As a consequence of the issues raised in the recent debates, I'm
amazed that there seems to be widespread assumption here that the gain
of a tube output stage ( SET *or* P-P ) is simply derived from a stock
equation.

In the gain equation the plate load determines the upper term.

Where the ( refelcted ) load has a variable impedance ( such as a
loudspeaker ) then this term is also variable.

Hence in the real world - it's impossible for such a circuit
configuration to have a flat frequency response. From first
principles.

A flat frequency response can only exist into a pure resitive load.
Speakers are *not* pure resistive by any means.

The response can be *improved* by negative feedback but the response
errors can never be eliminated.

This only applies to circuits with the load in the plate circuit.
Loads in the cathode have no such problem by reason of the circuit
operation ( some understanding of electronic theory is presumed ).

Graham

Pooh Bear wrote

As a consequence of the issues raised in the recent debates, I'm
amazed that there seems to be widespread assumption here that the
gain
of a tube output stage ( SET *or* P-P ) is simply derived from a
stock
equation

Eh? Where? Who thinks that?

...

Where the ( refelcted ) load has a variable impedance ( such as a
loudspeaker ) then this term [gain] is also variable.

...

This only applies to circuits with the load in the plate circuit.
Loads in the cathode have no such problem by reason of the circuit
operation ( some understanding of electronic theory is presumed ).

Er...falsely in your case I'm afraid.

cheers, Ian

Ian Iveson wrote:
Pooh Bear wrote

As a consequence of the issues raised in the recent debates, I'm
amazed that there seems to be widespread assumption here that the
gain
of a tube output stage ( SET *or* P-P ) is simply derived from a
stock
equation

Eh? Where? Who thinks that?

Yeah, when I saw that I wondered who decided it was safe to let the fat
Graham "Poopie" Stevenson near the kindergarten. Social Services will
later claim they didn't know about his nickname...

Andre Jute


...

Where the ( refelcted ) load has a variable impedance ( such as a
loudspeaker ) then this term [gain] is also variable.

...

This only applies to circuits with the load in the plate circuit.
Loads in the cathode have no such problem by reason of the circuit
operation ( some understanding of electronic theory is presumed ).

Er...falsely in your case I'm afraid.

cheers, Ian

http://members.lycos.co.uk/fiultra/K...dre%20Jute.htm
and scroll down to the piccie

Pooh Bear wrote:

In the gain equation the plate load determines the upper term.

Where the ( refelcted ) load has a variable impedance ( such as a
loudspeaker ) then this term is also variable.

Ian Iveson wrote:

Pooh Bear wrote

As a consequence of the issues raised in the recent debates, I'm
amazed that there seems to be widespread assumption here that the
gain
of a tube output stage ( SET *or* P-P ) is simply derived from a
stock
equation

Eh? Where? Who thinks that?

Apparently Mr Joot.


Where the ( refelcted ) load has a variable impedance ( such as a
loudspeaker ) then this term [gain] is also variable.

...

This only applies to circuits with the load in the plate circuit.
Loads in the cathode have no such problem by reason of the circuit
operation ( some understanding of electronic theory is presumed ).

Er...falsely in your case I'm afraid.

You don't understand why a cathode follower has a voltage gain of ~ 1 ?

The total absence of any sensible understanding of circuit theory here
is staggering.


Graham

In article , Pooh Bear
wrote:

As a consequence of the issues raised in the recent debates, I'm
amazed that there seems to be widespread assumption here that the gain
of a tube output stage ( SET *or* P-P ) is simply derived from a stock
equation.

In the gain equation the plate load determines the upper term.

Where the ( refelcted ) load has a variable impedance ( such as a
loudspeaker ) then this term is also variable.

Hence in the real world - it's impossible for such a circuit
configuration to have a flat frequency response. From first
principles.

A flat frequency response can only exist into a pure resitive load.
Speakers are *not* pure resistive by any means.

Isn't the same also true for transistors, substituting the word collector
for plate?


