Sound Practices Mailing List Files - Volume 2
=========================================================================
From: "Rice, Doug" <RICEDA@phibred.com>
Subject: [JN] 300b amp advice
Date: Thu, 25 May 2000 09:33:01 -0500
Source: Sound Digest Archive v02.n558
Hi everyone,
While pondering 300b amp circuits, I am concerned about my DS-025 OPTs and
how much current they like.
Mikey recommends 60mA, but I was wondering what experience any of you might
have running with these OPTs
with more current. Has anyone built a Flesh and Blood with these OPTs.
(Sorry Herb, I know it won't be a real F&B
without Tango's, but MQ is what I have. )
Any advice appreciated.
Best wishes,
Doug Rice
Des Moines, IA
=========================================================================
From: "BobC" <bobcx@bellatlantic.net>
Subject: Re: [JN] 300b amp advice
Date: Thu, 25 May 2000 20:43:05 -0400
Source: Sound Digest Archive v02.n558
- ----- Original Message -----
From: "Rice, Doug" <RICEDA@phibred.com>
To: <sound@lists.io.com>
Sent: Thursday, May 25, 2000 10:33 AM
Subject: [JN] 300b amp advice
> Hi everyone,
>
> While pondering 300b amp circuits, I am concerned about my DS-025 OPTs and
> how much current they like.
> Mikey recommends 60mA, but I was wondering what experience any of you
might
> have running with these OPTs
> with more current. Has anyone built a Flesh and Blood with these OPTs.
> (Sorry Herb, I know it won't be a real F&B
> without Tango's, but MQ is what I have. )
>
> Any advice appreciated.
Doug,
The 60ma is very conservative, you will have no problem if you run them
higher. I have run them at 75ma, and know other people who are running 70ma
+ and they are quite happy.
Here is some info I had gotten from Mike a few months ago on this same
subject. I hope it helps.
Here is the relationship between current rating and inductance on the
DS-025.
3V RMS 50Hz:
****************
60ma = 17.6H 70ma = 17.2H 80ma = 16.2H
6V RMS 50Hz:
****************
60ma = 18.2H 70ma = 17.8H 80ma = 17H
30V RMS 50Hz:
*****************
60ma = 20H 70ma = 19.8H 80 = 19.1H
50V RMS 50Hz:
*****************
60ma = 20.8H 70ma = 20.5H 80 = 19.8H
100V RMS 50Hz:
********************
60ma = 21.5H 70ma = 21.2H 80 = 20.3H
200V RMS 50Hz: (Which is 16 watts into 2500 ohms)
***********************************************************
60ma = 22H 70ma = 21.5H 80 = 19.7H
Mike told me he only did the testing up to 200 volts 80ma since this
represents a power level of 16 watts, which is substantially higher that the
power output of the tubes that are likely to be used. Even at 80ma 200V 16
watts, (which is double the output of a 300B and five times the output of a
2A3) the inductance level does not diminish significantly.
Good luck
Bob
=========================================================================
From: Christian Rintelen <rintelen@datacomm.ch>
Subject: [JN] 300B and 3rd harmonics
Date: Tue, 06 Apr 1999 20:12:35 +0200
Source: Sound Digest Archive v02.n112
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I have this wonderful chart telling me how many dB 2nd harmonics are
down with all kinds of operating points for 300Bs.
What I do wonder though is the 3rd harmonic with different 300B
operating points-- anybody with any info on that?
Christian
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<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
I have this wonderful chart telling me how many dB 2nd harmonics are down
with all kinds of operating points for 300Bs.
<p>What I do wonder though is the 3rd harmonic with different 300B operating
points-- anybody with any info on that?
<p>Christian</html>
- --------------01CA620B7DB0AED11FFE490A--
=========================================================================
From: Torsten.Loesch@enhar-ha.nthames.nhs.uk
Subject: Re: [JN] 300B and 3rd harmonics
Date: 07 Apr 1999 10:35:19 +0000
Source: Sound Digest Archive v02.n113
Hi there,
> I have this wonderful chart telling me how many dB 2nd harmonics are
> down with all kinds of operating points for 300Bs.
>
> What I do wonder though is the 3rd harmonic with different 300B
> operating points-- anybody with any info on that?
It's in the WE Datasheet.
And the one on-line from Fidelis Audio:
http://www.fidelisaudio.com/datalib/300b.htm
However, these Values are only valid for a 300B driven from a zero Impedance
and Zero Distortion Signal, hard to come by these days.
If there is any Distortion in the Driving Stage, the 2nd Harmonics will show
some cancellation and the 3rd will add....
If the driving impedance is high enough, similar distortion Cancellation
effects will take place at hig Volumes, increasing (most often) 3rd Harmonics
and reducing 2nd....
Later Thorsten
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 300B and 3rd harmonics
Date: Wed, 07 Apr 1999 20:55:39 +0200
Source: Sound Digest Archive v02.n113
At 10:35 7-4-99 +0000, Torsten.Loesch@enhar-ha.nthames.nhs.uk wrote:
>Hi there,
>
>> I have this wonderful chart telling me how many dB 2nd harmonics are
>> down with all kinds of operating points for 300Bs.
>>
>> What I do wonder though is the 3rd harmonic with different 300B
>> operating points-- anybody with any info on that?
>
>It's in the WE Datasheet.
>
>And the one on-line from Fidelis Audio:
>
>http://www.fidelisaudio.com/datalib/300b.htm
thanks
>However, these Values are only valid for a 300B driven from a zero Impedance
>and Zero Distortion Signal, hard to come by these days.
Well, with transistors and a lot of feedback :-)
>If there is any Distortion in the Driving Stage, the 2nd Harmonics will show
>some cancellation and the 3rd will add....
Bingo !
>If the driving impedance is high enough, similar distortion Cancellation
>effects will take place at hig Volumes, increasing (most often) 3rd Harmonics
>and reducing 2nd....
Yup, and so on
Valuable statements Thorsten, too often ignored.........
Guido
>Later Thorsten
>
>
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: [JN] 300B and 3rd harmonics
Date: Thu, 8 Apr 1999 09:46:28 +0200
Source: Sound Digest Archive v02.n114
- ----------
> De : Christian Rintelen <rintelen@datacomm.ch>
> A : Joenet <sound@lists.io.com>
> Objet : [JN] 300B and 3rd harmonics
> Date : mardi 6 avril 1999 20:12
> I have this wonderful chart telling me how many dB 2nd harmonics are
> down with all kinds of operating points for 300Bs.
> What I do wonder though is the 3rd harmonic with different 300B
> operating points-- anybody with any info on that?
Once I derived a relation from the published datas about the WE300B.
Roughly the ratio between the 3rd harmonics and the second is proportionnal
to:
( Ua ^ 1.5) / (Ia . Rl)
with
Ua and Ia = plate voltage and plate current at the quiescent point
Rl impedance at the primary of the OPT
Also with my own mathematical model for the 300B (yet published on the
Joenet) I could verify that there is not a single point on the useful ( Ua
, Ia ) field for which the H3 level is 0 on small signals whatever is the
load...
In fact there is very few tubes that possess such operating zones inside
which H3 is 0 on small signal. 12AU7 is one...
Best regards,
Jean-Michel Le Cleac'h
=========================================================================
From: Paul Joppa <pdj@ISDNseattle.net>
Subject: Re: [JN] 300B and 3rd harmonics
Date: Thu, 08 Apr 1999 09:53:12 -0700
Source: Sound Digest Archive v02.n114
Jean-Michel-
This post is **most** intriguing. Many thanks!
One interesting aspect is what it suggests about the "low and hot"
operating points (low voltage, high current), which are widely thought
to have a desirable, clean sound. By this correlation, they have
relatively high third harmonic distortion. Or I suppose more
accurately, they have low second harmonic without particularly low
third. Is this not the same effect as distortion cancellation? It
suggests in fact that there is a continuum from no second harmonic
(distortion cancellation or push-pull) through possibly an optimum to
complete domination by second harmonic. Certainly to my ears, a good
(class-A triode no feedback!) push-pull amp sounds "different",
cleaner but more clinical, than a regular SE triode. And the few amps
I've heard with really high current seem to have some of that very
clean sound - though my experience is not wide, and may be confounded
with the sound of nickel core output transformers.
The zero-third-harmonic point for a 12AU7 is of course also a real
teaser - will you tell us where it is? Have you used it with
satisfying results? Is it wide enough for a driver, or useful only in
a preamp?
- -Paul Joppa
Le Cleac'h J.-M. wrote:
> ...
> Once I derived a relation from the published datas about the WE300B.
>
> Roughly the ratio between the 3rd harmonics and the second is proportionnal
> to:
>
> ( Ua ^ 1.5) / (Ia . Rl)
> with
> Ua and Ia = plate voltage and plate current at the quiescent point
> Rl impedance at the primary of the OPT
>
> Also with my own mathematical model for the 300B (yet published on the
> Joenet) I could verify that there is not a single point on the useful ( Ua
> , Ia ) field for which the H3 level is 0 on small signals whatever is the
> load...
>
> In fact there is very few tubes that possess such operating zones inside
> which H3 is 0 on small signal. 12AU7 is one...
>
> Best regards,
>
> Jean-Michel Le Cleac'h
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: [JN] 300B and 3rd harmonics
Date: Thu, 8 Apr 1999 20:23:49 +0200
Source: Sound Digest Archive v02.n114
- ----------
> De : Paul Joppa <pdj@ISDNseattle.net>
> A : lecleach@cgis0.ensmp.fr
> Cc : Joelist <sound@deliverator.io.com>
> Objet : Re: [JN] 300B and 3rd harmonics
> Date : jeudi 8 avril 1999 18:53
> The zero-third-harmonic point for a 12AU7 is of course also a real
> teaser - will you tell us where it is? Have you used it with
> satisfying results? Is it wide enough for a driver, or useful only in
> a preamp?
Paul,
You are right in fact the lower H3/H2 ratio is obtained for very low value
of Vg1 (= low values of Ia).
There is often a mistake said about the low Ia region in tubes, it is in
fact in every triode the most linear region (to see how it is linear you
can enlarge the y axis scale on a graph obtained with a good mathemathical
model or even doing precise measurements at low Ia).
So it is not very surprising that the H3/H2 ratio is very reduced in such
regions.
For a graph about the variation of H2/H3 ratio for the 12AU7 you can give a
look at my graph:
http://web.mit.edu/cheever/www/fig6j.jpg
which is a part of a study I once did on the subject:
http://web.mit.edu/cheever/www/h3.htm
In the conditions the zero H3 is obtained until 6VRMS, can be interesting
or not for a driver depend on your opinion.
In a more general way (= for a very large range of load resistance) I also
could verified that such a zero H3 zone exists on the 12AU7 with the help
of my new mathematical model for 12AU7.
And yes I could also verified that it works on real tubes, bur it is only
interesting in differential stages or in PP stages.(In fact it is not a
single point but a line on the (Ia - Va) field.
