cda (CD audio).
You mean PCM 44.1kHz. 16 bits stereo 172kB/s and soundcard (audio
recording) software.
> Also, how good a job can such a sound cards do with analog audio, say > from a turntable?
You will need a RIAA PU pre-amp, or connect your turntable to your
audio amplifier PU input, and your soundcard to the TAPE-OUT,
this way you use the RIAA pre amp of your amplifier.
I'm not looking for esoteric Joelist-quality, just something that
> at least exceeds the quality of typical audio cassette.
Depends on the sound quality of your soundcard....
But you can reach the quality expected.
Greetings, Cuno
http://www.ariel.club.tip.nl
http://www.triode.club.tip.nl
=========================================================================
From: Scott Grammer <tubedude@cdc.net>
Subject: Re: [JN] question 2: CD-R
Date: Wed, 26 May 1999 19:24:23 -0400
Source: Sound Digest Archive v02.n153
Cuno Snoeren wrote:
> (snip)
> (Most Philips audio CD-mechanisms will also play CD-RW!!)
Except for the inexpensive 3 disc changers perched atop Philips/Magnavox "rack" units. These will no
t play any recordable CD format, not
even cdr.
S.G.
- --
TubeDude's Webpage of Vacuum Tube Lore! http://www.cdc.net/~tubedude/
Smoke Free Youth! http://www.cdc.net/~tubedude/smokefreeyouth.html
The Price of Privacy. http://www.cdc.net/~tubedude/privacy.html
"This is a new focus for the security community." "The actual user of
the PC - someone who can do anything they want - is the enemy."
--David Aucsmith, security architect for the Intel Pentium III.
=========================================================================
From: StepHydro@aol.com
Subject: [JN] Question: A2293 / CV4079 in PP
Date: Sun, 23 Jul 2000 13:56:58 EDT
Source: Sound Digest Archive v02.n609
Tube data and curves:
http://albums.photopoint.com/j/View?u=149682&a=1102709&p=15066870&Sequence=0
http://www.jeack.com.au/~lucas/circuits.htm Scroll down, it's towards the
bottom of his circuits page.
I want to try this tube something awful (Southern US talk for "really badly"
:-)
I have a pair of PP OPTs designed for 5BQ5/EL84 in a Magnavox console amp.
The Zp-p is probably in the range of 8K-10K ohms for 8 ohms on the secondary.
Anyone have an opinion as to whether this will match? There is only one
secondary winding on the OPT, so I can't mess with different Zsec.
I've roughed in a SE load line on the GEC curves indicating a load of appx.
4.2K (quiescent 215V and 50 mA), which I think means that my 8-10K pp OPTs
are at least in the ballpark for a PP pair of these valves. I'd rather run
them at higher plate voltage and lower current, but am not familiar enough
with the design process to know what happens when you go "off the end" of the
published curves.
Help is appreciated :-)
Cheers/Carron
=========================================================================
From: Steve Van Osdell <svanos@queencity.com>
Subject: [JN] Question about 100Hz Edgarhorns
Date: Sun, 06 May 2001 22:11:54 -0400
Source: Sound Digest Archive v02.n880
Guys,
I just received my pair of 100Hz horns Friday from Bruce Edgar. I've
got no instructions or photographs to go, by so I need to ask some
opinions.
These horns are just the 'innards'. They are made to accept an Altec
15" woofer. In the back is a 'box' (or cover) that will, after the
woofer is installed, cover it. There are binding post inset into the
back of this cover. My question is about building the 'box' to house
the horn. It appears that since there are binding posts on the back of
the rear cover, that this obviously wasn't meant to be closed up inside
a box. So, it appears to me that the enclosure would consist of just
four sides and the back of the enclosure will then become the bulkhead
that the woofer is mounting to, and that the woofer (and its rear cover)
will protrude out from the back.
Does this sound right to anyone who has a pair of these?
Thanks, Steve
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] Question about 100Hz Edgarhorns
Date: Mon, 7 May 2001 00:21:14 EDT
Source: Sound Digest Archive v02.n880
- --part1_6e.a5c1e1d.28277cba_boundary
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Greets!
Yup, If you want a finished back, you can run the speaker cables out the
bottom.
I am covering the soon to be hidden surfaces with self-stick vinyl floor
tiles to damp,
I am using 15" from Nick at Lambda... very nice.
Happy Ears!
Al B^}
- --part1_6e.a5c1e1d.28277cba_boundary
Content-Type: text/html; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
<HTML><FONT FACE=arial,helvetica><BODY BGCOLOR="#ffffff"><FONT SIZE=2>Greets!
<BR>
<BR>Yup, If you want a finished back, you can run the speaker cables out the
<BR>bottom.
<BR>
<BR>I am covering the soon to be hidden surfaces with self-stick vinyl floor
<BR>tiles to damp,
<BR>
<BR>I am using 15" from Nick at Lambda... very nice.
<BR>
<BR>Happy Ears!
<BR>Al B^}
<BR>
<BR></FONT></HTML>
- --part1_6e.a5c1e1d.28277cba_boundary--
=========================================================================
From: "Wolfgang Braun" <wb@braunbaustoffe.de>
Subject: Re: [JN] Question about 100Hz Edgarhorns
Date: Mon, 7 May 2001 07:48:43 +0200
Source: Sound Digest Archive v02.n880
This is a multi-part message in MIME format.
- ------=_NextPart_000_0437_01C0D6CA.23B3D5E0
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
I built a complete wooden plywoold box around the horn and filled it =
with sand.
Very very heavy but dead. It sounded much better than without damping =
and it gave a very good base for the midhorn
Wolfgang
- ------=_NextPart_000_0437_01C0D6CA.23B3D5E0
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 5.50.4134.100" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>I built a complete wooden =
plywoold box around=20
the horn and filled it with sand.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Very very heavy but dead. It sounded =
much better=20
than without damping and it gave a very good base for the =
midhorn</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Wolfgang</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3Darial,helvetica><FONT=20
size=3D2> </DIV></FONT></FONT></BODY></HTML>
- ------=_NextPart_000_0437_01C0D6CA.23B3D5E0--
=========================================================================
From: Steve Van Osdell <svanos@queencity.com>
Subject: [JN] Question about authenticiy of Altec cones
Date: Fri, 09 Mar 2001 18:48:01 -0500
Source: Sound Digest Archive v02.n829
I have a pair of Altec 15" woofers that I removed from a pair of Altec
Valencia cabinets. To my knowledge, and certainly not since I have
owned them, have they ever been reconed. I bought them from the
original owner who had them in his living room.
Upon examining the woofers, I find that they have no magnet covers, have
a number stamped on the back of the magnet, BUT they have no number
stamped in white on the rear of the cones. They have a small round
circle (about 1/2" diameter) that looks like some sort of proof mark or
brand mark, that is all. The cones, surrounds, and dust covers appear
totally original and in excellent condition with no evidence at all
(that I can see) of ever having been reconed.
I am having a person tell me that because they don't have a number on
the back of the cones, that this means they have been reconed at some
point in the past. Can someone offer an opinion about this?
Thanks, Steve
=========================================================================
From: "Greg Monfort" <wingracer@email.msn.com>
Subject: Re: [JN] Question about authenticiy of Altec cones
Date: Tue, 13 Mar 2001 00:38:35 -0500
Source: Sound Digest Archive v02.n830
FWIW, I have several drivers (515B, 421-8H) laying
about that have never been reconed, and all have a
number stenciled in white on the rear of the cone.
I also have two 515Bs that I had Altec recone, and
you can't tell them apart from the OEM's, except they
aren't marked in any way that I can tell.
GM
- ----- Original Message -----
> I am having a person tell me that because they
don't have a number on
> the back of the cones, that this means they have
been reconed at some
> point in the past. Can someone offer an opinion
about this?
>
> Thanks, Steve
>
=========================================================================
From: Steve Van Osdell <svanos@queencity.com>
Subject: [JN] Question about Caps on 300b 5.0V power
Date: Tue, 25 Jul 2000 20:29:37 -0400
Source: Sound Digest Archive v02.n609
I have a question... I am rectifying 6 VAC to DC for the filament on my
300B thru a full wave bridge rectifier. DC voltage out, without
capacitance, is about 4.25 Volts. I then add a 2200mfd cap, and voltage
comes up to about 5.1VDC which is close. But, I'm getting hum. Someone
suggested that I needed a cap 10 times this value (22K mfd). Then
another person told me that a cap this large would put big time stress
on the power tube trying to keep it charged and not to do it. Can
someone offer an opinion about what is going on here because I'm a
beginner.
Thanks, Steve
=========================================================================
From: "Paul@13E1.com" <triode@bow-tie.org.uk>
Subject: Re: [JN] Question about Caps on 300b 5.0V power
Date: Wed, 26 Jul 2000 11:05:08 +0100
Source: Sound Digest Archive v02.n609
Hello Steve,
I have spent some time developing a DC supply for a big valve and learned a
little in the process.
First, you say "full-wave bridge" what is this exactly? If your
transfromer provides 6v then a bridge with capacitor would give you 6 x
1.414 = 8.4V.
Full wave implies that you have a centre-tapped (3v-0-3v) transformer with a
diode on each leg. This would provide, with cap. input, 4.2v.
These voltages are dependent on current drawn of course: remember that you
cannot draw rated current with a bridge - only about 0.6of the rating.
When developing my supply, I wanted to use the minimum capacitance for
satisfactory running, so I just added capacitance until I got there. The
calculations can be done, but 2,200uf is almost certainly not enough. Try
4,700uf to start, making sure that you use a large (high ripple) capacitor.
Use fast diodes (Schottkys for preference) and by-pass them with 0.1 or 0.05
film caps to kill any rf that may be generated by the diodes switching.
My supply was designed to provide 10V @ 5A; I ended up with a 22,000uf cap,
0.5 ohms of resistance and an LM338 regulator.
I hope this helps.
regards,
Paul Leclercq
- ----- Original Message -----
From: Steve Van Osdell <svanos@queencity.com>
To: <sound@lists.io.com>
Sent: Wednesday, July 26, 2000 1:29 AM
Subject: [JN] Question about Caps on 300b 5.0V power
> I have a question... I am rectifying 6 VAC to DC for the filament on my
> 300B thru a full wave bridge rectifier. DC voltage out, without
> capacitance, is about 4.25 Volts. I then add a 2200mfd cap, and voltage
> comes up to about 5.1VDC which is close. But, I'm getting hum. Someone
> suggested that I needed a cap 10 times this value (22K mfd). Then
> another person told me that a cap this large would put big time stress
> on the power tube trying to keep it charged and not to do it. Can
> someone offer an opinion about what is going on here because I'm a
> beginner.