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

"Pooh Bear" wrote in message
...
: As a consequence of the issues raised in the recent debates, I'm
: amazed that there seems to be widespread assumption here that the gain
: of a tube output stage ( SET *or* P-P ) is simply derived from a stock
: equation.
:
: In the gain equation the plate load determines the upper term.
:
: Where the ( refelcted ) load has a variable impedance ( such as a
: loudspeaker ) then this term is also variable.
:
: Hence in the real world - it's impossible for such a circuit
: configuration to have a flat frequency response. From first
: principles.
:
: A flat frequency response can only exist into a pure resitive load.
: Speakers are *not* pure resistive by any means.
:
: The response can be *improved* by negative feedback but the response
: errors can never be eliminated.
:
: This only applies to circuits with the load in the plate circuit.
: Loads in the cathode have no such problem by reason of the circuit
: operation ( some understanding of electronic theory is presumed ).
:
: Graham
:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

o, btw, we know Rp is a dynamic, current dependent impedance
with ul or triodes in pp, that is of no concern as it balances out
and as long as that stays well below reflected impedance it is
close enough to a 'perfect voltage driven loudspeaker'.

with se you can make the change in Rp small by using a high
current bias, then using a transformer that will give a reflected
impedance well above Rp-avg., no problems, either

so what was ya gonna say ?

Ruud Broens wrote:
"Pooh Bear" wrote in message
...
: As a consequence of the issues raised in the recent debates, I'm
: amazed that there seems to be widespread assumption here that the gain
: of a tube output stage ( SET *or* P-P ) is simply derived from a stock
: equation.
:
: In the gain equation the plate load determines the upper term.
:
: Where the ( refelcted ) load has a variable impedance ( such as a
: loudspeaker ) then this term is also variable.
:
: Hence in the real world - it's impossible for such a circuit
: configuration to have a flat frequency response. From first
: principles.
:
: A flat frequency response can only exist into a pure resitive load.
: Speakers are *not* pure resistive by any means.
:
: The response can be *improved* by negative feedback but the response
: errors can never be eliminated.
:
: This only applies to circuits with the load in the plate circuit.
: Loads in the cathode have no such problem by reason of the circuit
: operation ( some understanding of electronic theory is presumed ).
:
: Graham
:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

o, btw, we know Rp is a dynamic, current dependent impedance
with ul or triodes in pp, that is of no concern as it balances out
and as long as that stays well below reflected impedance it is
close enough to a 'perfect voltage driven loudspeaker'.

with se you can make the change in Rp small by using a high
current bias, then using a transformer that will give a reflected
impedance well above Rp-avg., no problems, either

I've told Poopie that at least five times already. He's a celebrity of
the remedial class, a slow learner par excellence.

"High current bias" -- high current, period. It is ten years ago now
that I was first flamed by "engineers" for pointing out that driving an
ZNFB 845 with a miserable little 12AX7 is incompetent design, that a
minimum of 20mA drive current is essential. About the same time I wrote
about the advantages, and sometimes necessity, of high current
quiescent operating points in SE so often that I coined the acronym
HCHVHL to save typing the words "high current high voltage high load"
over and over. The five years of flaming from the Magnequest Scum in
the middle 1990s that wrecked first the Joenet and then RAT originated
directly in my Glass Audio editorial asking why high impedance plate
loads was a taboo subject in DIY tube amps. (I soon found out! It was
because Magnequest at the time made nothing except low impedane OPT!)
The Magnequest Scum and their outriders included platoons of
"engineers" who clearly didn't understand the principles of SE tube
operation, as concisely described by Rudy. I am not surprised to
discover that Poopie Stevenson, even -- or perhaps especially -- if he
is a solid state designer as he claims, doesn't understand what the
hell is going on with the tube. These are subtleties learned only by
constant experience building prototypes and measuring them, and
spending years with the extensive literature; solid state
preconceptions are luggage best jettisoned immediately one turns to
tubes and all the more so in DHT, SE and Class A1, which are all
anomalies outside the education and general mainstream experience of
those now fifty years old and over. (Patrick won't object to me
observing that what makes him so good is that he came to tubes late in
life without the baggage of a formal electronics education, with the
consequence that his mind was blank slate without solid state
preconceptions. It is that baggage which again and again sinks
"engineers" who come on RAT and start fanning their diploma and in some
cases -- e.g. Pinkerton's early career before he sold his soul to
become the boss postman of spam -- even quality experience.)

