My take on the Brook 10C Auto Bias

[John L Stewart]

The circuit as shewn in Figure One of the article published in Audio Engineering of June 1947 will not work as is. As soon as the power amp goes into AB2 the 2A3 grids will draw current & drive the grid bias further negative. The grids in AB2 need to be returned to a low impedance point, which they are not.

The working circuit solves that by interposing cathode followers to drive the 2A3 grids.

I’m not a fan of single ended DC amplifier like the bias amp in the Brook 10C. No allowance is made for tube characteristic drift. Any power supply disturbance or drift is a real problem.

The Lincoln Walsh circuit is a good idea but I think it could be better implemented.

And apologies to those who may have covered these points earlier. The noise got too loud here, it was hurting my ears!

My 2 € anyway.

[[email protected]]

On Jan 4, 10:24*am, John L Stewart <John.L.Stewart.
> wrote:
> The circuit as shewn in Figure One of the article published in Audio
> Engineering of June 1947 will not work as is. As soon as the power amp
> goes into AB2 the 2A3 grids will draw current & drive the grid bias
> further negative. The grids in AB2 need to be returned to a low
> impedance point, which they are not.
>
> The working circuit solves that by interposing cathode followers to
> drive the 2A3 grids.
>
> I’m not a fan of single ended DC amplifier like the bias amp in the
> Brook 10C. No allowance is made for tube characteristic drift. Any power
> supply disturbance or drift is a real problem.
>
> The Lincoln Walsh circuit is a good idea but I think it could be better
> implemented.
>
> And apologies to those who may have covered these points earlier. The
> noise got too loud here, it was hurting my ears!
>
> My 2 € anyway.
>
> +-------------------------------------------------------------------+
> |Filename: Brook 10C Basic Circuit.JPG * * * * * * * * * * * * * * *|
> |Download:http://www.audiobanter.com/attachment.php?attachmentid=253|
> +-------------------------------------------------------------------+
>
> --
> John L Stewart

Given the energy and finances I'd like to reverse engineer and
publish the "Auto Adaptive Bias" offered in PrimaLuna products. Be
interesting to compare.

[Patrick Turner]

On Jan 5, 2:01*pm, wrote:
> On Jan 4, 10:24*am, John L Stewart <John.L.Stewart.
>
>
>
>
>
> > wrote:
> > The circuit as shewn in Figure One of the article published in Audio
> > Engineering of June 1947 will not work as is. As soon as the power amp
> > goes into AB2 the 2A3 grids will draw current & drive the grid bias
> > further negative. The grids in AB2 need to be returned to a low
> > impedance point, which they are not.
>
> > The working circuit solves that by interposing cathode followers to
> > drive the 2A3 grids.
>
> > I’m not a fan of single ended DC amplifier like the bias amp in the
> > Brook 10C. No allowance is made for tube characteristic drift. Any power
> > supply disturbance or drift is a real problem.
>
> > The Lincoln Walsh circuit is a good idea but I think it could be better
> > implemented.
>
> > And apologies to those who may have covered these points earlier. The
> > noise got too loud here, it was hurting my ears!
>
> > My 2 € anyway.
>
> > +-------------------------------------------------------------------+
> > |Filename: Brook 10C Basic Circuit.JPG * * * * * * * * * * * * * * *|
> > |Download:http://www.audiobanter.com/attachment.php?attachmentid=253|
> > +-------------------------------------------------------------------+
>
> > --
> > John L Stewart
>
> *Given the energy and finances I'd like to reverse engineer and
> publish the "Auto Adaptive Bias" offered in PrimaLuna products. Be
> interesting to compare.- Hide quoted text -
>
> - Show quoted text -

I doubt any secrets contained in Important Light, ie, Prima Luna
products will lead you to some eternal audiological salvation. Just
have to buy some of their products, and draw the schematics. But at
least you'd have a working circuit on which to test ideas contained in
the circuit, to see how good the ideas work, or if they work as
claimed, of if the ideas are a dud, and never worth copying or
developing.

