Sander deWaal wrote:

Just look what Arny had to say to one of your posts about the use of
NFB ....the original was posted to RAO by our friend Brat Ludwig :-)

Ludwig is a thief. The material is copyright and clearly marked for use
on RAT only.

As for Arny, I read every one of his literal-minded misunderstandings
in the hope of learning something. I wasted my time. The kicker is in
Arny's remark that:

If NASA listened to Jute, the Rusians would have beaten us
to the moon.

Arny is welcome to listen to Russian hi-fi, hundred per cent negative
feedback, total silence on an airless surface, if he believes that
suits the closed-circuit aridity of his mind.

I'll stick to hi-fi which plays music.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"an unbelievably comprehensive web site" -- Hi-Fi News & Record Review

PS: Interestingly, Arny kicks the bejeezus out of his own organ
grinder's monkey, Pinkerton, who was the one who came up with the
ignorant 50dB feedback suggestion, in this passage:

(Jute
Before I even finished the design of the KISS 300B it was
forcefully suggested by a wannabe guru that with only
50dB more gain (about seven times as much as is likely to
be in the actual design) I can apply 50dB of negative
feedback to linearize my amplifier.
(Krueger
Good example of Jute's ignorance of feedback. It's highly
unlikely that one could apply 50 dB loop feedback to a power
amp with an output transformer and still have acceptable
stability.

Yeah, I know, Arny. As should be clear from the text even to an
illiterate engineer, I wasn't the one who made the silly 50dB
suggestion; your accolyte Stewart Pinkerton came up with it; that is
why I told Pinkothicko to **** off back to you and stop pretending he
was my guru.

Here's Arnie's letter as forwarded by Sander:

- begin long quote -
Arny Krueger said:

The Ultrafidelista view of Negative Feedback

by Andre Jute

Negative feedback is the paradigm of modern electronic
design. It is mother's milk to an electronics engineer.
He learns to say '100dB of NFB,' in his sleep before he
finishes his first week at the most humble polytechnic.

Good example of Jute's ignorance of the engineering
education process. Feedback is usually taught as it relates
to automatic control systems. Last time I looked courses
like these generally fit into the junior or senior years.

In short the idea that "He learns to say '100dB of NFB in
his sleep before he
finishes his first week at the most humble polytechnic" is
sheerist BS.

Before I even finished the design of the KISS 300B it was
forcefully suggested by a wannabe guru that with only
50dB more gain (about seven times as much as is likely to
be in the actual design) I can apply 50dB of negative
feedback to linearize my amplifier.

Good example of Jute's ignorance of feedback. It's highly
unlikely that one could apply 50 dB loop feedback to a power
amp with an output transformer and still have acceptable
stability.

Negative feedback, shorthanded as NFB, is the instant
response of the audio engineering fraternity to all ills,
real, perceived, non-existent. They don't even ask if
there is a problem, they swing the club of NFB
regardless. NFB has become a reflex axiom of mainstream
audio design. An audio engineer with his negative
feedback is like a policeman who runs out into the street
with his stick and starts beating a confession out of the
first housewife he sees. The difference is that the
policeman is relieved of duty to await punishment and the
audio engineer gets away with it. In the case of the
policeman it is unacceptable behaviour, in the case of
the audio engineer so much the expected norm that no one
except the ultrafidelista notice. I guess that if one in
ten million audio amplifiers does not have negative
feedback added, it will be a lot...

No amount of rediculous posturing can counter the fact that
NFB can be made to work very well and to great advantage,
thank you.

No one asked if my KISS Amp requires linearization. The
presumption by all except those already of the
ultrafidelista persuasion was that I would welcome
suggestions about A Good Thing.

If the kiss amp has less than 0.05% nonlinear distortion
with any power level or any frequency or combination of
frequencies 20-20 KHz, then its fine as is. I doubt it is
that good.

In the face of such overwhelming acceptance by qualified
engineers, why do we as ultrafidelista not take the same
easy path of negative feedback? Especially considering
that superficially NFB is easy to understand and apply.

How does negative feedback work?

Negative feedback is simply a negative voltage fed back
from the output to the input amplifying device to offset
part of the harmonic distortion which is present as a
positive voltage.

This is a highly incomplete explanation. In fact the voltage
fed back offsets not only the distortion but a goodly part
of the basic signal. Therefore, NFB generally reduces an
amplifier's gain for both the basic amplfied signal and also
the distortion.

It costs nothing except a loss of gain
and a few side effects such as phase shift and possible
instability which are well known in the mathematical
literature and more or less easily guarded against
depending on the level of NFB.

In fact NFB properly applied reduces, not increases an
amplifier's phase shift.

'Wow!' those meeting NFB for the first time will now say,
'Something for free! I'll grab some of that for my amp.'

Just just contrdicted the first phrase in the previous
paragraph that says that NFB has a price in the form of a
loss of gain.

Hey, I said it, and I am a professional intellectual, by
definition an infinite skeptic. NFB is a thing of beauty
that will draw you in. It is like an electronic Marxism
which admits of no contrary arguments because it has
subsumed them all into The Holy Measurements. To question
The Measurements is to commit heresy.

Jute's mistake here is that its not heresy to question
measurements, and people have been doing that for decades,
even in such conservative journals as the JAES.

You need to be of
strong mind to resist the blandishments of such a
universal panacea and of strong stomach to withstand the
hysterical assaults of the lesser engineers defending
their holy grail. (And when you do get hold of a superior
engineer to explain NFB to you, you need to be high-domed
indeed because suddenly NFB can turn very intricate.)

It is true that some advanced course work in calculus can be
of great help when designing systems with feedback. This
automatically disqualifies a great percentage of basement
geniuses and high end chief engineers, writers and
reviewers.

Unfortunately NFB doesn't come without a price. It levies
a cruel charge on the perceived quality of the sound.
Negative feedback is what gives all those 'blameless'
transistor and big PP tube amps their chillingly
unnatural sound.

Strange that these supposedly unnatural-sounding amplifiers
can pass a straight wire bypass test, and so many low-NFB
power amps can't.

Then how did NFB come to be such a panacea in amplifier
design?

Because when applied with reasonable care by competent
engineers, NFB works. NFB got men to the moon. NFB makes
your car idle and run. NFB keeps your water heater from
exploding. It keeps your house and oven at the temperature
you set on your thermostat. NFB makes cell phones work.
etc., etc.

Your guess is as good as mine. Hi-fi design is not
prestige work for engineers, or highly paid. The most
talented and best qualified engineers go into automobiles
or military hardware or big construction projects or
computer design.

All areas where NFB is highly depended on, and it works.

The left-overs design amplifiers in the
time they have to spare from writing up specs for
requesting a CE mark for a new electric kettle. Lemmings
storming en masse over a cliff come to mind; such people
don't see the necessity of original thought, or have the
mental equipment for it. The exceptions to this rule are
normally audio enthusiasts in charge of their own small
audio manufactories with niche markets; those who grow
larger from this base follow the mainstream mantra of
"mo' NFB give lowa' THD" because the marketing channels
demand it from them if they wish to grow. At this point
they usually cease to offer anything different, only the
exclusivity of a very high price. (I know, because a
sub-board I designed for a supplier to the trade turns up
in so many very expensive amps with so many different big
names neatly silkscreened on it... it strikes me as the
sort of detail a real designer, as distinct from a
marketer, would take under his own control.) Those very
few makers who will sell you an ultrafi amp without any
NFB operate even tinier shops, usually one man and a cat,
just hanging on.

