On Sat, 12 Mar 2005 02:38:09 GMT, Chris Hornbeck
wrote:

On Thu, 10 Mar 2005 18:14:43 +0000 (UTC), Stewart Pinkerton
wrote:

Not surprisingly, on www.imageshack.us

I'm way too dumb to be able to work this site. But I'd like
to see the proposed topology.

I also posted it in this thread, as a .jpeg.

Please, everyone, never post binaries to a text newsgroup.
It's a violation of the charter, and terribly rude. Also,
many ISP's will strip anyway. Thanks,

If the .jpg is a reasonable size, would you consider emailing
it to interested folks? If so, include me in.

It's on alt.binaries.schematics.electronic, under KISASS.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 11 Mar 2005 23:01:36 +0100, Sander deWaal
wrote:

Stewart Pinkerton said:

**** off, clown, imageshack was Sander's suggestion.

Yup, after placing the files on Imageshack, it's considered good
practice to post the clickable URL (at the bottom of the page) on the
newsgroup in order for people to actually see them ;-)

Indeed, although it's now on alt.binaries.schematics.electronic under
KISASS.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Chris Hornbeck" wrote in message
...
If the .jpg is a reasonable size, would you consider emailing
it to interested folks? If so, include me in.

Thanks,

Chris Hornbeck


Put me on the e-mail list too please.
Also a set of test results would be of interest.

Cordially,
Iain

On Sat, 12 Mar 2005 08:42:34 +0000 (UTC), Stewart Pinkerton
wrote:

It's on alt.binaries.schematics.electronic, under KISASS.

Great, got it. Looks fine. The lack of long loop feedback
seems promising.

Chris Hornbeck

On Sat, 12 Mar 2005 12:55:26 +0200, "Iain M Churches"
wrote:

"Chris Hornbeck" wrote in message
.. .
If the .jpg is a reasonable size, would you consider emailing
it to interested folks? If so, include me in.

Thanks,

Chris Hornbeck

Put me on the e-mail list too please.
Also a set of test results would be of interest.

It's on alt.binaries.schematics.electronics. And it's only a paper
design, so no test results. It's a simple design though, so predicting
performance isn't too hard, given a decent physical layout.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

John Byrns wrote:

In article , Stewart Pinkerton
wrote:

On Wed, 09 Mar 2005 11:40:00 -0600, (John Byrns) wrote:

As Easter approaches I am reminded that back in mid December Stewart
Pinkerton said with respect to his "KISASS" solid state amp, designed to
compete with Andre's "KISS 123" 300B tube amp, that "It's also the case
that the final design is unlikely to be posted before Easter, since this
is not a trivial exercise".

I wonder if Stewart has any progress to report, and what the target date
for a complete report on his "KISASS" design might now be, or if perhaps
he has found that a design within the guidelines is beyond his
capabilities, and he is hoping that we will all forget about his boast?

I don't boast, nor do I use inappropriate technologies.

At Sander's suggestion, I posted this design on imageshack.us weeks
ago. Here it is again. BTW, it is *not* intended as any kind of
competition, simply a SS alternative following the same 'minimalist'
design principles of having predominantly SE nonlinearity, minimal
parts count, Class A operation, less than ten watts output, and no
global NFB. If you want an optimum simple SS design of similar output
power, then the original Linsley Hood design is it. Now that *was* a
compettitive design, designed specifically to compete with the
legendary Williamson valve amp.

I'll be happy to discuss the particularities of the design once
everyone's had a look at the circuit.

Interesting, it's not quite what I expected from you though. It looks
like you got a good buy on power supply capacitors! The emitter followers
were always OK with me, and I expected that you would use a push pull
output stage, but I didn't think it would be quite so overt. I accept
your PP output stage as being within the spirit of the competition though,
since the rest of the design is so funky, and you kept the transistor
count within reason. I have to wonder how stable the voltage at the
output node connected to C4 is, with variations temperature and in
transistor beta? Do the values of R2 & R3 have to be adjusted to suit the
actual transistors used? What load impedance is it designed to drive, and
what is the power output and distortion into that load? It would be nice
to know a few of the basic operating parameters such as the voltage at the
collector of Tr3 as well as the static current through Tr2 and Tr3/4.

Designs similar to this were quite popular back in the 1960's, except that
they were usually biased for class AB operation, didn't use so many
capacitors in the power supply, and included an over all negative feedback
loop, which also helped to stabilize the operating point. In fact I have
a stereo version of one down in the basement that I built 38 years ago, I
will have to dust it off and give it a listen. I even made the power
transformer by rewinding the secondary of an existing transformer to give
the voltage I wanted.

I stuck with a true single ended output stage in all the versions of my
KISSASS amplifier, and didn't use any emitter followers, but I did use an
over all negative feedback loop in all three versions, which I felt was
necessary to stabilize the operating point. None of the first three
versions were quite what I wanted, I may have to try another.

Regards,

John Byrns

Surf my web pages at, http://users.rcn.com/jbyrns/

I continue to have the worst possible access to ABSE from my ISP.

Could somebody email me a copy of the Kissass.jpg amplifier?



Patrick Turner.

On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner
wrote:

Could somebody email me a copy of the Kissass.jpg amplifier?

I've reduced it to 800x600 and sent it to you.

Chris Hornbeck

Chris Hornbeck wrote:

On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner
wrote:

Could somebody email me a copy of the Kissass.jpg amplifier?