I should also observe that in the threads which gave rise to Graham
Stevenson's hectoring little lecture above, I several times clearly
posited an example of 300B loaded with a 5K6 transformer. 300B plate
impedance at modern operating bias settings is c625 ohm (the nominal
700R the usual googling "experts" cite is taken under vintage
conditions that don't apply to hi-fi), so Ro is 0.89 ohm. That's
respectable for SE with zero negative feedback, but in fact the dynamic
situation is far, far better than this static quiescent snapshot
because even with zero global feedback the 300B has c14dB of internal
local feedback and, furthermore, a proper SETH DHT amp is anyway
bandwidth-limited so that the speaker presents a much friendlier
dynamic load than the nominal specsheet case the "engineers" like to
cite with such wide-eyed horror. The test of the pudding is in the
eating.

It seems to me Graham "Pooh Bear" Stevenson either doesn't understand
how tubes work or he didn't run the numbers before he started shooting
from the hip as a reflex of his vitriolic hatred of me.

so what was ya gonna say ?

The problem with Stevenson is that he talks and talks without ever
listening. I have no hope for him. He will never be a useful
contributor to RAT; he's a slow learner. This is a matter of some
regret, because we could do with a humble, unimaginative (just the fax,
mam, we'll do the flights of fancy) textbook engineer to explain basics
to newbies and do some of the theoretical legwork for the rest of us.

What was so great about the some of the older engineers, gentlemen all,
that we used to have, Alan Douglas and a whole crowd of similar skill
and outlook, was that they didn't throw their undoubted weight around
but clearly considered themselves facilitators in the dissemination of
knowledge and thus to the rest of us. Oh well, I suppose the
generous-spirited principles of the ARRL were bound to die when the
Internet widened the user-base.

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

Ruud Broens wrote:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

"debating trade technique" -- I keep seeing this. Does it think what I
think it means, that the trailer park trash flaming the audio
conferences, e.g. Arny Krueger and Poopie Stevenson, have no legitimate
debating technique? Please advise.

If I am right, it will come as no surprise. You can tell by their total
ignorance of proper debating technique that they were educated at poor
schools and jumped-up polytechnics without debating societies. Debating
skill is learned, just like electronics. If you didn't learn to
communicate and persuade effectively, you probably didn't learn
electronics too well either. That could explain a lot of continual
exasperation with these two.

Andre Jute

Here's Poopie's hectoring kindergarten lecture and Ruud's full response
for context:

Ruud Broens wrote:
"Pooh Bear" wrote in message
...
: As a consequence of the issues raised in the recent debates, I'm
: amazed that there seems to be widespread assumption here that the gain
: of a tube output stage ( SET *or* P-P ) is simply derived from a stock
: equation.
:
: In the gain equation the plate load determines the upper term.
:
: Where the ( refelcted ) load has a variable impedance ( such as a
: loudspeaker ) then this term is also variable.
:
: Hence in the real world - it's impossible for such a circuit
: configuration to have a flat frequency response. From first
: principles.
:
: A flat frequency response can only exist into a pure resitive load.
: Speakers are *not* pure resistive by any means.
:
: The response can be *improved* by negative feedback but the response
: errors can never be eliminated.
:
: This only applies to circuits with the load in the plate circuit.
: Loads in the cathode have no such problem by reason of the circuit
: operation ( some understanding of electronic theory is presumed ).
:
: Graham
:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

o, btw, we know Rp is a dynamic, current dependent impedance
with ul or triodes in pp, that is of no concern as it balances out
and as long as that stays well below reflected impedance it is
close enough to a 'perfect voltage driven loudspeaker'.

with se you can make the change in Rp small by using a high
current bias, then using a transformer that will give a reflected
impedance well above Rp-avg., no problems, either

so what was ya gonna say ?

"Andre Jute" wrote in message
ups.com...
Ruud Broens wrote:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

"debating trade technique" -- I keep seeing this. Does it think what I
think it means, that the trailer park trash flaming the audio
conferences, e.g. Arny Krueger and Poopie Stevenson, have no legitimate
debating technique? Please advise.

It is debate in the political sense; deliberate and frequently adroit
misrepresentation, misdirection, or diversion. It incorporates all the
tricks of the masters of down-and-dirty street fighting, with none of the
ethics of scholastic debate.

Now permit me to ask a polite question. With respect to the argment on SET
frequency response, what is the impedance of the speakers you drive? Is it
on the order of 100 ohms, or in excess? With all due respect, speakers in
the normal range of mainstream commercial offerings do experience frequency
response variations due to nonconstant impedance over the audio band. One
way of dealing with this is with a Zobel network:
http://www.trueaudio.com/st_zobel.htm

Let's have an intelligent discussion. I am interested in learning what you
do.