Usually the cat knows as much if not more about calculus
than the man,

The mechanism by which NFB wrecks your sound

NFB wrecks the sound the same way NFB makes your water
heater explode: as a rule it doesn't.

Negative feedback at first acquaintance sounds good
enough to take to bed and cuddle. It isn't. It isn't even
as simple as a superficial acquaintance may suggest.
Follow the steps with me, from the theory as she is
received to what arrives at your brain as music:

1. In theory NFB reduces all harmonic distortion equally,
without discrimination.

Nope. NFB is often dependent on frequency. As a rule it
reduces higher harmonics less.

Strictly in theory it does not
reshape harmonic distortion by reducing the most
objectionable third and higher order odd harmonic
distortion to a greater extent than the relatively
harmless 2nd harmonic.

Actually, any order of nonlinear distortion, even Jute's
beloved order 2 can wreck the sound of music.

Thus NFB at its theoretically most
benign is already useless in terms of psychoacoustics, as
will become clear at point 4. If you disregard
psychoacoustics, as many audio engineers do, NFB is
brilliant in reducing total harmonic distortion to a
number as tiny as you want. You just pile on more NFB.

This paragraph really says nothing.

2. In real life, as distinct from simplified theory, NFB
adds artifacts of its own. Remember, it is a loop. The
signal starts at the input and is amplified by devices
until it reaches the output. From the output a part of
the signal called the negative feedback is fed back to
the input. Here a loop is completed and the combination,
less distorted, reaches the output again, a part of the
combination is fed back, endlessly. The artifacts we want
to consider here are created by the fed-back residue of
harmonic distortions adding to both the fundamental and
the distortions already created by the amplifier, then
some portion of the sum of the original and the feedback
distortion is fed back again and added on, until the
ooh-ah bird flies up its own fundament. It looks
marginally less disgusting as a recursive mathematical
formula with lots of nested parenthetical parcels of
noise being loaded onto your music.

This is for all practical purposes, total BS. The bottom
line is that a power amp with a properly designed NFB loop
has far lower distortion of all relevant orders because of
the NFB.

But it is a monkey on
the back of your sound, with a smaller monkey on the back
of the first monkey, a still smaller monkey on the back
of the second monkey, and so on ad infinitum. These
additive artifacts are all higher harmonics and the more
dominant ones are all odd. Suppose, for the sake of
simplicity, a superbly designed ultrafidelista amp with
some second harmonic and zero odd harmonics before NFB.
Add NFB and the second harmonic will be lowered but the
recombinant new loop now contains newly added
intermodulation effects between the fundamental and the
residual second harmonic, and that is third harmonic. In
the next cycle a small but nasty dose of fifth harmonic
that wasn't there before is added by interaction between
the still residual second harmonic and reduced newly
added third harmonic.

This is for all practical purposes, total BS. The bottom
line is that a power amp with a properly designed NFB loop
has far lower distortion of all relevant orders because of
the NFB.

In short, the artifacts NFB adds to
the distortion mix are all of the most harmful kind. But,
say the proponents of NFB, so what? Every time the loop
cycles the added artifacts are smaller, even if there are
more of them... The whole affair starts to smell of
trying to argue with a Marxist who simply declares any
inconvenient truth 'an anomaly'. (If this sounds like a
mess from which you should run a mile, you have come to
the right conclusion. Start running now. It gets worse.)

This is for all practical purposes, total BS. The bottom
line is that a power amp with a properly designed NFB loop
has far lower distortion of all relevant orders because of
the NFB.


3. We thus arrive at a situation where distortion has
been lowered by NFB but where the most disturbing odd
harmonic distortions are still present to some measure,
with the added disadvantage that new and extremely
disturbing artifacts of higher harmonic distortions have
been created by the very process of using negative
feedback to lower distortion.

This is for all practical purposes, total BS. The bottom
line is that a power amp with a properly designed NFB loop
has far lower distortion of all relevant orders because of
the NFB.


Regardless of the absolute
level of THD, or the volume setting, the mix of harmonics
has been adversely affected and now includes a higher
proportion of third and higher harmonics than before NFB.
Let me say that again: after NFB, third and higher
harmonics will make up a greater part of the distortion
than before.

But, all orders of distortion will be greatly reduced.

4. Low volume levels perforce accounts for 99 per cent of
audiophile listening because we all have families or
neighbours, and we would like to keep our ears.
Unfortunately for the lowest common denominator of hi-fi
designer, the one who specifies NFB as a conditioned
response much like Pavlov's dogs slavered when the bell
rang, human physiology and psycho-acoustic response is
such that odd harmonics are disproportionately more
disturbing at lower than at higher listening levels. This
inescapable effect is independent of definition of
'listening level.' At the 110dB in-room SPL (only 14dB
louder than an automatic riveter!) advocated by the
already deaf Transient Overload Elite known on newsgroups
as the Borg, this poisonous concoction of original
distortions and NFB recombinant artifacts will be least
disturbing (and soon not heard at all!). At any lower
level perceived interference of this harmonics cocktail
with the music will increase in inverse proportion to the
volume level. At low volume levels the artifacts
generated by NFB will by their nature as higher harmonic
distortions be disproportionately far more disturbing. At
these normal listening levels 0.75 per cent of second
harmonic distortion may be below the threshhold of
perception for sophisticated listeners, whereas tiny
amounts of third and higher odd harmonic distortions
grate.

NFB reduces distortion at all output levels, large or small.

And they still use Negative Feedback? Are they stupid?

No, they are wise.

No, they are not stupid. Most of them march to the drum
of a cost accountant on whom we wouldn't spit if he were
alight. NFB is as cheap in money terms as it is expensive
in terms of perceived quality of music. We shall come to
those who claim to be sympathetic to high-fidelity but
insist on devices which do not work without NFB, who have
another devious answer. Here, meanwhile, for you to keep
in mind, is a single-sentence summary of a complicated
interdisciplinary argument:

The case against NFB is that for 99 per cent of listening
the NFB cure is worse than the disease.

In fact the inverse is true.

But surely we don't have to do anything so stupid?

What's really stupid is avoiding NFB because of Jute's
senseless claims.

It follows from the argument above that ultrafidelista
should choose an intrinsically linear topology and device
which does not require added negative feedback to
'linearize' the output.

In fact good designs with NFB start out with circuits that
have as low distortion as is practical before the addition
of NFB. See Self's blameless power amp circuit for many
examples of this.

The intrinsically linear device
is the thermionic tube in either its triode form or as a
pentode hogtied to work as a triode, which can be a most
pleasing alternative both economically and sonically.

In fact triodes have built-in NFB.

The
topology is often single-ended operation, chosen also for
several other reasons described elsewhere in these
articles, including KISS; if the chosen topology is
push-pull operation, which is more difficult but far from
impossible to arrange without NFB, operation should be
specified as Class A1. Inside the argued case above lies
too the overwhelming reason to accept the potential small
disadvantage that may accompany the preferred topology in
comparison to the discarded alternatives. The
disadvantage is of course the potential for a residual
second harmonic that measures high by transistor or NFB
tube standards. (Note the word potential. With a
conservatively designed DHT amp the potential problem
should not arise.)

Push-pull operation is in fact a great way to make power
amps more linear prior to the application of feedback.