I've reduced it to 800x600 and sent it to you.

Chris Hornbeck

Many thanks,

Patrick Turner.

"Patrick Turner" wrote in message
...


Chris Hornbeck wrote:

On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner
wrote:

Could somebody email me a copy of the Kissass.jpg amplifier?

I've reduced it to 800x600 and sent it to you.

Chris Hornbeck

Many thanks,

Patrick Turner.

I have not been able to get it either.
Would some kind soul please e-mail it to me.
I asked SP to do so, but without response.

Iain

Iain M Churches wrote:

"Patrick Turner" wrote in message
...


Chris Hornbeck wrote:

On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner
wrote:

Could somebody email me a copy of the Kissass.jpg amplifier?

I've reduced it to 800x600 and sent it to you.

Chris Hornbeck

Many thanks,

Patrick Turner.

I have not been able to get it either.
Would some kind soul please e-mail it to me.
I asked SP to do so, but without response.

Iain

I just sent you a copy.

Patrick Turner.

On Sun, 13 Mar 2005 14:20:13 +0200, "Iain M Churches"
wrote:


"Patrick Turner" wrote in message
...


Chris Hornbeck wrote:

On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner
wrote:

Could somebody email me a copy of the Kissass.jpg amplifier?

I've reduced it to 800x600 and sent it to you.

Chris Hornbeck

Many thanks,

Patrick Turner.

I have not been able to get it either.
Would some kind soul please e-mail it to me.
I asked SP to do so, but without response.

I already told you that it's on alt.binaries.schematics.electronic,
under KISASS.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton wrote:

On Sun, 13 Mar 2005 14:20:13 +0200, "Iain M Churches"
wrote:


"Patrick Turner" wrote in message
...


Chris Hornbeck wrote:

On Sun, 13 Mar 2005 03:59:45 +1100, Patrick Turner
wrote:

Could somebody email me a copy of the Kissass.jpg amplifier?

I've reduced it to 800x600 and sent it to you.

Chris Hornbeck

Many thanks,

Patrick Turner.

I have not been able to get it either.
Would some kind soul please e-mail it to me.
I asked SP to do so, but without response.

I already told you that it's on alt.binaries.schematics.electronic,
under KISASS.

Pinky, many folks have very poor service from ISPs that
don't seem able to give reliable access to weird wacko
spurious old fart news groups like ABSE.
Or if ABSE is accessable, often its a week behind, or the binary
posts are never posted, and only the text posts are there,
or people outside a country cannot have what they post seen.

The system is simply not ****kin working.


I have nothing but trouble with ISPs over the last 12 mths
for decent binaries delivery from ABSE.

Same goes for alt.binaries.pictures.radio,
where schematics can also be posted.

Three ISPs so far swore they'd be able to give me reliable free access
to news groups,
but not one has succeeded.


Meanwhile access to alt.binaries.pictures.erotica.blondes
NEVER is interrupted; its always OK, because about 1/3 of all net
traffic is to that one site.

So we are back to the grape vine, where distribution of schematics is
via
generosity and co-operation between individuals.

If you had a website, things like that can be posted there.

I may include a section at my website for such ideas and some of the
pertinent discussion comments
if i ever find the time to fiddle with my website to upgrade it since
its long overdue.


Patrick Turner.




--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Stewart Pinkerton" wrote in message
...

It's on alt.binaries.schematics.electronics. And it's only a paper
design, so no test results. It's a simple design though, so predicting
performance isn't too hard, given a decent physical layout.

I was interested to build your design for audible comparison
with Andre's 300B. So this morning I took your drawing to
the broadcast lab for their comments.

The chief engineer looked at the schematic and said
" It is normal practice to stipulate the devices used in
any circuit"

He then looked at the caps as marked and said "We have no
4.7milliFarad electrolytic capacitors, and tossed the drawing
into the bin.

Ho hum:-)

Iain

On Mon, 14 Mar 2005 12:46:49 +0200, "Iain M Churches"
wrote:


"Stewart Pinkerton" wrote in message
.. .

It's on alt.binaries.schematics.electronics. And it's only a paper
design, so no test results. It's a simple design though, so predicting
performance isn't too hard, given a decent physical layout.

I was interested to build your design for audible comparison
with Andre's 300B. So this morning I took your drawing to
the broadcast lab for their comments.

The chief engineer looked at the schematic and said
" It is normal practice to stipulate the devices used in
any circuit"

He then looked at the caps as marked and said "We have no
4.7milliFarad electrolytic capacitors, and tossed the drawing
into the bin.

Ho hum:-)

Iain



Time to hire a new chief engineer, methinks!

d

Pearce Consulting
http://www.pearce.uk.com

"Don Pearce" wrote in message
...

Time to hire a new chief engineer, methinks!

Like yourself, Don, he is a digital network engineer,
an area in which attention to detail is normally regarded
as a positive attribute.

Iain

Iain M Churches wrote:

"Stewart Pinkerton" wrote in message
...

It's on alt.binaries.schematics.electronics. And it's only a paper
design, so no test results. It's a simple design though, so predicting
performance isn't too hard, given a decent physical layout.

I was interested to build your design for audible comparison
with Andre's 300B. So this morning I took your drawing to
the broadcast lab for their comments.