Flipper is the self-proclaimed Idiotic Expert on Brook 10C, but he
just won't build a 10C sample to back up his extensive range of
verbolic bull**** spewings on the subject.

Marketing is done on the basis of "If a claim for betterness can be
made, it shall be made, even if its utter bull****, for the buying
public subconsciously crave to be enthralled with tales of bull****,
and part with money to fund an imagined lifestyle. Patents must be
written to confuse and befuddle by lawyers, thus creating opportunites
for keeping lawyers employed defending aforesaid patents, gaining
money by legal standover tactics as well as from company profits from
legitimate and arguably illegitimate sales of product. The public
shall be milked of its dough by whatever means possible that anyone
can think of, and marketing always needs fresh ideas, and re-hashed
old ideas.

Fortunately, US lawyers don't have a monopoly on mind control, and
many ppl can smell them coming.

Patrick Turner.

[MarkS]

"Patrick Turner" wrote in message
...

On Jan 5, 2:01 pm, wrote:
> On Jan 4, 10:24 am, John L Stewart <John.L.Stewart.
>
>
>
>
>
> > wrote:
> > The circuit as shewn in Figure One of the article published in Audio
> > Engineering of June 1947 will not work as is. As soon as the power amp
> > goes into AB2 the 2A3 grids will draw current & drive the grid bias
> > further negative. The grids in AB2 need to be returned to a low
> > impedance point, which they are not.
>
> > The working circuit solves that by interposing cathode followers to
> > drive the 2A3 grids.
>
> > I’m not a fan of single ended DC amplifier like the bias amp in the
> > Brook 10C. No allowance is made for tube characteristic drift. Any power
> > supply disturbance or drift is a real problem.
>
> > The Lincoln Walsh circuit is a good idea but I think it could be better
> > implemented.
>
> > And apologies to those who may have covered these points earlier. The
> > noise got too loud here, it was hurting my ears!
>
> > My 2 € anyway.
>
> > +-------------------------------------------------------------------+
> > |Filename: Brook 10C Basic Circuit.JPG |
> > |Download:http://www.audiobanter.com/attachment.php?attachmentid=253|
> > +-------------------------------------------------------------------+
>
> > --
> > John L Stewart
>
> Given the energy and finances I'd like to reverse engineer and
> publish the "Auto Adaptive Bias" offered in PrimaLuna products. Be
> interesting to compare.- Hide quoted text -
>
> - Show quoted text -

> I doubt any secrets contained in Important Light, ie, Prima Luna
> products will lead you to some eternal audiological salvation. Just
> have to buy some of their products, and draw the schematics. But at
> least you'd have a working circuit on which to test ideas contained in
> the circuit, to see how good the ideas work, or if they work as
> claimed, of if the ideas are a dud, and never worth copying or
> developing.

> Flipper is the self-proclaimed Idiotic Expert on Brook 10C, but he
> just won't build a 10C.

<Snip lawyers, guns & money>

Well, dug up the Sams I had for the 10C (kept that but not the amp..go
figure).
If I wanted to build the 10C, what would you do for the driver choke? The
Sams claims the OT is a 4.3K primary.. easy enough, but the driver choke is
another story. The spec according to Sams is a 1 : 1 impedance ratio with ~
1.2K DCR per coil but no equivalent p/n's given.

I wonder why Walsh used all those 6J5's / 7A4's instead of 6SN7's..

Regards,

Mark

[flipper]

On Sat, 7 Jan 2012 11:45:35 -0800 (PST), Patrick Turner
> wrote:

