| Author |
Message |
Andre Jute
Guest
|
 Posted:
Wed Dec 08, 2004 6:13 am Post subject:
Once more into the breach, dear friends |
|
|
On Tue, 7 Dec 2004 18:28:07 +0200, "Iain M Churches"
<tael@kolumbus.fi> wrote in message cp4ln0$4kb$1@phys-news1.kolumbus.fi to Pinkerton:
| Quote: | We must be careful here to compare apples with apples,
so your brief should be to design an amplifier
with a similar power output to Andre's SE valve amp, with a similar
amount of feedback (if any).
No more. No less. For a man of your capabilility, it should present
no problems:-)
Iain
|
Iain:
I already stepped into the breach and published a most KISS
experimenter's silicon amp that can be made to sound more or less like
tubes as KISS 191A and 191B.
If Pinkerton has now decided to meet his promise to publish a silicon
design along the lines of my KISS 300B, the main parameters he should
match are single-ended output, 3W, all of it in Class A1, zero
negative feedback.
Slainte!
Andre Jute
On Tue, 7 Dec 2004 18:28:07 +0200, "Iain M Churches"
<tael@kolumbus.fi> wrote:
| Quote: |
"Stewart Pinkerton" <patent3@dircon.co.uk> wrote in message
news:c7m5r0pc2birunlp192stu142i3quauq1q@4ax.com...
On 4 Dec 2004 21:09:04 -0800, frankbte@yahoo.com (Frank B) wrote:
I too thought we were waiting for Pinkerton to deliver a transistor
amplifier. But now it appears we were wasting our time.
No one seems to be clear whether this is supposed to be a tranny
equivalent of Andre's design, an 'ultra-fidelity' SE SS amp, or an
amp
designed specifically to mimic the sound of a SE 300B design.
My own inclination would be to make it all BJT, with a CCS in the
supply rail and a CF input buffer, and employing a custom-wound
OPT.
That's about as KISS as it gets, IMHO.
Whichever, I have yet to dust down my slide rule on such a venture,
since it would for me be only a bit of fun, not any saerious
attempt
to produce a truly 'ultra-fidelity' amplifier, which requires
solid-state *and* push-pull for success.
--
Stewart Pinkerton | Music is Art - Audio is Engineering
Hello Stewart,
It was my suggestion that you could run a parallel thread to
Andre's excellent KISS amp thread, and take us through
the design of a low power SS amplifier, so that those of us
who are interested could build both and compare them.
This too will lead to an interesting new thread.
We must be careful here to compare apples with apples,
so your brief should be to design an amplifier
with a similar power output to Andre's SE valve amp, with a similar
amount of feedback (if any).
No more. No less. For a man of your capabilility, it should present
no problems:-)
Iain |
|
|
| Back to top |
|
 |
John Byrns
Guest
|
| Posted:
Wed Dec 08, 2004 6:13 am Post subject:
Re: Once more into the breach, dear friends |
|
|
In article <b2a8c01c.0412071826.3e1ace1d@posting.google.com>,
fiultra@yahoo.com (Andre Jute) wrote:
| Quote: | I already stepped into the breach and published a most KISS
experimenter's silicon amp that can be made to sound more or less like
tubes as KISS 191A and 191B.
|
An op amp is hardly a simple device, a more interesting project would be
to build an amp with a small number of transistors, perhaps as few as two.
| Quote: | If Pinkerton has now decided to meet his promise to publish a silicon
design along the lines of my KISS 300B, the main parameters he should
match are single-ended output, 3W, all of it in Class A1, zero
negative feedback.
|
I'm not sure why all these restrictions are necessary, why not just say
the amp can only use two transistors, just as the KISS amp uses only two
tubes, and let it go at that. Why disallow negative feedback if someone
wants to use it, after all the triodes in the KISS amp have built in
negative feedback and you are using them in the KISS amp, maybe you should
used pentodes in the KISS amp to avoid the inherent negative feedback of
triodes.
