Roy wrote:
"Andre Jute" wrote in message
oups.com...


I am a little mystified by the people who spend time on this forum
and yet have no interest whatsoever, and nothing to contribute on
the subject of tube audio. Why do they bother?

Dear Mr Jute,

From this comment and from a similar view you posted in another thread, it
seems your main issue is with "non-glassheads" coming onto your beloved
hobby group RAT with their anti valve (sorry tube) views. Why then do you
not make your responses on that group only? Why do you feel the need to
spread your contributions across other groups too (especially UKRA)?

Roy.

My dear Mr Roy,

I am always happy to explain my actions and words, but the words you
quote were not spoken by me but by the longtime Ukrainian Iain
Churches.

Here is my full post, with my own words (and those of Iain and Patrick
Turners as well), and the explanation you seek below that:

*****Iain Churches wrote:
"Patrick Turner" wrote in message
...

Iain Churches wrote:

So, a thread from Trevor, on the subject of NFB and stability
would be of interest to many I think.

I doubt if Trevor could do any better than feign interest in any tube
discussion.
We all know he is insincere though.

Let's see if he starts the NFB thread.

Wilson won't. There's a pattern here. Pinkerton, offered an opportunity

to design a tube amp to prove he knows more than we do, refused on the
ground that it would be "nitpicked to death". Wilson obviously has all
the time in the world to write thousands of words about my articles, to

iterate his silly demands that Patrick or I write about the intricacies

of NFB yet again. But when he is invited to contribute an article on
NFB, he claims's he's too busy. Pearce, Krueger, all the other flame
merchants, contribute nothing in their soundbites. Apparently they want

to nitpick everyone else to death but cannot bear exposing themselves
to criticism. They're probably right. If they ever tried to do what
Patrick Turner and John Byrns and you and I do daily, namely actually
explain things, we would soon discover how much they know. They clearly

fear that we will discover they know very little.

I am a little mystified by the people who spend time on this forum
and yet have no interest whatsoever, and nothing to contribute on
the subject of tube audio. Why do they bother?

It's an easy thing to explain for anyone who grew up in a small town.
Wilson, Pinkerton, Krueger, Pearce, and assorted hangers-on like
McKelvy, Wieck, etc, are dried up old maids. twitching their net
curtains, peering out at people having fun, pursing their sour little
mouths and calling the vicar to stop the parade. Their preference of
silicon is dead -- or they believe it is -- with nothing left to decide

except whether Bose or Apple will inherit the remains. There is no
interest left in silicon -- and can you actually believe that such arid

people ever really loved music? -- so our glee in our tubes is doubly
offensive to them, a condition aggravated by the malice ingrained in
their petty, spiteful personalities.

In short, this scum is hounding us for the same reason that school
bullies take the marbles from smaller boys: not because they really
want the marbles but for the sick satisfaction of denying someone else
pleasure. I would bet a year of Pinkerton's salary that every one of
them pulled the wings from butterflies when they were boys.

*******
So, now to answer your question:

The reason I post this to UKRA as well is that the silicon slime came
from UKRA about eighteen months ago with the good wishes of the rest of
the clowns on UKRA -- and with the express purpose of maliciously
wrecking a major project on which RAT was then embarked. I warned UKRA
then that there would be a price to pay; they sneered and jeered, of
course. I don't hear them sneering and jeering any more; before I
finish they will despise Pinkerton, Pearce and the rest of that clutch
of clowns as we on RAT do. I guarantee it.

In short, dear Mr Roy, the scum invaded my patch -- rather
ineffectually, admittedly, but their lack of success is irrelevant when
their impertinence stands on the record -- so now I'm showing them how
it is done by someone competent.

If you're squeamish, you might wish to take a sabbatical until the
Silicon Slime cuts and runs, as eventually they will, though I bet they
are obdurate enough to stay long enough for me to do a permanent job on
their reputations.

Andre Jute
When I stop smiling there is always blood on the carpet. Funny thing:
it is never mine.

On 29 Mar 2006 01:51:43 -0800, "Andre Jute" wrote:

Iain Churches wrote:

I am a little mystified by the people who spend time on this forum
and yet have no interest whatsoever, and nothing to contribute on
the subject of tube audio. Why do they bother?

It's an easy thing to explain for anyone who grew up in a small town.

Asitappens, I did. That's why I easily recognise clumsy Voortrekkers
like you.

Wilson, Pinkerton, Krueger, Pearce, and assorted hangers-on like
McKelvy, Wieck, etc, are dried up old maids. twitching their net
curtains, peering out at people having fun, pursing their sour little
mouths and calling the vicar to stop the parade.

Actually, I have lots of fun. Much of it comes from reading your
bull****.

Their preference of
silicon is dead -- or they believe it is -- with nothing left to decide
except whether Bose or Apple will inherit the remains.