I still didn't find any power triode for which the H3 level come through 0
at some place of the (Ia - Va) field but I find some which gives very low
H3...(still looking for!)
Best regards,
Jean-Michel Le Cleac'h, Paris, France
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: [JN] 300B and 3rd harmonics
Date: Thu, 8 Apr 1999 20:33:04 +0200
Source: Sound Digest Archive v02.n114
I wrote
"You are right in fact the lower H3/H2 ratio is obtained for very low
value
of Vg1 (= low values of Ia).
There is often a mistake said about the low Ia region in tubes, it is in
fact in every triode the most linear region (to see how it is linear you
can enlarge the y axis scale on a graph obtained with a good mathemathical
model or even doing precise measurements at low Ia).
So it is not very surprising that the H3/H2 ratio is very reduced in such
regions."
There is a mistake in that part of my last message, a confusion between the
ratio of H3/H2 and the absolute value of H3.
Seems I am a bit tired and it is true that I am still at work very late
(8H30mn PM), I will clarified the thing this evening and post something
better tomorrow..
But the end of my previous message is still true...
Best regards,
Jean-Michel Le Cleac'h
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: [JN] 300B and 3rd harmonics
Date: Fri, 9 Apr 1999 10:15:19 +0200
Source: Sound Digest Archive v02.n116
Hello,
Last evening I took my old calculations about H3/H2 for the 300B that I did
with the published datas as in the WE table.
I tried to concentrate only on H3 as the ratio is another kind of beast,
very useful but who can mask the real levels of H3.
I looked for a possible empirical formula giving the H3 level versus the
operating conditions.
I obtained a family of expressions but the more accurate 2 were:
H3 (%) roughly proportionnal to ( Ua^1.3 / Ia ) * ( 1 / Rl^1.1)
H3 (%) roughly proportionnal to ( Ua^1.2 / Ia^1.2 ) * ( 1 / Rl)
In fact the 2 expresion lead to a similar conclusion:
for the 300B, the lower H3 content is obtained for operating conditions
such as:
- low plate voltage
- high plate current
- large resistance load
But this is for the 300B, I don't want to generalize.
(In one of my post yesterday I tried to do a parallel between the 300B and
the 12AU7 but their behaviour is too much different, most probably for the
300B as in the 12AU7 it exists at very low Ia and also at positive grid
bias a zone with low H3 but it is useless...)
Best regards,
Jean-Michel Le Cleac'h
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: [JN] 300B GEC ?
Date: Fri, 31 Mar 2000 14:51:57 +0200
Source: Sound Digest Archive v02.n505
Hello,
I have a pair of NOS NIB 300B that went in GEC box.
They possess a red brown bakelite base.
The logo on them represents 3 head (2 profile view, 1 front view, that one
with an Indian hat)
Plate are black, tough building
Here is an ASCII view of the plate + heater when looking from the from the
top of the tube:
_
/ \
| ° |
| o |
| |
___| o |___
(___ ___)
| o |
| |
| o |
| |
| ° |
\_/
They were probably common in USA, not by there.
Does someone can give informations to me on those tubes (can I use them?).
Thank you very much.
Best regards,
Jean-Michel Le cleac'h, Paris, France
=========================================================================
From: StepHydro@aol.com
Subject: Re: [JN] 300B GEC ?
Date: Fri, 31 Mar 2000 14:54:01 EST
Source: Sound Digest Archive v02.n506
In a message dated 03/31/2000 9:<BR15:<BR50 AM
Eastern Standard , lecleach@cgi.ensmp.fr writes:
> I have a pair of NOS NIB 300B that went in GEC box.
They possess a red brown bakelite base.
The logo on them represents 3 head (2 profile view, 1 front view, that one
with an Indian hat)
They were probably common in USA, not by there.
> Does someone can give informations to me on those tubes (can I use them?).
Jean-Michel,
Those are totally unusable. Please send them to me for proper disposal.
Cheers/Don Carron
=========================================================================
From: "Le Cleac'h J.-M." <lecleach@cgi.ensmp.fr>
Subject: Re: [JN] 300B GEC ?
Date: Mon, 3 Apr 2000 09:42:54 +0200
Source: Sound Digest Archive v02.n508
- ---------
> De : StepHydro@aol.com
> A : lecleach@cgis0.ensmp.fr; sound@deliverator.io.com
> Objet : Re: [JN] 300B GEC ?
> Date : vendredi 31 mars 2000 21:54
>
> In a message dated 03/31/2000 9:<BR15:<BR50 AM
> Eastern Standard , lecleach@cgi.ensmp.fr writes:
> > I have a pair of NOS NIB 300B that went in GEC box.
> They possess a red brown bakelite base.
> The logo on them represents 3 head (2 profile view, 1 front view, that
one
> with an Indian hat)
> They were probably common in USA, not by there.
> > Does someone can give informations to me on those tubes (can I use
them?).
> Those are totally unusable. Please send them to me for proper disposal.
Hello,
According to someone to whom I described them, those tubes seem to be
Chinese tubes (from the Shinguang factory). I don't know if GEC did a
selection on them before to put their logo on though.
Best regards,
Jean-Michel Le Cleac'h, Paris, France
=========================================================================
From: Kurt Steffensen <kurt-steffensen@teliamail.dk>
Subject: Re: [JN] 300B GEC ?
Date: Mon, 03 Apr 2000 11:57:31 +0300
Source: Sound Digest Archive v02.n508
Hi Jean-Michel
Has the spring reached Paris ?
I guess so. Up here , the light , the smell and that "something" in the air ,
tells me it is close.
I enjoy the spring so much each year. Even more , the older I become.
The rebirth of everything , and all the promised adventures in the spring.
When I saw your post about the GEC 300B's , I was rather surprised.
I have never heard , seen or even read about such before.
I wondered if they were indeed GEC's. I doubted that very much. I suspected
that they had to be STC made.
I deducted that on some very simple facts.
The demand for 300B's , has always been very low. Only WE made them , and
licensed to companies such as STC/ITT , Northern Electric , associated
with WE in the first place.
Much later companies such as Cetron put it in to production as well. But
Cetron produced valves , should always be taken with a grain of salt
They actually re labelled , and semi produced much of their items.
Well, back to the GEC.
I a customer wanted some 300B's , they would know all about where to get
them.
Ordering them from GEC , would be very unlikely indeed , and that GEC should
thank yes to such a inquiry , is even more unlikely.
If GEC should produce a series of these tubes themselves , they would need to
get access to all the information , and custom made the toolings.
And the prices would be much higher than anyone else could offer the tubes
at.
If we imagine , that GEC were indeed asked to produce this tube , and that
they agreed to that , they would most simple re-order them from a company
such as STC.
That is all rather speculative , and very unlikely in my ears.
A while ago , I saw some NIB KT 88's GEC at eBay.
I could tell , even from the pix , that these were chinese made. The seller
were from Taiwan , and the text describing the tubes , actually made room for
the possibility
that something were indeed "weird" about these tubes.
I suspected that the seller knew very well , that these tubes were not
genuine.
It does seems that some bastards out there , actually speculate in false
branded tubes.
It is indeed sad , but not unexpected.
If you bring the tubes to the summer meet , I would love to take a look at
them.
I am 100 % certain that we are able to tell if they are Chineese/Sovjet made.
If they indeed turns out to be genuine Western made tubes , they are very ,
very rare , and actually a little piece of tube history.
I hope they are.
- - Kurt
=========================================================================
From: David Home <tubehead@vcn.bc.ca>
Subject: [JN] 300B heating question please...
Date: Tue, 25 May 1999 11:45:38 -0700 (PDT)
Source: Sound Digest Archive v02.n151
Is a center tapped filiment winding superior sonicily or electrically to a
hum pot? I could do either on my amp project but need to plan for the
extra transformer now. I have an unused non-tapped 5V winding on my power
transformer that would be so easy to use with a pot...
Joe Roberts refers in his WE91 article to avoiding the big ugly wire wound
pot in the circuit. Comments appreciated.
Regards, David
=========================================================================
From: Cuno Snoeren <c.snoeren@tip.nl>
Subject: Re: [JN] 300B heating question please...
Date: Tue, 25 May 1999 22:14:32 +0200
Source: Sound Digest Archive v02.n151
Hi Dave
> Is a center tapped filiment winding superior sonicily or electrically > to a hum pot?
If your 300B is nice symmetrical it would be the best.
But most 300B's are not symmetrical, so you probably NEED a hum pot..
(most 2A3 or 45 will work fine without)
You can test it by connecting two 22 ohms resistors over the 5Volt
winding and connect the cathode resistor to the point of these two
resistors.If the hum is low enough, you can go for a center tap.
If not, don't worry, take a pot of 100 ohm and put the two 22 ohms
resistor over each leg of the pot.
This way most (audio) signal will go through the resistors instead of
the pot.(I got this old trick of Guido Tent).
Good luck,
Cuno
c.snoeren@tip.nl
http://www.triode.club.tip.nl
I could do either on my amp project but need to plan for the
> extra transformer now. I have an unused non-tapped 5V winding on my power
> transformer that would be so easy to use with a pot...
> Joe Roberts refers in his WE91 article to avoiding the big ugly wire wound
> pot in the circuit. Comments appreciated.
> Regards, David
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: [JN] 300B heating question please...
Date: Wed, 26 May 1999 00:13:45 -0400
Source: Sound Digest Archive v02.n151
Isn't there another side to this argument, that the pot is preferable than
having the return through the filament transformer? And can be placed closer
to the tube?
David Home wrote:
>
> Is a center tapped filiment winding superior sonicily or electrically to a
> hum pot? I could do either on my amp project but need to plan for the
> extra transformer now. I have an unused non-tapped 5V winding on my power
> transformer that would be so easy to use with a pot...
> Joe Roberts refers in his WE91 article to avoiding the big ugly wire wound
> pot in the circuit. Comments appreciated.
> Regards, David
- --
Grover Gardner
groverg@postoffice.att.net
=========================================================================
From: "Mike Hathaway" <triode@t-three.com>
Subject: Re: [JN] 300B heating question please... -Reply
Date: Wed, 26 May 1999 10:37:57 -0700
Source: Sound Digest Archive v02.n152
I haven't used AC for a long time, although I've been told I ought to, but
it was my experience when I was using it that you really need to use
dedicated filament trannies to achieve decent hum cancellation. The
complexity of combined plate and filament transformers virtually insures
that the secondaries won't be evenly split. I've had good luck with Signal
split-bobbin designs, which happen to come in convenient values, and seem to
be available from a number of sources. Magnatek and Allied, among others,
offer this designs. Their construction is also pretty decent from a stray
field standpoint. However, even then the balance is not as good as you can
achieve with a hum balance network. I ultimately found (before abandoning
AC) that a pair of 22 ohm resistors straddling a 10 ohm pot to be the best
solution.