The ultrafidelista, who are as keen on silent amps as
anyone else, accept this small potential difficulty
because it is the lesser evil compared to NFB.
Unbelievers (largely unwashed, according to reports)
sneer that ultrafidelista like this approach because of
the 'added euphonics', which is bow-wow techie talk for
the warmth a big chunk of second harmonic lays on a zero
negative feedback single-ended amplifier. But competent
design can easily reduce the level of second harmonic to
below the level of perception without the need for NFB
and its deleterious after-effects. In any event, it is
your amplifier. You paid for it. You have a right to tune
it as you please. The key thing is to get rid of NFB and
to understand why you did it.

If you did it because of Jute's posturing, you're an old
kind of fool.

Can we prove any of this scientifically?

Hard to do because Jute's so-called scientific claims are
bogus.

We have already.

LOL!

All of this is the technical subtext to
my longtime contention that what the ultrafidelista hear
and love is not a directly heated triode sound as is
claimed by many enthusiasts but a Class A1, ZNFB sound.
(Admittedly, as we have seen above, the right sound is
virtually guaranteed with a ZNFB DHT SE amp of
conservative provenance but may have to be developed the
hard way with more economical or higher-power
contenders.) In comparative ABX tests conducted over a
number of years, I found that professional musicians,
certified golden ears, choose the triode-linked Class A1
PP ZNFB EL34 whenever it is present in the test over all
other contenders including SE 300B and 'blameless'
high-NFB silicon.

Show us your level-controlled, bias-controlled listening
tests, Andre.

Science also proceeds by pure reason.

Actually, science proceedes by both pure reasoning and
practical experience.


Ultrafidelista have
long doubted whether what engineers insist we measure
(the absolute level of distortion, THD) predicts success
in audio gear. This is the full circle, because I have
just proven by logical, individually uncontested steps
that what matters, once a certain modest level of silence
is assured to an amplifier, is not the absolute level of
disharmonics but their composition. The same proof
demonstrates that a more beneficial distribution follows
instantly from doing without NFB.


NFB lowers all relevant forms of distortion. Distortion is
one of those things where less is more.


But transistor amps won't work at all without NFB!

Absolute BS. Transistor amps without NFB were built in the
early days, before the refinements that enable the use of
NFB are possible.

That is not our problem. Those who choose inefficient
speakers and consequently are forced to accept monstrous
amps made possible only by gigadeciBels of NFB, will
receive our sympathy - and the music they deserve.

Seneseless posturing.

Engineering hangers-on of transistor attempts at high
fidelity, where the measure of success is vanishing THD
rather than sonic hedonism, pretend to be enthusiasts for
NFB. To make it work for them, they have attempted to
change the rules so that we won't hear what their
treasured NFB does to our sound. They sneer that low
level listening, which 99 per cent of us prefer and where
NFB does most to wreck the sound, is 'easy listening' and
therefore not permissible. According to them we should
all be forced to listen at the high volume level which
suits NFB amps, which they call 'realistic'. This is a
contemptible circular argument, only too characteristic
of a fascist mentality in a part of the audiophile
spectrum which wants to prescribe their arid vision
without regard for our enjoyment.

More senseless posturing.

We can recommend a good tailor to them. It hurts every
time you wear his suit. No pain, no gain, fellers!



In summary

Almost everyone listens at low level most of the time.

And, SS high feedback amps are what they use as a rule.

NFB wrecks everybody's sound at all levels but most
wretchedly at normal listening levels.

Wrong. NFB can work well at both low and high levels.

e started out
with a contemptible circular argument and we have met
another along the way. We can now put both in context:



An 'engineer' who designs an amplifier which does not
work perfectly without negative feedback is like a tailor
cutting the suit incompetently and then demanding that
you walk like a cripple to make it fit, so that everyone
can admire the brilliance of your tailor.

The joke is that Jute prizes triodes, which are just
pentodes with NFB added back in.


Negative feedback is a bodge. That is why it is
despicable to the ultrafidelista.

If NASA listened to Jute, the Rusians would have beaten us
to the moon.

- end long quote -

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

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

Sander deWaal wrote:

Just look what Arny had to say to one of your posts about the use of
NFB ....the original was posted to RAO by our friend Brat Ludwig :-)

Ludwig is a thief. The material is copyright and clearly marked for use
on RAT only.

This was my reply to Arny. Your comment is invited:

The above reply by Arny Krueger is garbage. There is no legitimate reason to
draw from other fields to either justify or demonize negative feedback. The
question under discussion is negative feedback applied to audio amplifiers.
These nonsequitur references are trademarks of Arny's dirty debating
tactics.

I will give the same answer I gave regarding turntable design. How good an
amplifier is cannot be determined by looking at the feedback loop, or any
other single element of the design. The only valid test is how it sounds.

There seems to be some concern by hifi purists which is based on the
following:
1. The number of iterations within a feedback loop is infinite. How long is
the total transit time, through multiple interations, until inaudibility is
reached?
2. Feedback causes a relative increase in the proportion of higher
harmonics. There is no psychometric for this effect.

These two questions, which are, in fact interrelated, remain current because
amplifier measurement techniques are not sufficiently valid to predict how
an amplifier will sound. The only universally accepted fact seems to be the
established threshold of harmonic distortion. The regimes of amplifier
operation are a multivariate affair in the extreme.

"Robert Morein" said:

This was my reply to Arny. Your comment is invited:


Well, what's good for the Space Shuttle, surely must be good for your
amplifier.

Those servo-motors are soooooo hifi!

For the ISS, NASA should switch to tubes, the vacuum is already
there....

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

"Sander deWaal" wrote in message
...
: "Robert Morein" said:
:
: This was my reply to Arny. Your comment is invited:
:
:
: Well, what's good for the Space Shuttle, surely must be good for your
: amplifier.
:
you know, Arny doesn't use your regular or unleaded to fool
his car: what's good for rockets...:-)

: Those servo-motors are soooooo hifi!
:
yeah, my subwoofer uses Sanyo stepper motors. Got a problem with that ?

: For the ISS, NASA should switch to tubes, the vacuum is already
: there....

...but switch _with_ tubes ?
let's give ss ~some~ credit, it makes for damned good switches :-)
Rudy

: --
:
: "Audio as a serious hobby is going down the tubes."
: - Howard Ferstler, 25/4/2005

"Ruud Broens" said:

you know, Arny doesn't use your regular or unleaded to fool
his car: what's good for rockets...:-)


Nice Freudian slip......fool his car.

Hardly rocket science, BTW.
Those minivans will run on collected farts if necessary.


: Those servo-motors are soooooo hifi!

yeah, my subwoofer uses Sanyo stepper motors. Got a problem with that ?


Do they tilt the entire enclosure, or merely move the core in and out
of the series coil? :-)


: For the ISS, NASA should switch to tubes, the vacuum is already
: there....

..but switch _with_ tubes ?
let's give ss ~some~ credit, it makes for damned good switches :-)


No need to get slick, Clyde.
One day you'll be old and senile just like me, you will note.

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

"Sander deWaal" wrote in message

"Robert Morein" said:

This was my reply to Arny. Your comment is invited:


Well, what's good for the Space Shuttle, surely must be
good for your amplifier.

Those servo-motors are soooooo hifi!

Sander is obviously unaware of the fact that hi fi amps, for
example Crown amps are widely used for servo drivers where
they fit. Both servos and hi fi are about accuracy,
load-handling capabilities, clean power output, etc.

BTW, I checked your purported EE credentials, and they look
like they came from a trade school type of program, not what
we call undergraduate university classes in the US.