Apple just might be in a bit of trouble there.......

There is no
interest left in silicon -- and can you actually believe that such arid
people ever really loved music? -- so our glee in our tubes is doubly
offensive to them, a condition aggravated by the malice ingrained in
their petty, spiteful personalities.

It's fun to watch people gleefully building crap........

BTW, there's *loads* of interest in silicon, which is why tubes
account for less than 0.1% of the hi-fi market - and no, that's *not*
the top 0.1%................

In short, this scum is hounding us for the same reason that school
bullies take the marbles from smaller boys: not because they really
want the marbles but for the sick satisfaction of denying someone else
pleasure. I would bet a year of Pinkerton's salary that every one of
them pulled the wings from butterflies when they were boys.

Not me - but then, unlike you, I never boasted of having people shot
at dawn, either.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Stewart Pinkerton" wrote in message
...
: On Wed, 29 Mar 2006 15:32:14 +0200, "Ruud Broens"
: wrote:
: :
: : hm, about 12 W / 8 Ohm available, 7 % THD, 88 W idle with the 2SA1216
: : and CCS - you're saying there are no tubes that can beat that ?
: :
: : I read less than that into those curves, but even if true, that's
: : better than you'll get with the 300B.
: :
: : You are of course conveniently forgetting something else, the greatly
: : superior gain of the 2SA216. In the KISASS design, Tr2, the equivalent
: : of the 300B in KISS, has its emitter and collector loads set for a
: : stage gain of 6.25, to make it as similar as possible to the KISS amp.
: : This applies more than 20dB of local regeneration, equivalent to the
: : internal feedback of the 300B, cutting the distortion to about 0.5%.
: : Apples to apples, KISASS totally outperforms KISS.
: :
: : --
: :
: : Stewart Pinkerton | Music is Art - Audio is Engineering
:
: not forgetting anything here, just sticking with the topic - again -
: being inherent device linearity, not what you can do with fb - remember ?
:
: Yes, but PT already conceded that the 300B has internal feedback, so
: he had no problem with local degeneration in KISASS. After all,
: putting in a larger emitter resistor doesn't create any of the
: supposed horrors of loop feedback. Note also that you already conceded
: that it's as good or better than a 300B, without *any* feedback.
:
: ...40V supply, - 15 % efficiency and a large 1K/W heatsink for
: that 2SA1216 and say an LM350.
:
: See KISASS, if you can't remember the basic parameters of KISS.
: KISASS runs a 30 volt rail at the voltage amplifier, and is designed
: to run 100 mA idle current in the voltage amplifier stage.
:
err, wasn't remembering, just exemplifying what it takes.

: you are also conveniently forgetting that - as is -, you have an input
: impedance of about 5 Ohms ...
:
: See KISASS for the solution. Tubes use lotsa volts, BJTs use lotsa
: milliamps, same thing in the end for the 'black box' solution.

aha, now we're getting somewhere :-)
so if someone now comes up with an SE pentode output stage, so no fb,
that can do 12W out at 7 % THD, 88W dissipation,
you'll agree that even the 2SA1216 can be beaten ?
ok ;-)

(btw triodes don't have build-in feedback, more precisely,
they have a build-in feedback facilitating mechanism - as is
evident when you lock the anode voltage; no ~fb~ then)