Andre Jute wrote:

Ruud Broens wrote:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

"debating trade technique" -- I keep seeing this. Does it think what I
think it means, that the trailer park trash flaming the audio
conferences, e.g. Arny Krueger and Poopie Stevenson, have no legitimate
debating technique? Please advise.

If I am right, it will come as no surprise. You can tell by their total
ignorance of proper debating technique that they were educated at poor
schools and jumped-up polytechnics without debating societies. Debating
skill is learned, just like electronics. If you didn't learn to
communicate and persuade effectively, you probably didn't learn
electronics too well either. That could explain a lot of continual
exasperation with these two.

You're very mistaken about my education in that case.

Truth is - I've never met such an ignorant self-serving, opinionated,
waffling, lying jerk as yourself posing as "Mr bloody Know-All" when you
could actually fit your knowledge of audio electronics on the back of a
postage stamp.

Graham

Pooh Bear, Fattest DJ in the Universe, wrote:
Andre Jute wrote:

Ruud Broens wrote:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

"debating trade technique" -- I keep seeing this. Does it think what I
think it means, that the trailer park trash flaming the audio
conferences, e.g. Arny Krueger and Poopie Stevenson, have no legitimate
debating technique? Please advise.

If I am right, it will come as no surprise. You can tell by their total
ignorance of proper debating technique that they were educated at poor
schools and jumped-up polytechnics without debating societies. Debating
skill is learned, just like electronics. If you didn't learn to
communicate and persuade effectively, you probably didn't learn
electronics too well either. That could explain a lot of continual
exasperation with these two.

You're very mistaken about my education in that case.

Truth is - I've never met such an ignorant self-serving, opinionated,
waffling, lying jerk as yourself posing as "Mr bloody Know-All" when you
could actually fit your knowledge of audio electronics on the back of a
postage stamp.

Graham

And one might add a couple of things about Graham Poopie Stevenson:

1. Debating in a civilized manner in school and college, where young
passions migh flare, is excellent training in anger management and
channelling into socially productive activies. Instead, having missed
out, he is a disruptive influence.

2. Zero culture-damaged hearing syndrome. The only music at Poopie
Stevenson's jumped-up provincial poly was very loud rock played in a
hall with concrete beams in the ceiling. Draw your own conclusion.

Andre Jute

Robert Morein wrote:
"Andre Jute" wrote in message
ups.com...
Ruud Broens wrote:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

"debating trade technique" -- I keep seeing this. Does it think what I
think it means, that the trailer park trash flaming the audio
conferences, e.g. Arny Krueger and Poopie Stevenson, have no legitimate
debating technique? Please advise.

It is debate in the political sense; deliberate and frequently adroit
misrepresentation, misdirection, or diversion. It incorporates all the
tricks of the masters of down-and-dirty street fighting, with none of the
ethics of scholastic debate.

In the States that may be true. But I doubt Krueger would be let into a
political campaign at any level; he is simply too crude.

In Britain elections are amazingly clean. There are laws, strictly
enforced about personal smear campaigns on opposition pols. So
Stevenson didn't learn his dirty tricks in British politics either.

Perhaps Krueger and Poopie are just clumsy and abusive by character,
that is, to everyone.

I'm moving the rest of your post to a separate thread because we don't
want it contaminated by the "down-and-dirty street fighting" of the
usual slime.

Andre Jute

in article , Andre Jute
at wrote on 12/19/05 6:42 PM:


Pooh Bear, Fattest DJ in the Universe, wrote:
Andre Jute wrote:

Ruud Broens wrote:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

"debating trade technique" -- I keep seeing this. Does it think what I
think it means, that the trailer park trash flaming the audio
conferences, e.g. Arny Krueger and Poopie Stevenson, have no legitimate
debating technique? Please advise.

If I am right, it will come as no surprise. You can tell by their total
ignorance of proper debating technique that they were educated at poor
schools and jumped-up polytechnics without debating societies. Debating
skill is learned, just like electronics. If you didn't learn to
communicate and persuade effectively, you probably didn't learn
electronics too well either. That could explain a lot of continual
exasperation with these two.

You're very mistaken about my education in that case.