For the ISS, NASA should switch to tubes, the vacuum is
already there....

There's plenty of vacuum in your typical tube-bigot's
brains, it seems.

What do you call Jute, Ludwig, Allison, Morein and various other
prima-donnas herein up to their necks in concrete?









Not enough concrete.

When one of these turkeys gets involved in a thread, no civil discourse
is possible.

Peter Wieck
Wyncote, PA

"Andre Jute" wrote in message
oups.com

PS: Interestingly, Arny kicks the bejeezus out of his own
organ grinder's monkey, Pinkerton, who was the one who
came up with the ignorant 50dB feedback suggestion, in
this passage:

I just checked google, and the 50 dB NFB thing seems to have
first came up in posts by Patrick Turner.

Correct me if you can...

"Arny Krueger" said:

BTW, I checked your purported EE credentials, and they look
like they came from a trade school type of program, not what
we call undergraduate university classes in the US.


A trade school program? I wish!
Would make a lot more money that way...........

My alma mater Rens & Rens doesn't exist any more, sadly.
Went belly-up last year.

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

wrote in message
oups.com...
What do you call Jute, Ludwig, Allison, Morein and various other
prima-donnas herein up to their necks in concrete?

Peter, we're neighbors. I'm in Dresher. Give me a scream some time: (215)
646-4894.
I'll be back later this evening.

"Sander deWaal" wrote in message
...
: "Ruud Broens" said:
:
: you know, Arny doesn't use your regular or unleaded to fool
: his car: what's good for rockets...:-)
:
:
: Nice Freudian slip......fool his car.
:
: Hardly rocket science, BTW.
: Those minivans will run on collected farts if necessary.
:
:
: : Those servo-motors are soooooo hifi!
:
: yeah, my subwoofer uses Sanyo stepper motors. Got a problem with that ?
:
:
: Do they tilt the entire enclosure, or merely move the core in and out
: of the series coil? :-)
:
you nailed it, slyde - it's in a feedback loop to offset the DC at the
output of my amps, lot"sZ :-)


: : For the ISS, NASA should switch to tubes, the vacuum is already
: : there....
:
: ..but switch _with_ tubes ?
: let's give ss ~some~ credit, it makes for damned good switches :-)
:
:
: No need to get slick, Clyde.
: One day you'll be old and senile just like me, you will note.


that'll be the day, Mr Duell, not !
R.
: --
:
: "Audio as a serious hobby is going down the tubes."
: - Howard Ferstler, 25/4/2005

"Ruud Broens" wrote in message
...

"Robert Morein" wrote in message
...
:
: wrote in message
: oups.com...
: What do you call Jute, Ludwig, Allison, Morein and various other
: prima-donnas herein up to their necks in concrete?
:
: Peter, we're neighbors. I'm in Dresher. Give me a scream some time:
(215)
: 646-4894.
: I'll be back

.. as robocop morein ?

later this evening.
:
hawhawhaw

Just a friendly, humorous invitation.
Of course, if he wants to scream, it would be interesting

"Robert Morein" wrote in message
...
:
: wrote in message
: oups.com...
: What do you call Jute, Ludwig, Allison, Morein and various other
: prima-donnas herein up to their necks in concrete?
:
: Peter, we're neighbors. I'm in Dresher. Give me a scream some time: (215)
: 646-4894.
: I'll be back

... as robocop morein ?

later this evening.
:
hawhawhaw

Robert Morein said:

Peter, we're neighbors. I'm in Dresher.

Wyncote is much nicer than Dresher.

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


Robert Morein said:

Peter, we're neighbors. I'm in Dresher.

Wyncote is much nicer than Dresher.

Yes, Wyncote is definitely prettier.
Most of Dresher was built in the last thirty years, with all the negatives
that implies.
We have a nicer plot than most, with lots of trees we planted ourselves.

So you've been to both?

Robert Morein said:

Wyncote is much nicer than Dresher.

Yes, Wyncote is definitely prettier.

So move there already. Unless you think you wouldn't fit in.

We have a nicer plot than most, with lots of trees we planted ourselves.

Plant a tree, displace a 'borg.

So you've been to both?

You're clever, you are. ;-)

"Sander deWaal" wrote in message
...
"Arny Krueger" said:

BTW, I checked your purported EE credentials, and they look
like they came from a trade school type of program, not what
we call undergraduate university classes in the US.

Arny went to Black and Decker U.

"Arny Krueger" wrote in message
...
, etc.

BTW, I checked your purported EE credentials, and they look like they came
from a trade school type of program,

A la Oakland University!!!!

On 6 Dec 2005 11:14:51 -0800, "Andre Jute" wrote:

PS: Interestingly, Arny kicks the bejeezus out of his own organ
grinder's monkey, Pinkerton, who was the one who came up with the
ignorant 50dB feedback suggestion, in this passage:

(Jute
Before I even finished the design of the KISS 300B it was
forcefully suggested by a wannabe guru that with only
50dB more gain (about seven times as much as is likely to
be in the actual design) I can apply 50dB of negative
feedback to linearize my amplifier.
(Krueger
Good example of Jute's ignorance of feedback. It's highly
unlikely that one could apply 50 dB loop feedback to a power
amp with an output transformer and still have acceptable
stability.

Yeah, I know, Arny. As should be clear from the text even to an
illiterate engineer, I wasn't the one who made the silly 50dB
suggestion; your accolyte Stewart Pinkerton came up with it; that is
why I told Pinkothicko to **** off back to you and stop pretending he
was my guru.

As with most of your posturing, that is a combination of flat lies and
technical ignorance. That you are too stupid and ignorant to
understand what was acrtually said, is not *my* problem.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

So why don't you tell us what was "acrtually" said, Pinko. Patrick and
I both remember distinctly that you advised me to add 50dB more gain so
that I could use 50dB of NFB - - on a tube amp with transformer output!
That was what finally persuaded me that you are an ignoramus who
listened in school as little as you do now. Go on, tell us what you
"acrtually" said, so we can have another giggle. -- Andre Jute

Pinko Porg Butcher wrote:
On 6 Dec 2005 11:14:51 -0800, "Andre Jute" wrote:

PS: Interestingly, Arny kicks the bejeezus out of his own organ
grinder's monkey, Pinkerton, who was the one who came up with the
ignorant 50dB feedback suggestion, in this passage:

(Jute
Before I even finished the design of the KISS 300B it was
forcefully suggested by a wannabe guru that with only
50dB more gain (about seven times as much as is likely to
be in the actual design) I can apply 50dB of negative
feedback to linearize my amplifier.
(Krueger
Good example of Jute's ignorance of feedback. It's highly
unlikely that one could apply 50 dB loop feedback to a power
amp with an output transformer and still have acceptable
stability.

Yeah, I know, Arny. As should be clear from the text even to an
illiterate engineer, I wasn't the one who made the silly 50dB
suggestion; your accolyte Stewart Pinkerton came up with it; that is
why I told Pinkothicko to **** off back to you and stop pretending he
was my guru.

As with most of your posturing, that is a combination of flat lies and
technical ignorance. That you are too stupid and ignorant to
understand what was acrtually said, is not *my* problem.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Tue, 6 Dec 2005 18:17:55 -0500, "Robert Morein"
wrote:


"Sander deWaal" wrote in message
.. .
"Arny Krueger" said:

BTW, I checked your purported EE credentials, and they look
like they came from a trade school type of program, not what
we call undergraduate university classes in the US.