Rudy

: more of a win some - loose some scenario, it seems,
: Stewart ;-)
:
: Not really, as KISS suffers similar problems. Naturally, one wouldn't
: expect a tubie to acknowledge this.
:
: -- -- --
: To reiterate the design process:
:
: KISASS came about as a suggestion by Iain Churches that I design a SS
: equivalent of Andre Jute's (so far mythical) KISS design, supposedly a
: single-ended tube amp with 300B output tube, a double-triode
: input/driver stage, zero loop feedback, and an output of less than ten
: watts. Ignoring a bunch of tube-centric 'rules' spouted by Patrick
: Turner, I had a think about how this should be done.
:
: In terms of parts count, we cannot beat the Nelson Pass ZEN design,
: which uses a single MOSFET, so we will use BJTs, the 'bete noir' of
: the tube fan. In terms of excellent performance from a minimal parts
: count, we have the classic 1969 Linsley Hood design, which ticks most
: of the boxes but does use global NFB.
:
: Where to go from here? OK, let's start from the simplest possible gain
: stage, a common-emitter BJT with emitter and collector loads (Tr2 in
: the schematic, the 2SC2922 device is recommended). This will set the
: transfer curve, and hence the sonic signature, of the amplifier. Such
: a stage does of course have a quite low input impedance, so we place a
: simple emitter follower buffer (Tr1, the MJE15028 will do, or any
: other decent medium power NPN BJT) ahead of it to allow a wider choice
: of source devices. The output impedance (as with the 300B) is much too
: high to drive a loudspeaker, so we need an impedance transformer. As
: one of the great advances of SS was that it allowed the removal of the
: OPT, we will not use iron. A simple pair of emitter followers (Tr3 and
: Tr4, for which the 2SC2922 and 2SA1216 will work well, but other
: modern complementary pairs may substitute) provide output impedance
: reduction without affecting voltage gain, and there we have the design
: in a nutshell.
:
: Further philosophical decisions were the avoidance of bootstrapping
: from the output to the gain stage (that could be construed as loop
: feedback), and the use of a heavily filtered power supply to keep the
: noise floor clean. The latter was in the cause of maintaining the
: 'first watt is the most important' philosophy, without which this
: design is utterly pointless. R15 and R16 reduce the rail voltage to
: give a maximum output power of less than ten watts into loads between
: 8 and 4 ohms, meeting one of the principal design parameters, while
: R12, R13 and R14 maintain the rail voltage of the gain stage at 5
: volts higher than the output rail, allowing better driving of the
: output while maintaining the natural transfer function of the gain
: stage.
:
: The bias current of the output stage is set to about 1 amp by R6,
: while the quiescent output voltage point is set primarily by R1/R2.
: This amplifier should be d.c. and thermally stable, but will reward
: careful layout, particularly in the utilisation of the 'star earth'
: philosophy, i.e. one central ground point to which all 'zero volt'
: connections are made. Given this, I'd expect less than 0.1% THD plus
: noise right across the audio band at an output of 1 watt into 4-8
: ohms, rising to several per cent just below clipping, in the usual
: 'SET' style. The output impedance will also be in the half-ohm region
: over most of the audio band.
:
: In terms of construction, it should be noted that R15 and R16
: dissipate 5 watts each, so should be at least ten-watt rated, while R5
: dissipates about 3 watts, and should be at least a 5-watt component.
: R12, R13 and R14 should be 2-watt rated, the others should be
: half-watt metal films. Note that for thermal stability, D1, D2, Tr3
: and Tr4 must share the same heatsink.
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

On 28 Mar 2006 23:53:14 -0800, "Andre Jute" wrote:


Ruud Broens wrote:

"Stewart Pinkerton" wrote in message
...
: On Tue, 28 Mar 2006 08:59:43 GMT, Patrick Turner
: wrote:
:
:
:
: Arny Krueger wrote:
:
: "Patrick Turner" wrote in message
:
:
: They are only as linear as a triode with regard to
: voltage gain when external loops of NFB have been applied,
: as in the case of the emitter follower connection or
: having a few BJTs with a loop of NFB around the
: lot of them to correct all their mistakes.
:
: BJTs are inherently non linear for voltage gain and MUST
: rely on large amounts of externally connected loops of
: NFB.
:
: Simply not true. Local feedback works well with BJTs.
:
: Local loops are externally applied loops of NFB.
:
: Bjts are so damned non linear with regard to voltage gain that large amount of
: NFB, local or otherwises must be applied
: to linearize the outcome, as well as raise input impedance.
:
: Some BJTs are more linear than say a 300B. Why do you keep ignoring
: this *fact*. Heresy?
:
: It isn't ludicous to drag people screaming back to the basics.
: The basic fact is that bjts WITHOUT ANY NFB, LOCAL OR OTHERWISE applied
anywhere
: have hopelessly poor
: voltage gain linearity.
:
: Utter bunk, check the spec sheet for the 2SA1216. Gain linearity is
: flat as a pancake at elevated junction temperatures, as would be
: experienced in a Class A amplifier.


yep, checking, i found it he
http://users.otenet.gr/~athsam/database.htm

the third graph shows Vbe - Ic, the _run hot_ curve
does 0.8 V Vbe @ 6 A, 400 mVtt giving 6 Att with 1.6 % distortion
certainly impressive. but, now realize the curves are taken at a
constant Vce=4V - not very realistic, is it ?

now, Hfe about 100, at this 24W class A idle point,
60 mA of base current is required. oops, at 10 A, Hfe has
gone south to only 60, creating an additional few dozens
of THD %.

2nd take:
0.6Vbe, 2.2 A idle now Hfe stays flat with 200 mVtt in, 4Att out,
distortion is 7 % or so that's indeed quite an achievement

but considering it's taken at constant Vce
reality will be worse

: Statements have been made on the group that what i am saying is untrue.
:
: That's because it is - see above.

hm, about 12 W / 8 Ohm available, 7 % THD, 8.8 W idle with the 2SA1216
you're saying there are no tubes that can beat that ?
hmmm

the truth,
Rudy

Sheesh, Rudy, this BJT the silicon clowns want to flog you isn't much
chop; in fact it appears to be just a "modern" device number assigned
to the same old silicon excrement I rejected forty years ago.

Thanks for once again demonstrating your ignorance of electronics.