Truth is - I've never met such an ignorant self-serving, opinionated,
waffling, lying jerk as yourself posing as "Mr bloody Know-All" when you
could actually fit your knowledge of audio electronics on the back of a
postage stamp.

Graham

And one might add a couple of things about Graham Poopie Stevenson:

1. Debating in a civilized manner in school and college, where young
passions migh flare, is excellent training in anger management and
channelling into socially productive activies. Instead, having missed
out, he is a disruptive influence.

2. Zero culture-damaged hearing syndrome. The only music at Poopie
Stevenson's jumped-up provincial poly was very loud rock played in a
hall with concrete beams in the ceiling. Draw your own conclusion.

Andre Jute



McCoy,

You call your histrionics a "civilized debate?" I've never known a competent
debater to use the devices and fallacies that employ with every opportunity.

I don't know where you were educated, but obviously you were shortchanged in
the subjects of logic and debate.

- Jon

Andre Jute wrote:

Pooh Bear, Fattest DJ in the Universe, wrote:
Andre Jute wrote:

Ruud Broens wrote:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

"debating trade technique" -- I keep seeing this. Does it think what I
think it means, that the trailer park trash flaming the audio
conferences, e.g. Arny Krueger and Poopie Stevenson, have no legitimate
debating technique? Please advise.

If I am right, it will come as no surprise. You can tell by their total
ignorance of proper debating technique that they were educated at poor
schools and jumped-up polytechnics without debating societies. Debating
skill is learned, just like electronics. If you didn't learn to
communicate and persuade effectively, you probably didn't learn
electronics too well either. That could explain a lot of continual
exasperation with these two.

You're very mistaken about my education in that case.

Truth is - I've never met such an ignorant self-serving, opinionated,
waffling, lying jerk as yourself posing as "Mr bloody Know-All" when you
could actually fit your knowledge of audio electronics on the back of a
postage stamp.

Graham

And one might add a couple of things about Graham Poopie Stevenson:

1. Debating in a civilized manner in school and college, where young
passions migh flare, is excellent training in anger management and
channelling into socially productive activies. Instead, having missed
out, he is a disruptive influence.

I reserve my wrath for those who truly deserve it.

I am remarkably tolerant in my everyday life but I have little tolerance for
charlatans like yourself.


2. Zero culture-damaged hearing syndrome. The only music at Poopie
Stevenson's jumped-up provincial poly was very loud rock played in a
hall with concrete beams in the ceiling. Draw your own conclusion.

Typical idiotic rant based on nothing of substance. One thing about being the
sound engineer is that you're actually a long way from the speakers btw ! I
don't believe in using *excessive* spl anyway. I have indeed walked away from
events I considered stupidly loud.

The only 'poly' I've been to was the local one at Hatfield where some friends
were studying. It had a decent SU bar and some good gigs in the various halls.

I went to London University. The school wanted me to apply to Cambridge but as
I wasn't gay it didn't appeal.

Graham

John Byrns wrote:

In article , Pooh Bear
wrote:

As a consequence of the issues raised in the recent debates, I'm
amazed that there seems to be widespread assumption here that the gain
of a tube output stage ( SET *or* P-P ) is simply derived from a stock
equation.

In the gain equation the plate load determines the upper term.

Where the ( refelcted ) load has a variable impedance ( such as a
loudspeaker ) then this term is also variable.

Hence in the real world - it's impossible for such a circuit
configuration to have a flat frequency response. From first
principles.

A flat frequency response can only exist into a pure resitive load.
Speakers are *not* pure resistive by any means.

Isn't the same also true for transistors, substituting the word collector
for plate?

If transistor amps were collector loaded - then yes.

Most audio SS amps today use an emitter follower output. That arrangement
simply doesn't care about the load Z. It's important that the emitter
follower has enough current gain though ( use darlingtons or triples ) or the
load might still 'reflect' back to the previous voltage gain stage and
possibly cause stability problems ( usually phase angle related ).

Those that do have a collector load use serious nfb to correct the issue of
response errors.