>On Jan 5, 2:01*pm, wrote:
>> On Jan 4, 10:24*am, John L Stewart <John.L.Stewart.
>>
>>
>>
>>
>>
>> > wrote:
>> > The circuit as shewn in Figure One of the article published in Audio
>> > Engineering of June 1947 will not work as is. As soon as the power amp
>> > goes into AB2 the 2A3 grids will draw current & drive the grid bias
>> > further negative. The grids in AB2 need to be returned to a low
>> > impedance point, which they are not.
>>
>> > The working circuit solves that by interposing cathode followers to
>> > drive the 2A3 grids.
>>
>> > I’m not a fan of single ended DC amplifier like the bias amp in the
>> > Brook 10C. No allowance is made for tube characteristic drift. Any power
>> > supply disturbance or drift is a real problem.
>>
>> > The Lincoln Walsh circuit is a good idea but I think it could be better
>> > implemented.
>>
>> > And apologies to those who may have covered these points earlier. The
>> > noise got too loud here, it was hurting my ears!
>>
>> > My 2 € anyway.
>>
>> > +-------------------------------------------------------------------+
>> > |Filename: Brook 10C Basic Circuit.JPG * * * * * * * * * * * * * * *|
>> > |Download:http://www.audiobanter.com/attachment.php?attachmentid=253|
>> > +-------------------------------------------------------------------+
>>
>> > --
>> > John L Stewart
>>
>> *Given the energy and finances I'd like to reverse engineer and
>> publish the "Auto Adaptive Bias" offered in PrimaLuna products. Be
>> interesting to compare.- Hide quoted text -
>>
>> - Show quoted text -
>
>I doubt any secrets contained in Important Light, ie, Prima Luna
>products will lead you to some eternal audiological salvation. Just
>have to buy some of their products, and draw the schematics. But at
>least you'd have a working circuit on which to test ideas contained in
>the circuit, to see how good the ideas work, or if they work as
>claimed, of if the ideas are a dud, and never worth copying or
>developing.
>
>Flipper is the self-proclaimed Idiotic Expert on Brook 10C, but he
>just won't build a 10C sample to back up his extensive range of
>verbolic bull**** spewings on the subject.

And I'm not going to 'build a V8' just to show you how an internal
combustion engine works either.


>Marketing is done on the basis of "If a claim for betterness can be
>made, it shall be made, even if its utter bull****, for the buying
>public subconsciously crave to be enthralled with tales of bull****,
>and part with money to fund an imagined lifestyle. Patents must be
>written to confuse and befuddle by lawyers, thus creating opportunites
>for keeping lawyers employed defending aforesaid patents, gaining
>money by legal standover tactics as well as from company profits from
>legitimate and arguably illegitimate sales of product. The public
>shall be milked of its dough by whatever means possible that anyone
>can think of, and marketing always needs fresh ideas, and re-hashed
>old ideas.
>
>Fortunately, US lawyers don't have a monopoly on mind control, and
>many ppl can smell them coming.

Fantasy land gibberish from the ignorant.

Ever worked in a marketing department? I have. Ever worked with patent
lawyers on patent filings? I have.

Unfortunately, Patrick is immune to rhyme or reason inside his cocoon
of delusions.

>Patrick Turner.

[flipper]

On Wed, 4 Jan 2012 16:24:53 +0000, John L Stewart
> wrote:

>
>The circuit as shewn in Figure One of the article published in Audio
>Engineering of June 1947 will not work as is. As soon as the power amp
>goes into AB2 the 2A3 grids will draw current & drive the grid bias
>further negative. The grids in AB2 need to be returned to a low
>impedance point, which they are not.

It would work Class AB but don't think it's intended to be an
'operational' circuit. It's a 'conceptual' diagram.

>The working circuit solves that by interposing cathode followers to
>drive the 2A3 grids.
>
>I’m not a fan of single ended DC amplifier like the bias amp in the
>Brook 10C. No allowance is made for tube characteristic drift. Any power
>supply disturbance or drift is a real problem.

Now *that* would be a reason to build and experiment with the circuit,
if one were inclined to incorporate it into their own design.
Although, these days, simulations could give most of the answers.

It *is* a servo loop, though, so it should, at least partially,
compensate but 'how much' is an interesting question and I always
found it curious there's not a single adjustment to the thing.

Of course, there's seldom an 'adjustment' for self bias amps either,
you just 'live with' a certain degree of fluctuation, and emulating
that behavior was his second of two goals.

