It is clear from his posts on the KISS amp thread so
far, that Andre has spent considerable time and effort
in preparing what promises to be one of the most
interesting articles on RAT for a very long time.

It would be a pity to allow this discussion to degenerate
into a bar-room brawl.

No one would expect to heckle a lecturer at university
or technical college, or a speaker at an AES convention
in such a manner, so why should such gross behaviour
be deemed appropriate in this NG?

Why can't we extend to Andre the courtesy he deserves,
and listen to what he has to tell us? There will, no doubt,
be room for the discussion at the end of each chapter, and
also the opportunity for questions and answers when the
design process is complete.

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Cordially,

Iain

On Sun, 28 Nov 2004 15:19:12 +0200, Iain M Churches wrote:

It is clear from his posts on the KISS amp thread so far, that Andre has
spent considerable time and effort in preparing what promises to be one of
the most interesting articles on RAT for a very long time.

It would be a pity to allow this discussion to degenerate into a bar-room
brawl.

No one would expect to heckle a lecturer at university or technical
college, or a speaker at an AES convention in such a manner, so why should
such gross behaviour be deemed appropriate in this NG?

Why can't we extend to Andre the courtesy he deserves, and listen to what
he has to tell us? There will, no doubt, be room for the discussion at
the end of each chapter, and also the opportunity for questions and
answers when the design process is complete.

After that, perhaps Stewart will give us the benefit of his long
experience as an engineer in SS analogue design, and begin a new thread to
take us through the process of designing and building a lower power
solid-state amp with a similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.



Thanks Iain. May I add that I am in complete agreement - without having to
say "me too"? :-)


--
Mick
(no M$ software on here... :-) )
Web: http://www.nascom.info
Web: http://projectedsound.tk

in article , Iain M Churches at
wrote on 11/28/04 8:19 AM:

It is clear from his posts on the KISS amp thread so
far, that Andre has spent considerable time and effort
in preparing what promises to be one of the most
interesting articles on RAT for a very long time.

It would be a pity to allow this discussion to degenerate
into a bar-room brawl.

No one would expect to heckle a lecturer at university
or technical college, or a speaker at an AES convention
in such a manner, so why should such gross behaviour
be deemed appropriate in this NG?

Why can't we extend to Andre the courtesy he deserves,
and listen to what he has to tell us? There will, no doubt,
be room for the discussion at the end of each chapter, and
also the opportunity for questions and answers when the
design process is complete.

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Cordially,

Iain



Iain,

I respect and appreciate your call for civility. The NG would certainly
benefit from that.

Your lecturer analogy would be true when applied to most, but not to Mr.
Jute. Jute begins his lectures quietly enough, but can't resist attacking
and belittling his audience after about 5 mins. Into the speech.

'Dre would deserve reciprocal courtesy of he were capable of good manners
himself. But he is not; and reading prior threads I gather that he never
has been. Scan his recent posts and see for yourself.

I'm particularly amused by older posts where 'Dre whined and bleated that
had received 300+ unsolicited attacks from this NG. He said he was going to
write a book about the abuse of newsgroups in general and R.A.T. In
particular. (Undeserved, of course, just like the reaction he's getting
now).

I dare say that book was never submitted for print ant that project, like so
many others in 'Dre's imagination, are so much bovine excrement.

I've blocked his posts, but I suspect that the K.I.S.S. discussion will have
a difficult transformation going from words to the math. I could be proved
wrong, however, and I'd welcome that because it would mean that 'Dre
actually contributed something of relevance and value.

Cheers from across the pond,

Jon

"Jon Yaeger" wrote in message
...
in article , Iain M Churches at
wrote on 11/28/04 8:19 AM:

It is clear from his posts on the KISS amp thread so
far, that Andre has spent considerable time and effort
in preparing what promises to be one of the most
interesting articles on RAT for a very long time.

It would be a pity to allow this discussion to degenerate
into a bar-room brawl.

No one would expect to heckle a lecturer at university
or technical college, or a speaker at an AES convention
in such a manner, so why should such gross behaviour
be deemed appropriate in this NG?

Why can't we extend to Andre the courtesy he deserves,
and listen to what he has to tell us? There will, no doubt,
be room for the discussion at the end of each chapter, and
also the opportunity for questions and answers when the
design process is complete.

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.



Iain,

I respect and appreciate your call for civility. The NG would certainly
benefit from that.

Your lecturer analogy would be true when applied to most, but not to Mr.
Jute. Jute begins his lectures quietly enough, but can't resist attacking
and belittling his audience after about 5 mins. Into the speech.


(snip)
I've blocked his posts, but I suspect that the K.I.S.S. discussion will
have
a difficult transformation going from words to the math. I could be
proved
wrong, however, and I'd welcome that because it would mean that 'Dre
actually contributed something of relevance and value.

Cheers from across the pond,

Jon


Hi Jon,

I was surprised at what you wrote, and I can only speak as I find.
Some time ago, I posted on RAT asking for help with psu ripple
question. There were several replies, and one of the best
of these was from Andre who went out of his way to make
sure that I understood the replies to my questions.
He was even kind enough to send me a spreadsheet in
Excel as an e-mail attachment, together with several references
for further reading.

Although he could see my level of expertise was not high, he was
kind, polite and considerate. At no time did he attack or belittle me
for my lack of knowledge.

I was, and still am, grateful for his guidance, and for the time he took
to assist me.


Cordially,
from across the Baltic sea,


Iain

On Sun, 28 Nov 2004 15:19:12 +0200, "Iain M Churches"
wrote:

It is clear from his posts on the KISS amp thread so
far, that Andre has spent considerable time and effort
in preparing what promises to be one of the most
interesting articles on RAT for a very long time.

Shame about the false assumptions on which it's based, but whatever.

It would be a pity to allow this discussion to degenerate
into a bar-room brawl.

Indeed. It's regrettable that Andre has found it necessary to generate
four separate attack threads over this issue, but that seems to be his
SOP.

No one would expect to heckle a lecturer at university
or technical college, or a speaker at an AES convention
in such a manner, so why should such gross behaviour
be deemed appropriate in this NG?

Because Andre is seriously unqualified to do either? :-)

Besides, it's not heckling. By its very nature, Usenet allows the
speaker to complete his post, and await rebuttal, to be responded to
in his own time, and after every opportunity to consider the argument.
Some posters seem to have severe difficulty in handling rebuttal,
however........

Why can't we extend to Andre the courtesy he deserves,
and listen to what he has to tell us? There will, no doubt,
be room for the discussion at the end of each chapter, and
also the opportunity for questions and answers when the
design process is complete.

Indeed so. Note that he has divided his posts into 'lessons', each
self-contained and hence open to refutation of his basic premises.

He does *not* however wish to enter into any kind of discussion of
what he is claiming, he simply generates pure attack threads, with
scientifically interesting titles such as "On the exclusivity of the
red-arsed baboon". Calm, considered rebuttal, or just spiteful flame
in lieu of any real argument?

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

Hmmm. That's a thought. It would certainly be possible to produce such
a design, and I could even utilise FETs to provide not dissimilar
transfer curves. A 6-watt SEFET amp would not be difficult to
implement, and would of course be *vastly* cheaper than the 300B
equivalent, so pretty easy (and safe!) to knock up over a weekend.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

They would largely differ through the absence of an OPT in the SS
design (I would use a resistive source load, and damn the
efficiency!). Otherwise, they would be equally crippled by SE
asymmetry and low output.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Hi Jon,

I was surprised at what you wrote, and I can only speak as I find.
Some time ago, I posted on RAT asking for help with psu ripple
question. There were several replies, and one of the best
of these was from Andre who went out of his way to make
sure that I understood the replies to my questions.
He was even kind enough to send me a spreadsheet in
Excel as an e-mail attachment, together with several references
for further reading.

Although he could see my level of expertise was not high, he was
kind, polite and considerate. At no time did he attack or belittle me
for my lack of knowledge.

I was, and still am, grateful for his guidance, and for the time he took
to assist me.


Cordially,
from across the Baltic sea,


Iain


Iain,


Similarly, many moons ago Andre offered a helpful reply to one of my
queries. Frankly, I was surprised and appreciative.

The question is, why the multiplicity of "other" stuff? I don't deny that
Andre is capable of good things; but that's not what we often see. Lo ipse
dixit.

Jon

Iain M Churches wrote:

It is clear from his posts on the KISS amp thread so
far, that Andre has spent considerable time and effort
in preparing what promises to be one of the most
interesting articles on RAT for a very long time.

It would be a pity to allow this discussion to degenerate
into a bar-room brawl.

No one would expect to heckle a lecturer at university
or technical college, or a speaker at an AES convention
in such a manner, so why should such gross behaviour
be deemed appropriate in this NG?

The Internet is a complete rabble compared to an AES
convention or university. The Net has no exclusive membership
hurdles to enter.

Those setting out to display an idea about an amp like AJ is currently
attempting should just ignore the chattering gallery of sages and fools,
and *just do it*, imho.



Why can't we extend to Andre the courtesy he deserves,
and listen to what he has to tell us? There will, no doubt,
be room for the discussion at the end of each chapter, and
also the opportunity for questions and answers when the
design process is complete.

Such decorum is alien to the Net; its a place which has long demolished
the
manners of the formal real world institutions, so those who tread the
net's stage
boards in any limelight have to be prepared for the roses *and the
rotten eggs*.



After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

Don't hold your breath.

And would he not have all thse ppl then whinging about solid state
"wrongness" desribed in detail on this tubes group.





There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Indeed.

Patrick Turner.



Cordially,

Iain

"Iain M Churches" wrote in message
...
It is clear from his posts on the KISS amp thread so
far, that Andre has spent considerable time and effort
in preparing what promises to be one of the most
interesting articles on RAT for a very long time.

It would be a pity to allow this discussion to degenerate
into a bar-room brawl.

No one would expect to heckle a lecturer at university
or technical college, or a speaker at an AES convention
in such a manner, so why should such gross behaviour
be deemed appropriate in this NG?

Why can't we extend to Andre the courtesy he deserves,
and listen to what he has to tell us? There will, no doubt,
be room for the discussion at the end of each chapter, and
also the opportunity for questions and answers when the
design process is complete.

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Cordially,

Iain




Can we then expect to see two individual and hopefully unique designs posted
on a binaries soon complete with the designers accompanying notes on their
own design strategy and performance expectations.
I look forward to this in anticipation of some really creative designs that
reflect their indviduality and their respective long experiences in both
valve and SS technologies.

Mike

"Mike Gilmour" wrote in message
...