Mike
- -----Original Message-----
From: RALPH POWER <POWER.RALPH@epamail.epa.gov>
To: sound@deliverator.io.com <sound@deliverator.io.com>
Cc: tubehead@vcn.bc.ca <tubehead@vcn.bc.ca>
Date: Wednesday, May 26, 1999 10:20 AM
Subject: [JN] 300B heating question please... -Reply
>
>Hi David,
>
>You said :
>
>>Is a center tapped filiment winding superior sonicily or electrically to a
>>hum pot?
>
>I tried this as a first option when I built my SE VV30B amp, hummed like
>the dickens !
>
>I immediately rewired it for humpots with GREAT hum reduction.
>
>I think the problem is finding a filament tranny with matched halves...
>
>My 2 cents,
>
> - Ralph
>
>
>
=========================================================================
From: David Home <tubehead@vcn.bc.ca>
Subject: Re: [JN] 300B heating question please... -Reply
Date: Wed, 26 May 1999 10:53:00 -0700 (PDT)
Source: Sound Digest Archive v02.n152
Thanks Ralph and all who replyed to my inquiry. It would seem that with a
perfectly centred winding tap AND a perfectly centered 300B filiment, that
this would be the best option. However, as I need to plan for the
transformer in my layout, I guess the hum pot is the most foolproof
option. As this saved me another transformer on a crowded 50lb mono block,
so be it! Regards, David
On Wed, 26 May 1999, RALPH POWER wrote:
>
> Hi David,
>
> You said :
>
> >Is a center tapped filiment winding superior sonicily or electrically to a
> >hum pot?
>
> I tried this as a first option when I built my SE VV30B amp, hummed like
> the dickens !
>
> I immediately rewired it for humpots with GREAT hum reduction.
>
> I think the problem is finding a filament tranny with matched halves...
>
> My 2 cents,
>
> - Ralph
>
>
>
=========================================================================
From: RALPH POWER <POWER.RALPH@epamail.epa.gov>
Subject: [JN] 300B heating question please... -Reply
Date: Wed, 26 May 1999 12:46:51 -0400
Source: Sound Digest Archive v02.n152
Hi David,
You said :
>Is a center tapped filiment winding superior sonicily or electrically to a
>hum pot?
I tried this as a first option when I built my SE VV30B amp, hummed like
the dickens !
I immediately rewired it for humpots with GREAT hum reduction.
I think the problem is finding a filament tranny with matched halves...
My 2 cents,
- Ralph
=========================================================================
From: Cuno Snoeren <c.snoeren@tip.nl>
Subject: Re: [JN] 300B heating question please... -Reply
Date: Thu, 27 May 1999 00:00:55 +0200
Source: Sound Digest Archive v02.n152
RALPH POWER wrote:
> I immediately rewired it for humpots with GREAT hum reduction.
>
> I think the problem is finding a filament tranny with matched halves...
No finding a 300B with symmetric cathode/heater is the problem!
Just measure the voltage and you will see (2.7V and 2.3V or so).
Greetings, Cuno
http://www.triode.club.tip.nl
=========================================================================
From: "Kurt Th. Steffensen" <kurt-steffensen@teliamail.dk>
Subject: Sv: [JN] 300B heating question please... -Reply
Date: Thu, 27 May 1999 10:53:08 +0300
Source: Sound Digest Archive v02.n153
Hi there Cuno.
>No finding a 300B with symmetric cathode/heater is the problem!
>Just measure the voltage and you will see (2.7V and 2.3V or so).
I can not figure out how you measure that.
Please , explain.
- - Sincerely Kurt
>
>Greetings, Cuno
>http://www.triode.club.tip.nl
>
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 300B heating question please... -Reply
Date: Sat, 29 May 1999 15:15:49 +0200
Source: Sound Digest Archive v02.n156
At 12:46 26/05/99 -0400, RALPH POWER wrote:
>
>Hi David,
>
>You said :
>
>>Is a center tapped filiment winding superior sonicily or electrically to a
>>hum pot?
>
>I tried this as a first option when I built my SE VV30B amp, hummed like
>the dickens !
>
>I immediately rewired it for humpots with GREAT hum reduction.
>
>I think the problem is finding a filament tranny with matched halves...
No, the problem is to find a tapped fillament transformer that matches to
your tube. Measure voltages across both parts of the pot and the values wil
differ !
Guido
>My 2 cents,
>
> - Ralph
>
>
>
>
=========================================================================
From: borlan <bpan@panda.uchc.edu>
Subject: [JN] 300B Help
Date: Sat, 17 Apr 1999 13:39:17 -0400
Source: Sound Digest Archive v02.n127
Hello,
I am fairly new at building amps but would like to build a 300B based
amp. My question is about choosing the proper cathode bias resistor
values for a 300B amp. I have built Bottleheads SEX amp with the
Magnequest TFA204s and want to convert it to a 300B amp. I was thinking
of building a variant of Angelas JELabs 300B using my OPTs (3000 Ohm,
60mA at ~400V).
I think I understand how the load line is derived from the anode current
through the tube, the plate voltage and the TFA204 transformer
impedance. However, I don't completely understand how the cathode
resistor value is derived. The JELabs amp specifies 425 B+, 80mA and
300Ohm OPT. According to the curves for the 300B the grid bias appears
to -90V. The JELabs design specifies a 880 Ohm resistor. My calculations
specify 90V/0.08A=1125V which is much higher. How is this value
correctly obtained? Thanks for help on this newbie question, any help on
this would be greatly appreciated.
bp
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 300B Help
Date: Sun, 18 Apr 1999 12:29:11 +0200
Source: Sound Digest Archive v02.n127
At 13:39 17-4-99 -0400, borlan wrote:
>Hello,
Borlan,
Both values you found might work. The point is that the final operating
point depends on tube manufacturer, batch and so on, mainly due to
mechanical tolerances.
Another point are exact values. Imagine the anode voltage changes 5 V, then
the current rises with about 5V/Rp = 5V/700 ohm = 8 mA (assumed that no
other parameters change)
Start with for example 750 ohm 1k5//1k5 and connect a 1 k pot of sufficient
power in series. As such you can make what you need
Succes
Guido
>I am fairly new at building amps but would like to build a 300B based
>amp. My question is about choosing the proper cathode bias resistor
>values for a 300B amp. I have built Bottleheads SEX amp with the
>Magnequest TFA204s and want to convert it to a 300B amp. I was thinking
>of building a variant of Angelas JELabs 300B using my OPTs (3000 Ohm,
>60mA at ~400V).
>
>I think I understand how the load line is derived from the anode current
>through the tube, the plate voltage and the TFA204 transformer
>impedance. However, I don't completely understand how the cathode
>resistor value is derived. The JELabs amp specifies 425 B+, 80mA and
>300Ohm OPT. According to the curves for the 300B the grid bias appears
>to -90V. The JELabs design specifies a 880 Ohm resistor. My calculations
>specify 90V/0.08A=1125V which is much higher. How is this value
>correctly obtained? Thanks for help on this newbie question, any help on
>this would be greatly appreciated.
>
>bp
>
>
=========================================================================
From: Rich <rconte@attglobal.net>
Subject: [JN] 300B Min. and Max. Filament Voltages AC
Date: Mon, 21 Feb 2000 13:34:27 -0500
Source: Sound Digest Archive v02.n457
Dear Readers and Experts Alike,
Has anyone any direct experience, (already been to the DHT Steve Bench
model of Starved Filament supply), with the low and the high VAC for the
filaments on 300B's.
I am curious as the the min. and max. one can apply to a 5.0VAC
filament before it expires...best distortion figures and sound stage.
My thoughts say, I have a 115V Supply that generates 5.0VAC...if the
tube is a late model or NOS 300B, how low can the 5.0VAC go, say I use a
LAMBDA Bench power supply and decrease/increase the incoming 115VAC to
get a 4.0-5.6VAC, thereby altering the bias but keeping the plate supply
the same on a separate PT...I am just experimenting, probably will use
VA 300B's since they are cheap, prior to actually deploying NOS 300B's.
Any thoughts.
I tried this with great success on Indirectly Heated tubes and VT52's
where I decreased the 6.3VAC Supply down to about 5.6VAC and got much
better distortion figures, but 5.6 was the lowest I could go without
killing the tone.
Thanks for any information, specific to only 300B's.
Cheers.
=========================================================================
From: Christian Rintelen <rintelen@datacomm.ch>
Subject: Re: [JN] 300B Min. and Max. Filament Voltages AC
Date: Mon, 21 Feb 2000 21:01:49 +0100
Source: Sound Digest Archive v02.n458
Rich wrote:
> I tried this with great success on Indirectly Heated tubes and VT52's
> where I decreased the 6.3VAC Supply down to about 5.6VAC and got much
> better distortion figures, but 5.6 was the lowest I could go without
> killing the tone.
I've been running 6A3s on 5 VAC for years now. So far it neither killed the
tone nor the tube.
Christian
=========================================================================
From: Rich <rconte@attglobal.net>
Subject: Re: [JN] 300B Min. and Max. Filament Voltages AC
Date: Tue, 22 Feb 2000 08:26:23 -0500
Source: Sound Digest Archive v02.n458
To all who sent me information and messages of encouragement thanks so
kindly.
I found a way to keep the 300B's, they are direct coupled ala' 6385's, I
set the amp at exactly 115VAC via the LAMBDA and kept the filament
supply between 4.5VAC and 5.6VAC...I took plate, grid and bias
measurements to determine where things might fall...I did these, risky,
with the NOS300b's, yikes.
I discovered that there is not much of a bias change betw. say 4.5VAC
and 5.6VAC, but the plate voltages swing wildly by about 40VDC or better
in each direction, where current changes about +/- 10-14mA...I ended up
setting the tubes at a low plate voltage and filaments right on 5.0VAC,
the current is fine at across a 3K/5W R, giving me about 40'ish current,
with about 370'ish plate, grid is about -46.
Thanks...oh rectification is GZ32, power transformer is 390-0-390 185mA,
Stancor Chicago Standard...
Outputs are SE Hammond Open Frame.
Martin/Campbell family wrote:
>
> When I inadvertently had the filament voltage slightly low on a VV32B I
> could not get a stable bias current using fixed bias. [VV32B is like a 300B
> with a higher plate dissipation rating] What was happening was that I'd
> turn up the current slightly, the tube would slowly heat up, that would heat
> the filament slightly more and then the current would start to run away.
> Correcting the bias would let the tube slowly cool and the bias current
> would then slowly decline again. I could never get it stable. Once the
> filament current was slightly higher (and on spec.) the bias has remained
> stable for a couple of years.
> Peter Campbell
> ----------
> >From: Rich <rconte@attglobal.net>
> >To: sound@lists.io.com
> >Subject: [JN] 300B Min. and Max. Filament Voltages AC
> >Date: Tue, 22 Feb 2000 5:34
> >
>
> >Dear Readers and Experts Alike,
> >
> >Has anyone any direct experience, (already been to the DHT Steve Bench
> >model of Starved Filament supply), with the low and the high VAC for the
> >filaments on 300B's.
> >
> >I am curious as the the min. and max. one can apply to a 5.0VAC
> >filament before it expires...best distortion figures and sound stage.