>The Lincoln Walsh circuit is a good idea but I think it could be better
>implemented.

Careful. You're on the verge of speaking heresy, and invoking Turner's
wrath, by implying there's even a rat's chance in hell it might
actually work.

Yes, it can be improved a lot with solid state techniques, which is
why I never contemplated building the circuit as shown.

>And apologies to those who may have covered these points earlier. The
>noise got too loud here, it was hurting my ears!
>
>My 2 € anyway.
>
>
>+-------------------------------------------------------------------+
>|Filename: Brook 10C Basic Circuit.JPG |
>|Download: http://www.audiobanter.com/attachment.php?attachmentid=253|
>+-------------------------------------------------------------------+

[Patrick Turner]

On Jan 9, 5:04*pm, flipper > wrote:
> On Sat, 7 Jan 2012 11:45:35 -0800 (PST), Patrick Turner
>
>
>
>
>
> > wrote:
> >On Jan 5, 2:01*pm, wrote:
> >> On Jan 4, 10:24*am, John L Stewart <John.L.Stewart.
>
> >> > wrote:
> >> > The circuit as shewn in Figure One of the article published in Audio
> >> > Engineering of June 1947 will not work as is. As soon as the power amp
> >> > goes into AB2 the 2A3 grids will draw current & drive the grid bias
> >> > further negative. The grids in AB2 need to be returned to a low
> >> > impedance point, which they are not.
>
> >> > The working circuit solves that by interposing cathode followers to
> >> > drive the 2A3 grids.
>
> >> > I’m not a fan of single ended DC amplifier like the bias amp in the
> >> > Brook 10C. No allowance is made for tube characteristic drift. Any power
> >> > supply disturbance or drift is a real problem.
>
> >> > The Lincoln Walsh circuit is a good idea but I think it could be better
> >> > implemented.
>
> >> > And apologies to those who may have covered these points earlier. The
> >> > noise got too loud here, it was hurting my ears!
>
> >> > My 2 € anyway.
>
> >> > +-------------------------------------------------------------------+
> >> > |Filename: Brook 10C Basic Circuit.JPG * * * * * * * * * * * * * * *|
> >> > |Download:http://www.audiobanter.com/attachment.php?attachmentid=253|
> >> > +-------------------------------------------------------------------+
>
> >> > --
> >> > John L Stewart
>
> >> *Given the energy and finances I'd like to reverse engineer and
> >> publish the "Auto Adaptive Bias" offered in PrimaLuna products. Be
> >> interesting to compare.- Hide quoted text -
>
> >> - Show quoted text -
>
> >I doubt any secrets contained in Important Light, ie, Prima Luna
> >products will lead you to some eternal audiological salvation. Just
> >have to buy some of their products, and draw the schematics. But at
> >least you'd have a working circuit on which to test ideas contained in
> >the circuit, to see how good the ideas work, or if they work as
> >claimed, of if the ideas are a dud, and never worth copying or
> >developing.
>
> >Flipper is the self-proclaimed Idiotic Expert on Brook 10C, but he
> >just won't build a 10C sample to back up his extensive range of
> >verbolic bull**** spewings on the subject.
>
> And I'm not going to 'build a V8' just to show you how an internal
> combustion engine works either.
>
> >Marketing is done on the basis of "If a claim for betterness can be
> >made, it shall be made, even if its utter bull****, for the buying
> >public subconsciously crave to be enthralled with tales of bull****,
> >and part with money to fund an imagined lifestyle. Patents must be
> >written to confuse and befuddle by lawyers, thus creating opportunites
> >for keeping lawyers employed defending aforesaid patents, gaining
> >money by legal standover tactics as well as from company profits from
> >legitimate and arguably illegitimate sales of product. The public
> >shall be milked of its dough by whatever means possible that anyone
> >can think of, and marketing always needs fresh ideas, and re-hashed
> >old ideas.
>
> >Fortunately, US lawyers don't have a monopoly on mind control, and
> >many ppl can smell them coming.
>
> Fantasy land gibberish from the ignorant.
>
> Ever worked in a marketing department? I have. Ever worked with patent
> lawyers on patent filings? I have.
>
> Unfortunately, Patrick is immune to rhyme or reason inside his cocoon
> of delusions.