"Iain M Churches" wrote in message
...
It is clear from his posts on the KISS amp thread so
far, that Andre has spent considerable time and effort
in preparing what promises to be one of the most
interesting articles on RAT for a very long time.

It would be a pity to allow this discussion to degenerate
into a bar-room brawl.

No one would expect to heckle a lecturer at university
or technical college, or a speaker at an AES convention
in such a manner, so why should such gross behaviour
be deemed appropriate in this NG?

Why can't we extend to Andre the courtesy he deserves,
and listen to what he has to tell us? There will, no doubt,
be room for the discussion at the end of each chapter, and
also the opportunity for questions and answers when the
design process is complete.

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Cordially,

Iain




Can we then expect to see two individual and hopefully unique designs
posted on a binaries soon complete with the designers accompanying notes
on their own design strategy and performance expectations.
I look forward to this in anticipation of some really creative designs
that reflect their indviduality and their respective long experiences in
both valve and SS technologies.

Mike



Yes. Hopefully we can expect this. I for one would be interested to learn
something from both parties, and build both their amplifiers. I am sure
that each design will have its strengths and its weaknesses.

If several members of this group build both amplifiers, this too will be a
topic
for a very interesting thread.

Cordially,
Iain

"Iain M Churches" wrote in message
...

"Mike Gilmour" wrote in message
...

"Iain M Churches" wrote in message
...
It is clear from his posts on the KISS amp thread so
far, that Andre has spent considerable time and effort
in preparing what promises to be one of the most
interesting articles on RAT for a very long time.

It would be a pity to allow this discussion to degenerate
into a bar-room brawl.

No one would expect to heckle a lecturer at university
or technical college, or a speaker at an AES convention
in such a manner, so why should such gross behaviour
be deemed appropriate in this NG?

Why can't we extend to Andre the courtesy he deserves,
and listen to what he has to tell us? There will, no doubt,
be room for the discussion at the end of each chapter, and
also the opportunity for questions and answers when the
design process is complete.

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Cordially,

Iain




Can we then expect to see two individual and hopefully unique designs
posted on a binaries soon complete with the designers accompanying notes
on their own design strategy and performance expectations.
I look forward to this in anticipation of some really creative designs
that reflect their indviduality and their respective long experiences in
both valve and SS technologies.

Mike



Yes. Hopefully we can expect this. I for one would be interested to learn
something from both parties, and build both their amplifiers. I am sure
that each design will have its strengths and its weaknesses.

If several members of this group build both amplifiers, this too will be a
topic
for a very interesting thread.

Cordially,
Iain


A practical and very interesting project. Members with suitable test gear
can post their measured specifications. Possibly some will be able to
report operational performance by performing ABX listening tests with
similar constructs whilst others by providing their own subjective
impressions.
As you say this promises to be a very interesting thread.

Regards,
Mike

On Sun, 28 Nov 2004 16:08:00 +0000, Stewart Pinkerton wrote:

snip

Hmmm. That's a thought. It would certainly be possible to produce such a
design, and I could even utilise FETs to provide not dissimilar transfer
curves. A 6-watt SEFET amp would not be difficult to implement, and would
of course be *vastly* cheaper than the 300B equivalent, so pretty easy
(and safe!) to knock up over a weekend.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

They would largely differ through the absence of an OPT in the SS design
(I would use a resistive source load, and damn the efficiency!).
Otherwise, they would be equally crippled by SE asymmetry and low output.

Go on, Stewart. Give it a go. I built a headphone amp a while ago using a
class A MOSFET with an op-amp gain stage, which was very encouraging. It
had, IIRC, a voltage regulator used as a current source for the output
stage instead of a resistor. Not a lot of power, but something upgraded
from that sort of thing would be interesting. Resistive sources get damn
hot.... sizzle ok for frying bacon while listening to music!

--
Mick
(no M$ software on here... :-) )
Web: http://www.nascom.info
Web: http://projectedsound.tk

Jon Yaeger said:

I was, and still am, grateful for his guidance, and for the time he took
to assist me.

Similarly, many moons ago Andre offered a helpful reply to one of my
queries. Frankly, I was surprised and appreciative.

Ditto. Andre once promised me to send something, and he delivered
promptly, free of charge.
I've never had unpleasant conversations with him, neither here in RAT
or in any newsgroup. Not before and not after.

I wasn't around during most of the Magnequest wars, and what I
gathered from it didn't make me happy.
It striked me as an unneccessary flame war, continued into the absurd.
No one wanted to lose face, of course.

The question is, why the multiplicity of "other" stuff? I don't deny that
Andre is capable of good things; but that's not what we often see. Lo ipse
dixit.

I for one appreciate it that finally someone is posting about tubes
and tube designing, instead of politics, Ebay scammers or Chinese
products flooding the world.

--
Sander de Waal
" SOA of a KT88? Sufficient. "

On Sun, 28 Nov 2004 16:49:38 -0000, "Mike Gilmour"
wrote:

"Iain M Churches" wrote in message
...

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Can we then expect to see two individual and hopefully unique designs posted
on a binaries soon complete with the designers accompanying notes on their
own design strategy and performance expectations.
I look forward to this in anticipation of some really creative designs that
reflect their indviduality and their respective long experiences in both
valve and SS technologies.

Oh bugger, I might have to dust off my slide rule! My problem with
this task would be the sheer futility of attempting to 'optimise' a
fundamentally crippled design, i.e. the low-powered single-ended
amplifier. Andre thinks that he's creating an 'ultra fidelity'
amplifier, I know that I would be attempting to create the fastest
three-legged horse....................

It smacks of performing cosmetic surgery on a terminal cancer patient.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Sun, 28 Nov 2004 17:09:56 -0000, "Mike Gilmour"
wrote:

A practical and very interesting project. Members with suitable test gear
can post their measured specifications. Possibly some will be able to
report operational performance by performing ABX listening tests with
similar constructs whilst others by providing their own subjective
impressions.

Hmmmmm. I could be tempted, if some honest level-matched double-blind
comparisons could be set up. I'd expect no audible differences if peak
levels are kept below 2/3 maximum output.

As you say this promises to be a very interesting thread.

It would certainly make a refreshing change from mud-slinging! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Sun, 28 Nov 2004 17:11:52 GMT, mick wrote:

On Sun, 28 Nov 2004 16:08:00 +0000, Stewart Pinkerton wrote:

snip

Hmmm. That's a thought. It would certainly be possible to produce such a
design, and I could even utilise FETs to provide not dissimilar transfer
curves. A 6-watt SEFET amp would not be difficult to implement, and would
of course be *vastly* cheaper than the 300B equivalent, so pretty easy
(and safe!) to knock up over a weekend.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

They would largely differ through the absence of an OPT in the SS design
(I would use a resistive source load, and damn the efficiency!).
Otherwise, they would be equally crippled by SE asymmetry and low output.

Go on, Stewart. Give it a go. I built a headphone amp a while ago using a
class A MOSFET with an op-amp gain stage, which was very encouraging. It
had, IIRC, a voltage regulator used as a current source for the output
stage instead of a resistor. Not a lot of power, but something upgraded
from that sort of thing would be interesting. Resistive sources get damn
hot.... sizzle ok for frying bacon while listening to music!

Well, when I say a resistive source, it could well be a
constant-current equivalent. The basic point is to avoid steel.

However, my interest *has* been piqued by Mick's suggestion of a
'shoot out' comparison of the legendary 300B SET with a SS equivalent.
I wonder if I could build in a little reverb and boost the 2HD... :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton said:

Oh bugger, I might have to dust off my slide rule! My problem with
this task would be the sheer futility of attempting to 'optimise' a
fundamentally crippled design, i.e. the low-powered single-ended
amplifier. Andre thinks that he's creating an 'ultra fidelity'
amplifier, I know that I would be attempting to create the fastest
three-legged horse....................

This reminds me of the remarkable post by our beloved Lord Valve, when
he wrote about transistors: "Those 3-legged fuses......" ;-)

It smacks of performing cosmetic surgery on a terminal cancer patient.

Isn't that a challenge then, instead of designing the umpteenth
"perfect" solid state amplifier?

--
Sander de Waal
" SOA of a KT88? Sufficient. "

In message , Stewart
Pinkerton writes
On Sun, 28 Nov 2004 16:49:38 -0000, "Mike Gilmour"
wrote:

"Iain M Churches" wrote in message
...

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Can we then expect to see two individual and hopefully unique designs posted
on a binaries soon complete with the designers accompanying notes on their
own design strategy and performance expectations.
I look forward to this in anticipation of some really creative designs that
reflect their indviduality and their respective long experiences in both
valve and SS technologies.

Oh bugger, I might have to dust off my slide rule! My problem with
this task would be the sheer futility of attempting to 'optimise' a
fundamentally crippled design, i.e. the low-powered single-ended
amplifier. Andre thinks that he's creating an 'ultra fidelity'
amplifier, I know that I would be attempting to create the fastest
three-legged horse....................

It smacks of performing cosmetic surgery on a terminal cancer patient.

I could send you my schematic of a single-ended choke-loaded
source-follower MOSFET amp. You'll need to find a 100mH 3A choke
though, which won't be easy, and you're not having mine! (It's got
servo-controlled current setting of the output stage, but the forward
audio path is all simple transistor circuitry). I never got round to
building it but it SPICEs very well indeed.

(Actually I do have a single 64mHy 3A choke which might just do the job
if you don't need the output ot go down to 20Hz.)
--
Chris Morriss

On Sun, 28 Nov 2004 21:53:50 +0000, Chris Morriss
wrote:

In message , Stewart
Pinkerton writes
On Sun, 28 Nov 2004 16:49:38 -0000, "Mike Gilmour"
wrote:

"Iain M Churches" wrote in message
...

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Can we then expect to see two individual and hopefully unique designs posted
on a binaries soon complete with the designers accompanying notes on their
own design strategy and performance expectations.
I look forward to this in anticipation of some really creative designs that
reflect their indviduality and their respective long experiences in both
valve and SS technologies.

Oh bugger, I might have to dust off my slide rule! My problem with
this task would be the sheer futility of attempting to 'optimise' a
fundamentally crippled design, i.e. the low-powered single-ended
amplifier. Andre thinks that he's creating an 'ultra fidelity'
amplifier, I know that I would be attempting to create the fastest
three-legged horse....................

It smacks of performing cosmetic surgery on a terminal cancer patient.

I could send you my schematic of a single-ended choke-loaded
source-follower MOSFET amp. You'll need to find a 100mH 3A choke
though, which won't be easy, and you're not having mine! (It's got
servo-controlled current setting of the output stage, but the forward
audio path is all simple transistor circuitry). I never got round to
building it but it SPICEs very well indeed.