Arny went to Black and Decker U.

If that were the case he'd be getting on with Sander a lot better than
he is.

(Think about it) :-)

I agree with you wholeheartedly. I have been saying the same things for
years.

I'm starting to wonder if Arny isn't thick and sly rather than
intelligent and obstructive. The evidence is building. For instance,
how can a guy who tells the whole wide world he's a Christian active in
the affairs of his church, as Arny does, on the same day, and for years
on end, perpetrate the slimy immorality of Arny's viciously dishonest
debating tactics, amply demonstrated by Patrick's analysis of Arny's
reply to my NFB article in the current threads. An honest, intelligent
man would go nuts trying to reconcile Christian beliefs with such
deceitful behaviour. A fool would not notice that his expressed beliefs
and his actions are opposed to each other. Other fools on the tube
conferences often make the same mistakes of comprehension Arny makes.

Andre Jute

Robert Morein wrote:
"Andre Jute" wrote in message
oups.com...

Sander deWaal wrote:

Just look what Arny had to say to one of your posts about the use of
NFB ....the original was posted to RAO by our friend Brat Ludwig :-)

Ludwig is a thief. The material is copyright and clearly marked for use
on RAT only.

This was my reply to Arny. Your comment is invited:

The above reply by Arny Krueger is garbage. There is no legitimate reason to
draw from other fields to either justify or demonize negative feedback. The
question under discussion is negative feedback applied to audio amplifiers.
These nonsequitur references are trademarks of Arny's dirty debating
tactics.

I will give the same answer I gave regarding turntable design. How good an
amplifier is cannot be determined by looking at the feedback loop, or any
other single element of the design. The only valid test is how it sounds.

There seems to be some concern by hifi purists which is based on the
following:
1. The number of iterations within a feedback loop is infinite. How long is
the total transit time, through multiple interations, until inaudibility is
reached?
2. Feedback causes a relative increase in the proportion of higher
harmonics. There is no psychometric for this effect.

These two questions, which are, in fact interrelated, remain current because
amplifier measurement techniques are not sufficiently valid to predict how
an amplifier will sound. The only universally accepted fact seems to be the
established threshold of harmonic distortion. The regimes of amplifier
operation are a multivariate affair in the extreme.

"Andre Jute" wrote in message
oups.com...
I agree with you wholeheartedly. I have been saying the same things for
years.

I'm starting to wonder if Arny isn't thick and sly rather than
intelligent and obstructive.

Those are symptoms. The underlying problem
is his insanity.

Andre Jute said:

... [Krooger] tells the whole wide world he's a Christian active in
the affairs of his church, as Arny does, on the same day, and for years
on end, perpetrate the slimy immorality of Arny's viciously dishonest
debating tactics, amply demonstrated by Patrick's analysis of Arny's
reply to my NFB article in the current threads. An honest, intelligent
man would go nuts trying to reconcile Christian beliefs with such
deceitful behaviour. A fool would not notice that his expressed beliefs
and his actions are opposed to each other.

Neither would a crazy person.

Andre Jute wrote:

So why don't you tell us what was "acrtually" said, Pinko. Patrick and
I both remember distinctly that you advised me to add 50dB more gain so
that I could use 50dB of NFB - - on a tube amp with transformer output!
That was what finally persuaded me that you are an ignoramus who
listened in school as little as you do now. Go on, tell us what you
"acrtually" said, so we can have another giggle. -- Andre Jute

Notice how Oinketon comes snuffling around like a pig looking
for truffles as soon as something contentious comes up for discussion.

The man has absolutely zero skill, knowledge, experience at anything to do
with tubecraft,
but when there is a chance for a donnybrook, here he is, muddy trotters
treading
all the garden to peices.

Going through Oinky's amp ideas again is not a pleasant thought.
I'd not worry about him myself.

Patrick Turner.



Pinko Porg Butcher wrote:
On 6 Dec 2005 11:14:51 -0800, "Andre Jute" wrote:

PS: Interestingly, Arny kicks the bejeezus out of his own organ
grinder's monkey, Pinkerton, who was the one who came up with the
ignorant 50dB feedback suggestion, in this passage:

(Jute
Before I even finished the design of the KISS 300B it was
forcefully suggested by a wannabe guru that with only
50dB more gain (about seven times as much as is likely to
be in the actual design) I can apply 50dB of negative
feedback to linearize my amplifier.
(Krueger
Good example of Jute's ignorance of feedback. It's highly
unlikely that one could apply 50 dB loop feedback to a power
amp with an output transformer and still have acceptable
stability.

Yeah, I know, Arny. As should be clear from the text even to an
illiterate engineer, I wasn't the one who made the silly 50dB
suggestion; your accolyte Stewart Pinkerton came up with it; that is
why I told Pinkothicko to **** off back to you and stop pretending he
was my guru.

As with most of your posturing, that is a combination of flat lies and
technical ignorance. That you are too stupid and ignorant to
understand what was acrtually said, is not *my* problem.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

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

A Google search for the exact phrase 50db negative feedback and Stewart
Pinkerton as the author came back with nothing.

What would be the best search phrases?

Can you explain how a triode based amp can be free of NFB?


"Andre Jute" wrote in message
oups.com...
I agree with you wholeheartedly. I have been saying the same things for
years.

I'm starting to wonder if Arny isn't thick and sly rather than
intelligent and obstructive. The evidence is building. For instance,
how can a guy who tells the whole wide world he's a Christian active in
the affairs of his church, as Arny does, on the same day, and for years
on end, perpetrate the slimy immorality of Arny's viciously dishonest
debating tactics, amply demonstrated by Patrick's analysis of Arny's
reply to my NFB article in the current threads. An honest, intelligent
man would go nuts trying to reconcile Christian beliefs with such
deceitful behaviour. A fool would not notice that his expressed beliefs
and his actions are opposed to each other. Other fools on the tube
conferences often make the same mistakes of comprehension Arny makes.

Andre Jute

Robert Morein wrote:
"Andre Jute" wrote in message
oups.com...

Sander deWaal wrote:

Just look what Arny had to say to one of your posts about the use of
NFB ....the original was posted to RAO by our friend Brat Ludwig :-)

Ludwig is a thief. The material is copyright and clearly marked for use
on RAT only.

This was my reply to Arny. Your comment is invited:

The above reply by Arny Krueger is garbage. There is no legitimate reason
to
draw from other fields to either justify or demonize negative feedback.
The
question under discussion is negative feedback applied to audio
amplifiers.
These nonsequitur references are trademarks of Arny's dirty debating
tactics.

I will give the same answer I gave regarding turntable design. How good
an
amplifier is cannot be determined by looking at the feedback loop, or any
other single element of the design. The only valid test is how it sounds.

There seems to be some concern by hifi purists which is based on the
following:
1. The number of iterations within a feedback loop is infinite. How long
is
the total transit time, through multiple interations, until inaudibility
is
reached?
2. Feedback causes a relative increase in the proportion of higher
harmonics. There is no psychometric for this effect.

These two questions, which are, in fact interrelated, remain current
because
amplifier measurement techniques are not sufficiently valid to predict
how
an amplifier will sound. The only universally accepted fact seems to be
the
established threshold of harmonic distortion. The regimes of amplifier
operation are a multivariate affair in the extreme.