The chief engineer looked at the schematic and said
" It is normal practice to stipulate the devices used in
any circuit"

He then looked at the caps as marked and said "We have no
4.7milliFarad electrolytic capacitors, and tossed the drawing
into the bin.

Ho hum:-)

Iain

I made some wrong assumptions when i looked at the schematic,
but not about electros.
The mF apparently are 10,000 uF.
There is a 4.7 ohm R leading from the diode bridge to the first 10,000 uF.
I cannot see why he'd do that, but its OK, because although that seems
queer,
it won't dissallow the circuit to work, it'd just make the B+
very poorly regulated. which is quite OK with a class A amp,
and even not a bad idea if a rail shorts, or a speaker shorts, because then
the 4.7 ohm R will have a large
voltage across it, and burn out, perhaps saving the transistor.

But he led me astray with no selection of transistors.

And analysis reveals that for best operation very high
current gain bjts are required for the outputs.

But anyway a class A emitter follower driver buffer would be a good idea
to lower the impedance of the output stage driver to
a few ohms at most, or less than 1 ohm, 1/ Gm, in fact.
Then he'd get Rout to have been well below the 1 ohm he has,
and the 70 dB of local emitter follower series voltage NFB would be
far more effective.
The input stage could be a single gain bjt with
current FB and low gain and therefore give a high enough Rin for any preamp.

I think the input emitter follower buffer is wrongly placed, and should be
between the gain stage and EF output stage.
Then he could make the emitter resistors of the output stage up to
1 ohm each, and Rout would still be about only 0.5 ohms.

If you read old Wireless world articles, a few samples of
class A bjt designs with no global FB were published,
and they relied on the bags of emitter follower NFB available.

In higher powered amps where one wants say 100watts into 8 ohms, we
need about 29vrms into the emitter follower output stage.
Ideas about cost and economy dictate class aB, with only milliwatss of class
A.
Therfore the main pirpose of the necessary applied global NFB is to
linearize
the not so wonderful VAS powering the output.

In the last 300w/channel amp I built on this basis, i had about a total
of 110 db of NFB, with about 50 db of that in the EF output stage, and the
rest to
linearize the driver stage by global means.
At 10 watts the thd is about 0.002% which is about what my oscillator makes.

The class A EF buffer drioving the output stage was still in there though,
and its use
kept thd 20 db below where it otherwise would have been.

The amp I made for a dude before Xmas had 10 output transistors per channel,

MJL2193/94, so the amp has a capacity for
enormous instantaneous current ability, but one does not
hear anything special at normal levels.

Just how cleanly an SS amp is working is seen when examining the error
signal,
and if there is enormous thd in that signal atv the output of the input
diffamp,
things are not optimised.

Its harder to see inside a 300B, and see its error signal, since there is
NFB in the tube.

But at least the 300B has just a bit of 2H, and not much else for a few
watts.....

Often the levels of thd in tube gear are nominated as the casue of the
euphony, valve sound, warmth, rosiness, etc.
But often the levels are less than 0.05%, so that argument seems limp to me.

Patrick Turner.

"Patrick Turner" wrote in message
...
I made some wrong assumptions when i looked at the schematic,
but not about electros.
The mF apparently are 10,000 uF.

The lab engineer was critical of what he called "mixed marking"
C5 is correctly marked with the "mu" sign, while C4 is marked in
milliFarads.

He has clearly been following UKRA, because over a cup of coffee,
he remarked "This is a schematic from the man who said that if we was
in recording or broadcasting he would be the digital console designer,
and yet he does not bother to mark up the simplest schematic with
accuracy. No cigar!"



Nevertheless, it will still be interesting to build it, and compare with
the 300B.

Iain

Iain M Churches wrote:

"Patrick Turner" wrote in message
...
I made some wrong assumptions when i looked at the schematic,
but not about electros.
The mF apparently are 10,000 uF.

The lab engineer was critical of what he called "mixed marking"
C5 is correctly marked with the "mu" sign, while C4 is marked in
milliFarads.

He has clearly been following UKRA, because over a cup of coffee,
he remarked "This is a schematic from the man who said that if we was
in recording or broadcasting he would be the digital console designer,
and yet he does not bother to mark up the simplest schematic with
accuracy. No cigar!"

Nevertheless, it will still be interesting to build it, and compare with
the 300B.

Interesting to some, but somehow not very exciting.

Pinky just needs to package it the right language,
and make a kit out of it.
Maybe he'd sell squillions of them.

Ill gotten gains if ever...... :-]

Patrick Turner.





Iain

On Mon, 14 Mar 2005 12:46:49 +0200, "Iain M Churches"
wrote:


"Stewart Pinkerton" wrote in message
.. .

It's on alt.binaries.schematics.electronics. And it's only a paper
design, so no test results. It's a simple design though, so predicting
performance isn't too hard, given a decent physical layout.

I was interested to build your design for audible comparison
with Andre's 300B. So this morning I took your drawing to
the broadcast lab for their comments.

The chief engineer looked at the schematic and said
" It is normal practice to stipulate the devices used in
any circuit"

My recommendations were separately listed, as builders may like to try
various options.

He then looked at the caps as marked and said "We have no
4.7milliFarad electrolytic capacitors, and tossed the drawing
into the bin.

Ah well, when I were a lad, the chief engineer would have had an RS or
Farnell catalogue on his desk. 1, 4.7 and 10mF capacitors aren't
exactly exotic components!