Regards,
John Byrns
Surf my web pages at, http://users.rcn.com/jbyrns/ |
|
| Back to top |
|
|
Stewart Pinkerton
Guest
|
| Posted:
Wed Dec 08, 2004 7:22 am Post subject:
Re: Once more into the breach, dear friends |
|
|
On Tue, 07 Dec 2004 22:37:52 -0600, jbyrns@rcn.com (John Byrns) wrote:
| Quote: | In article <b2a8c01c.0412071826.3e1ace1d@posting.google.com>,
fiultra@yahoo.com (Andre Jute) wrote:
I already stepped into the breach and published a most KISS
experimenter's silicon amp that can be made to sound more or less like
tubes as KISS 191A and 191B.
An op amp is hardly a simple device, a more interesting project would be
to build an amp with a small number of transistors, perhaps as few as two.
If Pinkerton has now decided to meet his promise to publish a silicon
design along the lines of my KISS 300B, the main parameters he should
match are single-ended output, 3W, all of it in Class A1, zero
negative feedback.
|
No such promise was made, and I am targeting an output voltage around
50% higher than this. Were Andre better fitted to the task, he'd be
aware that BJTs always draw 'grid' current, so the traditional
tube-based sub-divisions of Class A are meaningless, and that all
single-ended audio amplifiers operate in Class A at times, otherwise
they are clipping.
| Quote: | I'm not sure why all these restrictions are necessary, why not just say
the amp can only use two transistors, just as the KISS amp uses only two
tubes, and let it go at that. Why disallow negative feedback if someone
wants to use it, after all the triodes in the KISS amp have built in
negative feedback and you are using them in the KISS amp, maybe you should
used pentodes in the KISS amp to avoid the inherent negative feedback of
triodes.
|
Rest assured that I shall pay no attention to the mendacious
outpourings of that egomaniacal and acoustically ignorant old redneck.
Jute is a most appropriate name for such a sad sack............
Looks like the favourite signal path so far is an emitter follower
input impedance buffer, followed by a darlington or Sziklai pair main
stage. The design targets remain as 12 watts into 4 ohms, with less
than 1% THD from 20Hz to 20kHz at 75% of full output, no global NFB.
--
Stewart Pinkerton | Music is Art - Audio is Engineering |
|
| Back to top |
|
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Patrick Turner
Guest
|
| Posted:
Wed Dec 08, 2004 2:12 pm Post subject:
Re: Once more into the breach, dear friends |
|
|
Andre Jute wrote:
| Quote: | On Tue, 7 Dec 2004 18:28:07 +0200, "Iain M Churches"
tael@kolumbus.fi> wrote in message cp4ln0$4kb$1@phys-news1.kolumbus.fi to Pinkerton:
We must be careful here to compare apples with apples,
so your brief should be to design an amplifier
with a similar power output to Andre's SE valve amp, with a similar
amount of feedback (if any).
No more. No less. For a man of your capabilility, it should present
no problems:-)
Iain
Iain:
I already stepped into the breach and published a most KISS
experimenter's silicon amp that can be made to sound more or less like
tubes as KISS 191A and 191B.
If Pinkerton has now decided to meet his promise to publish a silicon
design along the lines of my KISS 300B, the main parameters he should
match are single-ended output, 3W, all of it in Class A1, zero
negative feedback.
Slainte!
Andre Jute
|
Well I think he has a problem because he will have to use NFB.
And then he has the input resistance problem with bjts.
But 300B has some "self regulation ", as Child mentions in his address in Terman's 1937
Radio Enginering book, where he describes the triode's electrostatic interaction,
later called negative feedback by others.
Question is, what would be the Ra, u and gM of the 300B if there was no
internal NFB?
Clue, it'd be like some sort of pentode.
What is the quantity of NFB electrostatically applied in dB?
Clue, depends on the gain and load...
If such a figure could be reliably established, then pinky
should be permitted to have at least the same amount of loop
series voltage NFB in his SS amp as the 300B has in its electrostatic gain structure.