> >
> >My thoughts say, I have a 115V Supply that generates 5.0VAC...if the
> >tube is a late model or NOS 300B, how low can the 5.0VAC go, say I use a
> >LAMBDA Bench power supply and decrease/increase the incoming 115VAC to
> >get a 4.0-5.6VAC, thereby altering the bias but keeping the plate supply
> >the same on a separate PT...I am just experimenting, probably will use
> >VA 300B's since they are cheap, prior to actually deploying NOS 300B's.
> >
> >Any thoughts.
> >
> >I tried this with great success on Indirectly Heated tubes and VT52's
> >where I decreased the 6.3VAC Supply down to about 5.6VAC and got much
> >better distortion figures, but 5.6 was the lowest I could go without
> >killing the tone.
> >
> >Thanks for any information, specific to only 300B's.
> >
> >Cheers.
> >
=========================================================================
From: "Martin/Campbell family" <martincampbell@apex.net.au>
Subject: Re: [JN] 300B Min. and Max. Filament Voltages AC
Date: Tue, 22 Feb 2000 19:32:52 +1100
Source: Sound Digest Archive v02.n458
When I inadvertently had the filament voltage slightly low on a VV32B I
could not get a stable bias current using fixed bias. [VV32B is like a 300B
with a higher plate dissipation rating] What was happening was that I'd
turn up the current slightly, the tube would slowly heat up, that would heat
the filament slightly more and then the current would start to run away.
Correcting the bias would let the tube slowly cool and the bias current
would then slowly decline again. I could never get it stable. Once the
filament current was slightly higher (and on spec.) the bias has remained
stable for a couple of years.
Peter Campbell
- ----------
>From: Rich <rconte@attglobal.net>
>To: sound@lists.io.com
>Subject: [JN] 300B Min. and Max. Filament Voltages AC
>Date: Tue, 22 Feb 2000 5:34
>
>Dear Readers and Experts Alike,
>
>Has anyone any direct experience, (already been to the DHT Steve Bench
>model of Starved Filament supply), with the low and the high VAC for the
>filaments on 300B's.
>
>I am curious as the the min. and max. one can apply to a 5.0VAC
>filament before it expires...best distortion figures and sound stage.
>
>My thoughts say, I have a 115V Supply that generates 5.0VAC...if the
>tube is a late model or NOS 300B, how low can the 5.0VAC go, say I use a
>LAMBDA Bench power supply and decrease/increase the incoming 115VAC to
>get a 4.0-5.6VAC, thereby altering the bias but keeping the plate supply
>the same on a separate PT...I am just experimenting, probably will use
>VA 300B's since they are cheap, prior to actually deploying NOS 300B's.
>
>Any thoughts.
>
>I tried this with great success on Indirectly Heated tubes and VT52's
>where I decreased the 6.3VAC Supply down to about 5.6VAC and got much
>better distortion figures, but 5.6 was the lowest I could go without
>killing the tone.
>
>Thanks for any information, specific to only 300B's.
>
>Cheers.
>
=========================================================================
From: Andrew Brandon <ajbrandon@yahoo.com>
Subject: [JN] 300b opinions
Date: Sun, 4 Jun 2000 08:43:42 -0700 (PDT)
Source: Sound Digest Archive v02.n564
Hi all,
I'm looking for opinions on decent "inexpensive" (up
to about $200/pair) 300b's. I need two pairs (p.p.
amps). So far I have the Angela nickel anode, and the
J.J's on my list.I also read somewhere about a new
Sovtek 300b by "electro-harmonix". I presently use
Sovtek 2A3's which I think sound very good.
I have never heard a 300b and the itch is just too
great not to scratch so... opinions anyone ?
Andrew
__________________________________________________
Do You Yahoo!?
Yahoo! Photos -- now, 100 FREE prints!
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=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 300b opinions
Date: Sun, 04 Jun 2000 18:08:21 +0200
Source: Sound Digest Archive v02.n564
hi all,
According Peter van Willenswaards review in Stereopile November 1999, the
JJ electronics would be your choice. Cost is USD 199,- /pair (by that time)
Little cheaper could be the Valve art C60 or the new Sovtek.
Guido
At 08:43 04/06/2000 -0700, Andrew Brandon wrote:
>Hi all,
>
>I'm looking for opinions on decent "inexpensive" (up
>to about $200/pair) 300b's. I need two pairs (p.p.
>amps). So far I have the Angela nickel anode, and the
>J.J's on my list.I also read somewhere about a new
>Sovtek 300b by "electro-harmonix". I presently use
>Sovtek 2A3's which I think sound very good.
>I have never heard a 300b and the itch is just too
>great not to scratch so... opinions anyone ?
>
>
>Andrew
>
>
>__________________________________________________
>Do You Yahoo!?
>Yahoo! Photos -- now, 100 FREE prints!
>http://photos.yahoo.com
>
>
=========================================================================
From: Cuno Snoeren <c.snoeren@tip.nl>
Subject: Re: [JN] 300b opinions
Date: Mon, 05 Jun 2000 18:09:53 +0200
Source: Sound Digest Archive v02.n566
Depending on what sound you expect from a 300B or 300B alike.
I have listened to severall brands and they all sound different.
The rest of the istallation was exactly the same, so the sound
difference could only be coased by the changed tubes.
Well the Svetlana SV300B sounds very naturall and soft like silk but the
bass could be better.
The JJ sounds very stereo-spacy (maybe to much for someone)
and the bass is poorer
The standard VA300B/Angela sounds poorer overall
The VA5300 (inside the same as the C60???) has got the best bass I ever
heard of a 300B but the overall sound is a bit more like a good mosfet
amp rather then a tube amp, so a bit less musical but a bit more
technical.
A nice combination should be the sound of the SV300B with yhe bass of
the VA5300 to my ears.
Ps. the amp is with an 1K resistor in autobias and a 5K C-core output
tranny.
Greetings,
Cuno
http://www.triode.club.tip.;nl
> Hi all,
>
> I'm looking for opinions on decent "inexpensive" (up
> to about $200/pair) 300b's. I need two pairs (p.p.
> amps). So far I have the Angela nickel anode, and the
> J.J's on my list.I also read somewhere about a new
> Sovtek 300b by "electro-harmonix". I presently use
> Sovtek 2A3's which I think sound very good.
> I have never heard a 300b and the itch is just too
> great not to scratch so... opinions anyone ?
>
> Andrew
>
> __________________________________________________
> Do You Yahoo!?
> Yahoo! Photos -- now, 100 FREE prints!
> http://photos.yahoo.com
=========================================================================
From: Andrew Brandon <ajbrandon@yahoo.com>
Subject: [JN] 300b opinions - thanks for the input !
Date: Mon, 5 Jun 2000 17:35:48 -0700 (PDT)
Source: Sound Digest Archive v02.n567
Thanks folks !!
__________________________________________________
Do You Yahoo!?
Yahoo! Photos -- now, 100 FREE prints!
http://photos.yahoo.com
=========================================================================
From: ToobWiz@aol.com
Subject: [JN] 300B Op Point question
Date: Sat, 15 Sep 2001 23:55:52 EDT
Source: Sound Digest Archive v02.n975
I've been looking at 300B operating points and comparing them to the
capabilities of my PSU transformers and chokes. I've run a bunch of figures
through PSUD and compared the output to the WE list of op points.
Has anyone tried the 400V @60mA and 3.5K load and fixed bias? This works well
with my PSU and I have 3250R primary OPTs, so that isn't far off.
I'd like to have listening impressions if any have them available. I can make
the B+ lower, and I don't need the 9W or so that this would give (10.5W
listed). However, I do need 8W and the 350V @60 mA won't give that much
power. I have a lot more current available, say up to 95 mA if there is a
lower hotter point that is better.
I'd appreciate feedback. This is for the 46 amps that I've been noodling with
for so long. I'vew become convinced that 1.3W was not going to work with my
96dB speaks, so am using the 46 as a driver.
Thanks/Don Carron
=========================================================================
From: "Kurt Steffensen" <kurt-steffensen@teliamail.dk>
Subject: Sv: [JN] 300B Op Point question
Date: Sun, 16 Sep 2001 15:24:15 +0200
Source: Sound Digest Archive v02.n975
Dear Don and other Joes
I like 300B's with 400 V , anode and 80 mA current , load 5 kOhm.
I have experimented quite a lot with 300B's , and I have had the best results with these conditions
, into many different speakers.
This goes for the WE , Cetron and direct copies.
All the new high power and different bias socalled 300B's are ofcourse NOT 300B's , and will have to
be dialed
in to other operation points.
The best I have heard is the AVVT super lineare AV 300B SL's.
These are quite better than the original 300B's , in to my ears , and every one else I know , that h
ave experimented with these triodes.
> Has anyone tried the 400V @60mA and 3.5K load and fixed bias? This works well
> with my PSU and I have 3250R primary OPTs, so that isn't far off.
If you are going for 3,5 kOhm , I suggest you find a spot , that fits with your PSU and components ,
in which you can draw as much current as possible.
- ------
>. This is for the 46 amps that I've been noodling with
> for so long. I'vew become convinced that 1.3W was not going to work with my
> 96dB speaks, so am using the 46 as a driver.
I haven't played with the 46's , but all 45's I have tried are quite better than the 300B's , and 46
's are reported to be just as good as the 45's
( In particually the old ones are full of magic , 245 etc. Tungsram's seems to be one of the best. I
also load these with 5 kOhms )
AV 300B SL are close to the 245's , and have lots of more power.
I have not had a chance to play with the new mesh plate Full Music 300B's yet , but I am pretty sure
it should be dealt with different than the original
300B's.
I tried them with 400V , 80 mA into 5 kOhm , and they sound very good , but in my ears not as good a
s the AV's. ( The triode session , at this years Triode Festival )
However , I have only listened to the Full Music at this specific operating point. - And as mesh pla
tes , are often better , tnan solid plates , I am certain that a "sweet point" can be found.
I look forward to play a little with these , this vinter.
- - sincerely Kurt
=========================================================================
From: sschenkel@juno.com
Subject: [JN] 300B's
Date: Fri, 18 May 2001 22:21:41 -0700
Source: Sound Digest Archive v02.n887
JC
I have been hearing some pretty good things about your EH 300B's. I am
waiting for a new 300B amp to be delivered to me from LDM and I need
tubes. What kind of price can you get me?
Thanks
Steve
________________________________________________________________
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=========================================================================
From: "JF" <jimfl@airmail.net>
Subject: Re: [JN] 304 and 833
Date: Thu, 12 Aug 1999 20:10:28 -0500
Source: Sound Digest Archive v02.n242
+AD4-Tom wrote:
+AD4-
+AD4-had originally been looking at a 304th which is 4 smaller triodes in one
+AD4-envelope but these are less available than the 833
+AD4-
I've had good success with the 304TL. I run it single-ended at 1250V,
220mA, -60Vg. Plate resistance measured about 1150ohms at this bias point.