Ho hum:-)

Humdrum, even.... :-)

Interesting that he apparaently had no other comments to make. Are you
sure he's an actual engineer, and not a mere paper-shuffler? :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Mon, 14 Mar 2005 23:05:53 +1100, Patrick Turner
wrote:

Iain M Churches wrote:

"Stewart Pinkerton" wrote in message
...

It's on alt.binaries.schematics.electronics. And it's only a paper
design, so no test results. It's a simple design though, so predicting
performance isn't too hard, given a decent physical layout.

I was interested to build your design for audible comparison
with Andre's 300B. So this morning I took your drawing to
the broadcast lab for their comments.

The chief engineer looked at the schematic and said
" It is normal practice to stipulate the devices used in
any circuit"

He then looked at the caps as marked and said "We have no
4.7milliFarad electrolytic capacitors, and tossed the drawing
into the bin.

Ho hum:-)

As someone else said - time for a new chief engineer! :-)

I made some wrong assumptions when i looked at the schematic,
but not about electros.
The mF apparently are 10,000 uF.

That would be the 10mF, yes.

There is a 4.7 ohm R leading from the diode bridge to the first 10,000 uF.
I cannot see why he'd do that, but its OK, because although that seems
queer,
it won't dissallow the circuit to work, it'd just make the B+
very poorly regulated. which is quite OK with a class A amp,
and even not a bad idea if a rail shorts, or a speaker shorts, because then
the 4.7 ohm R will have a large
voltage across it, and burn out, perhaps saving the transistor.

Partially correct, but it also provides some isolation from HF spikes
on the bridge, and gives 'soft-start' surge protection on switch-on. I
agree that it's not conventional wisdom in audio amps, but this isn't
a conventional amp.

But he led me astray with no selection of transistors.

Led you astray? They were separately listed on RAT, at least twice.

And analysis reveals that for best operation very high
current gain bjts are required for the outputs.

Yes - that's why I used the MJL4281/4302 pair.

But anyway a class A emitter follower driver buffer would be a good idea
to lower the impedance of the output stage driver to
a few ohms at most, or less than 1 ohm, 1/ Gm, in fact.

That would be another transistor, and another stage, which is hardly
adhering to KISS principles.

Then he'd get Rout to have been well below the 1 ohm he has,
and the 70 dB of local emitter follower series voltage NFB would be
far more effective.
The input stage could be a single gain bjt with
current FB and low gain and therefore give a high enough Rin for any preamp.

It's *supposed* to have highish output impedance, to simulate the
load-dependent FR variations of a SET amp. It's also supposed to be
d.c. stable and easy to build, which is why the raw gains of the BJTs
haven't been pushed to eliminate the input buffer.

I think the input emitter follower buffer is wrongly placed, and should be
between the gain stage and EF output stage.

Your opinion is noted, but I don't agree..................

Then he could make the emitter resistors of the output stage up to
1 ohm each, and Rout would still be about only 0.5 ohms.

If you read old Wireless world articles, a few samples of
class A bjt designs with no global FB were published,
and they relied on the bags of emitter follower NFB available.

In higher powered amps where one wants say 100watts into 8 ohms, we
need about 29vrms into the emitter follower output stage.
Ideas about cost and economy dictate class aB, with only milliwatss of class
A.
Therfore the main pirpose of the necessary applied global NFB is to
linearize
the not so wonderful VAS powering the output.

I *have* built a true class A amp with 80 watts/channel into 8 ohms,
but it was kinda big. It also drew about 450 watts from the wall at
idle, which was handy for the Scottish climate! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Mon, 14 Mar 2005 13:53:04 +0200, "Iain M Churches"
wrote:

"Don Pearce" wrote in message
...

Time to hire a new chief engineer, methinks!

Like yourself, Don, he is a digital network engineer,
an area in which attention to detail is normally regarded
as a positive attribute.

However, curiousity and initiative seem to be sadly lacking.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Mon, 14 Mar 2005 14:32:50 +0200, "Iain M Churches"
wrote:


"Patrick Turner" wrote in message
...
I made some wrong assumptions when i looked at the schematic,
but not about electros.
The mF apparently are 10,000 uF.

The lab engineer was critical of what he called "mixed marking"
C5 is correctly marked with the "mu" sign, while C4 is marked in
milliFarads.

Both are correct markings, which he *should* know. Would he expect a
1k5 resistor to be marked as 1500R? Modern ISO component marking
convention suggests a 3-character designation for any E12 value
component, so in strict adherence I should have marked the 100mu as
0m1 - but that goes against custom and practice in the industry.

He has clearly been following UKRA, because over a cup of coffee,
he remarked "This is a schematic from the man who said that if we was
in recording or broadcasting he would be the digital console designer,
and yet he does not bother to mark up the simplest schematic with
accuracy. No cigar!"

This guy does not understand correct component markings, and he's your
chief engineer?

Nevertheless, it will still be interesting to build it, and compare with
the 300B.

Keep that digital klutz away from it, he's clearly at sea with
analogue circuitry.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Mon, 14 Mar 2005 23:50:26 +1100, Patrick Turner
wrote:

Iain M Churches wrote:

"Patrick Turner" wrote in message
...
I made some wrong assumptions when i looked at the schematic,
but not about electros.
The mF apparently are 10,000 uF.