Unfortunately, Flipper cannot substantiate one single claim he makes
about the Brook 10C because he won't build a sample and observe it,
and prefers to try to be an arsole **** and demolish anyone who
questions his reasoning. Seems like he just swallows lawyer-spiel of
the brook patent without question thus showing everyone what a ****ing
dumbass idiot he is to believe all he reads, rather than believe what
he could prove to himself in his workshop by soldering and measuring.

Flipper, like so many objectionable ppl, fails to accept others have
very good reason to doubt his version of the truth about anything.

He begs the wrath of anyone with a real brain.

Patrick Turner.

[Patrick Turner]

On Jan 9, 5:38*pm, flipper > wrote:
> On Wed, 4 Jan 2012 16:24:53 +0000, John L Stewart
>
> > wrote:
>
> >The circuit as shewn in Figure One of the article published in Audio
> >Engineering of June 1947 will not work as is. As soon as the power amp
> >goes into AB2 the 2A3 grids will draw current & drive the grid bias
> >further negative. The grids in AB2 need to be returned to a low
> >impedance point, which they are not.
>
> It would work Class AB but don't think it's intended to be an
> 'operational' circuit. It's a 'conceptual' diagram.
>
> >The working circuit solves that by interposing cathode followers to
> >drive the 2A3 grids.
>
> >I’m not a fan of single ended DC amplifier like the bias amp in the
> >Brook 10C. No allowance is made for tube characteristic drift. Any power
> >supply disturbance or drift is a real problem.
>
> Now *that* would be a reason to build and experiment with the circuit,
> if one were inclined to incorporate it into their own design.
> Although, these days, simulations could give most of the answers.

There's another reason why Flipper should arrise of his big fat lazy
****in arse and go solder a sample Brook 10C output stage to see how
it really works.
>
> It *is* a servo loop, though, so it should, at least partially,
> compensate but 'how much' is an interesting question and I always
> found it curious there's not a single adjustment to the thing.
>
> Of course, there's seldom an 'adjustment' for self bias amps either,
> you just 'live with' a certain degree of fluctuation, and emulating
> that behavior was his second of two goals.
>
> >The Lincoln Walsh circuit is a good idea but I think it could be better
> >implemented.
>
> Careful. You're on the verge of speaking heresy, and invoking Turner's
> wrath, by implying there's even a rat's chance in hell it might
> actually work.

Again Flipper fails to understand my simple stance, and it is not
about rat's chances in Hell. It is about pointing out to all the
shortcomings of Flipper's statements about the Brook 10C.

Flipper has failed to convince anyone he understands the Brook 10C
biasing control circuit and won't build a sample to find out.

Flipper spews buckets of vomit at us about about patents, lawyer
spiel, simulations, and the rightness and infalliblity of himself, but
no real evidence he understands what he says. The only way I see that
Flipper can redeem himself is to build a sample Brook 10C output stage
which would be so easy.

Hell may freeze over before he moves to prove anything to anyone,
including to himself, so meanwhile, we may all consider Flipper the
ignorant fool of the group because he thinks he's so perfectly correct
and infallible.

> Yes, it can be improved a lot with solid state techniques, which is
> why I never contemplated building the circuit as shown.

That's right Flipper, never solder or make anything in case you find
you didn't understand it in the first instance.

I have to say not much truth comes from those wannabe solderers
unwilling to solder stuff up and measure it properly.

Patrick Turner.