This electrostatic field effect gain structure and feedback path
was made possible because the God Of Triodes had invented some Laws of Nature
that came in handy when triodes were devised by mankind.
I think a God managed to do NFB a bit simpler than a man could.
Patrick Turner.
| Quote: |
On Tue, 7 Dec 2004 18:28:07 +0200, "Iain M Churches"
tael@kolumbus.fi> wrote:
"Stewart Pinkerton" <patent3@dircon.co.uk> wrote in message
news:c7m5r0pc2birunlp192stu142i3quauq1q@4ax.com...
On 4 Dec 2004 21:09:04 -0800, frankbte@yahoo.com (Frank B) wrote:
I too thought we were waiting for Pinkerton to deliver a transistor
amplifier. But now it appears we were wasting our time.
No one seems to be clear whether this is supposed to be a tranny
equivalent of Andre's design, an 'ultra-fidelity' SE SS amp, or an
amp
designed specifically to mimic the sound of a SE 300B design.
My own inclination would be to make it all BJT, with a CCS in the
supply rail and a CF input buffer, and employing a custom-wound
OPT.
That's about as KISS as it gets, IMHO.
Whichever, I have yet to dust down my slide rule on such a venture,
since it would for me be only a bit of fun, not any saerious
attempt
to produce a truly 'ultra-fidelity' amplifier, which requires
solid-state *and* push-pull for success.
--
Stewart Pinkerton | Music is Art - Audio is Engineering
Hello Stewart,
It was my suggestion that you could run a parallel thread to
Andre's excellent KISS amp thread, and take us through
the design of a low power SS amplifier, so that those of us
who are interested could build both and compare them.
This too will lead to an interesting new thread.
We must be careful here to compare apples with apples,
so your brief should be to design an amplifier
with a similar power output to Andre's SE valve amp, with a similar
amount of feedback (if any).
No more. No less. For a man of your capabilility, it should present
no problems:-)
Iain |
|
|
| Back to top |
|
|
John Byrns
Guest
|
| Posted:
Wed Dec 08, 2004 10:13 pm Post subject:
Re: Once more into the breach, dear friends |
|
|
In article <jhadr05i1p3826q7ood9b89in59u8rs8h1@4ax.com>, Stewart Pinkerton
<patent3@dircon.co.uk> wrote:
| Quote: | On Tue, 07 Dec 2004 22:37:52 -0600, jbyrns@rcn.com (John Byrns) wrote:
In article <b2a8c01c.0412071826.3e1ace1d@posting.google.com>,
fiultra@yahoo.com (Andre Jute) wrote:
I already stepped into the breach and published a most KISS
experimenter's silicon amp that can be made to sound more or less like
tubes as KISS 191A and 191B.
An op amp is hardly a simple device, a more interesting project would be
to build an amp with a small number of transistors, perhaps as few as two.
If Pinkerton has now decided to meet his promise to publish a silicon
design along the lines of my KISS 300B, the main parameters he should
match are single-ended output, 3W, all of it in Class A1, zero
negative feedback.
No such promise was made, and I am targeting an output voltage around
50% higher than this. Were Andre better fitted to the task, he'd be
aware that BJTs always draw 'grid' current, so the traditional
tube-based sub-divisions of Class A are meaningless, and that all
single-ended audio amplifiers operate in Class A at times, otherwise
they are clipping.
I'm not sure why all these restrictions are necessary, why not just say
the amp can only use two transistors, just as the KISS amp uses only two
tubes, and let it go at that. Why disallow negative feedback if someone
wants to use it, after all the triodes in the KISS amp have built in
negative feedback and you are using them in the KISS amp, maybe you should
used pentodes in the KISS amp to avoid the inherent negative feedback of
triodes.
Rest assured that I shall pay no attention to the mendacious
outpourings of that egomaniacal and acoustically ignorant old redneck.