The lab engineer was critical of what he called "mixed marking"
C5 is correctly marked with the "mu" sign, while C4 is marked in
milliFarads.

He has clearly been following UKRA, because over a cup of coffee,
he remarked "This is a schematic from the man who said that if we was
in recording or broadcasting he would be the digital console designer,
and yet he does not bother to mark up the simplest schematic with
accuracy. No cigar!"

This is a comment from a man who doesn't understand industry-standard
component designations. Not even a Woodbine!

Nevertheless, it will still be interesting to build it, and compare with
the 300B.

Interesting to some, but somehow not very exciting.

Oh, if you cheesepare on the heatsinks or the power resistors, it
could get quite exciting!

Pinky just needs to package it the right language,
and make a kit out of it.
Maybe he'd sell squillions of them.

Sorry, I'm *way* too honest for that. Not that I'm especially honest,
just too honest for the SET racket, unlike say Nelson Pass, whose
'single-ended' Alpha series certainly aren't......

Ill gotten gains if ever...... :-]

Indeed. Remind me - what do you charge for toob amps? :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

In article , Stewart Pinkerton
wrote:

On Mon, 14 Mar 2005 12:46:49 +0200, "Iain M Churches"
wrote:

He then looked at the caps as marked and said "We have no
4.7milliFarad electrolytic capacitors, and tossed the drawing
into the bin.

Ah well, when I were a lad, the chief engineer would have had an RS or
Farnell catalogue on his desk. 1, 4.7 and 10mF capacitors aren't
exactly exotic components!

Interesting that he apparaently had no other comments to make. Are you
sure he's an actual engineer, and not a mere paper-shuffler? :-)

"Paper-shuffling" is a major and time honored part of engineering,
especially in union shops. It could be worse, he might be a "bit jockey".


Regards,

John Byrns


Surf my web pages at, http://users.rcn.com/jbyrns/

"Stewart Pinkerton" wrote in message
...
:
: Sorry, I'm *way* too honest for that. Not that I'm especially honest,
: just too honest for the SET racket, unlike say Nelson Pass, whose
: 'single-ended' Alpha series certainly aren't......
:
: Ill gotten gains if ever...... :-]
:
: Indeed. Remind me - what do you charge for toob amps? :-)
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

...an honest banker, playing racket ball ..developed the Nelson Pass..
drives souped up Alpha's ... ill gotten gains..

beginning to sound like a script, Pinky :-)
..the banker-detective.. a scottish tv prod. ?
;-)
Rudy

"Stewart Pinkerton" wrote in message
...

Interesting that he apparaently had no other comments to make. Are you
sure he's an actual engineer, and not a mere paper-shuffler? :-)

I think he was singularly unimpressed:-((

He has a PhD in digital design and broadcast technology.
(all the things you wish you had been?)
He certainly "shuffled your paper" straight into the bin:-)

Iain

On Mon, 14 Mar 2005 13:53:04 +0200, "Iain M Churches"
wrote:


"Don Pearce" wrote in message
...

Time to hire a new chief engineer, methinks!

Like yourself, Don, he is a digital network engineer,
an area in which attention to detail is normally regarded
as a positive attribute.

Iain


My history is that of the highest precision analogue engineering. I'm
involved in digital stuff right now for the sheer fun of it.

Even though I have been out of analogue engineering for a few years, I
know what a 4.7mF capacitor is, and I even have a few.

d

Pearce Consulting
http://www.pearce.uk.com

On Mon, 14 Mar 2005 12:37:23 -0600, (John Byrns) wrote:

In article , Stewart Pinkerton
wrote:

On Mon, 14 Mar 2005 12:46:49 +0200, "Iain M Churches"
wrote:

He then looked at the caps as marked and said "We have no
4.7milliFarad electrolytic capacitors, and tossed the drawing
into the bin.

Ah well, when I were a lad, the chief engineer would have had an RS or
Farnell catalogue on his desk. 1, 4.7 and 10mF capacitors aren't
exactly exotic components!

Interesting that he apparaently had no other comments to make. Are you
sure he's an actual engineer, and not a mere paper-shuffler? :-)

"Paper-shuffling" is a major and time honored part of engineering,
especially in union shops. It could be worse, he might be a "bit jockey".

Or even worse, a fader jockey! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Mon, 14 Mar 2005 21:42:59 +0200, "Iain M Churches"
wrote:

"Stewart Pinkerton" wrote in message
.. .

Interesting that he apparaently had no other comments to make. Are you
sure he's an actual engineer, and not a mere paper-shuffler? :-)

I think he was singularly unimpressed:-((

Perhaps, as is your wont, you carefully avoided mentioning (or failed
to understand) the design principles.

He has a PhD in digital design and broadcast technology.

OK, so he knows feck all about precision analogue engineering. I once
worked with a guy who gained his PhD in digital signal processing
while working with Rupert Neve, and he would have been *intrigued* by
KISASS, and would have been fascinated to know exactly *why* it did so
many things 'wrong'.

(all the things you wish you had been?)