>
> Thanks, Steve
>
>
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] Question about Caps on 300b 5.0V power
Date: Wed, 26 Jul 2000 20:09:33 +0200
Source: Sound Digest Archive v02.n610
Steve,
At 11:05 26/07/2000 +0100, Paul@13E1.com wrote:
>Hello Steve,
>
>I have spent some time developing a DC supply for a big valve and learned a
>little in the process.
>
>First, you say "full-wave bridge" what is this exactly? If your
>transfromer provides 6v then a bridge with capacitor would give you 6 x
>1.414 = 8.4V.
Now subtract 2 times 0.7V for diode voltage dropp and consider that the
average DC value depends on the riple that is left....
My 300b heater winding has about 5.5Vac, Schottky diodes and 2.200 uF give
about 5Vdc
>Full wave implies that you have a centre-tapped (3v-0-3v) transformer with a
>diode on each leg.
Or a single winding and 4 diodes in bridge
> This would provide, with cap. input, 4.2v.
Less, see above
>These voltages are dependent on current drawn of course: remember that you
>cannot draw rated current with a bridge - only about 0.6of the rating.
>
>When developing my supply, I wanted to use the minimum capacitance for
>satisfactory running, so I just added capacitance until I got there. The
>calculations can be done, but 2,200uf is almost certainly not enough.
Why ?
Try 4,700uf to start, making sure that you use a large (high ripple)
capacitor.
>Use fast diodes (Schottkys for preference) and by-pass them with 0.1 or 0.05
>film caps to kill any rf that may be generated by the diodes switching.
Do not bypass SB diodes, no need
Bypassing this way decreases the impedance between trannie and amp
Guido
>My supply was designed to provide 10V @ 5A; I ended up with a 22,000uf cap,
>0.5 ohms of resistance and an LM338 regulator.
>
>I hope this helps.
>
>regards,
>
>Paul Leclercq
>----- Original Message -----
>From: Steve Van Osdell <svanos@queencity.com>
>To: <sound@lists.io.com>
>Sent: Wednesday, July 26, 2000 1:29 AM
>Subject: [JN] Question about Caps on 300b 5.0V power
>
>
>> I have a question... I am rectifying 6 VAC to DC for the filament on my
>> 300B thru a full wave bridge rectifier. DC voltage out, without
>> capacitance, is about 4.25 Volts. I then add a 2200mfd cap, and voltage
>> comes up to about 5.1VDC which is close. But, I'm getting hum. Someone
>> suggested that I needed a cap 10 times this value (22K mfd). Then
>> another person told me that a cap this large would put big time stress
>> on the power tube trying to keep it charged and not to do it. Can
>> someone offer an opinion about what is going on here because I'm a
>> beginner.
>>
>> Thanks, Steve
>>
>>
>
>
>
=========================================================================
From: "C.snoeren" <c.snoeren@tip.nl>
Subject: Re: [JN] Question about Caps on 300b 5.0V power
Date: Wed, 26 Jul 2000 23:05:23 +0200
Source: Sound Digest Archive v02.n610
Steve Van Osdell wrote:
> I have a question... I am rectifying 6 VAC to DC for the filament on my
> 300B thru a full wave bridge rectifier. DC voltage out, without
> capacitance, is about 4.25 Volts. I then add a 2200mfd cap, and voltage
> comes up to about 5.1VDC which is close. But, I'm getting hum. Someone
> suggested that I needed a cap 10 times this value (22K mfd). Then
> another person told me that a cap this large would put big time stress
> on the power tube trying to keep it charged and not to do it. Can
> someone offer an opinion about what is going on here because I'm a
> beginner.
>
> Thanks, Steve
Just balance the filament of the 300B with two risistors of 22E or so to
the cathode resistor or grounds (auto or fixed bias?)
But why not try AC with these two risistors and a balance-pot of 50E?
If you think the 6VAC is the problem , just put some risitor in series
with it untill you have your 5 Volts....
- --
Greetings,Cuno
mailto:c.snoeren@tip.nl
http://www.ariel.club.tip.nl
http://www.triode.club.tip.nl
=========================================================================
From: Steve Van Osdell <svanos@queencity.com>
Subject: [JN] Question about Goodmans 1220c's
Date: Sat, 17 Mar 2001 19:51:53 -0500
Source: Sound Digest Archive v02.n836
I have a chance to purchase a pair studio 1220C's Goodmans (in
enclosures). Does anyone know much about them? Any ventures to guess
what a good price is (I don't want to pay too much). I understand that
they are exactly like the 612C, but 4 years later model (1968). The
cone is white with the treated plastic surround.
Thanks, Steve
=========================================================================
From: houndman@onix.com
Subject: [JN] Question about subscribing
Date: Sat, 11 Dec 1999 14:36:46 -0500
Source: Sound Digest Archive v02.n361
Met someone who want to join the list. Can anyone tell me so i can
tell him. I had found a link from another site to get on and can't
remember where that was.
- -----------------
\/ince ++
working on breeding an Afghan that Doesn't mat.... And
comes when called...
=========================================================================
From: "Aaron Bohnen" <bohnen@unixg.ubc.ca>
Subject: Re: [JN] Question about tube amps
Date: Mon, 8 Nov 1999 23:03:46 -0800
Source: Sound Digest Archive v02.n326
Hi Vince,
About your question:
> Is there any way to tell the output power of a tube amp besides
> measuring, What about tube types or numbers of them ?? It has 1-EL84/
> 6B05 Power Amp tube on each side and 1-12AX7 Tone Amp tube each.
[snip rest of tube compliment]
Assuming that's a stereo single-ended amplifier, the *maximum* likely
power you are going to see out of it is somewhere in the 6 to 7 wpc
range, with the EL84/6BQ5's connected in pentode. Running them
conservatively you are more likely to see 5 or so wpc. Running them
conservatively in triode mode will likely net you something closer to the
1 to 1.5 wpc sort of range. Flea power. Lowther territory... :>
Hope that helps,
Aaron
___________________________________________________________
Aaron Bohnen email: bohnen@unixg.ubc.ca
- -Ph.D. Student, Civil Engineering Department, U.B.C.
- -website: http://www.civil.ubc.ca/home/bohnen
=========================================================================
From: houndman@onix.com
Subject: [JN] Question about tube amps
Date: Tue, 9 Nov 1999 01:50:24 -0500
Source: Sound Digest Archive v02.n326
Is there any way to tell the output power of a tube amp besides
measuring, What about tube types or numbers of them ?? It has 1-EL84/
6B05 Power Amp tube on each side and 1-12AX7 Tone Amp tube each. 5Y3GT
Rectifier Tube and One Type FP cap with 40 mfd/ 350 VDC repeated 4
times. It is out of an old Motorola big, suitcase looking stereo record
player. It has a large looking power transformer and smallish
looking output ones. Have to clean them off to get the numbers.
Thanks,
- -----------------
\/ince ++
working on breeding an Afghan that Doesn't mat.... And
comes when called...
=========================================================================
From: Rick Francis <rfrancis@glasscity.net>
Subject: Re: [JN] Question about tube amps
Date: Tue, 09 Nov 1999 07:28:48 -0500
Source: Sound Digest Archive v02.n326
houndman@onix.com wrote:
>
> Is there any way to tell the output power of a tube amp besides
> measuring, What about tube types or numbers of them ?? It has 1-EL84/
> 6B05 Power Amp tube on each side and 1-12AX7 Tone Amp tube each. 5Y3GT
> Rectifier Tube and One Type FP cap with 40 mfd/ 350 VDC repeated 4
> times. It is out of an old Motorola big, suitcase looking stereo record
> player. It has a large looking power transformer and smallish
> looking output ones. Have to clean them off to get the numbers.
>
The RCA tube manuals give the output power for a single Class A 6BQ5 --
from memory I think it's 4.5 or 5 watts with 8-10% distortion. You
might be getting a reasonably clean 3-4 watts out. But my advice is
FORGET THE POWER NUMBERS. Get it running right, make sure the coupling
cap is adequate and the filter caps are doing what they should or
replace them, clean the contacts, and (if not already provided), mount
input jacks that connect BETWEEN the two stages of the 12AX7. (First
stage provides the gain needed for the phono, second is all you need
from CD or preamp).
Even with small OPTs, it may surprise you with the quality of the sound!
Is there a global feedback loop from an OPT secondary to the second half
of the 12AX7?
Once you get it all going, you might stick a 5AR4 in for the 5Y3 and see
what happens. It sounds like great cheap fun!
Rick
=========================================================================
From: houndman@onix.com
Subject: Re: [JN] Question about tube amps
Date: Tue, 9 Nov 1999 09:23:46 -0500
Source: Sound Digest Archive v02.n326
RF>FORGET THE POWER NUMBERS. Get it running right, make sure the coupling
RF>cap is adequate and the filter caps are doing what they should or
RF>replace them, clean the contacts, and (if not already provided), mount
RF>input jacks that connect BETWEEN the two stages of the 12AX7. (First
RF>stage provides the gain needed for the phono, second is all you need
RF>from CD or preamp).
RF>Even with small OPTs, it may surprise you with the quality of the sound!
RF>Is there a global feedback loop from an OPT secondary to the second half
RF>of the 12AX7?
RF>Rick
Ahhh, think I'm gona need an electronics to english dictionary. Wish I
had a schematic for this thing. I Guess the filter cap is in the power
supply and coupling ones are the small ones connected to the tubes.
Don't get Any meter movement on Any of the small ones even ceramics.
This might be a challenge... My kind of project though I wish I took the
Easy ways. Now where is my 56' Electronics Made Easy book I just glued
back together...
- -----------------
\/ince ++
working on breeding an Afghan that Doesn't mat.... And
comes when called...
=========================================================================
From: John Levreault <jlevro@mediaone.net>
Subject: Re: [JN] Question on 5881 and SE-40
Date: Mon, 12 Feb 2001 10:54:04 -0500
Source: Sound Digest Archive v02.n805
Alfia MAk wrote:
> Hi,
> Any recommendation on the best sounding 5881 tube replacement for the Golden
> tube SE-40 PE?