Jute is a most appropriate name for such a sad sack............
Looks like the favourite signal path so far is an emitter follower
input impedance buffer, followed by a darlington or Sziklai pair main
stage. The design targets remain as 12 watts into 4 ohms, with less
than 1% THD from 20Hz to 20kHz at 75% of full output, no global NFB.
|
When can we expect to see a rough schematic of this concoction, or have a
fuller description, there are a couple of interesting design issues that
need to be addressed. I notice that you carefully say "no global NFB"
leaving the door open for local "NFB". Will your design make use of local
"NFB" other than in the "emitter follower input impedance buffer". I
wonder when local "NFB" becomes "global NFB", for example is "NFB" around
a Darlington pair local or global "NFB".
Regards,
John Byrns
Surf my web pages at, http://users.rcn.com/jbyrns/ |
|
| Back to top |
|
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Sander deWaal
Guest
|
| Posted:
Wed Dec 08, 2004 10:13 pm Post subject:
Re: Once more into the breach, dear friends |
|
|
jbyrns@rcn.com (John Byrns) said:
| Quote: | When can we expect to see a rough schematic of this concoction, or have a
fuller description, there are a couple of interesting design issues that
need to be addressed.
|
Hey, give the man a break! I'm pretty sure he'll keep us updated on
the progress.
| Quote: | I notice that you carefully say "no global NFB"
leaving the door open for local "NFB". Will your design make use of local
"NFB" other than in the "emitter follower input impedance buffer". I
wonder when local "NFB" becomes "global NFB", for example is "NFB" around
a Darlington pair local or global "NFB".
|
Loop or global feedback is considered to work around an amplifying
device as a whole. From output to input out of phase.
Local feedback is considered ....well....local, like a cathode or
emitter resistor. Even when it is a Darlington.
Even feedback from the plate of a power tube to the preceding driver
tube is considered local.
Another form of local feedback is inside a triode, an UL connection of
the power stage or CFB windings like Quad II and McIntosh had.
--
Sander de Waal
" SOA of a KT88? Sufficient. " |
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| Back to top |
|
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Stewart Pinkerton
Guest
|
| Posted:
Thu Dec 09, 2004 12:58 am Post subject:
Re: Once more into the breach, dear friends |
|
|
On Wed, 08 Dec 2004 14:13:39 -0600, jbyrns@rcn.com (John Byrns) wrote:
| Quote: | In article <jhadr05i1p3826q7ood9b89in59u8rs8h1@4ax.com>, Stewart Pinkerton
patent3@dircon.co.uk> wrote:
On Tue, 07 Dec 2004 22:37:52 -0600, jbyrns@rcn.com (John Byrns) wrote:
In article <b2a8c01c.0412071826.3e1ace1d@posting.google.com>,
fiultra@yahoo.com (Andre Jute) wrote:
I already stepped into the breach and published a most KISS
experimenter's silicon amp that can be made to sound more or less like
tubes as KISS 191A and 191B.
An op amp is hardly a simple device, a more interesting project would be
to build an amp with a small number of transistors, perhaps as few as two.
If Pinkerton has now decided to meet his promise to publish a silicon
design along the lines of my KISS 300B, the main parameters he should
match are single-ended output, 3W, all of it in Class A1, zero
negative feedback.
No such promise was made, and I am targeting an output voltage around
50% higher than this. Were Andre better fitted to the task, he'd be
aware that BJTs always draw 'grid' current, so the traditional
tube-based sub-divisions of Class A are meaningless, and that all
single-ended audio amplifiers operate in Class A at times, otherwise
they are clipping.
I'm not sure why all these restrictions are necessary, why not just say
the amp can only use two transistors, just as the KISS amp uses only two
tubes, and let it go at that. Why disallow negative feedback if someone
wants to use it, after all the triodes in the KISS amp have built in
negative feedback and you are using them in the KISS amp, maybe you should
used pentodes in the KISS amp to avoid the inherent negative feedback of
triodes.