A modern
300B amp, designed with high voltage, high current and high bias in the
modern Jute style has *less* distortion at full power, and practically
no 3rd harmonic distortion.

Rudy has his numbers mixed up, especially once you figure local
degeneration into the equation, to match stage gains.

I show the results of a challenge to me by
another incompetent pair of idiots. "BobC" Chernofsky and Michael
LeFevre of Magnequest Transformers. Note that even an incompetently
designed 300B such as the Bubbaland 300Bis still a more attractive
(lower odd harmonics) amplifying device than the sliver of silicon ****
this street-seller of crisped porkfat is trying to palm off on you.


Table reads right in Courier 10 pt.

Bob C's "Bubbaland" Andre's "Hedonist"

Grid Plate Grid Plate
Voltage Current (mA) Voltage Current (mA)
0.0 102 0.0 136
-22.3 87 -23.4 119
-76.0 50 -80.0 80
-129.7 18 -136.6 44
-152.0 6 -160.0 30

Load Resistance 5,000 Load Resistance 5,000
Supply Voltage 350 Supply Voltage 390
Plate Dissipation 17.5 Plate Dissipation 31.2
Power Output 5.9 Power Output 7.0
% 2nd Harmonic 4.13 % 2nd Harmonic 2.83
% 3rd Harmonic 0.82 % 3rd Harmonic 0.03

(Table courtesy of John Byrns)

******
Of course, while a silicon amp might be designed to use with
incompently insensitive speakers and will thus *require* all its power,
a tube amp like those above (including the now apparently--by
comparison to the silicon PinkoStinko is trying to flog--not quite so
incompetent Chernofsky/LeFevre noise generator), is created as part of
a chain designed back from highly sensitive speakers (both the above
amps were designed for use with Lowther horns).

Shame that those speakers sound like **** on anything with an extended
frequency range................

Thus the normal mode of
the transistor might be flat out while the 300B will idle on
milliwatts, with vanishing distortion; that is why this class of tube
amp is normally specified at the 1W it will never in normal working
see, and the transistor device at full chat.

Actually, the modern SS amp will happily deliver 500 watts of power at
less than 0.1% THD, and distortion at low levels vanishes well beneath
the (lower than that of a SET) noise floor. Shame that your flea-power
SETs are not capable of driving proper loudspeakers with a genuinely
flat response across the entire audio band.

Please also note that most top-class modern speakers are around
90dB/W/m, a mere 10dB below Jute's beloved Lowthers, so the power
required is only ten times greater. Puts those flea-powered SETs which
are utterly incompetent above 5 watts into perspective....

Especially since the first watt of a decent SS amp is still cleaner
than the first watt of a SET.

Doesn't seem to be anything left to say, does there? (Unless one wants
to gloat, and we'd never do that, would we?)

Well, you couldn't, could you? :-)

Hell, our legislators managed to criminalize fox hunting and smoking; I
wonder when they will get off their collective fat arse and criminalize
negative feedback. It is clearly consumed only by undesirables.

Since you are clearly the most deranged sociopath to stalk the audio
newsgroups since the late unlamented Alan Derrida, you're hardly in a
position to judge such matters.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Wed, 29 Mar 2006 20:27:29 +0200, "Ruud Broens"
wrote:

"Stewart Pinkerton" wrote in message
.. .
: On Wed, 29 Mar 2006 15:32:14 +0200, "Ruud Broens"
: wrote:

: you are also conveniently forgetting that - as is -, you have an input
: impedance of about 5 Ohms ...
:
: See KISASS for the solution. Tubes use lotsa volts, BJTs use lotsa
: milliamps, same thing in the end for the 'black box' solution.

aha, now we're getting somewhere :-)
so if someone now comes up with an SE pentode output stage, so no fb,
that can do 12W out at 7 % THD, 88W dissipation,
you'll agree that even the 2SA1216 can be beaten ?
ok ;-)

That'd be fine, as it would even more convincingly (for a tubie)
demonstrate that triodes (and especially DHTs) just aren't what you
want to use in a genuinely top-quality amplifier. Of course, you still
come back to the basic that in a 'black box' with equal voltage gain,
the BJT will win.