>
> The SE-40 use 3 5881 per channel (Parallel single end) with fixed bias, if I
> pull 1 5881 from each channel, how would this affect the sound other than
> decrease in output power ? Better or worse ? How should I adjust the bias ?
> Will this work at all ?
>
> Thanks
A friend of mine had good luck with the Philips 7581A's.
JL
=========================================================================
From: Dan Marshall <mdaniel7@uswest.net>
Subject: Re: [JN] Question on 5881 and SE-40
Date: Mon, 12 Feb 2001 14:26:43 +0000
Source: Sound Digest Archive v02.n805
Hi,
I am not familiar with that particular unit, but I have done a fair bit
of distortion measurements on most of the 6L6 variants using a spectrum
analyzer. In the 6L6 family I found the Tungsol 5881s to be the lowest
distortion and I presume the best sounding of the entire lot, though I
did not conduct listening comparisons. Better yet, a bit above the 6L6
family, would be genuine English KT66s, even better EL37s. Some
consider them to be in the 6L6 family, but they are a cut above the
other 6L6 variants, at least in my book. I have not measured KT77s, but
I presume they would also perform quite excellently. Since the way a
particular tube sounds in a particular amp cannot be easily quantified,
you likely will have to try various brands/types and see how they sound
to you, unless you luck out and find someone who has already done this
and is willing to share his impressions. Still, they are only his
impressions, not yours, and are how the amp sounds on his speakers and
in accordance with his preferences and prejudices.
As far as how it would sound when pulling an output tube, that quite
possibly would depend on your speakers. It perhaps would change the
damping factor which could improve or degrade the sound, depending. I
seem to recall that that amp uses feedback, in which case, the damping
factor may not change significantly. Your best bet is to yank one and
see how it sounds. David H says this amp uses fixed bias. If so,
pulling a tube should be OK. If you go to the KT66, EL37 or KT77, you
would need to rebias the amplifier. I would follow the manufacturers
instructions. Or, failing access to the instructions, would probably
run them at something like 80 percent of their dissipation rating. The
original design was (hopefully) optimized for a specific plate current,
so it would be best to find out what this was and try to keep close to
it. Mind you, this is just a WAG, as I do not have first hand
experience with that unit. If you do try different types, as a first
approximation, you could measure the plate current on both channels and
try to stay somewhere around this value, assuming the current tubes are
not weak.
Another respondent suggested that a friend had liked the Philips 7581As
in that amp. I measured those and found them to perform essentially as
6L6GCs, with similar distortion characteristics, not bad, but not
spectacular either. Some 6L6GCs seem to work pretty well, if well
matched. I found their distortion characteristics (using third harmonic
in a PP amp as the reference measurement) to decrease to a relatively
low value after a substantial warmup period, while similarly matched
KT66s exhibited distortion components down in the baseline at turnon.
However, the measurements were not conducted on a sufficiently large
sample of tubes to draw concrete conclusions. For instance, you may
find that Tungsols are smoother while the 7581s are more aggressive with
more punchy bass, or whatever. Try to borrow some tubes and give it a
listen before investing $$$.
Dan Marshall
Alfia MAk wrote:
>
> Hi,
> Any recommendation on the best sounding 5881 tube replacement for the Golden
> tube SE-40 PE?
>
> The SE-40 use 3 5881 per channel (Parallel single end) with fixed bias, if I
> pull 1 5881 from each channel, how would this affect the sound other than
> decrease in output power ? Better or worse ? How should I adjust the bias ?
> Will this work at all ?
>
> Thanks
=========================================================================
From: David Home <David_Home@creoscitex.com>
Subject: RE: [JN] Question on 5881 and SE-40
Date: Mon, 12 Feb 2001 17:07:05 +0100
Source: Sound Digest Archive v02.n805
This will affect the sound as the output transformer is designed to load
three tubes, not two.
My guess is the sound will get 'wetter' and less controlled in the bass.
As your amp is fixed bias, you won't hurt anything by pulling a tube.
Try it and see if you like the change.
Regards, David
- -----Original Message-----
From: Alfia MAk [mailto:alfiamak@hkstar.com]
Sent: Monday, February 12, 2001 4:46 PM
To: JOELIST
Subject: [JN] Question on 5881 and SE-40
Hi,
Any recommendation on the best sounding 5881 tube replacement for the Golden
tube SE-40 PE?
The SE-40 use 3 5881 per channel (Parallel single end) with fixed bias, if I
pull 1 5881 from each channel, how would this affect the sound other than
decrease in output power ? Better or worse ? How should I adjust the bias ?
Will this work at all ?
Thanks
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: [JN] Question on 5881 and SE-40
Date: Mon, 12 Feb 2001 18:43:21 -0700
Source: Sound Digest Archive v02.n805
Dan Marshall wrote:
> Hi,
> I am not familiar with that particular unit, but I have done a fair bit
> of distortion measurements on most of the 6L6 variants using a spectrum
> analyzer. In the 6L6 family I found the Tungsol 5881s to be the lowest
> distortion and I presume the best sounding of the entire lot, though I
> did not conduct listening comparisons. Better yet, a bit above the 6L6
> family, would be genuine English KT66s, even better EL37s. Some
> consider them to be in the 6L6 family, but they are a cut above the
> other 6L6 variants, at least in my book. I have not measured KT77s, but
> I presume they would also perform quite excellently. Since the way a
> particular tube sounds in a particular amp cannot be easily quantified,
> you likely will have to try various brands/types and see how they sound
> to you, unless you luck out and find someone who has already done this
> and is willing to share his impressions. Still, they are only his
> impressions, not yours, and are how the amp sounds on his speakers and
> in accordance with his preferences and prejudices.
It's funny how the world goes round: just the other day my assistant
e-mailed me a link - now lost - for a two page article on the 5881 written
in the 50s by an engineer at Tung Sol.
Many matters relevant to the design of stable, long-lived tube outputs
stages are taken up . . . along with some of the very subjects mentioned on
the list in the last while.
Although in need of a little editorial assistance, it was so good that I
made it into a PDF and included, as the third page, my work on the secondary
emission characteristics of nickel vs. graphite anodes in tetrode connected
(as opposed to *beam* tetrode connected) 813s.
To receive a copy of this, end me an e-mail with "5881" as the subject.
Thanks to all for your kind words wrt to the other PDFs I've made
available . . . .
SNIP
> Dan Marshall
Bill - PEARL, Inc.
=========================================================================
From: "Alfia MAk" <alfiamak@hkstar.com>
Subject: [JN] Question on 5881 and SE-40
Date: Mon, 12 Feb 2001 23:46:10 +0800
Source: Sound Digest Archive v02.n805
Hi,
Any recommendation on the best sounding 5881 tube replacement for the Golden
tube SE-40 PE?
The SE-40 use 3 5881 per channel (Parallel single end) with fixed bias, if I
pull 1 5881 from each channel, how would this affect the sound other than
decrease in output power ? Better or worse ? How should I adjust the bias ?
Will this work at all ?
Thanks
=========================================================================
From: John Levreault <jlevro@mediaone.net>
Subject: [JN] Question on TQWT
Date: Sun, 09 Jan 2000 10:10:08 -0500
Source: Sound Digest Archive v02.n393
Joesters-
I'm a bit confused about the optimum pipe area of a TQWT. Weems' article
in 2/87 Speaker Builder recommends a maximum cross-sectional area at the
end of the pipe of 2.5X the driver's effective cone area. However, the
designs I've found documented on the web (i.e. at:
http://www.infomaniak.ch/~bonavolt/tqwt.htm
seem quite a bit larger.
Can anyone help clarify this? Is there a relationship with the driver Q,
such that, say, a lower-Q driver might like a "bigger" pipe diameter?
Thanks!
JL
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] Question on TQWT
Date: Sun, 9 Jan 2000 14:59:31 EST
Source: Sound Digest Archive v02.n393
In a message dated 1/9/00 8:14:07 AM US Mountain Standard Time,
jlevro@mediaone.net writes:
> recommends a maximum cross-sectional area at the
> end of the pipe of 2.5X the driver's effective cone area.
Hi JL
Yup, Voight UK patent (1936, thanks Dr. Edgar!) specs one cone area cross
section behind the driver and 2.5 cone area's MAX for pipe mouth.
Other specs are length is one quarter wavelength of resonant freq of driver
and driver is mounted one/third from closed end.
Happy Ears!
Al B^}
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] Question on TQWT
Date: Sun, 9 Jan 2000 15:11:36 EST
Source: Sound Digest Archive v02.n393
In a message dated 1/9/00 1:04:34 PM US Mountain Standard Time,
TubeGarden@aol.com writes:
> Voight UK patent
er,
F. G. A. H. VOIGT
I keep adding the h :)
Actually the patent covers many versions, including the Bose Wave double
chamber...
AL
=========================================================================
From: David Barnett <davidbarnett@aristotle.net>
Subject: Re: [JN] Question on TQWT
Date: Sun, 09 Jan 2000 17:57:30 -0600
Source: Sound Digest Archive v02.n393
On Sun, 9 Jan 2000 15:11:36 EST, TubeGarden@aol.com wrote:
>F. G. A. H. VOIGT
That's P. G. A. H. Voigt...
- --dnb
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] Question on TQWT
Date: Sun, 9 Jan 2000 19:35:04 EST
Source: Sound Digest Archive v02.n393
In a message dated 1/9/00 5:02:24 PM US Mountain Standard Time,
davidbarnett@aristotle.net writes:
> That's P. G. A. H. Voigt...
Yup.
And I love my pipes ... with Fostex FE164.
Hey, Joe, you were right, I only run my pre at high noon with the 92 dB
VonHelsing 1C... Pipes are fully voiced at a little after 9 :)
Happy Ears!
Al B^}
=========================================================================
From: =?iso-8859-1?q?Josef=20Aigner?= <josef_aigner@yahoo.com>
Subject: Re: [JN] Question on TQWT
Date: Mon, 10 Jan 2000 07:36:40 -0800 (PST)
Source: Sound Digest Archive v02.n394
Hi David,
what about more details on the FE 164 in pipes? I use them as cheapo
in an bass reflex enclosure, sounds nice.
but maybe I try the pipes....