[flipper]

On Mon, 9 Jan 2012 18:03:44 -0800 (PST), Patrick Turner
> wrote:

>On Jan 9, 5:04*pm, flipper > wrote:
>> On Sat, 7 Jan 2012 11:45:35 -0800 (PST), Patrick Turner
>>
>>
>>
>>
>>
>> > wrote:
>> >On Jan 5, 2:01*pm, wrote:
>> >> On Jan 4, 10:24*am, John L Stewart <John.L.Stewart.
>>
>> >> > wrote:
>> >> > The circuit as shewn in Figure One of the article published in Audio
>> >> > Engineering of June 1947 will not work as is. As soon as the power amp
>> >> > goes into AB2 the 2A3 grids will draw current & drive the grid bias
>> >> > further negative. The grids in AB2 need to be returned to a low
>> >> > impedance point, which they are not.
>>
>> >> > The working circuit solves that by interposing cathode followers to
>> >> > drive the 2A3 grids.
>>
>> >> > I’m not a fan of single ended DC amplifier like the bias amp in the
>> >> > Brook 10C. No allowance is made for tube characteristic drift. Any power
>> >> > supply disturbance or drift is a real problem.
>>
>> >> > The Lincoln Walsh circuit is a good idea but I think it could be better
>> >> > implemented.
>>
>> >> > And apologies to those who may have covered these points earlier. The
>> >> > noise got too loud here, it was hurting my ears!
>>
>> >> > My 2 € anyway.
>>
>> >> > +-------------------------------------------------------------------+
>> >> > |Filename: Brook 10C Basic Circuit.JPG * * * * * * * * * * * * * * *|
>> >> > |Download:http://www.audiobanter.com/attachment.php?attachmentid=253|
>> >> > +-------------------------------------------------------------------+
>>
>> >> > --
>> >> > John L Stewart
>>
>> >> *Given the energy and finances I'd like to reverse engineer and
>> >> publish the "Auto Adaptive Bias" offered in PrimaLuna products. Be
>> >> interesting to compare.- Hide quoted text -
>>
>> >> - Show quoted text -
>>
>> >I doubt any secrets contained in Important Light, ie, Prima Luna
>> >products will lead you to some eternal audiological salvation. Just
>> >have to buy some of their products, and draw the schematics. But at
>> >least you'd have a working circuit on which to test ideas contained in
>> >the circuit, to see how good the ideas work, or if they work as
>> >claimed, of if the ideas are a dud, and never worth copying or
>> >developing.
>>
>> >Flipper is the self-proclaimed Idiotic Expert on Brook 10C, but he
>> >just won't build a 10C sample to back up his extensive range of
>> >verbolic bull**** spewings on the subject.
>>
>> And I'm not going to 'build a V8' just to show you how an internal
>> combustion engine works either.
>>
>> >Marketing is done on the basis of "If a claim for betterness can be
>> >made, it shall be made, even if its utter bull****, for the buying
>> >public subconsciously crave to be enthralled with tales of bull****,
>> >and part with money to fund an imagined lifestyle. Patents must be
>> >written to confuse and befuddle by lawyers, thus creating opportunites
>> >for keeping lawyers employed defending aforesaid patents, gaining
>> >money by legal standover tactics as well as from company profits from
>> >legitimate and arguably illegitimate sales of product. The public
>> >shall be milked of its dough by whatever means possible that anyone
>> >can think of, and marketing always needs fresh ideas, and re-hashed
>> >old ideas.
>>
>> >Fortunately, US lawyers don't have a monopoly on mind control, and
>> >many ppl can smell them coming.
>>
>> Fantasy land gibberish from the ignorant.
>>
>> Ever worked in a marketing department? I have. Ever worked with patent
>> lawyers on patent filings? I have.
>>
>> Unfortunately, Patrick is immune to rhyme or reason inside his cocoon
>> of delusions.
>
>Unfortunately, Flipper cannot substantiate one single claim he makes
>about the Brook 10C

An obvious falsehood as I've provided supporting evidence and
commercial examples for everything I've said.

You, on the other hand, have provided nothing but insults.

> because he won't build a sample and observe it,

Because I can read and comprehend what's written by people who've
already done it.

>and prefers to try to be an arsole **** and demolish anyone who
>questions his reasoning.

No, that's your 'technique'.