(Actually I do have a single 64mHy 3A choke which might just do the job
if you don't need the output ot go down to 20Hz.)

As noted, to optimise the design (however fundamentally crippled) is
to avoid iron.

--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Iain M Churches" wrote in message ...
It is clear from his posts on the KISS amp thread so
far, that Andre has spent considerable time and effort
in preparing what promises to be one of the most
interesting articles on RAT for a very long time.

It would be a pity to allow this discussion to degenerate
into a bar-room brawl.

No one would expect to heckle a lecturer at university
or technical college, or a speaker at an AES convention
in such a manner, so why should such gross behaviour
be deemed appropriate in this NG?

Why can't we extend to Andre the courtesy he deserves,
and listen to what he has to tell us? There will, no doubt,
be room for the discussion at the end of each chapter, and
also the opportunity for questions and answers when the
design process is complete.

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Cordially,

Iain

Well said, Mr Churches. Mr Jute is a substantial engineer voluntarily
giving us his time and expertise. He is entitled to courtesy.

I have been grateful to Mr Jute in his engineering mode ever since my
first day at GM. My supervisor gave me a copy of Designing and
Building Special Cars by Andre Jute and told me it was my bible. I
still give new recruits to my department a copy.

An engineer is not defined by a diploma but by his ability to add
value to knowledge or a pile of components. Pinkerton may possess some
kind of a diploma but as an engineer he will be forgotten when he
leaves the newsgroup. You may be certain Mr Jute will live in the
hearts of all those he helped in automobile engineering, in computers
and in various arts.

Frank B.

mick wrote:

On Sun, 28 Nov 2004 16:08:00 +0000, Stewart Pinkerton wrote:

snip

Hmmm. That's a thought. It would certainly be possible to produce such a
design, and I could even utilise FETs to provide not dissimilar transfer
curves. A 6-watt SEFET amp would not be difficult to implement, and would
of course be *vastly* cheaper than the 300B equivalent, so pretty easy
(and safe!) to knock up over a weekend.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

They would largely differ through the absence of an OPT in the SS design
(I would use a resistive source load, and damn the efficiency!).
Otherwise, they would be equally crippled by SE asymmetry and low output.

Go on, Stewart. Give it a go. I built a headphone amp a while ago using a
class A MOSFET with an op-amp gain stage, which was very encouraging. It
had, IIRC, a voltage regulator used as a current source for the output
stage instead of a resistor. Not a lot of power, but something upgraded
from that sort of thing would be interesting. Resistive sources get damn
hot.... sizzle ok for frying bacon while listening to music!

Could use a choke.

But then most SS orientated people froth at the mouth about chokes and
transformers.
Its understandable. Back emfs can ruin a transistor with such ease.....

Patrick Turner.



--
Mick
(no M$ software on here... :-) )
Web: http://www.nascom.info
Web: http://projectedsound.tk

Stewart Pinkerton wrote:

On Sun, 28 Nov 2004 16:49:38 -0000, "Mike Gilmour"
wrote:

"Iain M Churches" wrote in message
...

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Can we then expect to see two individual and hopefully unique designs posted
on a binaries soon complete with the designers accompanying notes on their
own design strategy and performance expectations.
I look forward to this in anticipation of some really creative designs that
reflect their indviduality and their respective long experiences in both
valve and SS technologies.

Oh bugger, I might have to dust off my slide rule! My problem with
this task would be the sheer futility of attempting to 'optimise' a
fundamentally crippled design, i.e. the low-powered single-ended
amplifier. Andre thinks that he's creating an 'ultra fidelity'
amplifier, I know that I would be attempting to create the fastest
three-legged horse....................

Rubbish.

A keen trainer here just won the Melbourne Cup by entering a
trained kangaroo fed on Vita Brits for a week.

And a kangaroo has only two legs, and they are used both at once,
and yer canna get more single ended than that young fella.

Start thinking laterally.

Patrick Turner.



It smacks of performing cosmetic surgery on a terminal cancer patient.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Mon, 29 Nov 2004 21:39:12 +1100, Patrick Turner
wrote:

mick wrote:

On Sun, 28 Nov 2004 16:08:00 +0000, Stewart Pinkerton wrote:

snip

Hmmm. That's a thought. It would certainly be possible to produce such a
design, and I could even utilise FETs to provide not dissimilar transfer
curves. A 6-watt SEFET amp would not be difficult to implement, and would
of course be *vastly* cheaper than the 300B equivalent, so pretty easy
(and safe!) to knock up over a weekend.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

They would largely differ through the absence of an OPT in the SS design
(I would use a resistive source load, and damn the efficiency!).
Otherwise, they would be equally crippled by SE asymmetry and low output.

Go on, Stewart. Give it a go. I built a headphone amp a while ago using a
class A MOSFET with an op-amp gain stage, which was very encouraging. It
had, IIRC, a voltage regulator used as a current source for the output
stage instead of a resistor. Not a lot of power, but something upgraded
from that sort of thing would be interesting. Resistive sources get damn
hot.... sizzle ok for frying bacon while listening to music!

Could use a choke.

But then most SS orientated people froth at the mouth about chokes and
transformers.
Its understandable. Back emfs can ruin a transistor with such ease.....

It's not that, it's the *nonlinearity* of the iron that makes us foam
at the mouth. Heck, even some of the more extreme tubies worship at
the alter of OPTless amps! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Iain M Churches wrote:

It would be a pity to allow this discussion to degenerate
into a bar-room brawl.


It's the rough and tumble of usenews. One needs a fairly
thick skin to hang around here. It's possible that some
of the worst offenders may be fast friends in person...

some ppl sez that best parts in some McIntosh amp of SS era are output
autoformers.........
I dunno personally.....


--
.................................................. ........................
Choky
Prodanovic Aleksandar
YU

"don't use force, "don't use force,
use a larger hammer" use a larger tube
- Choky and IST"
- ZM
.................................................. ...........................
"Stewart Pinkerton" wrote in message
...
On Mon, 29 Nov 2004 21:39:12 +1100, Patrick Turner
wrote:

mick wrote:

On Sun, 28 Nov 2004 16:08:00 +0000, Stewart Pinkerton wrote:

snip

Hmmm. That's a thought. It would certainly be possible to produce
such a
design, and I could even utilise FETs to provide not dissimilar
transfer
curves. A 6-watt SEFET amp would not be difficult to implement, and
would
of course be *vastly* cheaper than the 300B equivalent, so pretty
easy
(and safe!) to knock up over a weekend.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

They would largely differ through the absence of an OPT in the SS
design
(I would use a resistive source load, and damn the efficiency!).
Otherwise, they would be equally crippled by SE asymmetry and low
output.

Go on, Stewart. Give it a go. I built a headphone amp a while ago using
a
class A MOSFET with an op-amp gain stage, which was very encouraging.
It
had, IIRC, a voltage regulator used as a current source for the output
stage instead of a resistor. Not a lot of power, but something upgraded
from that sort of thing would be interesting. Resistive sources get
damn
hot.... sizzle ok for frying bacon while listening to music!

Could use a choke.

But then most SS orientated people froth at the mouth about chokes and
transformers.
Its understandable. Back emfs can ruin a transistor with such ease.....

It's not that, it's the *nonlinearity* of the iron that makes us foam
at the mouth. Heck, even some of the more extreme tubies worship at
the alter of OPTless amps! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

hehe-beloved 'till he lick Andre's ass

--
.................................................. ........................
Choky
Prodanovic Aleksandar
YU

"don't use force, "don't use force,
use a larger hammer" use a larger tube
- Choky and IST"
- ZM
.................................................. ...........................
"Sander deWaal" wrote in message
...
This reminds me of the remarkable post by our beloved Lord Valve, when
he wrote about transistors: "Those 3-legged fuses......" ;-)

--
Sander de Waal
" SOA of a KT88? Sufficient. "

Stewart Pinkerton wrote:

On Mon, 29 Nov 2004 21:39:12 +1100, Patrick Turner
wrote:

mick wrote:

On Sun, 28 Nov 2004 16:08:00 +0000, Stewart Pinkerton wrote:

snip

Hmmm. That's a thought. It would certainly be possible to produce such a
design, and I could even utilise FETs to provide not dissimilar transfer
curves. A 6-watt SEFET amp would not be difficult to implement, and would
of course be *vastly* cheaper than the 300B equivalent, so pretty easy
(and safe!) to knock up over a weekend.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

They would largely differ through the absence of an OPT in the SS design
(I would use a resistive source load, and damn the efficiency!).
Otherwise, they would be equally crippled by SE asymmetry and low output.

Go on, Stewart. Give it a go. I built a headphone amp a while ago using a
class A MOSFET with an op-amp gain stage, which was very encouraging. It
had, IIRC, a voltage regulator used as a current source for the output
stage instead of a resistor. Not a lot of power, but something upgraded
from that sort of thing would be interesting. Resistive sources get damn
hot.... sizzle ok for frying bacon while listening to music!

Could use a choke.

But then most SS orientated people froth at the mouth about chokes and
transformers.
Its understandable. Back emfs can ruin a transistor with such ease.....

It's not that, it's the *nonlinearity* of the iron that makes us foam
at the mouth. Heck, even some of the more extreme tubies worship at
the alter of OPTless amps! :-)

Chokes have to be used carefully.

The key to using them in signal paths is to have a low impedance drive
attactched to them.

You see the inductance appears to change during a wave cycle, and
the inductance varies with amplitude of the wave, and frequency comes into it.

This means its poisenous to sound if you have a pentode driving a
choke, or a transformer in its anode circuit.
Same goes for having inductance in the collector or drain circuits of SS gear.

The typical distortion is 3H, which starts off high as a %, often right in the
middle
of the range of signals used, then the % falls, and rises again when saturation is
reached.
And it occurs over a wide range of F.

Air gapping helps in the case of chokes carrying DC, and in fact
thier distortion contribution is negligible since the inductance does stay pretty
constant
with signal, only large DC changes affect the L value.

So, using a gapped L instead of a current sink in a class A SS amp where you have
a bunch
of source follower mosfets is very ok.

Its because the Ro of say 4 mosfets in SF is about 0.28 ohms, so this
almost completely shunts the value of the equivalent non linear inductive
impedance.

One has to think of the L and being a perfect L but with some non linear impedance
strapped
across it. the value of this, whatever it may be, could be described
mathematically
by the whiz kids here, but I am not one, but I know the lower the driver source
impedance,
the lower the thd caused by the iron.

To see how bad it can be, try connecting a 5k R in series with the mains to an
average
mains tranny which is unloaded, and look at the wave form.
It has terrible 3H included.

I use a non gapped choke to supply DC to the triodes used as balanced driver
voltage
gain stages in my PP amps where I have EL84 in triode.