--

Stewart Pinkerton | Music is Art - Audio is Engineering

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"Stewart Pinkerton" wrote in message
...
: On Wed, 29 Mar 2006 20:27:29 +0200, "Ruud Broens"
: wrote:
:
: "Stewart Pinkerton" wrote in message
: .. .
: : On Wed, 29 Mar 2006 15:32:14 +0200, "Ruud Broens"
: : wrote:
:
: : you are also conveniently forgetting that - as is -, you have an input
: : impedance of about 5 Ohms ...
: :
: : See KISASS for the solution. Tubes use lotsa volts, BJTs use lotsa
: : milliamps, same thing in the end for the 'black box' solution.
:
: aha, now we're getting somewhere :-)
: so if someone now comes up with an SE pentode output stage, so no fb,
: that can do 12W out at 7 % THD, 88W dissipation,
: you'll agree that even the 2SA1216 can be beaten ?
: ok ;-)
:
: That'd be fine, as it would even more convincingly (for a tubie)
: demonstrate that triodes (and especially DHTs) just aren't what you
: want to use in a genuinely top-quality amplifier. Of course, you still
: come back to the basic that in a 'black box' with equal voltage gain,
: the BJT will win.
:
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

i think you'll find the combination
[ SS ]- Tube - SS, hybrid in that order
from input to output will deliver the highest
gain/distortion ratio,

which is what we want
no use having 10 times the gain comparing X with Y
when Y has 13 times more distortion,
is there ?

if distortion is your game
clean gain is the name,
:-)
Rudy

Below Pinkerton bull****s to everyone about how to make a simple SS amp.

He did it last year too.

He's repeating the same mistake.

He didn't make or test the amp he tried to foist onto us. Nobody here afaik tried to
build what he suggested;
we wouldn't, since we prefer tubes.

I even said he could use 12dB of NFB because that is how much is in a 300B by my
estimate.
He didn't even check that out of course because he has not the slightest idea how to
establish how much NFB there is in any triode.

But his SS design used a huge total amount of NFB. But he can't cheat while I'm
around.

How come Stewart Oinkerton, the class A pork seller can't build a simple amp?

Nelson Pass beat Oinkerton in this race of course.

Sue Parker also has beaten him.

Patrick Turner.



Stewart Pinkerton wrote:

On Wed, 29 Mar 2006 15:32:14 +0200, "Ruud Broens"
wrote:


"Stewart Pinkerton" wrote in message
.. .
: On Tue, 28 Mar 2006 23:07:46 +0200, "Ruud Broens"
: wrote:
:
:
: : Bjts are so damned non linear with regard to voltage gain that large amount
of
: : NFB, local or otherwises must be applied
: : to linearize the outcome, as well as raise input impedance.
: :
: : Some BJTs are more linear than say a 300B. Why do you keep ignoring
: : this *fact*. Heresy?
: :
: : It isn't ludicous to drag people screaming back to the basics.
: : The basic fact is that bjts WITHOUT ANY NFB, LOCAL OR OTHERWISE applied
: anywhere
: : have hopelessly poor
: : voltage gain linearity.
: :
: : Utter bunk, check the spec sheet for the 2SA1216. Gain linearity is
: : flat as a pancake at elevated junction temperatures, as would be
: : experienced in a Class A amplifier.
:
:
: yep, checking, i found it he
: http://users.otenet.gr/~athsam/database.htm
:
: the third graph shows Vbe - Ic, the _run hot_ curve
: does 0.8 V Vbe @ 6 A, 400 mVtt giving 8 Att with 1.6 % distortion
: certainly impressive. but, now realize the curves are taken at a
: constant Vce=4V - not very realistic, is it ?
:
: now, Hfe about 100, at this 24W class A idle point,
: 60 mA of base current is required. oops, at 10 A, Hfe has
: gone south to only 60, creating an additional few dozens
: of THD %.
:
: 2nd take:
: 0.6Vbe, 2.2 A idle now Hfe stays flat with 200 mVtt in, 4Att out,
: distortion is 7 % or so that's indeed quite an achievement
:
: but considering it's taken at constant Vce
: reality will be worse
:
: : Statements have been made on the group that what i am saying is untrue.
: :
: : That's because it is - see above.
:
: hm, about 12 W / 8 Ohm available, 7 % THD, 8.8 W idle with the 2SA1216
: you're saying there are no tubes that can beat that ?
:
: I read less than that into those curves, but even if true, that's
: better than you'll get with the 300B.
:
: You are of course conveniently forgetting something else, the greatly
: superior gain of the 2SA216. In the KISASS design, Tr2, the equivalent
: of the 300B in KISS, has its emitter and collector loads set for a
: stage gain of 6.25, to make it as similar as possible to the KISS amp.
: This applies more than 20dB of local regeneration, equivalent to the
: internal feedback of the 300B, cutting the distortion to about 0.5%.
: Apples to apples, KISASS totally outperforms KISS.
:
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

not forgetting anything here, just sticking with the topic - again -
being inherent device linearity, not what you can do with fb - remember ?

Yes, but PT already conceded that the 300B has internal feedback, so
he had no problem with local degeneration in KISASS. After all,
putting in a larger emitter resistor doesn't create any of the
supposed horrors of loop feedback. Note also that you already conceded
that it's as good or better than a 300B, without *any* feedback.

it seems you didn't get the impossibility to create 12W out with 8.8 W idle
class A, the '-4V Vce from the graph' * 2.2 A idle.