Mine is to provide supporting documentation and examples, which I did.

> Seems like he just swallows lawyer-spiel of
>the brook patent without question thus showing everyone what a ****ing
>dumbass idiot he is to believe all he reads, rather than believe what
>he could prove to himself in his workshop by soldering and measuring.

Which further proves you can't read because I have explained over and
over again with commercial examples, simulations, and authoritative
sources like RDH4.

>Flipper, like so many objectionable ppl, fails to accept others have
>very good reason to doubt his version of the truth about anything.

Except you've never provided any 'reason' other than you simply hate
Brook. Not that that is anything 'special' as you spew hate at just
about any and every thing.

>He begs the wrath of anyone with a real brain.

Anyone with a "real brain" can read for themselves the source material
I provided.

What can they get from you?

>Patrick Turner.

[flipper]

On Mon, 9 Jan 2012 18:18:55 -0800 (PST), Patrick Turner
> wrote:

>On Jan 9, 5:38*pm, flipper > wrote:
>> On Wed, 4 Jan 2012 16:24:53 +0000, John L Stewart
>>
>> > wrote:
>>
>> >The circuit as shewn in Figure One of the article published in Audio
>> >Engineering of June 1947 will not work as is. As soon as the power amp
>> >goes into AB2 the 2A3 grids will draw current & drive the grid bias
>> >further negative. The grids in AB2 need to be returned to a low
>> >impedance point, which they are not.
>>
>> It would work Class AB but don't think it's intended to be an
>> 'operational' circuit. It's a 'conceptual' diagram.
>>
>> >The working circuit solves that by interposing cathode followers to
>> >drive the 2A3 grids.
>>
>> >I’m not a fan of single ended DC amplifier like the bias amp in the
>> >Brook 10C. No allowance is made for tube characteristic drift. Any power
>> >supply disturbance or drift is a real problem.
>>
>> Now *that* would be a reason to build and experiment with the circuit,
>> if one were inclined to incorporate it into their own design.
>> Although, these days, simulations could give most of the answers.
>
>There's another reason why Flipper should arrise of his big fat lazy
>****in arse and go solder a sample Brook 10C output stage

Try actually reading something for a change. And I quote myself: "if
one were inclined to incorporate it into their own design."

I am not, nor ever was, inclined to build a 6SN7 Automatic Bias
Control so I couldn't care less if that particular implementation has
any of the 'problems' Stewart speculated about.

> to see how
>it really works.

I already know "how it really works."

>> It *is* a servo loop, though, so it should, at least partially,
>> compensate but 'how much' is an interesting question and I always
>> found it curious there's not a single adjustment to the thing.
>>
>> Of course, there's seldom an 'adjustment' for self bias amps either,
>> you just 'live with' a certain degree of fluctuation, and emulating
>> that behavior was his second of two goals.
>>
>> >The Lincoln Walsh circuit is a good idea but I think it could be better
>> >implemented.
>>
>> Careful. You're on the verge of speaking heresy, and invoking Turner's
>> wrath, by implying there's even a rat's chance in hell it might
>> actually work.
>
>Again Flipper fails to understand my simple stance, and it is not
>about rat's chances in Hell. It is about pointing out to all the
>shortcomings of Flipper's statements about the Brook 10C.

You haven't come up with a single 'shortcoming'. All you do is call
people liars and idiots.

>Flipper has failed to convince anyone he understands the Brook 10C
>biasing control circuit and won't build a sample to find out.

There you go again pretending to speak for 'everyone'.

When are you going to get it through that 'open mind' of yours that
you aren't 'everyone'?

>Flipper spews buckets of vomit at us about about patents, lawyer
>spiel, simulations, and the rightness and infalliblity of himself, but
>no real evidence he understands what he says.

You left out RDH4, wikipedia, and commercial examples.

What have you provided besides "buckets of vomit?"

> The only way I see that
>Flipper can redeem himself is to build a sample Brook 10C output stage
>which would be so easy.

Then you go build one because I have no need.