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


Andre Jute said:

... [Krooger] tells the whole wide world he's a Christian active in
the affairs of his church, as Arny does, on the same day, and for years
on end, perpetrate the slimy immorality of Arny's viciously dishonest
debating tactics, amply demonstrated by Patrick's analysis of Arny's
reply to my NFB article in the current threads. An honest, intelligent
man would go nuts trying to reconcile Christian beliefs with such
deceitful behaviour. A fool would not notice that his expressed beliefs
and his actions are opposed to each other.

Neither would a crazy person.

I'm still waiting to hear Arny's statement on the status of his NAMBLA
membership.
A member "in bad standing" ?

Robert Morein said:

I'm still waiting to hear Arny's statement on the status of his NAMBLA
membership. A member "in bad standing" ?

DementoBorg has variously protested that it's a lie to say he is a member
of NAMBLA and a lie to say he's not a member. Perhaps you've identified the
curious Limbo-like state of Krooger's twilight existence: Neither real nor
unreal, neither factual nor fictional. Krooger is an un-being.

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


Robert Morein said:

I'm still waiting to hear Arny's statement on the status of his NAMBLA
membership. A member "in bad standing" ?

DementoBorg has variously protested that it's a lie to say he is a member
of NAMBLA and a lie to say he's not a member. Perhaps you've identified
the
curious Limbo-like state of Krooger's twilight existence: Neither real nor
unreal, neither factual nor fictional. Krooger is an un-being.




Can't you just check your list and see if his name is on it?

wrote:
Can you explain how a triode based amp can be free of NFB?

You've misunderstood. No amplifier can be free of negative feedback.
There is negative feedback built into many devices, including Directly
Heated Triodes, the most linear devices known to audiophile man
(duck!). There is negative feedback inescapably inherent in many
goodsounding topologies popular with the ultrafidelista tube
fraternity. (The ultrafidelista love me as little for saying so as the
cramped, unimaginative wing of the cost engineers love me for pointing
out that their beloved NFB has a downside. Read the outraged tone of
Arny's comments. The less intelligent ultrafidelista when they abuse me
for consorting, as they see it, with cost engineers like Arny and
Pinkerton, who to them are Beelzebub.)

My case is that one should choose devices which require the least
additional, added, fat and sugar, high cholesterol, nasty, sound
artery-clogging, negative feedback. Any added NFB is bad, but loop
feedback is worse than local feedback.

HTH.

Andre Jute



"Andre Jute" wrote in message
oups.com...
I agree with you wholeheartedly. I have been saying the same things for
years.

I'm starting to wonder if Arny isn't thick and sly rather than
intelligent and obstructive. The evidence is building. For instance,
how can a guy who tells the whole wide world he's a Christian active in
the affairs of his church, as Arny does, on the same day, and for years
on end, perpetrate the slimy immorality of Arny's viciously dishonest
debating tactics, amply demonstrated by Patrick's analysis of Arny's
reply to my NFB article in the current threads. An honest, intelligent
man would go nuts trying to reconcile Christian beliefs with such
deceitful behaviour. A fool would not notice that his expressed beliefs
and his actions are opposed to each other. Other fools on the tube
conferences often make the same mistakes of comprehension Arny makes.

Andre Jute

Robert Morein wrote:
"Andre Jute" wrote in message
oups.com...

Sander deWaal wrote:

Just look what Arny had to say to one of your posts about the use of
NFB ....the original was posted to RAO by our friend Brat Ludwig :-)

Ludwig is a thief. The material is copyright and clearly marked for use
on RAT only.

This was my reply to Arny. Your comment is invited:

The above reply by Arny Krueger is garbage. There is no legitimate reason
to
draw from other fields to either justify or demonize negative feedback.
The
question under discussion is negative feedback applied to audio
amplifiers.
These nonsequitur references are trademarks of Arny's dirty debating
tactics.

I will give the same answer I gave regarding turntable design. How good
an
amplifier is cannot be determined by looking at the feedback loop, or any
other single element of the design. The only valid test is how it sounds.

There seems to be some concern by hifi purists which is based on the
following:
1. The number of iterations within a feedback loop is infinite. How long
is
the total transit time, through multiple interations, until inaudibility
is
reached?
2. Feedback causes a relative increase in the proportion of higher
harmonics. There is no psychometric for this effect.

These two questions, which are, in fact interrelated, remain current
because
amplifier measurement techniques are not sufficiently valid to predict
how
an amplifier will sound. The only universally accepted fact seems to be
the
established threshold of harmonic distortion. The regimes of amplifier
operation are a multivariate affair in the extreme.

On 7 Dec 2005 14:42:47 -0800, "Andre Jute" wrote:

My case is that one should choose devices which require the least
additional, added, fat and sugar, high cholesterol, nasty, sound
artery-clogging, negative feedback.

Oh, THAT feedback! You should have said.

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

A Google search for the exact phrase 50db negative feedback and Stewart
Pinkerton as the author came back with nothing.

What would be the best search phrases?

Ask Arny. He claimed in a post yesterday to have found the relevant
message. Or perhaps Arny is just lying for debating advantage as he so
often does. Or ask Pinkothicko, who claims to have been
misunderstood--maybe he looked up the message though that is hardly
likely because he continues to be caught out being slack about details
and lying a lot.

Certainly, it happened before I posted the KISS 123 article on NFB,
because it was the stupidity of Arny's monkey Pinkerton which inspired
me to post it. (PinkoThicko is the "wannabe guru" in the opening par of
the main piece. There is an intro with a relevant joke before that but
the humorless Brat Ludwig cut it, presumably because he believes that
no one on RAO has a sense of humor.) That site was put together from
about Sept 2004 forwards, so that must limit the scope of the search. A
search of RAT messages will certainly tell you when I first posted the
article because I would have announced it. Pinkerton's gross error, so
eloquently highlighted by the monkey's organ grinder, Arny Krueger,
must be before that date.

Unfortunately there are a lot of posts about that time, as Patrick
Turner was indulging his St Francis passion for salvaging lame vultures
and trying to teach poor Pinkothicko, who had challenged me to a design
contest, the basics of electronic design and making a ****ing awful
meal of it because Pinko isn't called Thicko for nothing.

HTH

Andre Jute
"If now you're even more confused-- well, that too." -- Andre Jute,
radio comedy

Goofball_star_dot_etal wrote:
On 7 Dec 2005 14:42:47 -0800, "Andre Jute" wrote:

My case is that one should choose devices which require the least
additional, added, fat and sugar, high cholesterol, nasty, sound
artery-clogging, negative feedback.

Oh, THAT feedback! You should have said.

I did, repeatedly. People don't read what I write; they react with
their prejudices and deepseated fears that if what they were trained to
do is no long important, they won't be important.

The version of my article that Brat Ludwig stole and posted on RAO was
specially prepared to infuriate cost-engineering railroad minds--check
the effect it had on Arny, and imagine how the more explosive
personalities reacted. (I described it as the time as "a staked pit
into which Pinkerton dived face first".) That mindlessly unfunny
grinder Ludwig cut the significant joke at the beginning which serves
as a hint to the discriminating that I intend more than an engineering
treatise. Thanks for reminding me of it.

So here's the Goofy version of KISS 113 -- NFB complete, not the
butchered version offered on RAO before. Note copyright information at
end.
--
Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"an unbelievably comprehensive web site" -- Hi-Fi News & Record Review


KISS 123

*****

The customer complained that his new suit didn't fit. 'The sleeves are
too short,' he said to the tailor.