If I was compelled to use only resistances, I'd have to have a +400v supply,
and have 10k anode Rs to allow 20 mA idle in each tube, and have +200v at the
anodes.
If I have to drive quite a few output tubes, the following CR coupled bias R might
be
22k, so the R load seen by the EL84 has dwindled to 6.9k.

But I keep the above set up, but I add a 200H+ ct with the CT taken to the B+,
and the ends taken to the 10k.

The combination of the L+R means that at 1 kHz, the impedance of the elements
supplying
DC to the tubes is maybe 200k anode to anode, and a completely insignificant
load value from the signal operational point ot view.
Then the only real loads seen by the EL84s are the 22k bias R of the following
stage.

The Ra of the EL84 is about 2k, so a-a it is 4k, and this is quite low enough to
suppress the non linearity of the choke, also isolated by the 10k R.

The thd is then about 10 dB lower than what you'd get with pure resistive
loadings,
and the drive voltage can be 85vrms at each anode, yet the thd is quite
negligible,
perhaps 0.5%, which is reduced by the global NFB.
The normal voltage used during listening might be 8v, and thd is less than 0.05%,
and the choke's contribution to this is negligible.

Same goes for PP output transformers when well designed with GOSS material.

Such material isn't really necessary. I built an 8585 with largish OPTs,
plain old iron, and the thd is not above what is expected of the tubes, mainly
because of the NFB used, and the design of the wound item.

So now you've said you don't like iron, wash that mouth out with soap.

It ain't what you got that counts, its how you use it.

I also have built class A mosfet amps with an OPT,
using a topology normally reserved for tubes.
I doubt there would be anyone who could tell me I have CR and transformer coupling

after a listen, if they didn't know what was in the box.

Patrick Turner.




--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Choky" said:

Lord Valve

hehe-beloved 'till he lick Andre's ass

As you probably know, LV and I aren't the best of friends.
I have respect for his tube knowledge and business, though.

--
Sander de Waal
" SOA of a KT88? Sufficient. "

On Wed, 01 Dec 2004 00:27:35 +1100, Patrick Turner
wrote:



Stewart Pinkerton wrote:

On Mon, 29 Nov 2004 21:39:12 +1100, Patrick Turner
wrote:

mick wrote:

On Sun, 28 Nov 2004 16:08:00 +0000, Stewart Pinkerton wrote:

snip

Hmmm. That's a thought. It would certainly be possible to produce such a
design, and I could even utilise FETs to provide not dissimilar transfer
curves. A 6-watt SEFET amp would not be difficult to implement, and would
of course be *vastly* cheaper than the 300B equivalent, so pretty easy
(and safe!) to knock up over a weekend.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

They would largely differ through the absence of an OPT in the SS design
(I would use a resistive source load, and damn the efficiency!).
Otherwise, they would be equally crippled by SE asymmetry and low output.

Go on, Stewart. Give it a go. I built a headphone amp a while ago using a
class A MOSFET with an op-amp gain stage, which was very encouraging. It
had, IIRC, a voltage regulator used as a current source for the output
stage instead of a resistor. Not a lot of power, but something upgraded
from that sort of thing would be interesting. Resistive sources get damn
hot.... sizzle ok for frying bacon while listening to music!

Could use a choke.

But then most SS orientated people froth at the mouth about chokes and
transformers.
Its understandable. Back emfs can ruin a transistor with such ease.....

It's not that, it's the *nonlinearity* of the iron that makes us foam
at the mouth. Heck, even some of the more extreme tubies worship at
the alter of OPTless amps! :-)

Chokes have to be used carefully.

The key to using them in signal paths is to have a low impedance drive
attactched to them.

You see the inductance appears to change during a wave cycle, and
the inductance varies with amplitude of the wave, and frequency comes into it.

This means its poisenous to sound if you have a pentode driving a
choke, or a transformer in its anode circuit.
Same goes for having inductance in the collector or drain circuits of SS gear.

The typical distortion is 3H, which starts off high as a %, often right in the
middle
of the range of signals used, then the % falls, and rises again when saturation is
reached.
And it occurs over a wide range of F.

Air gapping helps in the case of chokes carrying DC, and in fact
thier distortion contribution is negligible since the inductance does stay pretty
constant
with signal, only large DC changes affect the L value.

So, using a gapped L instead of a current sink in a class A SS amp where you have
a bunch
of source follower mosfets is very ok.

Its because the Ro of say 4 mosfets in SF is about 0.28 ohms, so this
almost completely shunts the value of the equivalent non linear inductive
impedance.

One has to think of the L and being a perfect L but with some non linear impedance
strapped
across it. the value of this, whatever it may be, could be described
mathematically
by the whiz kids here, but I am not one, but I know the lower the driver source
impedance,
the lower the thd caused by the iron.

To see how bad it can be, try connecting a 5k R in series with the mains to an
average
mains tranny which is unloaded, and look at the wave form.
It has terrible 3H included.

I use a non gapped choke to supply DC to the triodes used as balanced driver
voltage
gain stages in my PP amps where I have EL84 in triode.

If I was compelled to use only resistances, I'd have to have a +400v supply,
and have 10k anode Rs to allow 20 mA idle in each tube, and have +200v at the
anodes.
If I have to drive quite a few output tubes, the following CR coupled bias R might
be
22k, so the R load seen by the EL84 has dwindled to 6.9k.

But I keep the above set up, but I add a 200H+ ct with the CT taken to the B+,
and the ends taken to the 10k.

The combination of the L+R means that at 1 kHz, the impedance of the elements
supplying
DC to the tubes is maybe 200k anode to anode, and a completely insignificant
load value from the signal operational point ot view.
Then the only real loads seen by the EL84s are the 22k bias R of the following
stage.

The Ra of the EL84 is about 2k, so a-a it is 4k, and this is quite low enough to
suppress the non linearity of the choke, also isolated by the 10k R.

The thd is then about 10 dB lower than what you'd get with pure resistive
loadings,
and the drive voltage can be 85vrms at each anode, yet the thd is quite
negligible,
perhaps 0.5%, which is reduced by the global NFB.
The normal voltage used during listening might be 8v, and thd is less than 0.05%,
and the choke's contribution to this is negligible.

Same goes for PP output transformers when well designed with GOSS material.

Such material isn't really necessary. I built an 8585 with largish OPTs,
plain old iron, and the thd is not above what is expected of the tubes, mainly
because of the NFB used, and the design of the wound item.

So now you've said you don't like iron, wash that mouth out with soap.

If your figures are correct, and apply from 15Hz to 30kHz, then it
might fly - certainly helps a lot with electrical efficiency, when
compared to a CC load.

It ain't what you got that counts, its how you use it.

I bet you say that to all the girls! :-)

I also have built class A mosfet amps with an OPT,
using a topology normally reserved for tubes.
I doubt there would be anyone who could tell me I have CR and transformer coupling

after a listen, if they didn't know what was in the box.

I saw your 50-watt design - very 'tubey' topology......... :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Thank you and well said. I also enjoy Andre's comments.

I would point out that this is rec.audio.tubes. Although I have used a
transistor or two in my life, I enjoy vacuum tubes. I probably won't bother
to build a solid state amp. Been there and done that. I enjoyed that then
and enjoy tubes more. When the output transistors glow, there's a serious
problem.

Please let Andre speak and extend him the courtesy of listening or if you
don't want to listen, at least wait for him to finish so others can listen.

Rob



"Iain M Churches" wrote in message
...
It is clear from his posts on the KISS amp thread so
far, that Andre has spent considerable time and effort
in preparing what promises to be one of the most
interesting articles on RAT for a very long time.

It would be a pity to allow this discussion to degenerate
into a bar-room brawl.

No one would expect to heckle a lecturer at university
or technical college, or a speaker at an AES convention
in such a manner, so why should such gross behaviour
be deemed appropriate in this NG?

Why can't we extend to Andre the courtesy he deserves,
and listen to what he has to tell us? There will, no doubt,
be room for the discussion at the end of each chapter, and
also the opportunity for questions and answers when the
design process is complete.

After that, perhaps Stewart will give us the benefit of
his long experience as an engineer in SS analogue design,
and begin a new thread to take us through the process of
designing and building a lower power solid-state amp with a
similar specification to Andre's valve amplifier.

There are probably many of us who would be interested to build both
designs, and measure and compare audibly the merits of each.

Cordially,

Iain

So now you've said you don't like iron, wash that mouth out with soap.

If your figures are correct, and apply from 15Hz to 30kHz, then it
might fly - certainly helps a lot with electrical efficiency, when
compared to a CC load.

This is one benefit of a choke.
Efficiency is of course inaudible.

The inductance used with a class A source follower amp
does not have to be a huge amount.
If it is 200mH, then an 8 ohm load L together in parallel
have an impedance of 5.6 ohms at 6.36 Hz.
such a choke for a class A amp idling with say 3 amps of current
needs to have a low dcr, say 1 ohm, and even so, 9 watts is dissipated in 1 ohm at
3 amps.

The use of CR coupling on the input of the source follower is advisable to prevent the
open loop gain going down to DC.
Thus the mosfets will never have to cope with the 1 ohm DCR of the choke.

So the L has to be at least a Kg, maybe more, and bean counters hate weight, since
weight always costs,
so chokes are outlawed in mainstream design.
People don't know how to gap the choke.
Bean counters try to use an infinite sized gap, and the amp has no room
for such a choke.


It ain't what you got that counts, its how you use it.

I bet you say that to all the girls! :-)

I do try to educate Nicole and Kylie about how to use my old mower for the lawns.
They want a ride-on model mower, but I tell then you gotta push mine around to cut the
grass.
The ladder and hedge clipping is a real challenge for them.....
They argue about who holds the ladder....



I also have built class A mosfet amps with an OPT,
using a topology normally reserved for tubes.
I doubt there would be anyone who could tell me I have CR and transformer coupling

after a listen, if they didn't know what was in the box.

I saw your 50-watt design - very 'tubey' topology......... :-)

It could have been done better and more simply with pnp type mosfets.
Then the output stage could have been direct coupled to the input npn fets,
and in a sort of zsiclai pp pair.

Instead of an OPT, one simply uses a CT single winding auto transformer.
The CT is grounded.
Then you have the output for 8 ohms off the ends of the one winding, which will be at
equal DC potentials of a volt or two depending on the DC idle currents which balance in
the
primary.