Output is 40W, class A1. A slight change in the operating point will
produce 60W. These numbers are from memory, I can measure them if someone
requires more accuracy.
The 304TL mu is speced at 12 versus 20 for the 304TH. The TL generates too
much filament hum for me. I don't have a TH, but I'd expect it to hum the
same amount, or maybe even worse due to the higher mu. I prefer to add hum
cancellation circuitry as the thirsty filament draw (12.5A or 25A depending
on series or parallel connection) makes building a current source or dc
voltage source a non-trivial matter. I think your plan was for a push-pull
stage which I think should solve any filament hum problems.
I rarely find a 304TH, but come across a TL regularly (monthly?). The
sockets are much harder to find than the tubes. I used a homebrew socket
until I found a pair of Johnsons.
I have a couple 833s, but I haven't tried them in an amp yet. The plate
curves from RCA and Svetlana indicate that grid drive (class A2) is needed
at practical plate voltage. I think the plate resistance is about 3kohm at
zero grid bias. My plan is for class A2, low and hot, with a cathode
feedback winding from the OT like I used in my 810 and 100TH amps.
The above may make it sound like I'm awash in amplifiers. That is not the
case. I build one on a breadboard, change it, and change it again. I
forget who made the comment in a recent post, but I am definitely more of a
yacht builder than a sailor.
JF
=========================================================================
From: "JF" <jimfl@CyberRamp.net>
Subject: Re: [JN] 304TL amp
Date: Mon, 8 Feb 1999 18:26:38 -0600
Source: Sound Digest Archive v02.n034
I built an SE 304TL monoblock amp using parafeed and a direct coupled
driver. Tried both a 3.8kohm and 5.5kohm OT. Output power was about 40W+ADs- a
change in operating point would easily get 60W. About 1200V on the plate at
220mA and measured plate resistance 1.3kohm. I liked the sound but the
filament hum is hard to suppress. Changing to dc on the fils solved the
hum, but 5V at 25A is not trivial. The sockets are hard to find+ADs- I made my
own, but I'm still looking.
To paraphrase Doc B in an old VALVE, +ACI-The 304TL is actually four parallel
triodes in one glass envelope so you single tube purists may now turn up
your nose.+ACI- Hey, I like it anyway.
I also tried an 805 in a Shishido style amp. It showed a lot of promise,
but the proper cathode-feedback OT is hard to come by. I wound my own OT so
that probably accounts for the less than spectacular sound. Output power
was about 25 to 30 watts.
Don't get me wrong, I think either of these tubes will sound great with some
work.
JF
- -----Original Message-----
From: Rick Francis +ADw-rfrancis+AEA-glasscity.net+AD4-
To: Michael Cameron +ADw-mncameron+AEA-worldnet.att.net+AD4-
Cc: sound+AEA-deliverator.io.com +ADw-sound+AEA-deliverator.io.com+AD4-
Date: Monday, February 08, 1999 4:38 PM
Subject: Re: +AFs-JN+AF0- SE 805 experiences? NOW 304TL
+AD4-At 08:16 AM 2/8/99 -0800, Michael Cameron wrote:
+AD4APg-
+AD4APg-Have any of you built a circuit using 805? Care to share your
+AD4-experiences, what iron used, operating points, how +AD4-they sound, etc?
+AD4-
+AD4-I have heard of some folks using these, and really liking them over 845's
+AD4-and other TT's. Output impedance is not as high as some TT's, and they look
+AD4-cool too. They cost less than 211's (805's are between +ACQ-80 and +ACQ-90 from
+AD4-AES, but that's half what they charge for a 211), too.
+AD4-
+AD4-I looked at them cuz I got a pair in a batch of tubes. Then I got a 304TL
+AD4--- now THERE'S a tube+ACE- 300 watts PD, and according to ARRL, plate to plate
+AD4-impedance is 2.4K, as I recall, at the +ACI-low+ACI- operating point of 1500 volts
+AD4-in AB1. I wonder what it would be in a low and hot class A operating point+ACE-
+AD4-To my poor brain, that would seem that someone might actually be able to
+AD4-wind a wide bandwidth OPT for it, and for PP, maybe it already exists...
+AD4-
+AD4-So has anyone tried a 304TL amp???
+AD4-
+AD4-Rick Francis
+AD4-
=========================================================================
From: rcjones1@mmm.com
Subject: [JN] 311B and 171A tubes.
Date: Thu, 31 May 2001 08:33:23 -0500
Source: Sound Digest Archive v02.n896
Hi,
I have a bunch of WE 311B tubes. They are very strange. 5 pin base with a
top cap, looks like a pentode. Any ideas what these are? I have at least
6 of them NOS. Value?
Also I have a 171A (71A) Sylvania with the green leaf emblem actually on
the top of the glass. The plates are shiny metal. Anyone interested in
it? I only have the one.
I wonder if I can make a PP pentode amp with those 311B's.
Richard
=========================================================================
From: "Carter Hendricks" <carter@i1.net>
Subject: RE: [JN] 311B and 171A tubes.
Date: Thu, 31 May 2001 10:44:50 -0500
Source: Sound Digest Archive v02.n896
-----Original Message-----
> From: owner-sound@lists.io.com [mailto:owner-sound@lists.io.com]On
> Behalf Of rcjones1@mmm.com
> Sent: Thursday, May 31, 2001 8:33 AM
> To: sound@lists.io.com
> Subject: [JN] 311B and 171A tubes.
>
>
> Hi,
>
> I have a bunch of WE 311B tubes. They are very strange.
Richard,
The WE 311B is a pentode used in carrier telephone
systems "where outputs of 2W were required." It is
an indirect heated tube with 10 volt heater and a
grid cap. Atarashi used them in some of his
experiments.
--Carter
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: [JN] 3.18us calcuation in RIAA filtration
Date: Fri, 17 Nov 2000 08:56:22 -0500
Source: Sound Digest Archive v02.n736
David sez:
>>>In both Morgan Jones book and Allen Wright's article, the 3.18us corner
seems to be calculated only using the value of the 75us cap itself that the
resistor will go under ( between the cap and ground). In calculating the
75us filter component values, ALL resistances and stray capacitances seen
by the filter need to be accounted for. Why is this not necessary for the
3.18us filter as well? <<<
David - you are correct, it is necessary to include ALL the associated
impedances when calculating any T/C - I'm not familiar with Morgans
implimentation of this curve point but I don't know why you assume this is
not the case in my "article".
The 3n3 with the 1k4 gives 4.62uS, which is not very close to 3.18uS.
But if you factor in all the other parts in the area, the 32k4, the 25K
anode load, the effective anode resistance of the tube with it's unbypassed
cathde R, AND the 50K pot in parallel with the whole mess (but in series
with it's coupling cap) you might get a little closer.
But don't think I did this by calculation - life is much to much fun to
bother with that - I just set it all up and used a trimmer in both the
"32k4" and "1k4" positions to get the correct response via an inverse RIAA
source incorporating the 3.18 step.
And with it set this way it then gets listened to for a while and tweaked
by ear for my own preferred top end effect. This seems to be different for
different designs, and for my own personal FVP5 it seemed best with
3n3/1k4.
YMMV...
Allen (VSE)
PS Have you all heard about Morgan Jone's wonderful article in last months
Electronics World? He not only gives a theoretical reason why NOS tubes
can go noisy after a month or so of use - but gives a tested way of making
them like new - get the magazine!
=========================================================================
From: David Home <David_Home@creoscitex.com>
Subject: [JN] 3.18us calcuation in RIAA filtration
Date: Fri, 17 Nov 2000 12:32:28 +0100
Source: Sound Digest Archive v02.n736
Hello Friends.
In both Morgan Jones book and Allen Wright's article, the 3.18us corner seems to be calculated only
using the value of the 75us cap itself that the resistor will go under ( between the cap and ground)
. In calculating the 75us filter component values, ALL resistances and stray capacitances seen by th
e filter need to be accounted for. Why is this not necessary for the 3.18us filter as well?
Is this corner affected by the Miller capacitance of the following stage?
Is this corner affected by the parallel resistance of the previous stage and/or the grid leak resist
or of the following stage?
Regards, David
=========================================================================
From: John Levreault <jlevro@mediaone.net>
Subject: Re: [JN] 3.18us calcuation in RIAA filtration
Date: Fri, 17 Nov 2000 16:14:53 -0500
Source: Sound Digest Archive v02.n737
David Home wrote:
> I should explain that I without my test gear for about a year, and am trying to get as close as po
ssible to a good RIAA by crunching the numbers. I know that it is not a substitute for real listenin
g.
Are you saying that you're going to tune your RIAA network by ear?
Personally, I feel very strongly that getting as close as possible to
the exact RIAA response is well worth the effort.
JL
=========================================================================
From: "Ellen Oler" <ellenoler@earthlink.net>
Subject: Re: [JN] 3.18us calcuation in RIAA filtration
Date: Fri, 17 Nov 2000 21:07:09 -0500
Source: Sound Digest Archive v02.n737
David wrote:
>I seem to be digging this hole deeper and deeper...
>What I meant was: I will in time be reunited with my frequency generator and scope.
>Until then, I want to get my RIAA as close as possible by straight math.
>So I do need to calculate the 3.18us ( and all the others as well) taking
>into account all the influences. Rather then using Allen's method of
>dialing in the best inverse RIAA filtered 1K square wave, looking at the
>scope and adjusting trimmer pots.
While I am sure that Allen is correct (he always is!) about the benefits of
a scope reality check on the true end result of all the calculations, one
thing David and I have been enjoying with this is climbing up the learning
curve together as we learn the theoretical implications. Kudos to Messrs.
Jones and Wright (or is that Right?) for packing so much good stuff in their
books. It gives us a lot to chew on.
While I was hacking away at my modified Bob Danielak Octal RIAA
implementation, Bob was kind enough to run a few things through a simulator
and that did a lot to make me feel confident of the parts changes. I got
good advice from Bob and Mick Maloney, and I think the place I ended up with
the 3.18 was with Mick's comment that I should try a different (smaller)
75uS cap and *no* series resistor, and listen to it that way. (At this high
frequency, there's a lot of parasitics involved.)
Which I haven't done yet, but I plan on getting around to. Mick's point, and
Allen's too, is that after getting nice math results, you have to trust yur
ears for the final tweakery. Mine sounds very good as it stands, I am sure
it could sound better but that damned Viking will have to send my best power
amp back before I will trust what I'm hearing at the frequency extremes.
Those Vikings. They can't help it - plundering is in their blood!
Anyway I understand what David's driving at - it helps to have some
understanding of the math etc., so you can get close at least. And so you
can get close enough to have something worth listening to as a baseline
before embarking on the tweaks that make it magical. As for me, I plan on
building up another one with a cascode, high-gm tubes and all that fancy
stuff, but I am walking first and it is very satisfying tio be learning each
bit as I go. I can certainly see why Mick ended up trying so many phonos -
it's quite the challenge.