Sure I got it, but obviously KISASS doesn't use a 4 volt rail.....

to make it work for an 8 Ohm, 12 W output, you'll actually need about
40V supply voltage and a current sink pulling 2.2A, together using 88W
to get that 12W out - 15 % efficiency and a large 1K/W heatsink for
that 2SA1216 and say an LM350.

See KISASS, if you can't remember the basic parameters of KISS.
KISASS runs a 30 volt rail at the voltage amplifier, and is designed
to run 100 mA idle current in the voltage amplifier stage.

To reiterate the design process:

KISASS came about as a suggestion by Iain Churches that I design a SS
equivalent of Andre Jute's (so far mythical) KISS design, supposedly a
single-ended tube amp with 300B output tube, a double-triode
input/driver stage, zero loop feedback, and an output of less than ten
watts. Ignoring a bunch of tube-centric 'rules' spouted by Patrick
Turner, I had a think about how this should be done.

In terms of parts count, we cannot beat the Nelson Pass ZEN design,
which uses a single MOSFET, so we will use BJTs, the 'bete noir' of
the tube fan. In terms of excellent performance from a minimal parts
count, we have the classic 1969 Linsley Hood design, which ticks most
of the boxes but does use global NFB.

Where to go from here? OK, let's start from the simplest possible gain
stage, a common-emitter BJT with emitter and collector loads (Tr2 in
the schematic, the 2SC2922 device is recommended). This will set the
transfer curve, and hence the sonic signature, of the amplifier. Such
a stage does of course have a quite low input impedance, so we place a
simple emitter follower buffer (Tr1, the MJE15028 will do, or any
other decent medium power NPN BJT) ahead of it to allow a wider choice
of source devices. The output impedance (as with the 300B) is much too
high to drive a loudspeaker, so we need an impedance transformer. As
one of the great advances of SS was that it allowed the removal of the
OPT, we will not use iron. A simple pair of emitter followers (Tr3 and
Tr4, for which the 2SC2922 and 2SA1216 will work well, but other
modern complementary pairs may substitute) provide output impedance
reduction without affecting voltage gain, and there we have the design
in a nutshell.

Further philosophical decisions were the avoidance of bootstrapping
from the output to the gain stage (that could be construed as loop
feedback), and the use of a heavily filtered power supply to keep the
noise floor clean. The latter was in the cause of maintaining the
'first watt is the most important' philosophy, without which this
design is utterly pointless. R15 and R16 reduce the rail voltage to
give a maximum output power of less than ten watts into loads between
8 and 4 ohms, meeting one of the principal design parameters, while
R12, R13 and R14 maintain the rail voltage of the gain stage at 5
volts higher than the output rail, allowing better driving of the
output while maintaining the natural transfer function of the gain
stage.

The bias current of the output stage is set to about 1 amp by R6,
while the quiescent output voltage point is set primarily by R1/R2.
This amplifier should be d.c. and thermally stable, but will reward
careful layout, particularly in the utilisation of the 'star earth'
philosophy, i.e. one central ground point to which all 'zero volt'
connections are made. Given this, I'd expect less than 0.1% THD plus
noise right across the audio band at an output of 1 watt into 4-8
ohms, rising to several per cent just below clipping, in the usual
'SET' style. The output impedance will also be in the half-ohm region
over most of the audio band.

In terms of construction, it should be noted that R15 and R16
dissipate 5 watts each, so should be at least ten-watt rated, while R5
dissipates about 3 watts, and should be at least a 5-watt component.
R12, R13 and R14 should be 2-watt rated, the others should be
half-watt metal films. Note that for thermal stability, D1, D2, Tr3
and Tr4 must share the same heatsink.

you are also conveniently forgetting that - as is -, you have an input
impedance of about 5 Ohms ...

See KISASS for the solution. Tubes use lotsa volts, BJTs use lotsa
milliamps, same thing in the end for the 'black box' solution.

more of a win some - loose some scenario, it seems,
Stewart ;-)

Not really, as KISS suffers similar problems. Naturally, one wouldn't
expect a tubie to acknowledge this.

T reiterate
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Patrick Turner wrote:
Below Pinkerton bull****s to everyone about how to make a simple SS amp.

He did it last year too.

He's repeating the same mistake.

He didn't make or test the amp he tried to foist onto us. Nobody here afaik tried to
build what he suggested;
we wouldn't, since we prefer tubes.

I even said he could use 12dB of NFB because that is how much is in a 300B by my
estimate.
He didn't even check that out of course because he has not the slightest idea how to
establish how much NFB there is in any triode.

But his SS design used a huge total amount of NFB. But he can't cheat while I'm
around.

How come Stewart Oinkerton, the class A pork seller can't build a simple amp?

More class G for gross, I think

Nelson Pass beat Oinkerton in this race of course.