For 2 ohms loads, you have taps 1/2 way between the winding ends and the CT.
For any other load, you place pairs of taps appropriately.
A toroidal core is doable, and for a 50 watt class A amp a GOSS toroidal core normally
used
for a 300 watt mains tranny will do.
About 200 turns of 1.6 mm dia wire is all that's needed, so a diyer can do such
an item using a broomstick shuttle to wind the toroid.
The efficiency of the toroidal auto transformer is a lot higher than for an isolation
transformer.
Bandwidth is usually 7 Hz to 100 kHz....distortion is very low... and you can't get a
huge speaker destroying
DC offset across the speaker terminals.

Patrick Turner.

On Tue, 30 Nov 2004 13:05:19 -0700, "Rob & Lyn Lewis"
wrote:

Thank you and well said. I also enjoy Andre's comments.

I would point out that this is rec.audio.tubes. Although I have used a
transistor or two in my life, I enjoy vacuum tubes. I probably won't bother
to build a solid state amp. Been there and done that. I enjoyed that then
and enjoy tubes more. When the output transistors glow, there's a serious
problem.

Admittedly, I see little point in creating a single-ended SS amp, as
it would possess most of the failings of its valved equivalent. Tim de
Paravicini has already created such a pairing with his EAR Yoshino
series, so it wouldn't even be a ground-breaking experiment.

Please let Andre speak and extend him the courtesy of listening or if you
don't want to listen, at least wait for him to finish so others can listen.

You seem to be confusing a Usenet newsgroup with a debating chamber.
It is not physically possible to interrupt Andre, one must always wait
for him to finish, and he's posting in 'EE 101' 'lessons', so it's
perfectly legitimate to comment on an individual section. I note
however that Andre does not choose to rebut my correction of his
errors, but simply starts personal attack threads in lieu of a
substantive argument. Is this the 'courtesy' you seek?

--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton wrote:

On Tue, 30 Nov 2004 13:05:19 -0700, "Rob & Lyn Lewis"
wrote:

Thank you and well said. I also enjoy Andre's comments.

I would point out that this is rec.audio.tubes. Although I have used a
transistor or two in my life, I enjoy vacuum tubes. I probably won't bother
to build a solid state amp. Been there and done that. I enjoyed that then
and enjoy tubes more. When the output transistors glow, there's a serious
problem.

Admittedly, I see little point in creating a single-ended SS amp, as
it would possess most of the failings of its valved equivalent.

Why would this be the case?

If it used the normal high amount of NFB, it would have none of the **alleged**
defects
of a valve amp.
It'd just be another SS amp.

But if it was class A, no need for so much NFB, and a whole gain stage can be
omitted.

Nelson Pass amps come to mind....

But in many SS amps, the input drive amp is a differential balanced pair of small
transistors,
then you often have a SINGLE ENDED DRIVER STAGE albeit one with
a CCS load for the gain transistor, and not fabulously linear, but the amount of
gain is *huge* and so the open loop linearity is of little concern because the
vast amount of
NFB straightens it all out.



Tim de
Paravicini has already created such a pairing with his EAR Yoshino
series, so it wouldn't even be a ground-breaking experiment.

I am not familiar with these amps.



Please let Andre speak and extend him the courtesy of listening or if you
don't want to listen, at least wait for him to finish so others can listen.

You seem to be confusing a Usenet newsgroup with a debating chamber.
It is not physically possible to interrupt Andre, one must always wait
for him to finish, and he's posting in 'EE 101' 'lessons', so it's
perfectly legitimate to comment on an individual section. I note
however that Andre does not choose to rebut my correction of his
errors, but simply starts personal attack threads in lieu of a
substantive argument. Is this the 'courtesy' you seek?

The "attacks" have been minimal, more like a man letting off a bit of steam.
If you fart in his direction, he'll fart back.

Maybe he feels a bit iritated by your whole attitude to 300B amps.

He is under no obligation to rebut any of your claims.

This is the internet, there *are no rules*.
Its not a scientific debating forum, with dire consequences if the agenda isn't
agreed on by a fraternity of electronic engineers.
We are not building an aeroplane or a bridge here, just a bloomin
low power amp.

Patrick Turner.







--

Stewart Pinkerton | Music is Art - Audio is Engineering

Patrick Turner said:

We are not building an aeroplane or a bridge here, just a bloomin
low power amp.

It might take off or blow up, though.

--
Sander de Waal
" SOA of a KT88? Sufficient. "

On Thu, 02 Dec 2004 02:20:19 +1100, Patrick Turner
wrote:



Stewart Pinkerton wrote:

On Tue, 30 Nov 2004 13:05:19 -0700, "Rob & Lyn Lewis"
wrote:

Thank you and well said. I also enjoy Andre's comments.

I would point out that this is rec.audio.tubes. Although I have used a
transistor or two in my life, I enjoy vacuum tubes. I probably won't bother
to build a solid state amp. Been there and done that. I enjoyed that then
and enjoy tubes more. When the output transistors glow, there's a serious
problem.

Admittedly, I see little point in creating a single-ended SS amp, as
it would possess most of the failings of its valved equivalent.

Why would this be the case?

If it used the normal high amount of NFB, it would have none of the **alleged**
defects
of a valve amp.

Sure it would - assymetric clipping and low power. There's no escaping
those problems with a 5 watt SE amp, whether valve or SS.

But if it was class A, no need for so much NFB, and a whole gain stage can be
omitted.

Excuse me? It *has* to be class A! Did you have a brainfart? :-)

Nelson Pass amps come to mind....

Indeed, his Aleph 3 is a fine example of the breed, but of course ten
times as powerful as the flea-power amp we are discussing here. It's
often described as a '30 watt' amplifier, but it's really designed for
60 watts into 4 ohms.

But in many SS amps, the input drive amp is a differential balanced pair of small
transistors,
then you often have a SINGLE ENDED DRIVER STAGE albeit one with
a CCS load for the gain transistor, and not fabulously linear, but the amount of
gain is *huge* and so the open loop linearity is of little concern because the
vast amount of
NFB straightens it all out.

Not what I was considering at all, and hardly in the spirit of the
'less is more' SE approach.

Tim de
Paravicini has already created such a pairing with his EAR Yoshino
series, so it wouldn't even be a ground-breaking experiment.

I am not familiar with these amps.

Low-power SE designs, one valve and one transistor. He considered them
to be his 'flagship' products, naming them after his Japanese wife.

Please let Andre speak and extend him the courtesy of listening or if you
don't want to listen, at least wait for him to finish so others can listen.

You seem to be confusing a Usenet newsgroup with a debating chamber.
It is not physically possible to interrupt Andre, one must always wait
for him to finish, and he's posting in 'EE 101' 'lessons', so it's
perfectly legitimate to comment on an individual section. I note
however that Andre does not choose to rebut my correction of his
errors, but simply starts personal attack threads in lieu of a
substantive argument. Is this the 'courtesy' you seek?

The "attacks" have been minimal, more like a man letting off a bit of steam.
If you fart in his direction, he'll fart back.

He needs to generate *four* attack threads to have a fart? Well, he
does indeed seem to be all wind and **** - mebbe he's getting on a
bit, and has gas problems. He's certainly a windbag in other ways! :-)

Maybe he feels a bit iritated by your whole attitude to 300B amps.

I have nothing against the 300B, it's a fine valve when used sensibly
in a PP quad...................

He is under no obligation to rebut any of your claims.

And no one is under any obligation to believe his claims about
orchestral SPLs, or to believe that a 12" paper-coned PA speaker with
a central 'whizzer' cone will deliver 'ultra-fidelity' sound quality.

This is the internet, there *are no rules*.
Its not a scientific debating forum, with dire consequences if the agenda isn't
agreed on by a fraternity of electronic engineers.
We are not building an aeroplane or a bridge here, just a bloomin
low power amp.

Quite so - and that's the problem! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Sander deWaal wrote:

Patrick Turner said:

We are not building an aeroplane or a bridge here, just a bloomin
low power amp.

It might take off or blow up, though.

Yea, and electrocute the builders.

Fiesty things, amplifiers.

Patrick Turner.



--
Sander de Waal
" SOA of a KT88? Sufficient. "

Stewart Pinkerton wrote:

On Thu, 02 Dec 2004 02:20:19 +1100, Patrick Turner
wrote:



Stewart Pinkerton wrote:

On Tue, 30 Nov 2004 13:05:19 -0700, "Rob & Lyn Lewis"
wrote:

Thank you and well said. I also enjoy Andre's comments.

I would point out that this is rec.audio.tubes. Although I have used a
transistor or two in my life, I enjoy vacuum tubes. I probably won't bother
to build a solid state amp. Been there and done that. I enjoyed that then
and enjoy tubes more. When the output transistors glow, there's a serious
problem.

Admittedly, I see little point in creating a single-ended SS amp, as
it would possess most of the failings of its valved equivalent.

Why would this be the case?

If it used the normal high amount of NFB, it would have none of the **alleged**
defects
of a valve amp.

Sure it would - assymetric clipping and low power. There's no escaping
those problems with a 5 watt SE amp, whether valve or SS.

Who said anything about 5 watts?
I thought we were focused on 8 watts from a 300B, but
12 watts is possible from just one T03 SE class A bjt or mosfet.

And you don't remember that with a proper load match SE clipping is symetrical.

But nobody goes near clipping with these amps for long enough for it to ever matter.





But if it was class A, no need for so much NFB, and a whole gain stage can be
omitted.

Excuse me? It *has* to be class A! Did you have a brainfart? :-)

Well of course it the driver is class A. Most drive amps are, and SE at that.
But some have a VAS stage using a commom emitter complementary gain pair,
and they can work in PP with pair of symetrical pnp and npn diff pairs at the input,
which are paralled.
I have done thios for my 2 x 300w amp using mosfets on the output.

Any reflected capacitance latch ups are discharged by devices turning on, not by
CCS taking their time to discharge caps.
Therfore the drive stage can work class AB.....



Nelson Pass amps come to mind....

Indeed, his Aleph 3 is a fine example of the breed, but of course ten
times as powerful as the flea-power amp we are discussing here. It's
often described as a '30 watt' amplifier, but it's really designed for
60 watts into 4 ohms.

I was thinking of the Zen, for 17 watts from two devices dissipatiing
100 watts.

My pal has fried two lots of mosfets, and has put the charred remains
on a shelf for when he has time, patience, money and knowledge.

Ain't it amazing how many projects get started by completely
ignorant but well meaning diyers, but they never get finished.


But in many SS amps, the input drive amp is a differential balanced pair of small
transistors,
then you often have a SINGLE ENDED DRIVER STAGE albeit one with
a CCS load for the gain transistor, and not fabulously linear, but the amount of
gain is *huge* and so the open loop linearity is of little concern because the
vast amount of
NFB straightens it all out.

Not what I was considering at all, and hardly in the spirit of the
'less is more' SE approach.