Graham

Ruud Broens wrote:

"Pooh Bear" wrote in message
...
: As a consequence of the issues raised in the recent debates, I'm
: amazed that there seems to be widespread assumption here that the gain
: of a tube output stage ( SET *or* P-P ) is simply derived from a stock
: equation.
:
: In the gain equation the plate load determines the upper term.
:
: Where the ( refelcted ) load has a variable impedance ( such as a
: loudspeaker ) then this term is also variable.
:
: Hence in the real world - it's impossible for such a circuit
: configuration to have a flat frequency response. From first
: principles.
:
: A flat frequency response can only exist into a pure resitive load.
: Speakers are *not* pure resistive by any means.
:
: The response can be *improved* by negative feedback but the response
: errors can never be eliminated.
:
: This only applies to circuits with the load in the plate circuit.
: Loads in the cathode have no such problem by reason of the circuit
: operation ( some understanding of electronic theory is presumed ).
:
: Graham
:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

o, btw, we know Rp is a dynamic, current dependent impedance
with ul or triodes in pp, that is of no concern as it balances out
and as long as that stays well below reflected impedance it is
close enough to a 'perfect voltage driven loudspeaker'.

with se you can make the change in Rp small by using a high
current bias, then using a transformer that will give a reflected
impedance well above Rp-avg., no problems, either

so what was ya gonna say ?

Depends on your view of 'close enough'.

Yes - at the expense of total power output you can adjust the turns ratio of
the output transformer so as to make the output Z appear lower but you're
into a game of diminishing returns since you can't realistically get the
output Z of a non-nfb SET to a figure that's genuinely not going to give
freq response errors. Only a topology with a naturally low Z can do that..

It's a fundamental flaw of the topology. You can tinker with it to your
heart's content but it won't go way.

Why not consider my "new approach to the SET" ? Fixes the problem at source.

Graham

Robert Morein wrote:

"Andre Jute" wrote in message
ups.com...
Ruud Broens wrote:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

"debating trade technique" -- I keep seeing this. Does it think what I
think it means, that the trailer park trash flaming the audio
conferences, e.g. Arny Krueger and Poopie Stevenson, have no legitimate
debating technique? Please advise.

It is debate in the political sense; deliberate and frequently adroit
misrepresentation, misdirection, or diversion. It incorporates all the
tricks of the masters of down-and-dirty street fighting, with none of the
ethics of scholastic debate.

Now permit me to ask a polite question. With respect to the argment on SET
frequency response, what is the impedance of the speakers you drive? Is it
on the order of 100 ohms, or in excess? With all due respect, speakers in
the normal range of mainstream commercial offerings do experience frequency
response variations due to nonconstant impedance over the audio band. One
way of dealing with this is with a Zobel network:
http://www.trueaudio.com/st_zobel.htm

Let's have an intelligent discussion. I am interested in learning what you
do.

100 ohms ? You're kidding surely ?

You might be interested to know that I helped design a speaker that was
'impedance corrected' so as to maintain a very close to nominal 8 ohms over the
entire audio frequency range.

It did indeed use something similar to 'Zobels'.

Not much you can do about the LF resonance though.

Graham

On Tue, 20 Dec 2005 00:56:47 +0000, Pooh Bear
wrote:

Depends on your view of 'close enough'.

Yes - at the expense of total power output you can adjust the turns ratio of
the output transformer so as to make the output Z appear lower but you're
into a game of diminishing returns since you can't realistically get the
output Z of a non-nfb SET to a figure that's genuinely not going to give
freq response errors. Only a topology with a naturally low Z can do that..

For another conclusion from a perhaps surprising source,
the current speaker wire thread includes some detail by
Don Pierce regarding necessary and actual "damping ratios".
R.a.t's should read this too, BTW; good, solid stuff
and useful for any fundamental design work.

To compare to what I consider a practical SET design,
a number 845 triode into a 10,000 ohm nominal plate
load, factor in the working plate resistance if about
1/6 nominal load.

******Over the whole load line******

Why not consider my "new approach to the SET" ? Fixes the problem at source.

Cool beans! What is it?

Breathless anticipation subverted in an effort to
look cool, like Charlie Brown at the water cooler,

Chris Hornbeck

"Angels are, dreaming of you" - Sonic Youth

On Tue, 20 Dec 2005 02:29:26 GMT, Chris Hornbeck
wrote:

Who edits this crapola anyway? Sorry,
Let me try again:

For another conclusion from a perhaps surprising source,
the current speaker wire thread in r.a.p includes some detail by
Don Pierce regarding necessary and actual "damping ratios".
R.a.t's should read this too, BTW; good, solid stuff
and useful for any fundamental design work.