'Yes sir,' said the tailor, 'but if you hold your arm just so, at an
angle as if you're drinking tea with your auntie, it will show just the
right amount of cuff.'

The customer tried it. The tailor was right! 'But what about the other
sleeve? It is definitely too short.'

'Just lower your shoulder, sir. Yes, yes, a little more. Put your foot
out so you can lower your shoulder a little more still. Bend your knee.
Yes, that's it. See how beautifully your suitcoat now fits?'

The customer had to admit the tailor was right. 'Wow. But now the leg
of the pants is all twisted around.'

'That's easily fixed,' said the tailor. 'Just point your other toe
westward, sir, and look over your shoulder to where I am holding up the
hand mirror. See? Doesn't that fit beautifully?'

'Yes,' the customer said doubtfully, 'but-'

'Now would sir like to wear his brilliant new suit or shall we wrap
it?'

The customer was too intimidated to argue. He walked out into the
street in his new suit, his arm crooked as if he were drinking tea, his
other shoulder well down over a bent knee with his foot out to the
side, his other foot pointing westwards, his head twisted back between
hunched shoulders as if complaining to God about a cruel fate.

Behind him he heard a boy say to his father. 'Oh, Daddy, look at the
poor twisted cripple.'

'Hush,' the father said. 'Be grateful the poor man found such a
brilliant tailor.'

****

The Ultrafidelista view of Negative Feedback
by Andre Jute
Negative feedback is the paradigm of modern electronic design. It is
mother's milk to an electronics engineer. He learns to say '100dB of
NFB,' in his sleep before he finishes his first week at the most humble
polytechnic. At the great institutions the professor of feedback is the
most honoured man in the department. In Massachusetts and Minnesota the
feedback guru is the most honoured man on the entire campus, equal in
stature to the football coach. When a guru of transistor high fidelity
(and some in tubes) says, 'I studied under Ron,' one doesn't have to
ask which Ron, one just knows it is the holy name of the prophet of
feedback from the Midwest.

Before I even finished the design of the KISS 300B it was forcefully
suggested by a wannabe guru that with only 50dB more gain (about seven
times as much as is likely to be in the actual design) I can apply 50dB
of negative feedback to linearize my amplifier.

Negative feedback, shorthanded as NFB, is the instant response of the
audio engineering fraternity to all ills, real, perceived,
non-existent. They don't even ask if there is a problem, they swing the
club of NFB regardless. NFB has become a reflex axiom of mainstream
audio design. An audio engineer with his negative feedback is like a
policeman who runs out into the street with his stick and starts
beating a confession out of the first housewife he sees. The difference
is that the policeman is relieved of duty to await punishment and the
audio engineer gets away with it. In the case of the policeman it is
unacceptable behaviour, in the case of the audio engineer so much the
expected norm that no one except the ultrafidelista notice. I guess
that if one in ten million audio amplifiers does not have negative
feedback added, it will be a lot...

No one asked if my KISS Amp requires linearization. The presumption by
all except those already of the ultrafidelista persuasion was that I
would welcome suggestions about A Good Thing.

In the face of such overwhelming acceptance by qualified engineers, why
do we as ultrafidelista not take the same easy path of negative
feedback? Especially considering that superficially NFB is easy to
understand and apply.

How does negative feedback work?
Negative feedback is simply a negative voltage fed back from the output
to the input amplifying device to offset part of the harmonic
distortion which is present as a positive voltage. It costs nothing
except a loss of gain and a few side effects such as phase shift and
possible instability which are well known in the mathematical
literature and more or less easily guarded against depending on the
level of NFB.

'Wow!' those meeting NFB for the first time will now say, 'Something
for free! I'll grab some of that for my amp.' Hey, I said it, and I am
a professional intellectual, by definition an infinite skeptic. NFB is
a thing of beauty that will draw you in. It is like an electronic
Marxism which admits of no contrary arguments because it has subsumed
them all into The Holy Measurements. To question The Measurements is to
commit heresy. You need to be of strong mind to resist the
blandishments of such a universal panacea and of strong stomach to
withstand the hysterical assaults of the lesser engineers defending
their holy grail. (And when you do get hold of a superior engineer to
explain NFB to you, you need to be high-domed indeed because suddenly
NFB can turn very intricate.)

Unfortunately NFB doesn't come without a price. It levies a cruel
charge on the perceived quality of the sound. Negative feedback is what
gives all those 'blameless' transistor and big PP tube amps their
chillingly unnatural sound.

Then how did NFB come to be such a panacea in amplifier design?
Your guess is as good as mine. Hi-fi design is not prestige work for
engineers, or highly paid. The most talented and best qualified
engineers go into automobiles or military hardware or big construction
projects or computer design. The left-overs design amplifiers in the
time they have to spare from writing up specs for requesting a CE mark
for a new electric kettle. Lemmings storming en masse over a cliff come
to mind; such people don't see the necessity of original thought, or
have the mental equipment for it. The exceptions to this rule are
normally audio enthusiasts in charge of their own small audio
manufactories with niche markets; those who grow larger from this base
follow the mainstream mantra of "mo' NFB give lowa' THD" because the
marketing channels demand it from them if they wish to grow. At this
point they usually cease to offer anything different, only the
exclusivity of a very high price. (I know, because a sub-board I
designed for a supplier to the trade turns up in so many very expensive
amps with so many different big names neatly silkscreened on it... it
strikes me as the sort of detail a real designer, as distinct from a
marketer, would take under his own control.) Those very few makers who
will sell you an ultrafi amp without any NFB operate even tinier shops,
usually one man and a cat, just hanging on.

The mechanism by which NFB wrecks your sound
Negative feedback at first acquaintance sounds good enough to take to
bed and cuddle. It isn't. It isn't even as simple as a superficial
acquaintance may suggest. Follow the steps with me, from the theory as
she is received to what arrives at your brain as music:

1. In theory NFB reduces all harmonic distortion equally, without
discrimination. Strictly in theory it does not reshape harmonic
distortion by reducing the most objectionable third and higher order
odd harmonic distortion to a greater extent than the relatively
harmless 2nd harmonic. Thus NFB at its theoretically most benign is
already useless in terms of psychoacoustics, as will become clear at
point 4. If you disregard psychoacoustics, as many audio engineers do,
NFB is brilliant in reducing total harmonic distortion to a number as
tiny as you want. You just pile on more NFB.

2. In real life, as distinct from simplified theory, NFB adds artifacts
of its own. Remember, it is a loop. The signal starts at the input and
is amplified by devices until it reaches the output. From the output a
part of the signal called the negative feedback is fed back to the
input. Here a loop is completed and the combination, less distorted,
reaches the output again, a part of the combination is fed back,
endlessly. The artifacts we want to consider here are created by the
fed-back residue of harmonic distortions adding to both the fundamental
and the distortions already created by the amplifier, then some portion
of the sum of the original and the feedback distortion is fed back
again and added on, until the ooh-ah bird flies up its own fundament.
It looks marginally less disgusting as a recursive mathematical formula
with lots of nested parenthetical parcels of noise being loaded onto
your music. But it is a monkey on the back of your sound, with a
smaller monkey on the back of the first monkey, a still smaller monkey
on the back of the second monkey, and so on ad infinitum. These
additive artifacts are all higher harmonics and the more dominant ones
are all odd. Suppose, for the sake of simplicity, a superbly designed
ultrafidelista amp with some second harmonic and zero odd harmonics
before NFB. Add NFB and the second harmonic will be lowered but the
recombinant new loop now contains newly added intermodulation effects
between the fundamental and the residual second harmonic, and that is
third harmonic. In the next cycle a small but nasty dose of fifth
harmonic that wasn't there before is added by interaction between the
still residual second harmonic and reduced newly added third harmonic.
In short, the artifacts NFB adds to the distortion mix are all of the
most harmful kind. But, say the proponents of NFB, so what? Every time
the loop cycles the added artifacts are smaller, even if there are more
of them... The whole affair starts to smell of trying to argue with a
Marxist who simply declares any inconvenient truth 'an anomaly'. (If
this sounds like a mess from which you should run a mile, you have come
to the right conclusion. Start running now. It gets worse.)