What is your favoured design then?



Tim de
Paravicini has already created such a pairing with his EAR Yoshino
series, so it wouldn't even be a ground-breaking experiment.

I am not familiar with these amps.

Low-power SE designs, one valve and one transistor. He considered them
to be his 'flagship' products, naming them after his Japanese wife.

I heard about a zen master of output tranformers who ascended Mt Fuji for several
weeks to contemplate the
% of cobalt that should be used in cores he was considering.
He eventually came down from the mountain, with "greatly fine knowledge and
understanding."

But more to the point, he was very fond of the girls serving the fine tucker from the
kiosks around the mountain,
and he really went up there 'cos his wife is a rotten cook, and he only came down when
the money ran out.

Tube and Transistor.

Its not really as zingy as saying ying and yang.

Valve and Mosfet

Yuk, sounds even worse.....



Please let Andre speak and extend him the courtesy of listening or if you
don't want to listen, at least wait for him to finish so others can listen.

You seem to be confusing a Usenet newsgroup with a debating chamber.
It is not physically possible to interrupt Andre, one must always wait
for him to finish, and he's posting in 'EE 101' 'lessons', so it's
perfectly legitimate to comment on an individual section. I note
however that Andre does not choose to rebut my correction of his
errors, but simply starts personal attack threads in lieu of a
substantive argument. Is this the 'courtesy' you seek?

The "attacks" have been minimal, more like a man letting off a bit of steam.
If you fart in his direction, he'll fart back.

He needs to generate *four* attack threads to have a fart? Well, he
does indeed seem to be all wind and **** - mebbe he's getting on a
bit, and has gas problems. He's certainly a windbag in other ways! :-)

Maybe you are rather easily offended.....



Maybe he feels a bit iritated by your whole attitude to 300B amps.

I have nothing against the 300B, it's a fine valve when used sensibly
in a PP quad...................

I have no objection to that, but its never going to appeal to mimimalists.

Maximalists will still think about trashcans and 300Bs in the same thought,
nothing is enough to really satisfy...

But as Andre says, he has a lot of other gear, he isn't compelled to use the
300B if he don't want to. He isn't saying that we all *must* use an SET amp.

Just because I like to go places, I don't restrict myself to a bicycle.
I own a Ford Laser, 1986, a real lil beauty. Only 60,000 kms on the clock.

Now if I owned a Rolls, well, I wouldn't own it at all,
*it would own me*.

People should be welcomed to have and to hold whatever they marry.



He is under no obligation to rebut any of your claims.

And no one is under any obligation to believe his claims about
orchestral SPLs, or to believe that a 12" paper-coned PA speaker with
a central 'whizzer' cone will deliver 'ultra-fidelity' sound quality.

This is the internet, there *are no rules*.
Its not a scientific debating forum, with dire consequences if the agenda isn't
agreed on by a fraternity of electronic engineers.
We are not building an aeroplane or a bridge here, just a bloomin
low power amp.

Quite so - and that's the problem! :-)

Its **your** problem, and definately one not shared by
everyone building low powered amps.

Patrick Turner.


--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 03 Dec 2004 00:48:13 +1100, Patrick Turner
wrote:



Stewart Pinkerton wrote:

On Thu, 02 Dec 2004 02:20:19 +1100, Patrick Turner
wrote:



Stewart Pinkerton wrote:

On Tue, 30 Nov 2004 13:05:19 -0700, "Rob & Lyn Lewis"
wrote:

Thank you and well said. I also enjoy Andre's comments.

I would point out that this is rec.audio.tubes. Although I have used a
transistor or two in my life, I enjoy vacuum tubes. I probably won't bother
to build a solid state amp. Been there and done that. I enjoyed that then
and enjoy tubes more. When the output transistors glow, there's a serious
problem.

Admittedly, I see little point in creating a single-ended SS amp, as
it would possess most of the failings of its valved equivalent.

Why would this be the case?

If it used the normal high amount of NFB, it would have none of the **alleged**
defects
of a valve amp.

Sure it would - assymetric clipping and low power. There's no escaping
those problems with a 5 watt SE amp, whether valve or SS.

Who said anything about 5 watts?

Andre did.

I thought we were focused on 8 watts from a 300B, but
12 watts is possible from just one T03 SE class A bjt or mosfet.

But that would not then be equivalent to Andre's 'ultra-fidelity'
flea-power 300B SET.

And you don't remember that with a proper load match SE clipping is symetrical.

No it isn't, because the amp is 'freewheeling' in one direction but
has much higher drive capability in the other. It's push-rebound, not
push-pull.

But nobody goes near clipping with these amps for long enough for it to ever matter.

At 5 watts max output? Yeah riiiiiight............

But if it was class A, no need for so much NFB, and a whole gain stage can be
omitted.

Excuse me? It *has* to be class A! Did you have a brainfart? :-)

Well of course it the driver is class A. Most drive amps are, and SE at that.
But some have a VAS stage using a commom emitter complementary gain pair,
and they can work in PP with pair of symetrical pnp and npn diff pairs at the input,
which are paralled.
I have done thios for my 2 x 300w amp using mosfets on the output.

Any reflected capacitance latch ups are discharged by devices turning on, not by
CCS taking their time to discharge caps.
Therfore the drive stage can work class AB.....

Yecccchhhh.................

But we're still talking about a 5-watt amp here, no need for complex
drive circuitry.

Nelson Pass amps come to mind....

Indeed, his Aleph 3 is a fine example of the breed, but of course ten
times as powerful as the flea-power amp we are discussing here. It's
often described as a '30 watt' amplifier, but it's really designed for
60 watts into 4 ohms.

I was thinking of the Zen, for 17 watts from two devices dissipatiing
100 watts.

My pal has fried two lots of mosfets, and has put the charred remains
on a shelf for when he has time, patience, money and knowledge.

Ain't it amazing how many projects get started by completely
ignorant but well meaning diyers, but they never get finished.

Indeed - I still have a suitcase full of parts that will likely never
be used now!

But in many SS amps, the input drive amp is a differential balanced pair of small
transistors,
then you often have a SINGLE ENDED DRIVER STAGE albeit one with
a CCS load for the gain transistor, and not fabulously linear, but the amount of
gain is *huge* and so the open loop linearity is of little concern because the
vast amount of
NFB straightens it all out.

Not what I was considering at all, and hardly in the spirit of the
'less is more' SE approach.

What is your favoured design then?

Pretty much a FET or BJT copy of the standard 300B SET topology, just
for the fun of the comparison. Not suggesting by *any* means that this
is a good way to design amplifiers, of course! :-)

Tim de
Paravicini has already created such a pairing with his EAR Yoshino
series, so it wouldn't even be a ground-breaking experiment.

I am not familiar with these amps.

Low-power SE designs, one valve and one transistor. He considered them
to be his 'flagship' products, naming them after his Japanese wife.

I heard about a zen master of output tranformers who ascended Mt Fuji for several
weeks to contemplate the
% of cobalt that should be used in cores he was considering.
He eventually came down from the mountain, with "greatly fine knowledge and
understanding."

Yeah, sounds like Crazy Tim, all right! :-)

But more to the point, he was very fond of the girls serving the fine tucker from the
kiosks around the mountain,
and he really went up there 'cos his wife is a rotten cook, and he only came down when
the money ran out.

Tube and Transistor.

Its not really as zingy as saying ying and yang.

Valve and Mosfet

Yuk, sounds even worse.....

Solid state and hollow-state, all made from silicon.............

Please let Andre speak and extend him the courtesy of listening or if you
don't want to listen, at least wait for him to finish so others can listen.

You seem to be confusing a Usenet newsgroup with a debating chamber.
It is not physically possible to interrupt Andre, one must always wait
for him to finish, and he's posting in 'EE 101' 'lessons', so it's
perfectly legitimate to comment on an individual section. I note
however that Andre does not choose to rebut my correction of his
errors, but simply starts personal attack threads in lieu of a
substantive argument. Is this the 'courtesy' you seek?

The "attacks" have been minimal, more like a man letting off a bit of steam.
If you fart in his direction, he'll fart back.

He needs to generate *four* attack threads to have a fart? Well, he
does indeed seem to be all wind and **** - mebbe he's getting on a
bit, and has gas problems. He's certainly a windbag in other ways! :-)

Maybe you are rather easily offended.....

Nah, I obviously just touched a nerve and pricked the old gasbag!

Maybe he feels a bit iritated by your whole attitude to 300B amps.

I have nothing against the 300B, it's a fine valve when used sensibly
in a PP quad...................

I have no objection to that, but its never going to appeal to mimimalists.

Indeed so, but the minimalists don't appeal to me, so I guess that's
fair enough. :-)

Maximalists will still think about trashcans and 300Bs in the same thought,
nothing is enough to really satisfy...

Well, there's no denying that a Krell FPB300, or even an Arcam A85, is
a vastly superior device for driving loudspeakers.

But as Andre says, he has a lot of other gear, he isn't compelled to use the
300B if he don't want to. He isn't saying that we all *must* use an SET amp.

But he does claim that it has 'ultra fidelity', which must be worth a
raised eyebrow, if not a healthy belly laugh!

Just because I like to go places, I don't restrict myself to a bicycle.
I own a Ford Laser, 1986, a real lil beauty. Only 60,000 kms on the clock.

Now if I owned a Rolls, well, I wouldn't own it at all,
*it would own me*.

It's only a tarted-up BMW these days, y'know...... :-)

People should be welcomed to have and to hold whatever they marry.

Ahhh, so you haven't met my wife? :-)

He is under no obligation to rebut any of your claims.

And no one is under any obligation to believe his claims about
orchestral SPLs, or to believe that a 12" paper-coned PA speaker with
a central 'whizzer' cone will deliver 'ultra-fidelity' sound quality.

This is the internet, there *are no rules*.
Its not a scientific debating forum, with dire consequences if the agenda isn't
agreed on by a fraternity of electronic engineers.
We are not building an aeroplane or a bridge here, just a bloomin
low power amp.

Quite so - and that's the problem! :-)

Its **your** problem, and definately one not shared by
everyone building low powered amps.

Nope, it's an absolute problem, and 'everyone' is mostly certainly not
building low-powered amps. But hey, that's not really the point, is
it? Let's just see what Andre comes up with in his design process.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton wrote:

On Fri, 03 Dec 2004 00:48:13 +1100, Patrick Turner
wrote:



Stewart Pinkerton wrote:

On Thu, 02 Dec 2004 02:20:19 +1100, Patrick Turner
wrote:



Stewart Pinkerton wrote:

On Tue, 30 Nov 2004 13:05:19 -0700, "Rob & Lyn Lewis"
wrote:

Thank you and well said. I also enjoy Andre's comments.