Rest assured that I shall pay no attention to the mendacious
outpourings of that egomaniacal and acoustically ignorant old redneck.
Jute is a most appropriate name for such a sad sack............
Looks like the favourite signal path so far is an emitter follower
input impedance buffer, followed by a darlington or Sziklai pair main
stage. The design targets remain as 12 watts into 4 ohms, with less
than 1% THD from 20Hz to 20kHz at 75% of full output, no global NFB.
When can we expect to see a rough schematic of this concoction, or have a
fuller description, there are a couple of interesting design issues that
need to be addressed.
|
Dunno, still finkin' wiv me 'ead, guv.
Remember, Andre has been working on his design for many months (if not
years), so I'm not dashing into print with something half-baked which
will immediately be shredded by the 'local heroes'............
| Quote: | I notice that you carefully say "no global NFB"
leaving the door open for local "NFB". Will your design make use of local
"NFB" other than in the "emitter follower input impedance buffer".
|
Of course it will make use of local degeneration, such as is found
inside every triode. Indeed, Patrick seems to favour the use of an
emitter follower *output* stage, which I had taken to be a severe
no-no to the 'valvies', who seem to have something against CFs as a
matter of principle. I must admit that I don't understand that one.
| Quote: | wonder when local "NFB" becomes "global NFB", for example is "NFB" around
a Darlington pair local or global "NFB".
|
Good question, as this (and the question of whether a darlington or
Sziklai pair is counted as one or two stages) does rather affect how
the 'valvies' will react to the design as a reasonable equivalent to
Andres SET effort. I mean. it's not like I'm trying to produce an
optimum 'no holds barred' low-cost highly linear amplifier here...
Personally, and in terms of what should really matter, i.e. system
stability and loop response times, I feel that any form of local
degeneration is by definition harmless. Others may disagree.
--
Stewart Pinkerton | Music is Art - Audio is Engineering |
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| Back to top |
|
|
mick
Guest
|
| Posted:
Thu Dec 09, 2004 2:18 pm Post subject:
Re: Once more into the breach, dear friends |
|
|
On Thu, 09 Dec 2004 00:58:48 +0000, Stewart Pinkerton wrote:
<snip>
| Quote: |
Personally, and in terms of what should really matter, i.e. system
stability and loop response times, I feel that any form of local
degeneration is by definition harmless. Others may disagree.
|
Sounds fair enough to me. You *can't* build a 300B clone using
semiconductors. They work differently at a fundamental level. It doesn't,
therefore, seem fair that the ss amp should be restricted by having to
avoid techniques that are normal in a valve amp. Personally, I wouldn't
argue with the normal ss amp technique of using a lot of gain to allow a
lot of nfb if that's what you wanted to do. It would be expected to be
part of ss amp design. I'm pretty sure that some others wouldn't share
this view though - mind you, I use a mix of valve & ss amps so I'm not too
biased! :-)
--
Mick
(no M$ software on here... :-) )
Web: http://www.nascom.info
Web: http://projectedsound.tk |
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| Back to top |
|
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Patrick Turner
Guest
|
| Posted:
Thu Dec 09, 2004 7:44 pm Post subject:
Re: Once more into the breach, dear friends |
|
|
John Byrns wrote:
| Quote: | In article <jhadr05i1p3826q7ood9b89in59u8rs8h1@4ax.com>, Stewart Pinkerton
patent3@dircon.co.uk> wrote:
On Tue, 07 Dec 2004 22:37:52 -0600, jbyrns@rcn.com (John Byrns) wrote:
In article <b2a8c01c.0412071826.3e1ace1d@posting.google.com>,
fiultra@yahoo.com (Andre Jute) wrote:
I already stepped into the breach and published a most KISS
experimenter's silicon amp that can be made to sound more or less like
tubes as KISS 191A and 191B.
An op amp is hardly a simple device, a more interesting project would be
to build an amp with a small number of transistors, perhaps as few as two.