Well, granted I only picked up an MSc in digital techniques from
Heriot-Watt University, because Marconi thought I should broaden my
horizons from 'only analogue', and were happy to pay for it, but such
is life. Digital dorks deal in ones and zeroes, analogue engineers
handle *everything* from zero to infinity - and beyond! :-)

He certainly "shuffled your paper" straight into the bin:-)

Those who don't understand what's happening, often do that, especially
if they fear that their 'position' may be undermined if they admit to
bafflement. Any *real* engineer would have wondered why certain
highly unorthodox design features existed, and would have enough
curiosity to ask. I've met a lot of 'head of department' guys like him
in my career - time for a new 'chief engineer'!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Mon, 14 Mar 2005 20:28:28 +0100, "Ruud Broens"
wrote:

"Stewart Pinkerton" wrote in message
.. .
:
: Sorry, I'm *way* too honest for that. Not that I'm especially honest,
: just too honest for the SET racket, unlike say Nelson Pass, whose
: 'single-ended' Alpha series certainly aren't......
:
: Ill gotten gains if ever...... :-]
:
: Indeed. Remind me - what do you charge for toob amps? :-)
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

..an honest banker

WHOAA! HOLD THE PHONE!!!!!

I am **NOT** a banker, I only *work* for a bank. Of course, I have
often been called something which sounds much the same.............

playing racket ball

What? Are those meds wearing off?

..developed the Nelson Pass..

Nah, I wouldn't admit to any association with that guy. Intriguingly,
his best designs were those which didn't carry his name - the Adcoms.

drives souped up Alpha's

Actually, that bit's true. I've had three, and two of them were indeed
modified. However, being an engineer, I've now graduated to souped up
Audis. I didn't even tell SWMBO that her TT is chipped! :-)

... ill gotten gains..

Um, have to take the Fifth on that one! :-)

beginning to sound like a script, Pinky :-)
..the banker-detective.. a scottish tv prod. ?

I prefer 'The Pinkerton Man'....................... :-)

But hey, I know Adam Hart-Davies from a few years back, so maybe you
have something going there!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Stewart Pinkerton" wrote in message
...
: On Mon, 14 Mar 2005 20:28:28 +0100, "Ruud Broens"
: wrote:
:
: "Stewart Pinkerton" wrote in message
: .. .
: :
: : Sorry, I'm *way* too honest for that. Not that I'm especially honest,
: : just too honest for the SET racket, unlike say Nelson Pass, whose
: : 'single-ended' Alpha series certainly aren't......
: :
: : Ill gotten gains if ever...... :-]
: :
: : Indeed. Remind me - what do you charge for toob amps? :-)
: : --
: :
: : Stewart Pinkerton | Music is Art - Audio is Engineering
:
: ..an honest banker
:
: WHOAA! HOLD THE PHONE!!!!!
:
: I am **NOT** a banker, I only *work* for a bank. Of course, I have
: often been called something which sounds much the same.............
:
: playing racket ball
:
: What? Are those meds wearing off?
:
: ..developed the Nelson Pass..
:
: Nah, I wouldn't admit to any association with that guy. Intriguingly,
: his best designs were those which didn't carry his name - the Adcoms.
:
: drives souped up Alpha's
:
: Actually, that bit's true. I've had three, and two of them were indeed
: modified. However, being an engineer, I've now graduated to souped up
: Audis. I didn't even tell SWMBO that her TT is chipped! :-)
:
: ... ill gotten gains..
:
: Um, have to take the Fifth on that one! :-)
:
: beginning to sound like a script, Pinky :-)
: ..the banker-detective.. a scottish tv prod. ?
:
: I prefer 'The Pinkerton Man'....................... :-)
:
: But hey, I know Adam Hart-Davies from a few years back, so maybe you
: have something going there!
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

hehe, a comedy, then ?
Rudy

Stewart Pinkerton wrote:

On Mon, 14 Mar 2005 23:05:53 +1100, Patrick Turner
wrote:

Iain M Churches wrote:

"Stewart Pinkerton" wrote in message
...

It's on alt.binaries.schematics.electronics. And it's only a paper
design, so no test results. It's a simple design though, so predicting
performance isn't too hard, given a decent physical layout.

I was interested to build your design for audible comparison
with Andre's 300B. So this morning I took your drawing to
the broadcast lab for their comments.

The chief engineer looked at the schematic and said
" It is normal practice to stipulate the devices used in
any circuit"

He then looked at the caps as marked and said "We have no
4.7milliFarad electrolytic capacitors, and tossed the drawing
into the bin.

Ho hum:-)

As someone else said - time for a new chief engineer! :-)

I made some wrong assumptions when i looked at the schematic,
but not about electros.
The mF apparently are 10,000 uF.

That would be the 10mF, yes.

There is a 4.7 ohm R leading from the diode bridge to the first 10,000 uF.
I cannot see why he'd do that, but its OK, because although that seems
queer,
it won't dissallow the circuit to work, it'd just make the B+
very poorly regulated. which is quite OK with a class A amp,
and even not a bad idea if a rail shorts, or a speaker shorts, because then
the 4.7 ohm R will have a large
voltage across it, and burn out, perhaps saving the transistor.

Partially correct, but it also provides some isolation from HF spikes
on the bridge, and gives 'soft-start' surge protection on switch-on. I
agree that it's not conventional wisdom in audio amps, but this isn't
a conventional amp.

But he led me astray with no selection of transistors.

Led you astray? They were separately listed on RAT, at least twice.

I come from Astraya, and you ppl are always leading us astray.



And analysis reveals that for best operation very high
current gain bjts are required for the outputs.

Yes - that's why I used the MJL4281/4302 pair.