Chris Hornbeck

"Angels are, dreaming of you" - Sonic Youth

On Mon, 19 Dec 2005 08:22:32 +0000, Pooh Bear
wrote:

In the gain equation the plate load determines the upper term.

Only for a constant-current (high-Z) source. For
triodes, or other lower impedance sources, the source
dominates.

For *both* cases, the parallel of both impedances
is the magic number, natch. And, of course, these
things are true independent of topology, active
device, or even being electronic. They're fundamental
to power delivery in water hoses too.

Thanks, as always,

Chris Hornbeck

"Angels are, dreaming of you" - Sonic Youth

On Mon, 19 Dec 2005 08:22:32 +0000, Pooh Bear
wrote:

A flat frequency response can only exist into a pure resitive load.
Speakers are *not* pure resistive by any means.

The response can be *improved* by negative feedback but the response
errors can never be eliminated.

This only applies to circuits with the load in the plate circuit.
Loads in the cathode have no such problem by reason of the circuit
operation ( some understanding of electronic theory is presumed ).

On closer reading, I see a glaring error here. Heat
of the moment, surely,

Thanks, as always,

Chris Hornbeck

"Angels are, dreaming of you" - Sonic Youth

On 19 Dec 2005 14:54:45 -0800, "Andre Jute" wrote:

Does it think what I
think it means

Being a perfectionist, Andre, you might like to rephrase this.

Incidentally, endlessly picking at grammar and spelling is part of the
"debating trade". The best part, in my opinion. :-)

Chris Hornbeck wrote:

On Mon, 19 Dec 2005 08:22:32 +0000, Pooh Bear
wrote:

In the gain equation the plate load determines the upper term.

Only for a constant-current (high-Z) source. For
triodes, or other lower impedance sources, the source
dominates.

For *both* cases, the parallel of both impedances
is the magic number, natch. And, of course, these
things are true independent of topology, active
device, or even being electronic. They're fundamental
to power delivery in water hoses too.

My apologies. I was simplifying.

Graham

On 19 Dec 2005 15:59:38 -0800, "Andre Jute" wrote:


Robert Morein wrote:
"Andre Jute" wrote in message
ups.com...
Ruud Broens wrote:
Graham, if you reallly want to discuss something here,
start with dispensing with the debating trade technique,
then learn how to write coherently :-)

Rudy

"debating trade technique" -- I keep seeing this. Does it think what I
think it means, that the trailer park trash flaming the audio
conferences, e.g. Arny Krueger and Poopie Stevenson, have no legitimate
debating technique? Please advise.

It is debate in the political sense; deliberate and frequently adroit
misrepresentation, misdirection, or diversion. It incorporates all the
tricks of the masters of down-and-dirty street fighting, with none of the
ethics of scholastic debate.

In the States that may be true. But I doubt Krueger would be let into a
political campaign at any level; he is simply too crude.

In Britain elections are amazingly clean. There are laws, strictly
enforced about personal smear campaigns on opposition pols. So
Stevenson didn't learn his dirty tricks in British politics either.

Perhaps Krueger and Poopie are just clumsy and abusive by character,
that is, to everyone.

I'm moving the rest of your post to a separate thread because we don't
want it contaminated by the "down-and-dirty street fighting" of the
usual slime.


It's sweet when two geniuses meet on the crowded internet.

On Tue, 20 Dec 2005 12:22:03 +0000, Goofball_star_dot_etal
wrote:

I'm moving the rest of your post to a separate thread because we don't
want it contaminated by the "down-and-dirty street fighting" of the
usual slime.


It's sweet when two geniuses meet on the crowded internet.

Very sweet. Yet it's frightening to think what progeny such a union
would produce. :-)

"paul packer" wrote in message
...
On 19 Dec 2005 14:54:45 -0800, "Andre Jute" wrote:

Does it think what I
think it means

Being a perfectionist, Andre, you might like to rephrase this.

Incidentally, endlessly picking at grammar and spelling is part of the
"debating trade". The best part, in my opinion. :-)

Your last sentence is actually a fragment, lacking a verb

paul packer wrote:
On 19 Dec 2005 14:54:45 -0800, "Andre Jute" wrote:

Does it think what I
think it means

Being a perfectionist, Andre, you might like to rephrase this.