I would point out that this is rec.audio.tubes. Although I have used a
transistor or two in my life, I enjoy vacuum tubes. I probably won't bother
to build a solid state amp. Been there and done that. I enjoyed that then
and enjoy tubes more. When the output transistors glow, there's a serious
problem.

Admittedly, I see little point in creating a single-ended SS amp, as
it would possess most of the failings of its valved equivalent.

Why would this be the case?

If it used the normal high amount of NFB, it would have none of the **alleged**
defects
of a valve amp.

Sure it would - assymetric clipping and low power. There's no escaping
those problems with a 5 watt SE amp, whether valve or SS.

Who said anything about 5 watts?

Andre did.

Oh, yes, in the conext of aiming for 5 watts max to achieve low thd
at max 5 watts, but using appropriate speakers.

For a long time I used sensitive cheap lightweight cone speakers in my double garage sized
workshop.
The drivers were normally used as ceiling
speakers but I fitted them into reflexed boxes I found suitable, and I had 6BQ5 in pentode
with CFB and some global NFB, and I thought the sound was ex-ceee-lent for
backgound in the shed.




I thought we were focused on 8 watts from a 300B, but
12 watts is possible from just one T03 SE class A bjt or mosfet.

But that would not then be equivalent to Andre's 'ultra-fidelity'
flea-power 300B SET.

Well we could stipulate that the BJT dissipate no more than 12 watts, from which a max
of 5 watts class A SE could be available.

They used to fit cars with such class A amps using some of the early
T03 bjts. I fixed an ancient Astom Martin radio like that.
It must have sounded OK.....



And you don't remember that with a proper load match SE clipping is symetrical.

No it isn't, because the amp is 'freewheeling' in one direction but
has much higher drive capability in the other. It's push-rebound, not
push-pull.

The wave forms on the CRO of my SE amps into the rated load is symetrical.

But we are arguing BS here.

Who cares what the clipping symetry is?

It don't matter if it clips on one side before the other, its just clipping, and we try to
stay clear
of that level.




But nobody goes near clipping with these amps for long enough for it to ever matter.

At 5 watts max output? Yeah riiiiiight............

I just spent all evening with a guy using SE amps, and we never used more than about 3
watts.

Speaker sensitivity is only 89 dB/W/M....



But if it was class A, no need for so much NFB, and a whole gain stage can be
omitted.

Excuse me? It *has* to be class A! Did you have a brainfart? :-)

Well of course it the driver is class A. Most drive amps are, and SE at that.
But some have a VAS stage using a commom emitter complementary gain pair,
and they can work in PP with pair of symetrical pnp and npn diff pairs at the input,
which are paralled.
I have done thios for my 2 x 300w amp using mosfets on the output.

Any reflected capacitance latch ups are discharged by devices turning on, not by
CCS taking their time to discharge caps.
Therfore the drive stage can work class AB.....

Yecccchhhh.................

You can't knock PP complementary drive stages preceeded with symetrically arranged
diff pairs.

One can make them very linear with their own nested feedback loops,
or by using some R in the collector loading, and having emitter R to give current FB.....

The topologies available to the dabbler in SS is almost as great in number as there
are dabblers, since *so many* topologies will work well....

Whether it sounds right is beyond my typing capabilities after an evening
listening to blameless SE sound.



But we're still talking about a 5-watt amp here, no need for complex
drive circuitry.

Nelson Pass amps come to mind....

Indeed, his Aleph 3 is a fine example of the breed, but of course ten
times as powerful as the flea-power amp we are discussing here. It's
often described as a '30 watt' amplifier, but it's really designed for
60 watts into 4 ohms.

I was thinking of the Zen, for 17 watts from two devices dissipatiing
100 watts.

My pal has fried two lots of mosfets, and has put the charred remains
on a shelf for when he has time, patience, money and knowledge.

Ain't it amazing how many projects get started by completely
ignorant but well meaning diyers, but they never get finished.

Indeed - I still have a suitcase full of parts that will likely never
be used now!

Ah, you design skills are indicated by the tonnage of burnt parts, eh.. :-)



But in many SS amps, the input drive amp is a differential balanced pair of small
transistors,
then you often have a SINGLE ENDED DRIVER STAGE albeit one with
a CCS load for the gain transistor, and not fabulously linear, but the amount of
gain is *huge* and so the open loop linearity is of little concern because the
vast amount of
NFB straightens it all out.

Not what I was considering at all, and hardly in the spirit of the
'less is more' SE approach.

What is your favoured design then?

Pretty much a FET or BJT copy of the standard 300B SET topology, just
for the fun of the comparison. Not suggesting by *any* means that this
is a good way to design amplifiers, of course! :-)

Its a very easy thing to do, really.

You need an OPT, rather simple, since its step down ration need only be
about 10 to 5 ohms, but the wire will be thicker, and the turns lower for the primary,
while the core size and the secondary has to be the same as for the 300B amp.

A small signal fet could be used as a driver of the output mosfet
in common source mode.

NFB is essnetial since the drain resistance of a mosfet is about 220 ohms
and at the sec it will be 100 ohms, so enough loop FB is needed
to reduce the Ro to about 2 ohms to make it the equivalant of the 300B amp with no loop
FB.






Tim de
Paravicini has already created such a pairing with his EAR Yoshino
series, so it wouldn't even be a ground-breaking experiment.

I am not familiar with these amps.

Low-power SE designs, one valve and one transistor. He considered them
to be his 'flagship' products, naming them after his Japanese wife.

I heard about a zen master of output tranformers who ascended Mt Fuji for several
weeks to contemplate the
% of cobalt that should be used in cores he was considering.
He eventually came down from the mountain, with "greatly fine knowledge and
understanding."

Yeah, sounds like Crazy Tim, all right! :-)

He's different, rather than crazy.....



But more to the point, he was very fond of the girls serving the fine tucker from the
kiosks around the mountain,
and he really went up there 'cos his wife is a rotten cook, and he only came down when
the money ran out.

Tube and Transistor.

Its not really as zingy as saying ying and yang.

Valve and Mosfet

Yuk, sounds even worse.....

Solid state and hollow-state, all made from silicon.............

Neither fish nor feather, like a wandering spirit between worlds......

Maybe you are rather easily offended.....

Nah, I obviously just touched a nerve and pricked the old gasbag!

And you blow no gas?

Why, when suitably coupled by the hydraulic equivalent model of a pipework
output transformer, you could supply Greater London with after hours lighting energy....



Maybe he feels a bit iritated by your whole attitude to 300B amps.

I have nothing against the 300B, it's a fine valve when used sensibly
in a PP quad...................

I have no objection to that, but its never going to appeal to mimimalists.

Indeed so, but the minimalists don't appeal to me, so I guess that's
fair enough. :-)

I'll have to report you to the Anti Minimalist Discrimination Tribunal.

Watch out, loin clothed officers will be around to see you in the morning....



Maximalists will still think about trashcans and 300Bs in the same thought,
nothing is enough to really satisfy...

Well, there's no denying that a Krell FPB300, or even an Arcam A85, is
a vastly superior device for driving loudspeakers.

In your humble opinion....


But as Andre says, he has a lot of other gear, he isn't compelled to use the
300B if he don't want to. He isn't saying that we all *must* use an SET amp.

But he does claim that it has 'ultra fidelity', which must be worth a
raised eyebrow, if not a healthy belly laugh!

Poetic license. Nothing to worry about.

I got a license at 50 to do as I like and so did most others over 50, but the
Department Of Entertainment and Pleasure ( D.O.P.E.) could make my license invalaid at
the stroke of a pen if I breach the guidelines, but luckily poetic license was included as
an
amendment insisted upon opposition which controlled the senate at the time the bill was
passed
3 years ago by the conservative right wing anti fun party holding power..



Just because I like to go places, I don't restrict myself to a bicycle.
I own a Ford Laser, 1986, a real lil beauty. Only 60,000 kms on the clock.

Now if I owned a Rolls, well, I wouldn't own it at all,
*it would own me*.

It's only a tarted-up BMW these days, y'know...... :-)

Being owned by a tart is beyond the pale then....



People should be welcomed to have and to hold whatever they marry.

Ahhh, so you haven't met my wife? :-)

You haven't ruined her yet?


We are not building an aeroplane or a bridge here, just a bloomin
low power amp.

Quite so - and that's the problem! :-)

Its **your** problem, and definately one not shared by
everyone building low powered amps.

Nope, it's an absolute problem, and 'everyone' is mostly certainly not
building low-powered amps. But hey, that's not really the point, is
it? Let's just see what Andre comes up with in his design process.
--

Absolute meaning inherently without a solution.
It depends.....

Patrick Turner.


Stewart Pinkerton | Music is Art - Audio is Engineering

On Sat, 04 Dec 2004 01:18:26 +1100, Patrick Turner
wrote:

Stewart Pinkerton wrote:

On Fri, 03 Dec 2004 00:48:13 +1100, Patrick Turner
wrote:

My pal has fried two lots of mosfets, and has put the charred remains
on a shelf for when he has time, patience, money and knowledge.

Ain't it amazing how many projects get started by completely
ignorant but well meaning diyers, but they never get finished.

Indeed - I still have a suitcase full of parts that will likely never
be used now!

Ah, you design skills are indicated by the tonnage of burnt parts, eh.. :-)

No, they go in the bin, I meant that I have a sizeable stock of new
parts (well, NOS by now, I guess!), but I can buy a better amp than I
can build for the parts cost of that amp. Economies of scale, and all
that. I gave up building serious amps about fifteen years ago, it just
wasn't worth the effort any more. Of course, I was building *linear*
amps, not hollow-state tone controls... :-)

What is your favoured design then?

Pretty much a FET or BJT copy of the standard 300B SET topology, just
for the fun of the comparison. Not suggesting by *any* means that this
is a good way to design amplifiers, of course! :-)

Its a very easy thing to do, really.

You need an OPT, rather simple, since its step down ration need only be
about 10 to 5 ohms, but the wire will be thicker, and the turns lower for the primary,
while the core size and the secondary has to be the same as for the 300B amp.

A small signal fet could be used as a driver of the output mosfet
in common source mode.

NFB is essnetial since the drain resistance of a mosfet is about 220 ohms
and at the sec it will be 100 ohms, so enough loop FB is needed
to reduce the Ro to about 2 ohms to make it the equivalant of the 300B amp with no loop
FB.

Hmmm, I was thinking of keeping it just to local degeneration, with no
global NFB. Just to keep in the spirit of things SET. The drain
resistance does after all depend on the MOSFET(S) being used.