Regards,
Josef
__________________________________________________
Do You Yahoo!?
Talk to your friends online with Yahoo! Messenger.
http://im.yahoo.com
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] Question on TQWT
Date: Mon, 10 Jan 2000 11:02:39 EST
Source: Sound Digest Archive v02.n394
In a message dated 1/10/00 8:48:55 AM US Mountain Standard Time,
josef_aigner@yahoo.com writes:
> details on the FE 164 in pipes?
Gree J N
Baffle and back are 3/4" x 12" x 48" coated MDF shelves. Sides are 1" x 8" x
48" birch boards.
Internal divider is three 12" x 12" slate floor tiles taped in series with
duct tape.
Stuffing in closed end is wool/dacron yarn.
Happy Ears!
Al B^}
=========================================================================
From: Paul Mouritsen <mourip@erols.com>
Subject: [JN] Questions about an 83 Rectifier...
Date: Fri, 25 Jun 1999 21:40:08 -0400
Source: Sound Digest Archive v02.n188
Hi,
I put an 83 in my amp recently. Of the several rectifiers I have now
auditioned I like it the best. It is not an easy tube to live with however.
After putting it in I noticed that periodically I would get stray
"scratchy" sounds from the amp, especially if I touched the chassis. I
figured that this was some of the legendary RF being produced from the 83
and picked up by my 5842's, which I guess are notoriously susceptible to
RF. My rectifier is broadcasting to my driver... kind of fun. I fixed this
by running a ground wire from one of the bolts on my power transformer
directly to star ground. It seems fixed anyway :-)
My question is this. When my 83 has been on for a bit the blue gases
surrounding just one of the filaments begins to flicker and pulse quite a
lot. It looks like a candle in a slight breeze. The other side is basically
steady. Is this likely to be a problem or just more eccentric but tolerable
behavior? I have another week on the 30 day AES waranty so I would like to
figure this out. I did have the B+ coming from one of the filament pins and
the 5v centertap unused but I switched to pulling the B+ directly from the
5v CT thinking that this might help but it did not.
Thanks for any help,
Paul
Please remove the xxx's in my email address to reply.. Thanks
*****************************************************************************
Paul Mouritsen.....mourip@erols.com
If you want to make God laugh, tell him your plans...
La luce che tu dai
*****************************************************************************
=========================================================================
From: "Dave Slagle" <dslagle@earthlink.net>
Subject: Re: [JN] Questions about an 83 Rectifier...
Date: Sun, 27 Jun 1999 12:21:34 -0400
Source: Sound Digest Archive v02.n189
>My question is this. When my 83 has been on for a bit the blue gases
>surrounding just one of the filaments begins to flicker and pulse quite a
>lot. It looks like a candle in a slight breeze. The other side is basically
>steady. Is this likely to be a problem or just more eccentric but tolerable
>behavior? I have another week on the 30 day AES waranty so I would like to
>figure this out. I did have the B+ coming from one of the filament pins and
>the 5v centertap unused but I switched to pulling the B+ directly from the
>5v CT thinking that this might help but it did not.
paul,
i too have had this happen and have not figured out the cause... i suspect
if it happens contionuosly it may be a problem with the tube, but with my mv
rectafiers, this will happen on occasion, and not happen on others... i
wonder out loud if it could be a power line conditon causing the filcker.
i have yet to notce a pattern to the flicker... if it were a warmup thing i
could see a late day flicker showing up, but some days it shows up for luch
and is gone by dayend... it is also tube dependant... so if i swap tubes
left to right... it follows the tube.
dave
=========================================================================
From: "Dave Slagle" <dslagle@earthlink.net>
Subject: Re: [JN] Questions about an 83 Rectifier...
Date: Sun, 27 Jun 1999 12:36:08 -0400
Source: Sound Digest Archive v02.n189
>Well this "problem" is probably courced by the tolerance difference
>of the two diodes in the 83 rectifier (see the datasheet on Jim's VT-52
>page)
I don't think this is the case.
>One half of the tube is giving more current then the other.
>The flashing is because of the current in that side of the tube is just
>to small to give a steady blue glow, and just to high to not glow at
>all.
I could see this being the case if the tube were paralleled, but in normal
full wave operation the 1/2's are conducting out of phase, so one could not
conduct more that the other (or steal from the other)
plus the 83 shows a very gradual ramp up and even at the smallest current it
will conduct and operate flicker free... rarely have i seen two different
83's glow similarly for similar current... although the two 1/2's will
usually match... but going from one 83 to another will often show a
different glow for the same voltage current. this may be due to the
pressure and ampunt of mercury present and the heating of the filament.
an additional observation with my system, when one of my 1/2 wave rectafiers
starts to dim and flicker, it can often be fixed by reducing the B+ a bit,
and it will glow brighter and constant and match its partner. going the
other direction and increasing the B+ will keep the dissimilar operation
between the tubes.
dave
=========================================================================
From: Cuno Snoeren <c.snoeren@tip.nl>
Subject: Re: [JN] Questions about an 83 Rectifier...
Date: Sun, 27 Jun 1999 15:02:12 +0200
Source: Sound Digest Archive v02.n189
> My question is this. When my 83 has been on for a bit the blue gases
> surrounding just one of the filaments begins to flicker and pulse quite a
> lot. It looks like a candle in a slight breeze. The other side is basically
> steady. Is this likely to be a problem or just more eccentric but tolerable
> behavior?
Well this "problem" is probably courced by the tolerance difference
of the two diodes in the 83 rectifier (see the datasheet on Jim's VT-52
page)
http://www.vt52.com/data/rectifiers/83_sheet_2.jpg
http://www.vt52.com/data/rectifiers/83_sheet_1.jpg
One half of the tube is giving more current then the other.
The flashing is because of the current in that side of the tube is just
to small to give a steady blue glow, and just to high to not glow at
all.
Greetings, Cuno
http://www.triode.club.tip.nl
=========================================================================
From: Scott Grammer <tubedude@cdc.net>
Subject: Re: [JN] Questions about an 83 Rectifier...
Date: Sun, 27 Jun 1999 22:37:22 -0400
Source: Sound Digest Archive v02.n190
Paul Mouritsen wrote:
> Hi,
>
> I put an 83 in my amp recently. (snip)My question is this. When my 83 has been
> on for a bit the blue gases
> surrounding just one of the filaments begins to flicker and pulse quite a
> lot. It looks like a candle in a slight breeze. (snip)
I bet if you put silicon diodes in parallel it'll quit flickering....
;->
S.G.
- --
TubeDude's Webpage of Vacuum Tube Lore! http://www.cdc.net/~tubedude/
Smoke Free Youth! http://www.cdc.net/~tubedude/smokefreeyouth.html
The Price of Privacy. http://www.cdc.net/~tubedude/privacy.html
"The nice thing about standards is that you have so many to choose from."
-- Andrew S. Tanenbaum, _Computer Networks_, 2nd ed, p.254
=========================================================================
From: Cuno Snoeren <c.snoeren@tip.nl>
Subject: Re: [JN] Questions about an 83 Rectifier...
Date: Mon, 28 Jun 1999 00:16:18 +0200
Source: Sound Digest Archive v02.n190
> an additional observation with my system, when one of my 1/2 wave rectafiers
> starts to dim and flicker, it can often be fixed by reducing the B+ a bit,
> and it will glow brighter and constant and match its partner. going the
> other direction and increasing the B+ will keep the dissimilar operation
> between the tubes.
Yes, you said it just here!
When the B+ is different the power consumtion of the rectifier itself
(it has got an Ri of >50 ohms) will change.
Just try another B+ or another load (a few bulbs in series is a cheap
and nice load) and the light or flickering will change...
Greetings, Cuno
c.snoeren@tip.nl
http://www.triode.club.tip.nl
=========================================================================
From: mathews <mathews@txc.com>
Subject: [JN] Questions on Horns
Date: Tue, 15 May 2001 10:38:21 -0400
Source: Sound Digest Archive v02.n885
Hi all,
I have a few questions on horns.
1) What are the properties of a Circular Mid Horn as
compared to a Retangular Mid Horn? Like Dispersion,
Directivity.
2) The same with Bass Horns. How does circular horns
differ from retangular one?
Pointers to books or articles ?
Thanks.
Simmonds Mathews
=========================================================================
From: Richard C Nevill <rnevill@is.dal.ca>
Subject: [JN] quick cable question
Date: Wed, 10 Mar 1999 11:40:22 -0400 (AST)
Source: Sound Digest Archive v02.n070
Allen, et al
I gonna try building the twisted 3 wire interconnects you posted here
not all that long ago (just got the wire). My question is do you think
this cable would be suited for a long run between pre and power amp (say
15-20 ft.). I know the proper answer is try it and find out :-) but I was
just wondering if there would be any obvious problem before I sit down and
spend an evening braiding all that wire.
Cheers
and thanks
Richard Nevill
=========================================================================
From: Ken Gilbert <ride5000@ride.ri.net>
Subject: [JN] quick ? on magnetics
Date: Sun, 17 Dec 2000 14:24:11 -0500
Source: Sound Digest Archive v02.n761
hello joes,
someone out there will probably be able to answer this little brain-teaser in a
matter of seconds...
i've got some of those allied electronics interstage trannies here--they were
cheap, like under 20 bucks each. they are specced as 10k:10kct, 30mA max
primary I. there's about 10H of L across both primary and 2ndary.
i got to thinking that the 2ndary could be series-connected in phase with the
primary, yielding ~4x the inductance. when tested on my LCR bridge, i got
about 35H @ 120Hz, and over 40H @ 1KHz--not too bad!
my question is in regards to the max current in this configuration... it's down
to two choices:
a) the max current is 30mA/2, or 15mA, since there are two identical windings
now contributing to the static flux in the core.
b) the max current is 30mA/4, or 7.5mA, since you never get something for
nothing and i now have 4x the effective L, so it would only stand to reason.
so what's your take on the subject? i've tried reasoning it out and looking it
up in textbooks, but i ain't found shit, so to speak.
thanks for any help you could send my way...
ken
=========================================================================
From: SBench@aol.com
Subject: Re: [JN] quick ? on magnetics
Date: Sun, 17 Dec 2000 15:04:10 EST
Source: Sound Digest Archive v02.n761
In a message dated 00-12-17 14:26:26 EST, ride5000@ride.ri.net writes:
>
> a) the max current is 30mA/2, or 15mA, since there are two identical
> windings
> now contributing to the static flux in the core.