Incidentally, endlessly picking at grammar and spelling is part of the
"debating trade". The best part, in my opinion. :-)

Not at all, Paul. That is not a grammatical error, or a mistyping for
"that mean", that is a sideswipe at slime. "It", not he or she,
indicates that I believe that those who perpetrate these crimes upon
civilization, as expressed in audiophile pursuits, are aliens, not
humans, and "think" is of course a savagely sarcastic comment on their
braindead condition.

You'd get further arguing with me that Krueger and Poopie Stevenson and
their hangers-on aren't "braindead" because they never had any brains
to die, but I'm too nice to think that even of the enemies of fidelity.
Even under torture you'll never make me admit I thought such a
politically incorrect thing.

Andre Jute

PS Oh, by the way, Paul, it is politically very incorrect for you, and
beside poor manners utterly untypical of an Australian gentleman, to
abuse me, a poor stateless immigrant (I was when I became an
Australian), whose first language wasn't English, not by half a dozen
or so, for not speaking the language "proper". It is furthermore an
insult to the man who taught me Latin and Greek (and who christened me
the Crown Prince of Chaos, but I've forgiven him that) rather
effectively; for that, when I ascended to influence partly because I
could make politicians and industrialists believe, without ever telling
a lie of course, that I said what they wanted to hear, I had him in his
retirement given the rich contract to write the English textbook for
all the schools in the country, which made him an instant millionaire.

Dédé Jute wrote :

PS Oh, by the way, Paul, it is politically very incorrect for you,


You see Paul, even Dédé agrees with me.


--
"Nobody seemes to have actaully read what i wrote.
But what's new around here?"

Dave Weil, Sun, 05 Oct 2003 00:57:15

Robert Morein said:

The best part, in my opinion. :-)

Your last sentence is actually a fragment, lacking a verb

Your participle is dangling.

George M. Middius cmndr [underscore] george [at] comcast [dot] net
wrote:

Robert Morein said:

The best part, in my opinion. :-)

Your last sentence is actually a fragment, lacking a verb

Your participle is dangling.

In your (sick) dreams...

"George M. Middius" cmndr [underscore] george [at] comcast [dot] net wrote
in message ...


Robert Morein said:

The best part, in my opinion. :-)

Your last sentence is actually a fragment, lacking a verb

Your participle is dangling.


"At least" my participle is erect.

On Tue, 20 Dec 2005 10:35:48 -0500, "Robert Morein"
wrote:


"paul packer" wrote in message
...
On 19 Dec 2005 14:54:45 -0800, "Andre Jute" wrote:

Does it think what I
think it means

Being a perfectionist, Andre, you might like to rephrase this.

Incidentally, endlessly picking at grammar and spelling is part of the
"debating trade". The best part, in my opinion. :-)

Your last sentence is actually a fragment, lacking a verb

But I like it that way, so there. :-)

Clyde Slick said:

The best part, in my opinion. :-)

Your last sentence is actually a fragment, lacking a verb

Your participle is dangling.

"At least" my participle is erect.

No proof required. We're happy to take your word on it.

"George M. Middius" cmndr [underscore] george [at] comcast [dot] net wrote
in message ...


Clyde Slick said:

The best part, in my opinion. :-)

Your last sentence is actually a fragment, lacking a verb

Your participle is dangling.

"At least" my participle is erect.

No proof required. We're happy to take your word on it.

Your verb is down.

"paul packer" wrote in message
...
On Tue, 20 Dec 2005 10:35:48 -0500, "Robert Morein"
wrote:


"paul packer" wrote in message
...
On 19 Dec 2005 14:54:45 -0800, "Andre Jute" wrote:

Does it think what I
think it means

Being a perfectionist, Andre, you might like to rephrase this.

Incidentally, endlessly picking at grammar and spelling is part of the
"debating trade". The best part, in my opinion. :-)

Your last sentence is actually a fragment, lacking a verb

But I like it that way, so there. :-)

This is the sort of English up with which I will not put.

Robert Morein said:

This is the sort of English up with which I will not put.

Sometimes a cigar is just a cigar. LOt"S!

Lionel wrote:
Dédé Jute wrote :

PS Oh, by the way, Paul, it is politically very incorrect for you,


You see Paul, even Dédé agrees with me.

Pity. I was just starting to think he might be intelligent. :-)