If Pinkerton has now decided to meet his promise to publish a silicon
design along the lines of my KISS 300B, the main parameters he should
match are single-ended output, 3W, all of it in Class A1, zero
negative feedback.
No such promise was made, and I am targeting an output voltage around
50% higher than this. Were Andre better fitted to the task, he'd be
aware that BJTs always draw 'grid' current, so the traditional
tube-based sub-divisions of Class A are meaningless, and that all
single-ended audio amplifiers operate in Class A at times, otherwise
they are clipping.
I'm not sure why all these restrictions are necessary, why not just say
the amp can only use two transistors, just as the KISS amp uses only two
tubes, and let it go at that. Why disallow negative feedback if someone
wants to use it, after all the triodes in the KISS amp have built in
negative feedback and you are using them in the KISS amp, maybe you should
used pentodes in the KISS amp to avoid the inherent negative feedback of
triodes.
Rest assured that I shall pay no attention to the mendacious
outpourings of that egomaniacal and acoustically ignorant old redneck.
Jute is a most appropriate name for such a sad sack............
Looks like the favourite signal path so far is an emitter follower
input impedance buffer, followed by a darlington or Sziklai pair main
stage. The design targets remain as 12 watts into 4 ohms, with less
than 1% THD from 20Hz to 20kHz at 75% of full output, no global NFB.
When can we expect to see a rough schematic of this concoction, or have a
fuller description, there are a couple of interesting design issues that
need to be addressed. I notice that you carefully say "no global NFB"
leaving the door open for local "NFB". Will your design make use of local
"NFB" other than in the "emitter follower input impedance buffer". I
wonder when local "NFB" becomes "global NFB", for example is "NFB" around
a Darlington pair local or global "NFB".
|
If you have an emitter follower darlington pair, you have two lots of
cascaded NFB, one lot in the first emitter follower driving the base
of the output bjt then another lot in the output bjt, perhaps 100 dB in all.
Then you still have to linearize the driver amp, so one would have to use
a lot of current NFB at least, and total NFB for a
gain bjt driving a DP EF output is a shirtload more than any 300B amp.
Having all the devices used in common collector, and having just one loop
of NFB results in the least total amount of NFB for the greatest
amount of thd and Ro reduction and probably also with the largest
increase in Rin of the amp, also an overlooked product of using
normal global series voltage NFB.
Patrick Turner.
|
|
| Back to top |
|
|
Patrick Turner
Guest
|
| Posted:
Thu Dec 09, 2004 8:00 pm Post subject:
Re: Once more into the breach, dear friends |
|
|
Stewart Pinkerton wrote:
| Quote: | On Wed, 08 Dec 2004 14:13:39 -0600, jbyrns@rcn.com (John Byrns) wrote:
In article <jhadr05i1p3826q7ood9b89in59u8rs8h1@4ax.com>, Stewart Pinkerton
patent3@dircon.co.uk> wrote:
On Tue, 07 Dec 2004 22:37:52 -0600, jbyrns@rcn.com (John Byrns) wrote:
In article <b2a8c01c.0412071826.3e1ace1d@posting.google.com>,
fiultra@yahoo.com (Andre Jute) wrote:
I already stepped into the breach and published a most KISS
experimenter's silicon amp that can be made to sound more or less like
tubes as KISS 191A and 191B.
An op amp is hardly a simple device, a more interesting project would be
to build an amp with a small number of transistors, perhaps as few as two.
If Pinkerton has now decided to meet his promise to publish a silicon
design along the lines of my KISS 300B, the main parameters he should
match are single-ended output, 3W, all of it in Class A1, zero
negative feedback.
No such promise was made, and I am targeting an output voltage around
50% higher than this. Were Andre better fitted to the task, he'd be
aware that BJTs always draw 'grid' current, so the traditional
tube-based sub-divisions of Class A are meaningless, and that all
single-ended audio amplifiers operate in Class A at times, otherwise
they are clipping.