Sue Parker also has beaten him.

Patrick Turner

I couldn't care less about "beating" Pinkerton. I thought we were here
to exchange information to everyone's mutual benefit. I don't even see
what Pinkerton posts until someone replies and most of the time I just
skip those posts.

Less time spent on useless clowns leaves more time for building amps.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

Stewart Pinkerton wrote:

On Wed, 29 Mar 2006 15:32:14 +0200, "Ruud Broens"
wrote:


"Stewart Pinkerton" wrote in message
.. .
: On Tue, 28 Mar 2006 23:07:46 +0200, "Ruud Broens"
: wrote:
:
:
: : Bjts are so damned non linear with regard to voltage gain that large amount
of
: : NFB, local or otherwises must be applied
: : to linearize the outcome, as well as raise input impedance.
: :
: : Some BJTs are more linear than say a 300B. Why do you keep ignoring
: : this *fact*. Heresy?
: :
: : It isn't ludicous to drag people screaming back to the basics.
: : The basic fact is that bjts WITHOUT ANY NFB, LOCAL OR OTHERWISE applied
: anywhere
: : have hopelessly poor
: : voltage gain linearity.
: :
: : Utter bunk, check the spec sheet for the 2SA1216. Gain linearity is
: : flat as a pancake at elevated junction temperatures, as would be
: : experienced in a Class A amplifier.
:
:
: yep, checking, i found it he
: http://users.otenet.gr/~athsam/database.htm
:
: the third graph shows Vbe - Ic, the _run hot_ curve
: does 0.8 V Vbe @ 6 A, 400 mVtt giving 8 Att with 1.6 % distortion
: certainly impressive. but, now realize the curves are taken at a
: constant Vce=4V - not very realistic, is it ?
:
: now, Hfe about 100, at this 24W class A idle point,
: 60 mA of base current is required. oops, at 10 A, Hfe has
: gone south to only 60, creating an additional few dozens
: of THD %.
:
: 2nd take:
: 0.6Vbe, 2.2 A idle now Hfe stays flat with 200 mVtt in, 4Att out,
: distortion is 7 % or so that's indeed quite an achievement
:
: but considering it's taken at constant Vce
: reality will be worse
:
: : Statements have been made on the group that what i am saying is untrue.
: :
: : That's because it is - see above.
:
: hm, about 12 W / 8 Ohm available, 7 % THD, 8.8 W idle with the 2SA1216
: you're saying there are no tubes that can beat that ?
:
: I read less than that into those curves, but even if true, that's
: better than you'll get with the 300B.
:
: You are of course conveniently forgetting something else, the greatly
: superior gain of the 2SA216. In the KISASS design, Tr2, the equivalent
: of the 300B in KISS, has its emitter and collector loads set for a
: stage gain of 6.25, to make it as similar as possible to the KISS amp.
: This applies more than 20dB of local regeneration, equivalent to the
: internal feedback of the 300B, cutting the distortion to about 0.5%.
: Apples to apples, KISASS totally outperforms KISS.
:
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

not forgetting anything here, just sticking with the topic - again -
being inherent device linearity, not what you can do with fb - remember ?

Yes, but PT already conceded that the 300B has internal feedback, so
he had no problem with local degeneration in KISASS. After all,
putting in a larger emitter resistor doesn't create any of the
supposed horrors of loop feedback. Note also that you already conceded
that it's as good or better than a 300B, without *any* feedback.

it seems you didn't get the impossibility to create 12W out with 8.8 W idle
class A, the '-4V Vce from the graph' * 2.2 A idle.

Sure I got it, but obviously KISASS doesn't use a 4 volt rail.....

to make it work for an 8 Ohm, 12 W output, you'll actually need about
40V supply voltage and a current sink pulling 2.2A, together using 88W
to get that 12W out - 15 % efficiency and a large 1K/W heatsink for
that 2SA1216 and say an LM350.

See KISASS, if you can't remember the basic parameters of KISS.
KISASS runs a 30 volt rail at the voltage amplifier, and is designed
to run 100 mA idle current in the voltage amplifier stage.

To reiterate the design process:

KISASS came about as a suggestion by Iain Churches that I design a SS
equivalent of Andre Jute's (so far mythical) KISS design, supposedly a
single-ended tube amp with 300B output tube, a double-triode
input/driver stage, zero loop feedback, and an output of less than ten
watts. Ignoring a bunch of tube-centric 'rules' spouted by Patrick
Turner, I had a think about how this should be done.

In terms of parts count, we cannot beat the Nelson Pass ZEN design,
which uses a single MOSFET, so we will use BJTs, the 'bete noir' of
the tube fan. In terms of excellent performance from a minimal parts
count, we have the classic 1969 Linsley Hood design, which ticks most
of the boxes but does use global NFB.