I heard about a zen master of output tranformers who ascended Mt Fuji for several
weeks to contemplate the
% of cobalt that should be used in cores he was considering.
He eventually came down from the mountain, with "greatly fine knowledge and
understanding."

Yeah, sounds like Crazy Tim, all right! :-)

He's different, rather than crazy.....

A matter of opinion, perhaps. I'll certainly agree that he's
different! :-)

Nah, I obviously just touched a nerve and pricked the old gasbag!

And you blow no gas?

I have the right to remain silent, I choose not to exercise that
right! :-)

Why, when suitably coupled by the hydraulic equivalent model of a pipework
output transformer, you could supply Greater London with after hours lighting energy....

Hmmmm, perhaps there's some cash to be made there..............

Maybe he feels a bit iritated by your whole attitude to 300B amps.

I have nothing against the 300B, it's a fine valve when used sensibly
in a PP quad...................

I have no objection to that, but its never going to appeal to mimimalists.

Indeed so, but the minimalists don't appeal to me, so I guess that's
fair enough. :-)

I'll have to report you to the Anti Minimalist Discrimination Tribunal.

Watch out, loin clothed officers will be around to see you in the morning....

No problem, my lion doesn't wear clothes, and will be pleased to
invite them in for breakfast.

Maximalists will still think about trashcans and 300Bs in the same thought,
nothing is enough to really satisfy...

Well, there's no denying that a Krell FPB300, or even an Arcam A85, is
a vastly superior device for driving loudspeakers.

In your humble opinion....

Well, if you include sound quality rather than SPL and flat FR, I
guess that is just an opinion.

But as Andre says, he has a lot of other gear, he isn't compelled to use the
300B if he don't want to. He isn't saying that we all *must* use an SET amp.

But he does claim that it has 'ultra fidelity', which must be worth a
raised eyebrow, if not a healthy belly laugh!

Poetic license. Nothing to worry about.

I got a license at 50 to do as I like and so did most others over 50, but the
Department Of Entertainment and Pleasure ( D.O.P.E.)

Do you see the irony in the above? :-)

could make my license invalaid at
the stroke of a pen if I breach the guidelines, but luckily poetic license was included as
an
amendment insisted upon opposition which controlled the senate at the time the bill was
passed
3 years ago by the conservative right wing anti fun party holding power..

Just because I like to go places, I don't restrict myself to a bicycle.
I own a Ford Laser, 1986, a real lil beauty. Only 60,000 kms on the clock.

Now if I owned a Rolls, well, I wouldn't own it at all,
*it would own me*.

It's only a tarted-up BMW these days, y'know...... :-)

Being owned by a tart is beyond the pale then....

There's a name for that, and I'd look even silliier in a pink fur
fedora!..............

People should be welcomed to have and to hold whatever they marry.

Ahhh, so you haven't met my wife? :-)

You haven't ruined her yet?

One of the ruins that Henry knocked about a bit.........

Still haven't persuaded her that a Home Cinema is a *much* higher
priority than a new car............

We are not building an aeroplane or a bridge here, just a bloomin
low power amp.

Quite so - and that's the problem! :-)

Its **your** problem, and definately one not shared by
everyone building low powered amps.

Nope, it's an absolute problem, and 'everyone' is mostly certainly not
building low-powered amps. But hey, that's not really the point, is
it? Let's just see what Andre comes up with in his design process.
--

Absolute meaning inherently without a solution.
It depends.....

Absolute meaning it is a problem for everyone, and only soluble by
using extremely efficient speakers, which carries its own penalty of
size and cost.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton wrote:

On Sat, 04 Dec 2004 01:18:26 +1100, Patrick Turner
wrote:

Stewart Pinkerton wrote:

On Fri, 03 Dec 2004 00:48:13 +1100, Patrick Turner
wrote:

My pal has fried two lots of mosfets, and has put the charred remains
on a shelf for when he has time, patience, money and knowledge.

Ain't it amazing how many projects get started by completely
ignorant but well meaning diyers, but they never get finished.

Indeed - I still have a suitcase full of parts that will likely never
be used now!

Ah, you design skills are indicated by the tonnage of burnt parts, eh.. :-)

No, they go in the bin, I meant that I have a sizeable stock of new
parts (well, NOS by now, I guess!), but I can buy a better amp than I
can build for the parts cost of that amp. Economies of scale, and all
that. I gave up building serious amps about fifteen years ago, it just
wasn't worth the effort any more. Of course, I was building *linear*
amps, not hollow-state tone controls... :-)

What is your favoured design then?

Pretty much a FET or BJT copy of the standard 300B SET topology, just
for the fun of the comparison. Not suggesting by *any* means that this
is a good way to design amplifiers, of course! :-)

Its a very easy thing to do, really.

You need an OPT, rather simple, since its step down ration need only be
about 10 to 5 ohms, but the wire will be thicker, and the turns lower for the primary,
while the core size and the secondary has to be the same as for the 300B amp.

A small signal fet could be used as a driver of the output mosfet
in common source mode.

NFB is essnetial since the drain resistance of a mosfet is about 220 ohms
and at the sec it will be 100 ohms, so enough loop FB is needed
to reduce the Ro to about 2 ohms to make it the equivalant of the 300B amp with no loop
FB.

Hmmm, I was thinking of keeping it just to local degeneration, with no
global NFB. Just to keep in the spirit of things SET.

You mean source follower.

That's cheating, see the headmaster immediately.

The spirit of things means the NFB most not be greater than what's inside a 300B
already.

The drain
resistance does after all depend on the MOSFET(S) being used.

Most output mosfets will have a finite drain resistance, and its far too high
to ignore it. Even the Zen Pass amp with one active mosfet uses about 12 dB of NFB in a loop.

Its reasonable to ask, is a Zen amp as good as a 300B?




I heard about a zen master of output tranformers who ascended Mt Fuji for several
weeks to contemplate the
% of cobalt that should be used in cores he was considering.
He eventually came down from the mountain, with "greatly fine knowledge and
understanding."

Yeah, sounds like Crazy Tim, all right! :-)

He's different, rather than crazy.....

A matter of opinion, perhaps. I'll certainly agree that he's
different! :-)

Nah, I obviously just touched a nerve and pricked the old gasbag!

And you blow no gas?

I have the right to remain silent, I choose not to exercise that
right! :-)

Why, when suitably coupled by the hydraulic equivalent model of a pipework
output transformer, you could supply Greater London with after hours lighting energy....

Hmmmm, perhaps there's some cash to be made there..............

Oh but the stink.........



Maybe he feels a bit iritated by your whole attitude to 300B amps.

I have nothing against the 300B, it's a fine valve when used sensibly
in a PP quad...................

I have no objection to that, but its never going to appeal to mimimalists.

Indeed so, but the minimalists don't appeal to me, so I guess that's
fair enough. :-)

I'll have to report you to the Anti Minimalist Discrimination Tribunal.

Watch out, loin clothed officers will be around to see you in the morning....

No problem, my lion doesn't wear clothes, and will be pleased to
invite them in for breakfast.

No need to describe your unmentionable loins around here.....

And you may be fixated about them, and even have breakfast with them,
and there is no accounting for taste.



Maximalists will still think about trashcans and 300Bs in the same thought,
nothing is enough to really satisfy...

Well, there's no denying that a Krell FPB300, or even an Arcam A85, is
a vastly superior device for driving loudspeakers.

In your humble opinion....

Well, if you include sound quality rather than SPL and flat FR, I
guess that is just an opinion.

But as Andre says, he has a lot of other gear, he isn't compelled to use the
300B if he don't want to. He isn't saying that we all *must* use an SET amp.

But he does claim that it has 'ultra fidelity', which must be worth a
raised eyebrow, if not a healthy belly laugh!

Poetic license. Nothing to worry about.

I got a license at 50 to do as I like and so did most others over 50, but the
Department Of Entertainment and Pleasure ( D.O.P.E.)

Do you see the irony in the above? :-)

could make my license invalaid at
the stroke of a pen if I breach the guidelines, but luckily poetic license was included as
an
amendment insisted upon opposition which controlled the senate at the time the bill was
passed
3 years ago by the conservative right wing anti fun party holding power..

Just because I like to go places, I don't restrict myself to a bicycle.
I own a Ford Laser, 1986, a real lil beauty. Only 60,000 kms on the clock.

Now if I owned a Rolls, well, I wouldn't own it at all,
*it would own me*.

It's only a tarted-up BMW these days, y'know...... :-)

Being owned by a tart is beyond the pale then....

There's a name for that, and I'd look even silliier in a pink fur
fedora!..............

Well, if she's an old tart, you could get away with being an old toy boy.
But forget the pink fur and fedora, she may think you are alternatively inclined.


People should be welcomed to have and to hold whatever they marry.

Ahhh, so you haven't met my wife? :-)

You haven't ruined her yet?

One of the ruins that Henry knocked about a bit.........

Henry V, or VIII?
My your wife getting on a bit.
But if she's able to put up with you and still get dinner on the table,
you must be doin OK in this terrible age of people spending
so much time rubbishing the very idea of marriage.



Still haven't persuaded her that a Home Cinema is a *much* higher
priority than a new car............

Did you tell her that the HT can't get run into or have its paintwork
all scratched up in a car park? But boy, real HT needs a screen
about the equivalant of 8 x 26 inch telies in size, and they are almost the
price of a car.

I prefer to have No Television In The Home, its a very bad influence on anyone.
I see about one movie a week at the local film club, where its 30c per movie.
Its nice being out of the house.

Let's face it, watching movies is about seeing other people doing their lives, and avoiding
doing your own.
I actually like avoiding my own conundrums of life sometimes.
But not enough to wanna spend 12 grand on a decent HT system, so I coulod watch
more movies at home, and waste more time away from my friends, and watchin BS.

I am happy to have a minimal intrusion of media into my house.
I cannot understand how ppl can sit there hour after hour watching TV
and putting up with the adds, and the biased news services.


We are not building an aeroplane or a bridge here, just a bloomin
low power amp.

Quite so - and that's the problem! :-)

Its **your** problem, and definately one not shared by
everyone building low powered amps.

Nope, it's an absolute problem, and 'everyone' is mostly certainly not
building low-powered amps. But hey, that's not really the point, is
it? Let's just see what Andre comes up with in his design process.
--

Absolute meaning inherently without a solution.
It depends.....

Absolute meaning it is a problem for everyone, and only soluble by
using extremely efficient speakers, which carries its own penalty of
size and cost.

There ya go again makin out everyone has the same problems.
Alas ye are mistaken....

Patrick Turner.


--

Stewart Pinkerton | Music is Art - Audio is Engineering