I'm not sure why all these restrictions are necessary, why not just say
the amp can only use two transistors, just as the KISS amp uses only two
tubes, and let it go at that. Why disallow negative feedback if someone
wants to use it, after all the triodes in the KISS amp have built in
negative feedback and you are using them in the KISS amp, maybe you should
used pentodes in the KISS amp to avoid the inherent negative feedback of
triodes.
Rest assured that I shall pay no attention to the mendacious
outpourings of that egomaniacal and acoustically ignorant old redneck.
Jute is a most appropriate name for such a sad sack............
Looks like the favourite signal path so far is an emitter follower
input impedance buffer, followed by a darlington or Sziklai pair main
stage. The design targets remain as 12 watts into 4 ohms, with less
than 1% THD from 20Hz to 20kHz at 75% of full output, no global NFB.
When can we expect to see a rough schematic of this concoction, or have a
fuller description, there are a couple of interesting design issues that
need to be addressed.
Dunno, still finkin' wiv me 'ead, guv.
Remember, Andre has been working on his design for many months (if not
years), so I'm not dashing into print with something half-baked which
will immediately be shredded by the 'local heroes'............
I notice that you carefully say "no global NFB"
leaving the door open for local "NFB". Will your design make use of local
"NFB" other than in the "emitter follower input impedance buffer".
Of course it will make use of local degeneration, such as is found
inside every triode. Indeed, Patrick seems to favour the use of an
emitter follower *output* stage, which I had taken to be a severe
no-no to the 'valvies', who seem to have something against CFs as a
matter of principle. I must admit that I don't understand that one.
|
Whoa there, I said you *must not have EF output stage*
and went on to say just how much NFB that topology entails,
and it would be grossly unfair to allow your SS contraption to have
a squillion more dB of NFB than the 300B amp has, which is zero,
not including the Db of NFB inside the the tube.
I then have gone on to say that the amount of NFB you are permitted to use
must be no more than the amount already within a 300B.
Nobody has answered question, how much NF is there in a 300B?
| Quote: |
wonder when local "NFB" becomes "global NFB", for example is "NFB" around
a Darlington pair local or global "NFB".
Good question, as this (and the question of whether a darlington or
Sziklai pair is counted as one or two stages) does rather affect how
the 'valvies' will react to the design as a reasonable equivalent to
Andres SET effort. I mean. it's not like I'm trying to produce an
optimum 'no holds barred' low-cost highly linear amplifier here...
Personally, and in terms of what should really matter, i.e. system
stability and loop response times, I feel that any form of local
degeneration is by definition harmless. Others may disagree.
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"Degeneration", or emitter follower connection, is, in the case of a class A bjt,
a shiteload of normal series voltage NFB.
The idea for the KISS amp, even in SS form, is to use
almost no FB at all, just enough to get a DF of 4 with a 4 ohm load,
which the 300B amp achieves with no global of local loops.
I wish you well in your quest to train bananas to behave like carrots and be just
as nourishing,
but some how I doubt simplicity will ever be a part of it.
Patrick Turner.
| Quote: |
--
Stewart Pinkerton | Music is Art - Audio is Engineering |
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Iain M Churches
Guest
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| Posted:
Fri Dec 10, 2004 2:10 pm Post subject:
Re: Once more into the breach, dear friends |
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"Andre Jute" <fiultra@yahoo.com> wrote in message
news:b2a8c01c.0412071826.3e1ace1d@posting.google.com...
| Quote: | I already stepped into the breach and published a most KISS
experimenter's silicon amp that can be made to sound more or less like
tubes as KISS 191A and 191B.
If Pinkerton has now decided to meet his promise to publish a silicon
design along the lines of my KISS 300B, the main parameters he should
match are single-ended output, 3W, all of it in Class A1, zero
negative feedback.
Slainte!
Andre Jute
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Good! That sets the ground rules then!
We look forward, soldering irons at the ready, to
Stewart's design.
Kunniottaen
Iain |
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