Where to go from here? OK, let's start from the simplest possible gain
stage, a common-emitter BJT with emitter and collector loads (Tr2 in
the schematic, the 2SC2922 device is recommended). This will set the
transfer curve, and hence the sonic signature, of the amplifier. Such
a stage does of course have a quite low input impedance, so we place a
simple emitter follower buffer (Tr1, the MJE15028 will do, or any
other decent medium power NPN BJT) ahead of it to allow a wider choice
of source devices. The output impedance (as with the 300B) is much too
high to drive a loudspeaker, so we need an impedance transformer. As
one of the great advances of SS was that it allowed the removal of the
OPT, we will not use iron. A simple pair of emitter followers (Tr3 and
Tr4, for which the 2SC2922 and 2SA1216 will work well, but other
modern complementary pairs may substitute) provide output impedance
reduction without affecting voltage gain, and there we have the design
in a nutshell.

Further philosophical decisions were the avoidance of bootstrapping
from the output to the gain stage (that could be construed as loop
feedback), and the use of a heavily filtered power supply to keep the
noise floor clean. The latter was in the cause of maintaining the
'first watt is the most important' philosophy, without which this
design is utterly pointless. R15 and R16 reduce the rail voltage to
give a maximum output power of less than ten watts into loads between
8 and 4 ohms, meeting one of the principal design parameters, while
R12, R13 and R14 maintain the rail voltage of the gain stage at 5
volts higher than the output rail, allowing better driving of the
output while maintaining the natural transfer function of the gain
stage.

The bias current of the output stage is set to about 1 amp by R6,
while the quiescent output voltage point is set primarily by R1/R2.
This amplifier should be d.c. and thermally stable, but will reward
careful layout, particularly in the utilisation of the 'star earth'
philosophy, i.e. one central ground point to which all 'zero volt'
connections are made. Given this, I'd expect less than 0.1% THD plus
noise right across the audio band at an output of 1 watt into 4-8
ohms, rising to several per cent just below clipping, in the usual
'SET' style. The output impedance will also be in the half-ohm region
over most of the audio band.

In terms of construction, it should be noted that R15 and R16
dissipate 5 watts each, so should be at least ten-watt rated, while R5
dissipates about 3 watts, and should be at least a 5-watt component.
R12, R13 and R14 should be 2-watt rated, the others should be
half-watt metal films. Note that for thermal stability, D1, D2, Tr3
and Tr4 must share the same heatsink.

you are also conveniently forgetting that - as is -, you have an input
impedance of about 5 Ohms ...

See KISASS for the solution. Tubes use lotsa volts, BJTs use lotsa
milliamps, same thing in the end for the 'black box' solution.

more of a win some - loose some scenario, it seems,
Stewart ;-)

Not really, as KISS suffers similar problems. Naturally, one wouldn't
expect a tubie to acknowledge this.

T reiterate
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Thu, 30 Mar 2006 07:54:30 GMT, Patrick Turner
wrote:

Below Pinkerton bull****s to everyone about how to make a simple SS amp.

He did it last year too.

He's repeating the same mistake.

He didn't make or test the amp he tried to foist onto us.

'Foisted'? I was *invited* to design KISASS, as you well know.

Nobody here afaik tried to
build what he suggested;
we wouldn't, since we prefer tubes.

For no apparent reason..............

I even said he could use 12dB of NFB because that is how much is in a 300B by my
estimate.
He didn't even check that out of course because he has not the slightest idea how to
establish how much NFB there is in any triode.

You'd have to build a pentode, and then remove the other grids to get
an exact equivalence. It can be done quite readily in a high vacuum
lab of course, but I don't know if it's actually been done.

But his SS design used a huge total amount of NFB. But he can't cheat while I'm
around.

Turneroid, KISASS wasn't designed to cope with your tube-centric
'rules', it was designed to be a superior version of KISS, and it
performs that function well.

It uses emitter followers at input and output as impedance
transformers, otherwise the amount of *local* degeneration used is
quite modest. No cheating involved, as there are no 'rules', and I
don't care how round you get on all those tinnies.

How come Stewart Oinkerton, the class A pork seller can't build a simple amp?

I already said that I have no interest in building it.

Nelson Pass beat Oinkerton in this race of course.

As I clearly stated at the outset - but not with a BJT.

--

Stewart Pinkerton | Music is Art - Audio is Engineering

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On 24 Mar 2006 09:18:27 -0800, "Bret Ludwig"
wrote:

The details of transistor amplifiers have changed immensely and the
devices have improved, but the physics are still the same as when John
F. Kennedy was holding up operations at Idlewild while pounding on the
Monroe Doctrine in SAM 26000. Bipolar transistors are still low
impedance, current controlled, current controlling devices.

Yes, and your point is?

--

Stewart Pinkerton | Music is Art - Audio is Engineering

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