The most important factor I've hard so far is getting the parts match
between channels VERY VERY tight. It makes a huge difference.
- -j
>Regards, David
>
>-----Original Message-----
>From: John Levreault [mailto:jlevro@mediaone.net]
>Sent: Friday, November 17, 2000 10:15 PM
>To: David Home
>Cc: Allen Wright; Sound (E-mail); Epstein, Jeremy; Ellen Oler
>Subject: Re: [JN] 3.18us calcuation in RIAA filtration
>
>
>David Home wrote:
>
>> I should explain that I without my test gear for about a year, and am
>trying to get as close as possible to a good RIAA by crunching the numbers.
>I know that it is not a substitute for real listening.
>
>Are you saying that you're going to tune your RIAA network by ear?
>
>Personally, I feel very strongly that getting as close as possible to
>the exact RIAA response is well worth the effort.
>
>JL
>
=========================================================================
From: David Home <David_Home@creoscitex.com>
Subject: RE: [JN] 3.18us calcuation in RIAA filtration
Date: Fri, 17 Nov 2000 21:35:03 +0100
Source: Sound Digest Archive v02.n737
Hi Allen. Thanks for helping out a struggling vinyl junkie.
Sorry about the incorrect implication of my remark regarding your chosen values. I will get out the
calculator next time before firing off into the ether!
Anyway thanks for addressing the heart of my question. I should explain that I without my test gear
for about a year, and am trying to get as close as possible to a good RIAA by crunching the numbers.
I know that it is not a substitute for real listening.
Regards, David
- -----Original Message-----
From: Allen Wright [mailto:AllenVSE@compuserve.com]
Sent: Friday, November 17, 2000 2:56 PM
To: AAJoeNet
Subject: [JN] 3.18us calcuation in RIAA filtration
David sez:
>>>In both Morgan Jones book and Allen Wright's article, the 3.18us corner
seems to be calculated only using the value of the 75us cap itself that the
resistor will go under ( between the cap and ground). In calculating the
75us filter component values, ALL resistances and stray capacitances seen
by the filter need to be accounted for. Why is this not necessary for the
3.18us filter as well? <<<
David - you are correct, it is necessary to include ALL the associated
impedances when calculating any T/C - I'm not familiar with Morgans
implimentation of this curve point but I don't know why you assume this is
not the case in my "article".
The 3n3 with the 1k4 gives 4.62uS, which is not very close to 3.18uS.
But if you factor in all the other parts in the area, the 32k4, the 25K
anode load, the effective anode resistance of the tube with it's unbypassed
cathde R, AND the 50K pot in parallel with the whole mess (but in series
with it's coupling cap) you might get a little closer.
But don't think I did this by calculation - life is much to much fun to
bother with that - I just set it all up and used a trimmer in both the
"32k4" and "1k4" positions to get the correct response via an inverse RIAA
source incorporating the 3.18 step.
And with it set this way it then gets listened to for a while and tweaked
by ear for my own preferred top end effect. This seems to be different for
different designs, and for my own personal FVP5 it seemed best with
3n3/1k4.
YMMV...
Allen (VSE)
PS Have you all heard about Morgan Jone's wonderful article in last months
Electronics World? He not only gives a theoretical reason why NOS tubes
can go noisy after a month or so of use - but gives a tested way of making
them like new - get the magazine!
=========================================================================
From: "Epstein, Jeremy" <JEpstein@ndbcap.com>
Subject: RE: [JN] 3.18us calcuation in RIAA filtration
Date: Mon, 20 Nov 2000 12:26:25 -0500
Source: Sound Digest Archive v02.n740
Some damned Viking wrote:
> Ellen Oler wrote:
>
> > Mine sounds very good as it stands, I am sure
> > it could sound better but that damned Viking will have to
> send my best power
> > amp back before I will trust what I'm hearing at the
> frequency extremes.
> I wonder whom that Viking is ?
I would accept shipment from any of the Vikings, I'm not too picky.
> Well , it COULD be me , considering that I am one of the
> Vikings on this list....
Are you Wodin in this Valhalla then?
> And a very good amp indeed it is...
> A kind of "missing link" in the prove of measured results
> contra listening results.
> Measures almost as good as a $10,- pocket radio....
But close, right? The pocket radio doesn't measure THAT much better, does
it?
> Sounds like a $10k genuine audio amplifier. !
Aha!
What do you suppose, maestro? What does the trick? I think it is a trick,
myself, anyway.
> And what a WONDERFULL workmanship.. - Art , I would say..
> Beautifully potted Lundahl OPT's.....( With black PVC tape )
> CLEAN routed wires..( ALL over the inside )...and LOTS of
> solder tin....
Well, I thought I would include some extra solder in case I got to Arhus and
found none available - my impression was that the show (and its host) was
going to be VERY disorganized so I thought I'd protect myself.
> Hand polished wooden work , ( And I mean by HAND ! )
> Kitchen bend metal work..... - The components is placed ,
> with a lot of thought and
> consideration.
> It almost looks like someone has used a ruler....( Exactly
> how I imagined a blind man ,
> would use such a tool )
You forgot to mention the epoxy glue holding the humpots on.
Well, I come from a long line of incompetents. I'm glad you were impressed!
Once I get it back, I think I will try and make it neater inside. It will
probably sound like shit if I do, but it will make you happy, and that's
really all I care about. Maybe I can carve the base with sheaves of wheat
like the Vasa?
> > Those Vikings. They can't help it - plundering is in their blood!
>
> Yes , that is true..
> But it is also a matter of reputation and prestige..
> All the other Vikings , ( My neighbours , that is ) , kept
> asking me about the booty I
> gained from Wineland...
We call that "Keeping up with the Jonases."
> You see ? - I NEED to have something to point at , in order
> to honour my name , and the
> old traditions..
>
> Comprendo ?
Well, in that case I am sorry my amp didn't look any fancier: your
reputation must have taken a real beating. I will try and leave something
nicer behind next time I visit.
> Regarding the matter discussed , I do agree that a opposite
> threaded RIAA square is a
> good tool for the final adjustments.
> But there is several pitfalls in that method...
> - For instance how accurate is the opposite square to begin with...?
> - What frequency is best suited for the task...?
> - Do you wish to lift the 50 kHz point or not...?
>
> Nomatter what you do , I guess it will hold you sleepless for
> many good nights.
Meanwhile, Mr. Home and I are enjoying each other's company and
encouragement, as well as the input and encouragement from the Joes who
actually have some idea of what they are doing. It keeps me off of the steet
corners at night.
> As for the amp..... :-)
> It is out there in the Ocean , brought to you in a Viking
> wooden sailing ship...
> - Might take a while , but it is bound to arrive safe.... ( And wet )
Thanks! We will have a big party on the dock when it comes in!
That is, unless the NY Triode Mafia-controlled Longshoremen's Union doesn't
make it "disappear" the way they did Jimmy Hoffa's Fisher receiver and
Klipsch corner horns.
> I miss it :-(
>
> Thanks for the dinner... ( Both of them ;-)
Next time, in NY. And YOU pay!
> ( )
> ++
> U
My very own Viking horns! Thanks! I will wear them proudly! Let me just
loosen my belt . . . .
- -j
=========================================
Jeremy Epstein........jepstein@ndbcap.com
=========================================
=========================================================================
From: Kurt Steffensen <kurt-steffensen@teliamail.dk>
Subject: Re: [JN] 3.18us calcuation in RIAA filtration
Date: Mon, 20 Nov 2000 17:49:52 +0100
Source: Sound Digest Archive v02.n740
Ellen Oler wrote:
Mine sounds very good as it stands, I am sure
> it could sound better but that damned Viking will have to send my best power
> amp back before I will trust what I'm hearing at the frequency extremes.
I wonder whom that Viking is ?
Well , it COULD be me , considering that I am one of the Vikings on this list....
Hmm , 'cause also the fact that is was indeed me in person that lent that amp of yours ,
makes it more possible.
And a very good amp indeed it is...
A kind of "missing link" in the prove of measured results contra listening results.
Measures almost as good as a $10,- pocket radio....
Sounds like a $10k genuine audio amplifier. !
And what a WONDERFULL workmanship.. - Art , I would say..
Beautifully potted Lundahl OPT's.....( With black PVC tape )
CLEAN routed wires..( ALL over the inside )...and LOTS of solder tin....
Hand polished wooden work , ( And I mean by HAND ! )
Kitchen bend metal work..... - The components is placed , with a lot of thought and
consideration.
It almost looks like someone has used a ruler....( Exactly how I imagined a blind man ,
would use such a tool )
> Those Vikings. They can't help it - plundering is in their blood!
Yes , that is true..
But it is also a matter of reputation and prestige..
All the other Vikings , ( My neighbours , that is ) , kept asking me about the booty I
gained from Wineland...
You see ? - I NEED to have something to point at , in order to honour my name , and the
old traditions..
Comprendo ?
Regarding the matter discussed , I do agree that a opposite threaded RIAA square is a
good tool for the final adjustments.
But there is several pitfalls in that method...
- - For instance how accurate is the opposite square to begin with...?
- - What frequency is best suited for the task...?
- - Do you wish to lift the 50 kHz point or not...?
Nomatter what you do , I guess it will hold you sleepless for many good nights.
As for the amp..... :-)
It is out there in the Ocean , brought to you in a Viking wooden sailing ship...
- - Might take a while , but it is bound to arrive safe.... ( And wet )
I miss it :-(
Thanks for the dinner... ( Both of them ;-)
( )
++
U
=========================================================================
From: Rhthatcher@ra.rockwell.com
Subject: [JN] 396A/2C51 and 1629
Date: Wed, 24 Feb 1999 15:35:13 -0500
Source: Sound Digest Archive v02.n060
Well, I just got my hands on some 1629's and some 396A's. I have a
schematic
for a possible preamp with the 1629's. I may buy a super reg and roll out
one
of these suckers and see what i like.
see
http://members.aol.com/sbench101/Preamps/1629amp.gif
Any ideas for the 396A's? any schematics out there? what's your
experience with
these in preamps? how about in power amps?
randy
=========================================================================
From: Dan Kerl <dlkerl@ro.com>
Subject: Re: [JN] 396A/2C51 and 1629
Date: Wed, 24 Feb 1999 16:36:57 -0600
Source: Sound Digest Archive v02.n061
Rhthatcher@ra.rockwell.com wrote:
>
> Well, I just got my hands on some 1629's and some 396A's. I have a
> schematic for a possible preamp with the 1629's. I may buy a super
> reg and roll out one of these suckers and see what i like.
>
> see
> http://members.aol.com/sbench101/Preamps/1629amp.gif
I'm curious to see what the redeeming qualities of a "magic eye" tube
have for audio amplification. The amplifier triode in these tubes is
high mu, sorta like a 6SL7 I guess. I would also consider putting the
NiCd batteries in the cathode circuit. It looks like a fun thing to
try.