>
> b) the max current is 30mA/4, or 7.5mA, since you never get something for
> nothing and i now have 4x the effective L, so it would only stand to
reason.
>
> so what's your take on the subject? i've tried reasoning it out and
looking
> it
> up in textbooks, but i ain't found shit, so to speak.
>
> thanks for any help you could send my way...
>
Think energy. (0.5*L*I*I). Try 7.5mA
- -Steve
=========================================================================
From: "Dave Slagle" <dslagle@earthlink.net>
Subject: Re: [JN] quick ? on magnetics
Date: Sun, 17 Dec 2000 18:51:43 -0500
Source: Sound Digest Archive v02.n761
hey ken... not sure here... but i would guess that you get 15ma... its an
amp turns thing here.... you double the turns so the same amp turns ratio
would be 1/2 the amps... thats dc... for ac... you would get double the
available AC swing before saturation.... (so there is something for free...)
look at the tango stuff that allows for series parallel connection... the
TC-160 has a series connection of 160hy 15ma, the parallel has 40hy 30ma....
dave
- ----------
>From: Ken Gilbert <ride5000@ride.ri.net>
>To: sound@lists.io.com
>Subject: [JN] quick ? on magnetics
>Date: Sun, Dec 17, 2000, 2:24 PM
>
> hello joes,
>
> someone out there will probably be able to answer this little brain-teaser in
a
> matter of seconds...
>
> i've got some of those allied electronics interstage trannies here--they were
> cheap, like under 20 bucks each. they are specced as 10k:10kct, 30mA max
> primary I. there's about 10H of L across both primary and 2ndary.
>
> i got to thinking that the 2ndary could be series-connected in phase with the
> primary, yielding ~4x the inductance. when tested on my LCR bridge, i got
> about 35H @ 120Hz, and over 40H @ 1KHz--not too bad!
>
> my question is in regards to the max current in this configuration... it's
down
> to two choices:
>
> a) the max current is 30mA/2, or 15mA, since there are two identical windings
> now contributing to the static flux in the core.
>
> b) the max current is 30mA/4, or 7.5mA, since you never get something for
> nothing and i now have 4x the effective L, so it would only stand to reason.
>
> so what's your take on the subject? i've tried reasoning it out and looking
it
> up in textbooks, but i ain't found shit, so to speak.
>
> thanks for any help you could send my way...
>
> ken
>
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] quick ? on magnetics
Date: Tue, 19 Dec 2000 06:22:59 -0500
Source: Sound Digest Archive v02.n762
hi ken,
dc flux is directly proportional to amp-turns.
so since you've doubled the number of turns, you have to
halve the current.
so i'd say, 1/2 of 30mA, or 15mA.
however, i'm not sure i trust the 30mA rating o begin with...
hth,
bob.d.
> ----------
> From: Ken Gilbert[SMTP:ride5000@ride.ri.net]
> Sent: Sunday, December 17, 2000 11:24 AM
> To: sound@lists.io.com
> Subject: [JN] quick ? on magnetics
>
> hello joes,
>
> someone out there will probably be able to answer this little brain-teaser in a
> matter of seconds...
>
> i've got some of those allied electronics interstage trannies here--they were
> cheap, like under 20 bucks each. they are specced as 10k:10kct, 30mA max
> primary I. there's about 10H of L across both primary and 2ndary.
>
> i got to thinking that the 2ndary could be series-connected in phase with the
> primary, yielding ~4x the inductance. when tested on my LCR bridge, i got
> about 35H @ 120Hz, and over 40H @ 1KHz--not too bad!
>
> my question is in regards to the max current in this configuration... it's down
> to two choices:
>
> a) the max current is 30mA/2, or 15mA, since there are two identical windings
> now contributing to the static flux in the core.
>
> b) the max current is 30mA/4, or 7.5mA, since you never get something for
> nothing and i now have 4x the effective L, so it would only stand to reason.
>
> so what's your take on the subject? i've tried reasoning it out and looking it
> up in textbooks, but i ain't found shit, so to speak.
>
> thanks for any help you could send my way...
>
> ken
>
=========================================================================
From: Ken Gilbert <ride5000@ride.ri.net>
Subject: [JN] quick ? on magnetics--REPRISE
Date: Mon, 18 Dec 2000 18:34:32 -0500
Source: Sound Digest Archive v02.n762
steve bench said:
>Think energy. (0.5*L*I*I). Try 7.5mA
dave slagle said:
>hey ken... not sure here... but i would guess that you get 15ma... its an
>amp turns thing here.... you double the turns so the same amp turns ratio
>would be 1/2 the amps... thats dc... for ac... you would get double the
>available AC swing before saturation.... (so there is something for free...)
>
>look at the tango stuff that allows for series parallel connection... the
>TC-160 has a series connection of 160hy 15ma, the parallel has 40hy 30ma....
paul joppa said:
>The magnetization goes as the ampere-turns. Double the turns, and it
>will take half the amperes. You now have twice the DCR, so you did not
>quadruple the L so much as doubling the L/R - that's where you don't get
>something for nothing.
so we've got two votes for 15mA, and one for 7.5mA. come on guys, which is it?
;)
steve is correct in pointing out that the energy stored in the magnetic field
of an inductor is:
W (watt-seconds) = L (henries) * I^2 (amps) * 0.5 [1]
this is shown in various texts--the one i used was radio engineer's handbook by
f e terman.
it would stand to reason that if the magnetic field is a measure of energy, and
the strength of the magnetic field is what determines the saturation point of
the core, then there is a maximum magnetic field energy that can be maintained
by the core material before saturation.
since energy is a matter of current SQUARED, then 2x the effective magnetizing
current would create 4x the field energy--so sayeth the equation above. but,
that's assuming that the L doesn't change, which is quite important as i found
out.
now if we take dave's empirical observation of tango's specs, and plug them
into the formula, we get:
SERIES:
160H, 15mA
160 * (0.015)^2 * 0.5 = 0.018 watt-seconds
PARALLEL:
40H, 30mA
40 * (0.030)^2 * 0.5 = 0.018 watt-seconds
so they jive with the formula, and reinforce that the total watt-seconds of
magnetic field is what's important in terms of core saturation.
paul's contribution does sound reasonable as well...
now, where does that leave me?
well, the tranny is 10H and rated for 30 mills. plugging that into the
formula, we get:
10 * (0.030)^2 * 0.5 = 0.0045 watt-seconds
so that is the level of magnetic field energy at which saturation starts to
seriously cut into ac headroom.
here is a good time to introduce the other interesting thing i found (also in
the radio engineer's handbook), which is how to combine inductances that share
a mutual inductance. iow, two coils in series on the same core. it's not just
a simple multiplication, but rather:
L = L1 + L2 +/- 2M [2]
where L is the total effective inductance, L1 and L2 are the individual
inductances, and M is the mutual inductance between them.
in my particular case, measured at 1KHz:
L1 = 10.69H
L2 = 10.55H
Lseries (in phase) = 42.06H
Lseries (out phase) = 36.13mH
so i can attempt to find M, the mutual inductance.
(out phase case)
0.03613 = 10.69 + 10.55 - 2M
0.03613 = 21.24 - 2M
2M = 21.20
M = 10.6H
this makes good sense to me--the mutual inductance is about halfway between
each winding's individual inductance value.
(in phase case)
42.06 = 10.69 + 10.55 + 2M
42.06 = 21.24 + 2M
20.82 = 2M
M = 10.41H
this also makes sense, and is a very close match to the value determined above.
well, close enough for me! ;-)
finally, as a last hurrah, i measured each winding's leakage inductance by
shorting out the other. by definition, this leakage inductance would
contribute to the inductance of an individual winding, but would NOT contribute
to the mutual inductance. both windings measured 36.3 mH of leakage
inductance. that's suspiciously close to the composite effective out of phase
inductance, which makes sense.
what's interesting is that they didn't add to create 36+36mH of LL, but as i
think about it that makes sense too... the transformer doesn't care which side
is measured and which is shorted... any stray inductance hanging around, either
on the primary or on the secondary, will appear on the measured winding.
so, if i've got a (say) 40H inductor wound on a core that can take 0.0045
watt-seconds of magnetic field energy, then my max current will be:
W (watt-seconds) = L (henries) * I^2 (amps) * 0.5 [1]
0.0045 = 40 * I^2 * 0.5
0.009 = 40 * I^2
0.000225 = I^2
I = 0.015A
sunuvabitch... 15 mills of current.
what steve didn't seem to take into account is the fact that the inductance
value is also increasing, which (since my mutual inductance is just about as
high as it can go at 10H) ends up being 4x the original value, according to
empricical evidence as well as equation [2] stated earlier.
this can be more easily seen if we equate two [1] equations and cancel some
factors, leaving I^2 * L = I^2 * L for a given magnetic field strength.
thus, if L is now 4L, then I^2 is now (I^2)/4, which is equivalent to (I/2)^2,
or half the current into 4x the henries.
whew.
ken
ps. the formula i found for PARALLEL combos of mutual inductances is:
L = (L1 * L2 - M^2) / (L1 + L2 +/- 2M)
=========================================================================
From: SBench@aol.com
Subject: Re: [JN] quick ? on magnetics--REPRISE
Date: Mon, 18 Dec 2000 20:09:16 EST
Source: Sound Digest Archive v02.n762
In a message dated 00-12-18 18:37:08 EST, ride5000@ride.ri.net writes:
> steve bench said:
>
> >Think energy. (0.5*L*I*I). Try 7.5mA
>
<much good stuff snipped>
Hi Ken and all,
You covered it thoroughly. I gave the right idea, (one form of energy
is conserved) and gave the wrong "try 7.5 mA" . As you point out,
energy is conserved when i=15mA (in the running example).
Same will apply to multiple windings.
Sorry for the confusion. Dave and Paul came to the correct 15mA
conclusion.
- -Steve
=========================================================================
From: ALEXSCIFI@aol.com
Subject: [JN] Quicksilver 8417 amps?
Date: Fri, 24 Mar 2000 15:05:33 EST
Source: Sound Digest Archive v02.n494
I heard a pair of QS8417 amps (2 diode version) blow away a Jeff Roland
integrated amp and would like to ask a few questions:
1) Which is the more highly regarded version, the first (2 diode tubes)
or the second (1 diode tube and supposedly better output transformer)?