But anyway a class A emitter follower driver buffer would be a good idea
to lower the impedance of the output stage driver to
a few ohms at most, or less than 1 ohm, 1/ Gm, in fact.

That would be another transistor, and another stage, which is hardly
adhering to KISS principles.

No, becaue you do away with the input buffer.



Then he'd get Rout to have been well below the 1 ohm he has,
and the 70 dB of local emitter follower series voltage NFB would be
far more effective.
The input stage could be a single gain bjt with
current FB and low gain and therefore give a high enough Rin for any preamp.

It's *supposed* to have highish output impedance, to simulate the
load-dependent FR variations of a SET amp.

Why simulate anything else?

Just let it be what it will be.

Or else just allow the emitter resistors of the output stage to determine
the Rout; its a purer way of doing it.
And you'd have more class A bias stability.

It's also supposed to be
d.c. stable and easy to build, which is why the raw gains of the BJTs
haven't been pushed to eliminate the input buffer.

I think the input emitter follower buffer is wrongly placed, and should be
between the gain stage and EF output stage.

Your opinion is noted, but I don't agree..................

You'd be stubborn then.



Then he could make the emitter resistors of the output stage up to
1 ohm each, and Rout would still be about only 0.5 ohms.

If you read old Wireless world articles, a few samples of
class A bjt designs with no global FB were published,
and they relied on the bags of emitter follower NFB available.

In higher powered amps where one wants say 100watts into 8 ohms, we
need about 29vrms into the emitter follower output stage.
Ideas about cost and economy dictate class aB, with only milliwatss of class
A.
Therfore the main pirpose of the necessary applied global NFB is to
linearize
the not so wonderful VAS powering the output.

I *have* built a true class A amp with 80 watts/channel into 8 ohms,
but it was kinda big. It also drew about 450 watts from the wall at
idle, which was handy for the Scottish climate! :-)

Probably as big as a 350 watt class AB amp would be.

Heatsinks need to be about the same size, but yes, fine for Scottish weather.

Patrick Turner.


--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton wrote:

On Mon, 14 Mar 2005 23:50:26 +1100, Patrick Turner
wrote:

Iain M Churches wrote:

"Patrick Turner" wrote in message
...
I made some wrong assumptions when i looked at the schematic,
but not about electros.
The mF apparently are 10,000 uF.

The lab engineer was critical of what he called "mixed marking"
C5 is correctly marked with the "mu" sign, while C4 is marked in
milliFarads.

He has clearly been following UKRA, because over a cup of coffee,
he remarked "This is a schematic from the man who said that if we was
in recording or broadcasting he would be the digital console designer,
and yet he does not bother to mark up the simplest schematic with
accuracy. No cigar!"

This is a comment from a man who doesn't understand industry-standard
component designations. Not even a Woodbine!

Nevertheless, it will still be interesting to build it, and compare with
the 300B.

Interesting to some, but somehow not very exciting.

Oh, if you cheesepare on the heatsinks or the power resistors, it
could get quite exciting!

Pinky just needs to package it the right language,
and make a kit out of it.
Maybe he'd sell squillions of them.

Sorry, I'm *way* too honest for that. Not that I'm especially honest,
just too honest for the SET racket, unlike say Nelson Pass, whose
'single-ended' Alpha series certainly aren't......

What exactly?



Ill gotten gains if ever...... :-]

Indeed. Remind me - what do you charge for toob amps? :-)

Less than a lot of ppl charge for SS amps.

Patrick Turner.


--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Stewart Pinkerton" wrote in message
...

However, curiousity and initiative seem to be sadly lacking.

An alternative interpretation might be that he interests himself
in better things:-))


Cordially,
Iain

"Stewart Pinkerton" wrote in message
...

Keep that digital klutz away from it, he's clearly at sea with
analogue circuitry.

He has designed an analogue location console used by three
major broadcasting companies within EBU.

He also knows enough about analogue circuitry to have recognised
"your" vinyl RIAA stage as coming from a book book (either
Swedish or German) or possibly an early issue of Elektor.
Did the KISASS amp come from the same source?


Cordially,
Iain

"Patrick Turner" wrote in message
...
I made some wrong assumptions when i looked at the schematic,
but not about electros.
The mF apparently are 10,000 uF.



Stewart,

I am going to the component shop tomorrow.
Please confirm the value of C4.

Thanks.

Iain

"Stewart Pinkerton" wrote in message
...

"Paper-shuffling" is a major and time honored part of engineering,
especially in union shops. It could be worse, he might be a "bit jockey".

Or even worse, a fader jockey! :-)

Still showing a complete lack of understanding of what recording
personnel actually do. But it's still better than licking the stamps:-)

Iain

"Stewart Pinkerton" wrote in message
...
On Mon, 14 Mar 2005 20:28:28 +0100, "Ruud Broens"
wrote:

"Stewart Pinkerton" wrote in message
. ..
:
: Sorry, I'm *way* too honest for that. Not that I'm especially honest,
: just too honest for the SET racket, unlike say Nelson Pass, whose
: 'single-ended' Alpha series certainly aren't......
:
: Ill gotten gains if ever...... :-]
:
: Indeed. Remind me - what do you charge for toob amps? :-)
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

..an honest banker

WHOAA! HOLD THE PHONE!!!!!