- --
Dan Kerl
dlkerl@ro.com
=========================================================================
From: Ken Gilbert <ride5000@ride.ri.net>
Subject: Re: [JN] 396A/2C51 and 1629
Date: Wed, 24 Feb 1999 23:33:08 -0500
Source: Sound Digest Archive v02.n061
>Rhthatcher@ra.rockwell.com wrote:
>> see
>> http://members.aol.com/sbench101/Preamps/1629amp.gif
>
>I'm curious to see what the redeeming qualities of a "magic eye" tube
>have for audio amplification. The amplifier triode in these tubes is
>high mu, sorta like a 6SL7 I guess. I would also consider putting the
>NiCd batteries in the cathode circuit. It looks like a fun thing to
>try.
Dan, et al,
Steve's really got some good stuff on his home page, if you haven't already
been there. Check out the "starved filament reduces distortion to nearly
zero for certain types of DHT's" section.
ken
=========================================================================
From: Rhthatcher@ra.rockwell.com
Subject: Re: [JN] 396A/2C51 and 1629
Date: Thu, 25 Feb 1999 09:56:28 -0500
Source: Sound Digest Archive v02.n061
Dan Kerl <dlkerl@ro.com> on 02/24/99 05:36:57 PM
To: sound@deliverator.io.com
cc: (bcc: Randall H Thatcher/Cleveland/RA/Rockwell)
Subject: Re: [JN] 396A/2C51 and 1629
Rhthatcher@ra.rockwell.com wrote:
>>
>> Well, I just got my hands on some 1629's and some 396A's. I have a
>> schematic for a possible preamp with the 1629's. I may buy a super
>> reg and roll out one of these suckers and see what i like.
>>
>> see
>> http://members.aol.com/sbench101/Preamps/1629amp.gif
> I'm curious to see what the redeeming qualities of a "magic eye" tube
> have for audio amplification. The amplifier triode in these tubes is
> high mu, sorta like a 6SL7 I guess. I would also consider putting the
> NiCd batteries in the cathode circuit. It looks like a fun thing to
> try.
To be honest, i have no idea what the 1629 might sound like, but it would
certainly be a bonus if the preamp sounded great in my system and lit
up nicely! ever since i got an old telefunken table radio with a magic
eye tube for tuning i've been hot on the idea of putting eye tubes in
my system here and there... i guess this application cuts down on a
separate tube for amplification and magic eye, it does both jobs with
the 1629...
randy
=========================================================================
From: Simon Busbridge <S.C.Busbridge@bton.ac.uk>
Subject: Re: [JN] 396A/2C51 and 1629
Date: Fri, 26 Feb 1999 08:24:42 +0000 (BST)
Source: Sound Digest Archive v02.n062
Eh? Isn't the 1629 a magic eye indicator tube?
Why on earth use it as an amplifier?!
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
On Wed, 24 Feb 1999 Rhthatcher@ra.rockwell.com wrote:
>
>
> Well, I just got my hands on some 1629's and some 396A's. I have a
> schematic
> for a possible preamp with the 1629's. I may buy a super reg and roll out
> one
> of these suckers and see what i like.
>
> see
> http://members.aol.com/sbench101/Preamps/1629amp.gif
>
> Any ideas for the 396A's? any schematics out there? what's your
> experience with
> these in preamps? how about in power amps?
>
> randy
>
>
>
>
=========================================================================
From: "Brian Clark" <bdclark@talk21.com>
Subject: [JN] 3A/167M Ad.
Date: Tue, 18 Jul 2000 12:14:17 +0100
Source: Sound Digest Archive v02.n606
Dave
the ad refers to an Application Report, M8/109, you wouldn't have a copy I
suppose?
Brian.
=========================================================================
From: "Paul@13E1.com" <triode@bow-tie.org.uk>
Subject: Re: [JN] 3A/167M Ad.
Date: Tue, 18 Jul 2000 13:26:33 +0100
Source: Sound Digest Archive v02.n606
Yes;
I'd like to see one too!
Paul
- ----- Original Message -----
From: Brian Clark <bdclark@talk21.com>
To: <retrovox@bigpond.com>
Cc: Joenet <sound@lists.io.com>
Sent: Tuesday, July 18, 2000 12:14 PM
Subject: [JN] 3A/167M Ad.
> Dave
>
> the ad refers to an Application Report, M8/109, you wouldn't have a copy I
> suppose?
>
> Brian.
>
>
=========================================================================
From: David Crittle <retrovox@bigpond.com>
Subject: [JN] 3A/167M Ad.
Date: Wed, 19 Jul 2000 00:35:35 +1000
Source: Sound Digest Archive v02.n606
>the ad refers to an Application Report, M8/109, you wouldn't have a copy I
>suppose?
Click on this link, sorry about the poor quality scans
http://www.users.bigpond.com/retrovox/3A167M01.html
critter
=========================================================================
From: Thomas Dunker <dunker@invalid.ed.ntnu.no>
Subject: [JN] 3A/167M driving 300B, anyone?
Date: Sun, 25 Jul 1999 00:51:09 +0200 (CEST)
Source: Sound Digest Archive v02.n211
Hello all!
I picked up a pair of Tango U-708s from Koji at the post office the other
day. I'm using them in a spare/experimental pair of SE amps I've been
working on lately. Today I mounted a transformer on the first chassis
and whipped together a simple amp with a 3A/167M (UK WE437A equivalent)
input/driver RC coupled to a 300B with cathode bias. The thing played
music right away and on an old Coral Beta 8 (which is fairly efficient)
there was no noticeable hum. BUT I heard a hint of the characteristic
high pitch microphonic whine of the 3A/167M, which I fear might reach
an annoying level on compression driver horns at about 10x the efficiency
of those Corals.
The 3A/167M runs with about 30mA/200V, cathode bias and a 5K plate load.
Anybody else experimented with 3A/167M or WE437A as driver stage?
Since I have the loctal socket mounted I might try some other loctal
tube instead of the 3A/167M. I have some Siemens C3m pentodes that
I'd like to try. (There was an article in SP with an amp that used
C3m driving a 300B.)
While I'm at it, I'm looking for working singles of these two power
DH triodes: Telefunken RS241 and Philips F410.
I'm working on a detailed report from my Europe trip where I visited
Manfred Huber, Hartmut Quaschik, Thomas Mayer, Christian Rintelen and
Kurt Steffensen, and there will be plenty of pictures...all of it to
be readable on the web some time soon. I had a fabulous time wherever
I went on this trip, and thanks again to you guys who made it possible!
Tom
- ------------------------------------------------------------------------
_/\_ Thomas Dunker \ The Horn Speaker Home Page:
/ \ P.O.Box 2811 \ http://invalid.ed.ntnu.no/~dunker/horns.html
| | 7002 Trondheim \
| | NORWAY \--\ "Those with head above water
\____/ dunker@omegav.ntnu.no \ see only the tip of the iceberg"
|||| phone: (+47)73911068 \ (Gene Dalby)
- ------------------------------------------------------------------------
=========================================================================
From: hwang002@ms10.hinet.net
Subject: Re: [JN] 3A/167M driving 300B, anyone?
Date: Sun, 25 Jul 1999 08:32:29 +0800 (CST)
Source: Sound Digest Archive v02.n211
Hi Thomas:
I use 3A/167M(or 437A) to drive Tango NC-14, then 300B. Before that, I used
417A instead of 3A/167M. My friend told me amp with NC-14 sounded better
than that without NC-14. So, I keep NC-14 on the circuit.
Regards
stanley
=========================================================================
From: Thomas Dunker <dunker@invalid.ed.ntnu.no>
Subject: Re: [JN] 3A/167M driving 300B, anyone?
Date: Sun, 25 Jul 1999 12:06:56 +0200 (CEST)
Source: Sound Digest Archive v02.n212
On Sun, 25 Jul 1999 hwang002@ms10.hinet.net wrote:
> Hi Thomas:
>
> I use 3A/167M(or 437A) to drive Tango NC-14, then 300B. Before that, I used
> 417A instead of 3A/167M. My friend told me amp with NC-14 sounded better
> than that without NC-14. So, I keep NC-14 on the circuit.
I don't have any such ITs that I can use in these amps, but I bet that
works well.
JC Morrison once mentioned that he once built an amp with a 3A/167M
direct coupled to a 10Y/801 which sounded really good, but the power
supply on these amps I'm building don't permit DC coupling.
Tom
- ------------------------------------------------------------------------
_/\_ Thomas Dunker \ The Horn Speaker Home Page:
/ \ P.O.Box 2811 \ http://invalid.ed.ntnu.no/~dunker/horns.html
| | 7002 Trondheim \
| | NORWAY \--\ "Those with head above water
\____/ dunker@omegav.ntnu.no \ see only the tip of the iceberg"
|||| phone: (+47)73911068 \ (Gene Dalby)
- ------------------------------------------------------------------------
=========================================================================
From: "J. Gordon Rankin" <waudio@cinti.net>
Subject: Re: [JN] 3A/167M driving 300B, anyone?
Date: Mon, 26 Jul 99 11:10:57 -0400
Source: Sound Digest Archive v02.n212
>The 3A/167M runs with about 30mA/200V, cathode bias and a 5K plate load.
> Anybody else experimented with 3A/167M or WE437A as driver stage?
Thomas,
My Triton Signature 437A IT Coupled to 300B has been a big hit here! I
actually use the 437 by iteself in a single stage amplifier that is
really cool also. Man I can't get enough of this tube, or enough of them.
Gordon
=======> Wavelength Audio <=======
mailto:waudio@cinti.net
http://www.WavelengthAudio.com
ph.fx. 513-271-4186 USA
=========================================================================
From: Paul Mouritsen <mourip@erols.com>
Subject: [JN] 3B23
Date: Sat, 03 Jul 1999 16:33:02 -0400
Source: Sound Digest Archive v02.n194
Hi,
Does anyone have any info on this tube or know the pinout. I am thinking
about buying it. The description is:
Old, U.S. Navy issue balloon vacuume tube, Mfg. by Raytheon. Corp. Type CRP
38222. Twin caps; dated Nov. 11 1942. Approximately 6 ½" tall, with four
prongs;
stamped U.S. Navy on base. This tube is also known as 3B23 or RK-22
full wave
rectifier heater 2.5v @4A, 3.5KV @ 200ma.
...but I cannot find a reference to it either on one of the tube search
sites or in my GE Essential Chararcteristics.
Thanks,
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: "David B. Klein" <dklein@microtec.net>
Subject: [JN] Re: 3-channel stereo
Date: Thu, 02 Sep 1999 12:03:59
Source: Sound Digest Archive v02.n270
I've decided to experiment with a three-channel playback from two-channel
source, i.e. ersatz three-channel approach, using my Quad 57s, of which I
have [N + 1] for this application. I'm wondering if I ought to try a
matrixing approach or simply a mono center flanked by conventional stereo.
Any thoughts?
David
=========================================================================
From: "P. de R. L." <triode@bow-tie.org.uk>
Subject: Re: [JN] 3cx300a1?/4CX/250
Date: Tue, 8 Feb 2000 18:16:34 -0000
Source: Sound Digest Archive v02.n440
Here we go again!