I've read differing comments else where.
2) The 8417 is supposedly the best of the best with respect to PP
50-60 watt amps. Were they ever considered for SE use?
3) Is there a chance they might be reintroduced?
Thanks.
Alex
=========================================================================
From: Tim_Bailey@medibank.com.au
Subject: [JN] Re: Quicksilver 8417 amps? sound-digest V2 #494
Date: Mon, 27 Mar 2000 12:16:47 +1000
Source: Sound Digest Archive v02.n497
The first amp used two 5AR4's and choke / capacitor ladder power supply.
I heard these a lot at Duratone here in the '80's, driving the big Magnats (with
the Ion discharge tweeter), from Duratone's big Swiss (super) linear tracking
TT.
Very nice amps. The 8417 tubes went through a period of doubted/doubtful
availability, and this may have been the reason for QS changing to 6550's and
EL34's.
Unless the later one used a gutsier single Diode tube it is unlikley it could
sound better.
Tim B
****************************************************************
NOTICE - This message is intended only for the use of the
addressee named above and may contain privileged and
confidential information. If you are not the intended recipient
of this message you are hereby notified that you must not
disseminate, copy or take any action based upon it. If you
received this message in error please notify Medibank
Private Ltd immediately. Any views expressed in this
message are those of the individual sender, except where
the sender specifically states them to be the views of
Medibank Private Ltd.
****************************************************************
=========================================================================
From: Ken Gilbert <ride5000@ride.ri.net>
Subject: [JN] quick thought on the new allied IT
Date: Sun, 12 Nov 2000 21:26:41 -0500
Source: Sound Digest Archive v02.n731
so the tranny has two windings, and from end to end they're at unity turns
ratio, each good for about 10H of inductance, and the core can take 30 mA
through one of those two windings.
how about if we series the two windings, in phase?
do we then get a 40H choke good for 7.5 mA?
capacitance might be a problem, but still--that's a lot of henries!
kg
=========================================================================
From: Conrad Drake <conrad@directwest.iinet.net.au>
Subject: [JN] Quick Vancouver CA visit
Date: Wed, 30 Jun 1999 21:52:53 +0800
Source: Sound Digest Archive v02.n192
Hi all,
I will be in Vancouver CA for about 48 hours in two weeks. If any Joes
or Addicts have anything they need from Oz that I can bring let me know.
(Real Soon Now!)
I guess at least I can expediate the shipping from BlackArt or Tivoli
HiFi (!
Yours,
Conrad Drake
- --
Direct West Invs. Solutions for Embedded Systems.
conrad.drake@directwest.iinet.net.au (ph)+61 8 9285 1000
http://directwest.iinet.net.au (mb)+61 40 747 1611
12 Gayton Road, City Beach, WA 6015 AUSTRALIA
=========================================================================
From: MHuber@t-online.de (Manfred Huber)
Subject: Re: [JN] Quiet???
Date: Wed, 10 May 2000 13:09:20 +0200
Source: Sound Digest Archive v02.n542
Hugh
>A bit of controversy is in order!
Wanna talk about cathode followers? <g>
Ciao,
Manfred
- ------------------
Manfred Huber
MHuber@t-online.de
- ------------------
=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: Re: [JN] Quiet???
Date: Wed, 10 May 2000 18:10:15 GMT
Source: Sound Digest Archive v02.n542
Paul,
>Will someone PLEASE explain what the zener thing for strapping pentodes as
>triodes is all about?
>
>I asked once and so far, everyone's ignored me.
One guess.... Some Penthodes do not like their screens to be run at the HT
than their Anodes (If HT is high). Also, it will modify the curve the Valve,
perhaps towards less Distortion? Of course, Zenners have their own sonics
and might be fundamentally undesirable (they certainly are in Valve
Regulators).
Anyway, just talking of my rocker....
Later T
________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
=========================================================================
From: "P. de R. L." <triode@bow-tie.org.uk>
Subject: Re: [JN] Quiet???
Date: Wed, 10 May 2000 18:58:53 +0100
Source: Sound Digest Archive v02.n542
OK Hugh.
Will someone PLEASE explain what the zener thing for strapping pentodes as
triodes is all about?
I asked once and so far, everyone's ignored me.
Regards,
Paul
- ----- Original Message -----
From: Hugh R Dean <aspen@alphalink.com.au>
To: <sound@deliverator.io.com>
Sent: Wednesday, May 10, 2000 11:39 AM
Subject: [JN] Quiet???
> Joes,
>
> I don't believe love makes the world go round.
>
> It seems to have stopped the joenet dead in its tracks.......
>
> C'mon guys.
>
> A bit of controversy is in order!
>
> Cheers,
>
> Hugh R. Dean
> Melbourne, Australia
>
>
=========================================================================
From: "P. de R. L." <triode@bow-tie.org.uk>
Subject: Re: [JN] Quiet???
Date: Wed, 10 May 2000 18:59:18 +0100
Source: Sound Digest Archive v02.n542
Yes please; I love them.
Paul
- ----- Original Message -----
From: Manfred Huber <MHuber@t-online.de>
To: <sound@deliverator.io.com>
Sent: Wednesday, May 10, 2000 12:09 PM
Subject: Re: [JN] Quiet???
> Hugh
>
> >A bit of controversy is in order!
>
> Wanna talk about cathode followers? <g>
>
> Ciao,
> Manfred
>
>
> ------------------
> Manfred Huber
> MHuber@t-online.de
> ------------------
>
>
>
=========================================================================
From: "Hugh R Dean" <aspen@alphalink.com.au>
Subject: [JN] Quiet???
Date: Wed, 10 May 2000 20:39:51 +1000
Source: Sound Digest Archive v02.n542
Joes,
I don't believe love makes the world go round.
It seems to have stopped the joenet dead in its tracks.......
C'mon guys.
A bit of controversy is in order!
Cheers,
Hugh R. Dean
Melbourne, Australia
=========================================================================
From: William Gardner <wg44929@mail.navix.net>
Subject: Re: [JN] Quiet???
Date: Wed, 10 May 2000 21:10:40 -0500
Source: Sound Digest Archive v02.n543
>OK Hugh.
>
>
> >
> > C'mon guys.
> >
> > A bit of controversy is in order!
> >
> > Cheers,
> >
> > Hugh R. Dean
>perhaps ....... Quiet = Redundancy daaa yaa think, heres a few topics
>that maybe will get the fire growing ..... How about that Bass Box Pro
>software , what do you J netters think of it , how about isobaric push
>pull woofers , anyone ever tried it , compound ,
push/pull,cabasse woofers .... now there's a driver , or 6c33c's..... way
cool looking but a real bitch to drive ,or , someone PLEASE explain ( JC
are you F*&^&%%% lurking since your so busy testing Ruskie tubes ) RE: The
Feral eye circuit ..... Lets say we wanted to use 2 output tubes per
channel .... How would I direct couple the driver stage using a
parallel 5687 to the out put tubes .
L.D . Moore suggested this , I don't under stand , does it mean a new power
supply design , this should be a piece of pie for all you designers . Again
I'm not attempting to be a smart ass , I was able to achieve that status
many years ago (<:
also I'd like to thank Mr.Adnan Arduman for the great picture's of
everyone and their hi-fi systems Thanks Bill Gardner
=========================================================================
From: "P. de R. L." <triode@bow-tie.org.uk>
Subject: Re: [JN] Quiet???
Date: Wed, 10 May 2000 21:53:36 +0100
Source: Sound Digest Archive v02.n543
Whoops! caught out again!
I have built only CFs with resistors so far, but this is about to change; I
am planning active loads.
I have used 6SN7, 7119 and 5687 as cathode followers so far. 5687 sounds
especially nice - or did when I tried it.
I was just on the phone to somebody about the 6C45P (i have just tested a
few) and he (who also has a few was saying that he couldn't hear any
difference betwen them - I said that i doubt if I could hear the difference
between an EL34 and a 6V6!
Anyway my feeling is that transformers look boring and valves look great (I
know this is childish and I don't care!), so why not use cathode followers?
The 6C45P should make an excellent one I think; I am proposing to use the
GEC pentode Z759 as the sink: this has Ra of 500k and gm of 15; Pa is 5W.
Should make a nice 'follower I think!
Meanwhile, there was a lot of talk about chokes as grid leaks recently. It
occurs to me that they could be the answer for the rather gassy output
valves I am proposing to use in the new insanity model. These valves are
13E1 beam tetrodes. Pa strapped as a triode is 95W so if they start to run
I've had it! what about a choke as a grid leak to soak away those
microamps? Any idea on a suitable number of Henries so I don't lose my bass
response?
best of luck,
Paul
> What is your favourite circuit (CF)?
>
> Guido
>
>
> >Paul
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] Quiet???
Date: Wed, 10 May 2000 22:12:14 +0200
Source: Sound Digest Archive v02.n543
At 18:59 10/05/2000 +0100, P. de R. L. wrote:
>Yes please; I love them.
What is your favourite circuit (CF)?
Guido
>Paul
>
>----- Original Message -----
>From: Manfred Huber <MHuber@t-online.de>
>To: <sound@deliverator.io.com>
>Sent: Wednesday, May 10, 2000 12:09 PM
>Subject: Re: [JN] Quiet???
>
>
>> Hugh
>>
>> >A bit of controversy is in order!
>>
>> Wanna talk about cathode followers? <g>
>>
>> Ciao,
>> Manfred
>>
>>
>> ------------------
>> Manfred Huber
>> MHuber@t-online.de
>> ------------------
>>
>>
>>
>
>
>
=========================================================================
From: "Hugh R Dean" <aspen@alphalink.com.au>
Subject: [JN] Quiet???
Date: Mon, 7 Aug 2000 11:13:23 +1000
Source: Sound Digest Archive v02.n619
It's easy to see a lot of joes are travelling!
Not much traffic...
Should be lots of interesting reports soon.
Cheers,
Hugh
Hugh R. Dean
Melbourne, Australia
=========================================================================
From: peter davidoff <peterd@hcberger.com>
Subject: Re: [JN] Quiet.....
Date: Wed, 01 Aug 2001 12:40:26 -0600
Source: Sound Digest Archive v02.n938
> rather quiet before the Arhus storm .....