>Hell may freeze over before he moves to prove anything to anyone,
>including to himself, so meanwhile, we may all consider Flipper the
>ignorant fool of the group because he thinks he's so perfectly correct
>and infallible.

That's a hoot. The one who provides nothing whatsoever but insults
claims I need to 'prove' something.

>> Yes, it can be improved a lot with solid state techniques, which is
>> why I never contemplated building the circuit as shown.
>
>That's right Flipper, never solder or make anything in case you find
>you didn't understand it in the first instance.

I understand it just fine and have posted schematics of a solid state
version, combined with a balance servo, I once contemplated building.

However, my interests have shifted since then, as indicated by two AM
transmitters, modulation indicator, and FM transmitter I'm currently
working on.

>I have to say not much truth comes from those wannabe solderers
>unwilling to solder stuff up and measure it properly.

I have a house full of things I've built but I'm not going to put
together a Brook 10C clone just because you can't read.

>Patrick Turner.

[Edward Morris]

Hell may freeze over...
about rat's chances in Hell...

Boy Patrick. For a person who doesn't believe there is a God or Satan I
assume either, you certainly use words out of the Bible quite often.

Eddie

"Patrick Turner" > wrote in message
...
On Jan 9, 5:38 pm, flipper > wrote:
> On Wed, 4 Jan 2012 16:24:53 +0000, John L Stewart
>
> > wrote:
>
> >The circuit as shewn in Figure One of the article published in Audio
> >Engineering of June 1947 will not work as is. As soon as the power amp
> >goes into AB2 the 2A3 grids will draw current & drive the grid bias
> >further negative. The grids in AB2 need to be returned to a low
> >impedance point, which they are not.
>
> It would work Class AB but don't think it's intended to be an
> 'operational' circuit. It's a 'conceptual' diagram.
>
> >The working circuit solves that by interposing cathode followers to
> >drive the 2A3 grids.
>
> >I’m not a fan of single ended DC amplifier like the bias amp in the
> >Brook 10C. No allowance is made for tube characteristic drift. Any power
> >supply disturbance or drift is a real problem.
>
> Now *that* would be a reason to build and experiment with the circuit,
> if one were inclined to incorporate it into their own design.
> Although, these days, simulations could give most of the answers.

There's another reason why Flipper should arrise of his big fat lazy
****in arse and go solder a sample Brook 10C output stage to see how
it really works.
>
> It *is* a servo loop, though, so it should, at least partially,
> compensate but 'how much' is an interesting question and I always
> found it curious there's not a single adjustment to the thing.
>
> Of course, there's seldom an 'adjustment' for self bias amps either,
> you just 'live with' a certain degree of fluctuation, and emulating
> that behavior was his second of two goals.
>
> >The Lincoln Walsh circuit is a good idea but I think it could be better
> >implemented.
>
> Careful. You're on the verge of speaking heresy, and invoking Turner's
> wrath, by implying there's even a rat's chance in hell it might
> actually work.

Again Flipper fails to understand my simple stance, and it is not
about rat's chances in Hell. It is about pointing out to all the
shortcomings of Flipper's statements about the Brook 10C.

Flipper has failed to convince anyone he understands the Brook 10C
biasing control circuit and won't build a sample to find out.

Flipper spews buckets of vomit at us about about patents, lawyer
spiel, simulations, and the rightness and infalliblity of himself, but
no real evidence he understands what he says. The only way I see that
Flipper can redeem himself is to build a sample Brook 10C output stage
which would be so easy.

Hell may freeze over before he moves to prove anything to anyone,
including to himself, so meanwhile, we may all consider Flipper the
ignorant fool of the group because he thinks he's so perfectly correct
and infallible.

> Yes, it can be improved a lot with solid state techniques, which is
> why I never contemplated building the circuit as shown.

That's right Flipper, never solder or make anything in case you find
you didn't understand it in the first instance.

I have to say not much truth comes from those wannabe solderers
unwilling to solder stuff up and measure it properly.

Patrick Turner.