I'm very happy I've discovered (thanks to Joenet) the details for triode
connection of 6146.
4CX/250 is another one which can take stupendous voltages on its anode, and
peanuts on G2.
It's another I've looked at before.
I'm thinking about triode strapping again.
Perhaps I'll collect all these data and write a book with a title such as
"There is life after WE 300B"!
Paul
> or what about 4cx250?
>
> bob.d.
>
>
>
=========================================================================
From: Christian Rintelen <rintelen@datacomm.ch>
Subject: [JN] 3cx300a1?
Date: Mon, 07 Feb 2000 09:48:42 +0100
Source: Sound Digest Archive v02.n437
Joes,
has anybody of you considered or even built an amp with the Svetlana
3CX300A1? The specs are really remarkable - similar to 300Bs with lower
capacitance and an Rp of only 450 ohms. Too bad that it can only
dissipate 30 Watts without forced air cooling. I figure the reason why I
haven't seen much amps with this tube is that it doesn't glow. But does
an amp really have to glow in order to shine?? ;-)
Christian
http://www.svetlana.com/docs/TechBulletins/appnoteNO.11.html
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] 3cx300a1?
Date: Mon, 07 Feb 2000 12:45:44 -0500
Source: Sound Digest Archive v02.n438
hi christian,
check out the 3cx300 amp i built a while ago
http://www.geocities.com/TimesSquare/1965/pp3cx300.html
(gosh, has it really been almost 3 yrs...)
in any case, i'm reviving this design
and expect to have a stereo version at nyNoise!!!
i hear that there are a couple 3cx300 based designs
out there. i think one was shown at CES.
apparently this tube has finally caught on (in japan).
supplies are drying up quick. ?!?
bob.d.
> ----------
> From: Christian Rintelen[SMTP:rintelen@datacomm.ch]
> Reply To: rintelen@datacomm.ch
> Sent: Monday, February 07, 2000 3:48 AM
> To: Joelist
> Subject: [JN] 3cx300a1?
>
> Joes,
>
> has anybody of you considered or even built an amp with the Svetlana
> 3CX300A1? The specs are really remarkable - similar to 300Bs with lower
> capacitance and an Rp of only 450 ohms. Too bad that it can only
> dissipate 30 Watts without forced air cooling. I figure the reason why I
> haven't seen much amps with this tube is that it doesn't glow. But does
> an amp really have to glow in order to shine?? ;-)
>
> Christian
>
> http://www.svetlana.com/docs/TechBulletins/appnoteNO.11.html
>
=========================================================================
From: Ken Gilbert <ride5000@ride.ri.net>
Subject: RE: [JN] 3cx300a1?
Date: Mon, 07 Feb 2000 17:07:12 -0500
Source: Sound Digest Archive v02.n438
>apparently this tube has finally caught on (in japan).
>supplies are drying up quick. ?!?
>
>
>bob.d.
aww, comeon... now i gotta go run out and get my hands on some right quick, eh?
i'm planning on using them for an electric bass guitar amplifier! well, it's
actually between them and the el509's. i guess i can just wait it out. the
bass player's getting disgusted with his SS sound, but he doesn't have the
cashola to ante up.
my beloved kt90s are already hard to find. i really hate having to hunt for
the tube i want!
ken
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] 3cx300a1?
Date: Mon, 07 Feb 2000 18:51:07 -0500
Source: Sound Digest Archive v02.n439
> >apparently this tube has finally caught on (in japan).
> >supplies are drying up quick. ?!?
> >
> >
> >bob.d.
>
> aww, comeon... now i gotta go run out and get my hands on some right
> quick, eh?
>
>
we'll i have nothing to gain from a run on the market... ;)
just passing along some info i got from svetlana...
> i'm planning on using them for an electric bass guitar amplifier!
>
sounds like a plan...
i've had numerous e-mails from guys with the same idea.
bass guitar amp...
300W from a single pair.
i've yet to hear from any of them.
YOU might just be the guy for it.
(you did that 600W guitar amp, right?)
> well, it's
> actually between them and the el509's. i guess i can just wait it out.
> the
> bass player's getting disgusted with his SS sound, but he doesn't have the
> cashola to ante up.
>
isn't that always the case...
i think the el509's will wind up being cheaper in the end.
can get a sh*Tload of power from a quad...
very low rp for a beam tube.
> my beloved kt90s are already hard to find. i really hate having to hunt
> for
> the tube i want!
>
well, there do seem to be alternatives to the 3cx300.
mr. pearl might have a few hints.
also, there's another russian hockey-puck triode out there with
similar spec's.
or what about 4cx250?
bob.d.
=========================================================================
From: Kalman Rubinson <kr4@is2.nyu.edu>
Subject: [JN] 3-phase drive, again
Date: Fri, 25 Aug 2000 17:32:18 -0400 (EDT)
Source: Sound Digest Archive v02.n642
I stumbled on a few banterings about using a 3-phase
motor for a turntable drive and this is what I intend
to do. Has anyone actually done this with a true 3-phase
drive? Ideas?
Kal
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: Re: [JN] 3-phase drive, again
Date: Fri, 25 Aug 2000 19:54:29 -0600
Source: Sound Digest Archive v02.n642
Hi Kal, All:
Welllllll . . . I've thought about this a bit in the interim and being
first a gearhead and only second a geek, I have an electromechanical
"solution" for you.
Find a surplus NoBrush, 3 phase 240 volt alternator and drive it thru a
remotely controlled, Reeves VariSpeed drive that is servo-d back to your
platter's speed sensor.
Be sure to fit a a BLM centrifugal clutch to the, presumably, single
phase motor driving the VariSpeed so that you won't kill the motor's start
winding while to bringing the 30# flywheel you fitted to the alternator's
driven shaft - and the alternator's rotor, of course - up to speed . . . .
Any questions ? ? :>) :>) ? ? ?
. . . and . . . while you are at stepping that 240V 3ph Y down to 120V, why
not just wind yourself a 3 ph. 120V in, 60V out 3ph balanced power
transformer and that way you'd have rock solid, dead quiet 3ph, 120V
balanced power to run all your other stuff . . .
Arcane as this might sound to many . . that last paragraph is not really
off the wall at all.
I lately build a 5hp 240V single-to-three-phase convertor that works
like a hot d**n - until I get real 3ph pwr into the house. At that point I
am going to do *exactly* as I've suggested in that same paragraph
> I stumbled on a few banterings about using a 3-phase
> motor for a turntable drive and this is what I intend
> to do. Has anyone actually done this with a true 3-phase
> drive? Ideas?
>
> Kal
Bill - PEARL, Inc.
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: [JN] 3 Sets of TEK Certified 6AW8A Matched Prs.
Date: Tue, 14 Mar 2000 23:08:21 -0700
Source: Sound Digest Archive v02.n483
http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=281926174
=========================================================================
From: AnnaLogg@aol.com
Subject: [JN] 3 speed turntable
Date: Sun, 28 Mar 1999 16:12:26 EST
Source: Sound Digest Archive v02.n098
If anyone's looking for a decent 3-speed tt, good arm, excellent condition
with new cartridge, please get in touch.
Thanks.
Anna
p.s. also has what appears to be a VPI base.
=========================================================================
From: Kalman Rubinson <kr4@is2.nyu.edu>
Subject: Re: [JN] 3 speed turntable
Date: Sun, 28 Mar 1999 19:48:34 -0500 (EST)
Source: Sound Digest Archive v02.n099
On Sun, 28 Mar 1999 AnnaLogg@aol.com wrote:
> If anyone's looking for a decent 3-speed tt, good arm, excellent condition
> with new cartridge, please get in touch.
Intentionally obscure?
Kal
=========================================================================
From: AnnaLogg@aol.com
Subject: Re: [JN] 3 speed turntable
Date: Sun, 28 Mar 1999 20:13:08 EST
Source: Sound Digest Archive v02.n099
In a message dated 99-03-28 19:48:36 EST, kr4@is2.nyu.edu writes:
> > If anyone's looking for a decent 3-speed tt, good arm, excellent condition
> > with new cartridge, please get in touch.
>
> Intentionally obscure?
>
No, just didn't want to take up "bandwidth" with a commerical. But it is a
Technics SL1000, MKII equipped with an EPA500 (100?) arm and a brand new
Dynavector 20B cartridge. It is sitting on what appears to be a VPI suspension
base. Also has a "Platter Matter" pad accessory as well as a felt pad. This is
a BIG hummer that weighs a ton. I have no idea what it's worth but I think the
lady would like to get about $500 for the whole thing. If that's unrealistic,
I'd appreciate feedback so I can tell her.
Btw, those Orban equalizers are also still up for grabs. . .
Thanks,
Anna
=========================================================================
From: "Mark J. Mills" <markjmills@earthlink.net>
Subject: Re: [JN] 3 speed turntable
Date: Mon, 29 Mar 1999 01:35:01 -0500
Source: Sound Digest Archive v02.n099
Kal:
If this helps.... The arm is a Technics EPA-100, S-shaped wand, and made of
titanium nitride, with viscous damping applied at the counterweight end. Visual
inspection indicated that it was in great shape, but of course there was no
reasonable way to test the bearings; however, having met the owner and seen the
set-up, I'd bet dollars-to-doughnuts that this is/was a carefully-tended baby.
The TT is itself hernia inducing, so I believe the 'obsidian base' comment - if
nothing else, this would make an Herculean door-stop! The arm alone may well be
worth close to the $500 asked. I don't know if there is a separate PSU -- if
there is, it is behind the cabinet, hence out of sight.
Mark
AnnaLogg@aol.com wrote:
> In a message dated 99-03-28 23:05:49 EST, kr4@is2.nyu.edu writes:
>
> > OK. I am sorry but please indulge me for a minute because I
> > seem to have lost all the previous exchange. This is an
> > SL1000 (including the obsidian base) with arm and cartridge
> > for $400 or $450? Which arm? Is there a separate
> > ps/controller for this one?
> >
> > Based on reliable contention that it is in excellent shape,
> > it's what I am looking for.
> >
> No problem, Kal -- I just wish I knew more about this turntable. Mark looked
> at it and the model # (which is underneath) said SL1000 MK II (2?). What's
> confusing me is that on one piece of paper I wrote "EPA 100" and on a second
> "EPA 500" (@#*$&@!) But it's BIG and gorgeous and very impressive-looking
> arm. Said "Titanium Nitride". Does that help? I don't know what an
> "obsidian" base is, but this is a wooden box slightly larger than the plinth,
> made of the most incredibly heavy wood I have ever seen. It is [painted]
> black, and the top is like a separate piece that juuuuuuuust fits inside and
> sits on four large springs, one in each corner, that are stuffed with foam.
> The platter is a blue color, and he had a felt pad on top of it. Then there
> was this "Platter Matter" thing (made in Canada -- Toronto, to be exact), but
> it was in its box and looked new.
>
> I hope this helps.
>
> Anna la Dense
Tim Reese