> Guido
end of month. everyone's doing inventory....
peter
hc berger brewery
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: [JN] Quiet.....
Date: Wed, 01 Aug 2001 20:30:12 +0200
Source: Sound Digest Archive v02.n938
rather quiet before the Arhus storm .....
Guido
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: Re: [JN] Quiet.....
Date: Wed, 01 Aug 2001 17:33:34 -0500
Source: Sound Digest Archive v02.n939
Timo Christ wrote:
> Yo Jason,
>
> [I hope you don't mind me posting this publicly]
>
> Jason Watkins wrote:
> >
> > Was this inspired by those crazy guys putting basstech 7's in cars?
>
> i saw those, but i wanted to do it before. In fact, i designed my horns
> so that they both fit in the car. But i cannot take both along to Arhus
> because amps and trade material also has to fit in (barely).
>
> > http://www.tomchemie.de/allebildervonteamservodrive.htm
> >
Hi
Catching up on e-mail.
Thanks for the link, it is fun to see what people do with our stuff.
Do take pictures at Kurt's, once again the reality of life prevents me from
attending grrrrrrrrrrrrrr.
Too much to do, too hot outside.
Tom
>
> > any chance we could see some pics of yours?
>
> Sure! THIS TIME i have batteries for my digital cam, so i guess i'll
> bring around 100 pics home.
>
> cheers (yeah, i'm bringing BECKS, hope everyone else also brings beer
> from his hometown!)
> Timo
>
=========================================================================
From: Timo Christ <carnivor@uni-bremen.de>
Subject: Re: [JN] Quiet.....
Date: Wed, 01 Aug 2001 20:48:16 +0200
Source: Sound Digest Archive v02.n939
Hi Guido,
in my car it is not so quiet. i have installed a bass horn. <G>
this goes at least as loud as the VW Golf boomers - with no amp apart
from the 2W radio. muhahaaa..
I will have a nice cruise to Denmark tomorrow. Probably arrive at 14:30
like last year.
See you there!
boom boom goes the kangoo
:-)
T
evaguido wrote:
>
> rather quiet before the Arhus storm .....
>
> Guido
- --
/ /--' Timo Christ carnivore@uni-bremen.de
/ /<-. Electronics Engineering Student
__/ /__/ Horns 'r more fun:
' http://www-user.uni-bremen.de/~carnivor/
=========================================================================
From: Timo Christ <carnivor@uni-bremen.de>
Subject: Re: [JN] Quiet.....
Date: Wed, 01 Aug 2001 22:02:10 +0200
Source: Sound Digest Archive v02.n939
Yo Jason,
[I hope you don't mind me posting this publicly]
Jason Watkins wrote:
>
> Was this inspired by those crazy guys putting basstech 7's in cars?
i saw those, but i wanted to do it before. In fact, i designed my horns
so that they both fit in the car. But i cannot take both along to Arhus
because amps and trade material also has to fit in (barely).
> http://www.tomchemie.de/allebildervonteamservodrive.htm
>
> any chance we could see some pics of yours?
Sure! THIS TIME i have batteries for my digital cam, so i guess i'll
bring around 100 pics home.
cheers (yeah, i'm bringing BECKS, hope everyone else also brings beer
from his hometown!)
Timo
- --
/ /--' Timo Christ carnivore@uni-bremen.de
/ /<-. Electronics Engineering Student
__/ /__/ Horns 'r more fun:
' http://www-user.uni-bremen.de/~carnivor/
=========================================================================
From: "Kurt Steffensen" <kurt-steffensen@teliamail.dk>
Subject: Sv: [JN] Quiet.....
Date: Wed, 1 Aug 2001 23:43:23 +0200
Source: Sound Digest Archive v02.n939
Peter.
I was hoping you would be amoung the Festivallers this year.
Owners of beer breweries are VERY popular indeed at such occasions;-)
I would be happy to sponse some stickers to the beers.
> > rather quiet before the Arhus storm .....
> > Guido
>
> end of month. everyone's doing inventory....
... I am doing festival :-)
- - Kurt
>
> peter
> hc berger brewery
>
=========================================================================
From: Ken Gilbert <ride5000@ride.ri.net>
Subject: [JN] Quietest input stage?
Date: Sat, 25 Sep 1999 20:14:07 -0400
Source: Sound Digest Archive v02.n285
I am beginning to delve into the next project of insanity, which is
(surprise, surprise) a guitar preamp.
Enjoying both crystal clean and mondo gain distortion, I need the quietest
input stage I can muster. After all, this is where most of the noise is
from, and it's shared by all channels of the preamplifer (at least mine).
It serves as both the initial stage of VA as well as a buffer for the rest
of the channels downstream.
The following are TENTATIVE statements... if you see holes in the thinking
please be gentle.
So for an input stage, we want in general a low impedance circuit, to
minimise the thermal noise in the load/grid/cathode resistor, right?
And therefore we want a low plate impedance (to match well with the load)
and also a high transconductance (to provide adequate current swings into
the load).
One good way of accomplishing both is to parallel a couple of triodes
together. I have heard arguements that this sounds less than optimal--some
kind of mismatch in each section's transfer characteristics?--but THD is
not really a concern in this case. I can get double the gm and half the rp
for the same equivalent noise voltage and mu, right?
Low voltages are to be preferred to higher ones, which keep impedances low,
and shot noise down.
Triodes are better in the noise department than pentodes.
Zener shunt regulation removes ripple but adds noise.
I was thinking of a paralleled 6N1P, operated with 100V on the plate or so.
Sound reasonable?
The only downside I can think of is that the grid circuit impedance must be
at most 250K for this || arrangement. That's kinda loading the guitar
cable down, and I gots ta have my HF!
How about the venerable EF86 in triode mode? Any comparison?
Thank you, Joes.
Ken
=========================================================================
From: SBench@aol.com
Subject: Re: [JN] Quietest input stage?
Date: Sat, 25 Sep 1999 21:49:30 EDT
Source: Sound Digest Archive v02.n285
In a message dated 99-09-25 20:28:17 EDT, ride5000@ride.ri.net writes:
<<
Enjoying both crystal clean and mondo gain distortion, I need the quietest
input stage I can muster. After all, this is where most of the noise is
from, and it's shared by all channels of the preamplifer (at least mine).
It serves as both the initial stage of VA as well as a buffer for the rest
of the channels downstream.
The following are TENTATIVE statements... if you see holes in the thinking
please be gentle.
So for an input stage, we want in general a low impedance circuit, to
minimise the thermal noise in the load/grid/cathode resistor, right?
And therefore we want a low plate impedance (to match well with the load)
and also a high transconductance (to provide adequate current swings into
the load).
One good way of accomplishing both is to parallel a couple of triodes
together. I have heard arguements that this sounds less than optimal--some
kind of mismatch in each section's transfer characteristics?--but THD is
not really a concern in this case. I can get double the gm and half the rp
for the same equivalent noise voltage and mu, right?
Low voltages are to be preferred to higher ones, which keep impedances low,
and shot noise down.
Triodes are better in the noise department than pentodes.
Zener shunt regulation removes ripple but adds noise.
I was thinking of a paralleled 6N1P, operated with 100V on the plate or so.
Sound reasonable?
The only downside I can think of is that the grid circuit impedance must be
at most 250K for this || arrangement. That's kinda loading the guitar
cable down, and I gots ta have my HF!
How about the venerable EF86 in triode mode? Any comparison?
Thank you, Joes.
>>
Hi Joe Ken,
Paralleled 6N1Ps are likely to provide about 0.5uV or less flat noise;
triode connected EF86 slightly higher. Generally the equivalent input
noise with any device exceeds the gm limit due to cathode surface
effects. The gold pin 5842/417As will be the quietest for flat gain
applications (but not for 1/f applications).
If you use the Svet product line for EF86 or 6N1P, be sure to cycle
the filaments a few dozen times before ascertaining whether or not
they are quiet enough. I was able to get up to 7dB improvement in
Svet EF86 and some lesser improvements in 6N1P doing that.
BTW, those noise levels ought to be pretty good in your application.
Best Regards,
Steve
=========================================================================
From: David Barnett <davidbarnett@aristotle.net>
Subject: Re: [JN] Quietest input stage?
Date: Sun, 26 Sep 1999 02:34:48 -0500
Source: Sound Digest Archive v02.n286
On Sat, 25 Sep 1999 20:14:07 -0400, Ken Gilbert <ride5000@ride.ri.net>
wrote:
>The only downside I can think of is that the grid circuit impedance must be
>at most 250K for this || arrangement. That's kinda loading the guitar
>cable down, and I gots ta have my HF!
A 250K input impedance is a show-stopper, in my opinion. I wouldn't
want a guitar preamp's input Z below 1M, or else it's bye-bye to
highs. Have you considered a JFET for the first stage, followed by
tubes?
- --dnb
=========================================================================
From: "=?ISO-8859-1?Q?Torbj=F8rn_Lien?=" <mdrivekl@online.no>
Subject: Re: [JN] Quietest input stage?
Date: Sun, 26 Sep 1999 11:35:47 +0100
Source: Sound Digest Archive v02.n286
> >The only downside I can think of is that the grid
> >circuit impedance must be at most 250K for this
> >|| arrangement. That's kinda loading the guitar
> >cable down, and I gots ta have my HF!
>
> A 250K input impedance is a show-stopper, in my
> opinion.
Yepp,-most certainly is...
> I wouldn't want a guitar preamp's input Z
> below 1M, or else it's bye-bye to highs.
2M I'd say..the higher the better..
> Have you considered a JFET for the first stage,
> followed by tubes?
I've had nice result with a 2SK30A-GR. Noise
level wasn't that super lo, but decent enough.
Torbjoern, Norway
>
>
>
=========================================================================
From: "Kurt Th. Steffensen" <kurt-steffensen@teliamail.dk>
Subject: Sv: [JN] Quietest input stage?
Date: Sun, 26 Sep 1999 14:42:18 +0300
Source: Sound Digest Archive v02.n286
Dear Ken.
It is funny with these guitar amplifiers.
Nothing we have learned from the HiFi amp´s , is evident for these , and
vice versa.
Ceramic capacitors sounds GOOD in guitar amps , and the "sweet spots" in the tube set up is certainl
y often different , than those we use in HiFi.
Even HiFi OPT sounds "weird" in guitar amp´s.