I am **NOT** a banker, I only *work* for a bank. Of course, I have
often been called something which sounds much the same.............

playing racket ball

What? Are those meds wearing off?

..developed the Nelson Pass..

Nah, I wouldn't admit to any association with that guy. Intriguingly,
his best designs were those which didn't carry his name - the Adcoms.

drives souped up Alpha's

Actually, that bit's true. I've had three, and two of them were indeed
modified. However, being an engineer, I've now graduated to souped up
Audis. I didn't even tell SWMBO that her TT is chipped! :-)

... ill gotten gains..

Um, have to take the Fifth on that one! :-)

beginning to sound like a script, Pinky :-)
..the banker-detective.. a scottish tv prod. ?

I prefer 'The Pinkerton Man'....................... :-)

But hey, I know Adam Hart-Davies from a few years back, so maybe you
have something going there!
--

I once worked with a band called "Pinkerton's Assorted Colours"
They used an autoharp through a guitar amp. Totally dreadful.
Was that you in your younger days? :-)

Iain

On Tue, 15 Mar 2005 11:29:32 +1100, Patrick Turner
wrote:


I come from Astraya, and you ppl are always leading us astray.

IIRC, we spent most of our short sojourn over there trying to ensure
that you did *not* stray.................. :-)

And analysis reveals that for best operation very high
current gain bjts are required for the outputs.

Yes - that's why I used the MJL4281/4302 pair.

But anyway a class A emitter follower driver buffer would be a good idea
to lower the impedance of the output stage driver to
a few ohms at most, or less than 1 ohm, 1/ Gm, in fact.

That would be another transistor, and another stage, which is hardly
adhering to KISS principles.

No, becaue you do away with the input buffer.

OK, but I still prefer my original approach, I believe that it's
simpler in spirit.

Then he'd get Rout to have been well below the 1 ohm he has,
and the 70 dB of local emitter follower series voltage NFB would be
far more effective.
The input stage could be a single gain bjt with
current FB and low gain and therefore give a high enough Rin for any preamp.

It's *supposed* to have highish output impedance, to simulate the
load-dependent FR variations of a SET amp.

Why simulate anything else?

Just let it be what it will be.

Well no, because if it's not a SS equivalent of a tube SET, it has no
merit as an amplifier. Use the Linsley Hood design, for superior
results and an even simpler topology.

Or else just allow the emitter resistors of the output stage to determine
the Rout; its a purer way of doing it.
And you'd have more class A bias stability.

That's pretty much what I *did* do. You can certainly increase the
output emitter resistors to 1 ohm if you want the amp to be
rock-stable - and you're going to avoid low impedance speakers.

It's also supposed to be
d.c. stable and easy to build, which is why the raw gains of the BJTs
haven't been pushed to eliminate the input buffer.

I think the input emitter follower buffer is wrongly placed, and should be
between the gain stage and EF output stage.

Your opinion is noted, but I don't agree..................

You'd be stubborn then.

Oh yeah, more dig-in-ness than a Missouri mule! I think your
suggestion would spoil the basic ethos, that of a central 'character
determining' gain stage, with impedence transformers on either side.

Then he could make the emitter resistors of the output stage up to
1 ohm each, and Rout would still be about only 0.5 ohms.

If you read old Wireless world articles, a few samples of
class A bjt designs with no global FB were published,
and they relied on the bags of emitter follower NFB available.

In higher powered amps where one wants say 100watts into 8 ohms, we
need about 29vrms into the emitter follower output stage.
Ideas about cost and economy dictate class aB, with only milliwatss of class
A.
Therfore the main pirpose of the necessary applied global NFB is to
linearize
the not so wonderful VAS powering the output.

I *have* built a true class A amp with 80 watts/channel into 8 ohms,
but it was kinda big. It also drew about 450 watts from the wall at
idle, which was handy for the Scottish climate! :-)

Probably as big as a 350 watt class AB amp would be.

It was 18" wide, two feet deep, nine inches high, and weighed about
forty kilos! Sure intimidated visitors, who assumed it must put out
skull-splitting power levels! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Stewart Pinkerton" wrote in message
...

OK, so he knows feck all about precision analogue engineering.
I have replied to that in another mail.
Interesting that you call your amp
"precision analogue engineering" :-))))


I once
worked with a guy who gained his PhD in digital signal processing
while working with Rupert Neve, and he would have been *intrigued* by
KISASS,
and would have been fascinated to know exactly *why* it did so
many things 'wrong'.

I have yet to see a post where such a statement is made.

Well, granted I only picked up an MSc in digital techniques from
Heriot-Watt University, because Marconi thought I should broaden my
horizons from 'only analogue', and were happy to pay for it, but such
is life. Digital dorks deal in ones and zeroes, analogue engineers
handle *everything* from zero to infinity - and beyond! :-)

Surprising then that a man of your extraordinary capability has an
audio system comprised entirely of other peoples engineering (with
the possible exception of the vinyl pre-amp) Nothing of your own.

Surprising too that a man of your extraordinary capability is
working in a post room, and at only 57 years of age is
"sliding into retirement" (your words)

But never mind, when you retire they might pass the hat round
at the bank for a down payment on a Conrad Johnson or even,
if you have been a very good boy, a Radford.

You can then sell the boring old Audi, to your local cab firm,
and get youself a vintage motorcyle, or an early Aston and
start living:-))

Iain.