It is also cool to overdrive the stages in cascades.
It insures this "sweet" sustain. (Ala´Carlos Santana )
Lot´s of harmonics are good here.
It is true when you suggest that , using "small" resistances , will help a lot to keep the noise
down.
But it is also true , what has been mentiones , that this approach , kind of kills the life and
beauty of the guitar sound.
I think there is only one solution to all this.
You have to build the first stage into the guitar.
And if you insures low output resistance from here , and/or use a output transf./CF you , are able t
o have relative low input grid resistors.
Noise is way down , this way , without sacrify any of the good sound.
I would go for a parallel ECC 83 , 6948 or that alike.
(Sounds bad to parallel in HiFi , but acts really good in guitar amp´s i.m.o.)
Most of the noise in guitar amp.s comes from the resistors , and a lot of this , is from the first s
tages , as you suspect.
Allen Bradleys comp. resistors , sounds fantastic in guitar amp´s , and usually so in HiFi amps , bu
t they produce a hell lot of noise.
Many other carbon resistors are even worse.
You can cut 10-20 dB of noise in most guitar amps, only by changing resistors !
If you want to try the 6948´s , but do not know where to get them , or you belive that they are to e
xpensive , drop me a line , and I will send you a pair to play with.
But you have to find the sweet points for guitar , by yourselfe.
I havent made guitar amps for many years , and my notes for these are gone.
(PS , I do not like the EF 86 , ECC 88 for neither guitars , nor HiFi. But others do.
It is a matter of taste , I belive )
Sincerely
- - Kurt Steffensen
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: [JN] Quietest input stage?
Date: Sun, 26 Sep 1999 15:54:58 -0400
Source: Sound Digest Archive v02.n286
Ken asks about low noise hi Z front ends:
Ken, from years of optimizing tube and/or hybrid front ends for MM, MC,
microphone and tape head sources, but never guitar, (and always prefering
the highest possible loading for all these sources) I believe the best
possible mix comes from using a very high gM, low noise Jfet like the
2SK170 as the lower part in cascde with a 6922 or similar hi gM tube.
The benefits can be listed as:
1/ Very very low noise - the lowest I know short of trick bipolars like the
MAT 2 or LM394 - which are very hard to implement in a SE stage without
input caps.
2/ Very low miller capacitance allows a _consistant_ input Z - and the best
chance of maintaining your needed hi input Z at high frequencies.
3/ Gain can be VERY high, prob WAY more than you need as up to 70dB has
been obtained in one stage - but it is easily adjustable with the source
resistor(s).
4/ Very linear.
5/ Can be used SE or balanced - maybe a chance for the first balanced input
guitar preamp?
6/ They sound GREAT!
I suggest you take a look in my site (www.vacuumstate.com) for the
schematics for the FVP5 (single ended) and RTP (balanced preamps) that use
these hybrid cascodes, and for the FFT graphs that show their (absolutely
surprising) linearity!
Drop out the RIAA eq, tweek for the required gain, and you should have
something pretty interesting...
Allen (VSE)
PS Thorsten wrote me a few months ago saying how well this worked noise and
sonics wise in place of a 417!
=========================================================================
From: busbridge <S.C.Busbridge@bton.ac.uk>
Subject: Re: [JN] Quietest input stage?
Date: Mon, 27 Sep 1999 07:39:34 +0100 (BST)
Source: Sound Digest Archive v02.n286
Hi Ken,
I've got an old rsgb publication here with a useful chapter on valve
noise. The equivalent noise resistor of a triode = 2.5/g, with a pentode
considerably higher due to partition current.
If I remember correctly, each time you double the number of paralleled
vavles, the snr improves by 3 dB. (3, not 6 dB, because the noise
voltage is proportional to the square root of 2.5/g).
The EF86 has a fairly low g so would not be my first choice.
Simon
Simon Busbridge, BSc(Hons) PhD CPhys MInstP
School of Engineering
University of Brighton
Lewes Road
Moulsecoomb
Brighton BN2 4GJ
UNITED KINGDOM
Tel: 0044 (0)1273 642542
Fax: 0044 (0)1273 642327/642301
e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com
=========================================================================
From: "Bill Gaw" <whg@tiac.net>
Subject: Re: [JN] Quietest input stage?
Date: Mon, 27 Sep 1999 14:52:52 -0400
Source: Sound Digest Archive v02.n287
I have to second Allen's recommendation. I have one of his phono units with
70 dB. gain, it is dead silent and yet has that tube stage presentation. I
highly recommend it.
On another note, I just completed building a pair of Doc. Botlehead's 2A3
parafeed amps. The kits were easy to build with great directions, and good
parts. I will be writing areview of it for the www.enjoythemusic.com web
page just as soon as I get to listen to it and share it with some other
ears.
P.S. Don't worry Allen. I'm still waiting on your amps. Bill Gaw-----
Original Message -----
From: Allen Wright <AllenVSE@compuserve.com>
To: Ken Gilbert <ride5000@ride.ri.net>; JoeNet A <sound@lists.io.com>
Sent: Sunday, September 26, 1999 3:54 PM
Subject: [JN] Quietest input stage?
> Ken asks about low noise hi Z front ends:
>
> Ken, from years of optimizing tube and/or hybrid front ends for MM, MC,
> microphone and tape head sources, but never guitar, (and always prefering
> the highest possible loading for all these sources) I believe the best
> possible mix comes from using a very high gM, low noise Jfet like the
> 2SK170 as the lower part in cascde with a 6922 or similar hi gM tube.
>
> The benefits can be listed as:
>
> 1/ Very very low noise - the lowest I know short of trick bipolars like
the
> MAT 2 or LM394 - which are very hard to implement in a SE stage without
> input caps.
>
> 2/ Very low miller capacitance allows a _consistant_ input Z - and the
best
> chance of maintaining your needed hi input Z at high frequencies.
>
> 3/ Gain can be VERY high, prob WAY more than you need as up to 70dB has
> been obtained in one stage - but it is easily adjustable with the source
> resistor(s).
>
> 4/ Very linear.
>
> 5/ Can be used SE or balanced - maybe a chance for the first balanced
input
> guitar preamp?
>
> 6/ They sound GREAT!
>
> I suggest you take a look in my site (www.vacuumstate.com) for the
> schematics for the FVP5 (single ended) and RTP (balanced preamps) that use
> these hybrid cascodes, and for the FFT graphs that show their (absolutely
> surprising) linearity!
>
> Drop out the RIAA eq, tweek for the required gain, and you should have
> something pretty interesting...
>
> Allen (VSE)
>
> PS Thorsten wrote me a few months ago saying how well this worked noise
and
> sonics wise in place of a 417!
>
=========================================================================
From: Ken Gilbert <ride5000@ride.ri.net>
Subject: Re: [JN] Quietest input stage?
Date: Mon, 27 Sep 1999 17:29:09 -0400
Source: Sound Digest Archive v02.n287
First of all, thanks to all those who replied. It is very heartening to be
the recipient of good will and hard-earned information.
I have a pretty good idea of the implimentation I will attempt here, and it
is something like Allen's phono input. It seems a good topology since it
avoids Miller input capacitance and retains its low noise requirement. Not
to mention it's pretty trick as far as guitar front ends go. Having
something unique does bolster the ego a bit.
After downloading the schematics and doing a cursory search of parts
availability, I can find only one of the three "eqivalent" FETs, the
2sk170. As I only need one I do not need to match them. Unfortunately the
distributor who stocks the part requires a $200 minimum order. That's a
lot more than 1 FET.
I noticed that you have some available on your website, Allen. Would it be
possible to get a reduced price on a single part? Perhaps you could unload
an "unmatchable" FET that has no partner? Barring that, are there any
other recomendations as to low noise/high gm FETs?
David B. pointed out (and Torbjorn quickly seconded) that the requisite
grid input resistor with || 6N1P's is far too low to preserve bandwidth,
and I heartily agree. That means either A) not inputting directly to the
6N1P's grid or B) bootstrapping the grid leak resistor.
A) could mean either the cascode as Allen mentioned, or it could be a
discreet FET input stage. B) seems out of the question as the cathode will
be well bypassed for maximum voltage gain, and there isn't really a later
stage off of which to take an in-phase signal to feed the bootstrap.
Ron pointed out that the quicker you get the signal voltage up the less
likely it is to be affected by other circuitry noise/hum/etc. This is of
course true, but going from this logic it would seem that an input PENTODE
is even better--especially one plate loaded with a current source. Then I
could get as much voltage gain as I could possibly desire. I also remember
reading in RDH that a pentode has actually less IMD at the smaller output
voltages... So more gain, less IMD, but more noise though. Maybe that
12ax7 is a good compromise after all.
Kurt mentioned some idiosyncracies about guitar amps and their notorious
non-linearity. I am fairly confident that I will be able to tweak the
sound I want once I get past the most critical input stage. At these low
levels there is negligible distortion anyway--that input stage is really
the cleanest stage in the amp. That's why I thought I'd beg a question of
you phono guys, who know the most about pulling a weak signal out of the
background noise.
Kurt also talked of putting the input stage where it REALLY belongs, and
that is right at the guitar itself. It is interesting that he mentioned
this, because about a year or two ago I had the same thought. My
incarnation was to put a single 12ax7 in a small enclosure, which would be
clipped to the guitar strap, hooked up as a plate loaded stage direct
coupled into a CF. Voltage gain could be easily set to whatever seemed
prudent (maybe 10x) and the CF would provide a low Z driver for the cable
(and also the front end of the amp!). Thus one could have a tube input
stage AND low noise, low impedance cable drive no matter which kind of amp
one used.
The sticking points were the power supply, and the umbilical cord, obviously.
Finally Allen's comments on the balanced input also piqued my interest. It
would be relatively simple to wire the pickups in the guitar to a balanced
output with separate grounds, and a simple stereo 1/4" jack could be
employed to short ring (-) to sleeve (gnd) with a mono plug when normal SE
operation was desired. The only switch I use on the guitar is the pickup
selector anyway. I could do without tone/volume knobs very well.
If I understand correctly, the benefit here of balanced transmission would
lie in the input stage's CMRR, since any injected noise would be common
mode, and signal would be differential. Thus a very long "tail" would be
desired (since a transformer input would be a bit silly).
Any additional comments would kick ass, and my sincere thanks to the group
for the input thus far!
Ken
==============