3. We thus arrive at a situation where distortion has been lowered by
NFB but where the most disturbing odd harmonic distortions are still
present to some measure, with the added disadvantage that new and
extremely disturbing artifacts of higher harmonic distortions have been
created by the very process of using negative feedback to lower
distortion. Regardless of the absolute level of THD, or the volume
setting, the mix of harmonics has been adversely affected and now
includes a higher proportion of third and higher harmonics than before
NFB. Let me say that again: after NFB, third and higher harmonics will
make up a greater part of the distortion than before.

4. Low volume levels perforce accounts for 99 per cent of audiophile
listening because we all have families or neighbours, and we would like
to keep our ears. Unfortunately for the lowest common denominator of
hi-fi designer, the one who specifies NFB as a conditioned response
much like Pavlov's dogs slavered when the bell rang, human physiology
and psycho-acoustic response is such that odd harmonics are
disproportionately more disturbing at lower than at higher listening
levels. This inescapable effect is independent of definition of
'listening level.' At the 110dB in-room SPL (only 14dB louder than an
automatic riveter!) advocated by the already deaf Transient Overload
Elite known on newsgroups as the Borg, this poisonous concoction of
original distortions and NFB recombinant artifacts will be least
disturbing (and soon not heard at all!). At any lower level perceived
interference of this harmonics cocktail with the music will increase in
inverse proportion to the volume level. At low volume levels the
artifacts generated by NFB will by their nature as higher harmonic
distortions be disproportionately far more disturbing. At these normal
listening levels 0.75 per cent of second harmonic distortion may be
below the threshhold of perception for sophisticated listeners, whereas
tiny amounts of third and higher odd harmonic distortions grate.

And they still use Negative Feedback? Are they stupid?
No, they are not stupid. Most of them march to the drum of a cost
accountant on whom we wouldn't spit if he were alight. NFB is as cheap
in money terms as it is expensive in terms of perceived quality of
music. We shall come to those who claim to be sympathetic to
high-fidelity but insist on devices which do not work without NFB, who
have another devious answer. Here, meanwhile, for you to keep in mind,
is a single-sentence summary of a complicated interdisciplinary
argument:

The case against NFB is that for 99 per cent of listening the NFB cure
is worse than the disease.

But surely we don't have to do anything so stupid?
It follows from the argument above that ultrafidelista should choose an
intrinsically linear topology and device which does not require added
negative feedback to 'linearize' the output. The intrinsically linear
device is the thermionic tube in either its triode form or as a pentode
hogtied to work as a triode, which can be a most pleasing alternative
both economically and sonically. The topology is often single-ended
operation, chosen also for several other reasons described elsewhere in
these articles, including KISS; if the chosen topology is push-pull
operation, which is more difficult but far from impossible to arrange
without NFB, operation should be specified as Class A1. Inside the
argued case above lies too the overwhelming reason to accept the
potential small disadvantage that may accompany the preferred topology
in comparison to the discarded alternatives. The disadvantage is of
course the potential for a residual second harmonic that measures high
by transistor or NFB tube standards. (Note the word potential. With a
conservatively designed DHT amp the potential problem should not
arise.)

The ultrafidelista, who are as keen on silent amps as anyone else,
accept this small potential difficulty because it is the lesser evil
compared to NFB. Unbelievers (largely unwashed, according to reports)
sneer that ultrafidelista like this approach because of the 'added
euphonics', which is bow-wow techie talk for the warmth a big chunk of
second harmonic lays on a zero negative feedback single-ended
amplifier. But competent design can easily reduce the level of second
harmonic to below the level of perception without the need for NFB and
its deleterious after-effects. In any event, it is your amplifier. You
paid for it. You have a right to tune it as you please. The key thing
is to get rid of NFB and to understand why you did it.

Can we prove any of this scientifically?
We have already. All of this is the technical subtext to my longtime
contention that what the ultrafidelista hear and love is not a directly
heated triode sound as is claimed by many enthusiasts but a Class A1,
ZNFB sound. (Admittedly, as we have seen above, the right sound is
virtually guaranteed with a ZNFB DHT SE amp of conservative provenance
but may have to be developed the hard way with more economical or
higher-power contenders.) In comparative ABX tests conducted over a
number of years, I found that professional musicians, certified golden
ears, choose the triode-linked Class A1 PP ZNFB EL34 whenever it is
present in the test over all other contenders including SE 300B and
'blameless' high-NFB silicon.

Science also proceeds by pure reason. Ultrafidelista have long doubted
whether what engineers insist we measure (the absolute level of
distortion, THD) predicts success in audio gear. This is the full
circle, because I have just proven by logical, individually uncontested
steps that what matters, once a certain modest level of silence is
assured to an amplifier, is not the absolute level of disharmonics but
their composition. The same proof demonstrates that a more beneficial
distribution follows instantly from doing without NFB.

But transistor amps won't work at all without NFB!
That is not our problem. Those who choose inefficient speakers and
consequently are forced to accept monstrous amps made possible only by
gigadeciBels of NFB, will receive our sympathy - and the music they
deserve.

Engineering hangers-on of transistor attempts at high fidelity, where
the measure of success is vanishing THD rather than sonic hedonism,
pretend to be enthusiasts for NFB. To make it work for them, they have
attempted to change the rules so that we won't hear what their
treasured NFB does to our sound. They sneer that low level listening,
which 99 per cent of us prefer and where NFB does most to wreck the
sound, is 'easy listening' and therefore not permissible. According to
them we should all be forced to listen at the high volume level which
suits NFB amps, which they call 'realistic'. This is a contemptible
circular argument, only too characteristic of a fascist mentality in a
part of the audiophile spectrum which wants to prescribe their arid
vision without regard for our enjoyment.

We can recommend a good tailor to them. It hurts every time you wear
his suit. No pain, no gain, fellers!

In summary
Almost everyone listens at low level most of the time. NFB wrecks
everybody's sound at all levels but most wretchedly at normal listening
levels. We started out with a contemptible circular argument and we
have met another along the way. We can now put both in context:

An 'engineer' who designs an amplifier which does not work perfectly
without negative feedback is like a tailor cutting the suit
incompetently and then demanding that you walk like a cripple to make
it fit, so that everyone can admire the brilliance of your tailor.

Negative feedback is a bodge. That is why it is despicable to the
ultrafidelista.

THE VOLTAGES IN THIS AMP WILL KILL YOU.
GET EXPERIENCED SUPERVISION IF IT IS YOUR FIRST TUBE AMP

All text and illustration is Copyright © Andre Jute 2001, 2004
and may not be reproduced except in the thread KISS xxx on
rec.audio.tubes

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

wrote:
Can you explain how a triode based amp can be free of NFB?

You've misunderstood. No amplifier can be free of negative feedback.
There is negative feedback built into many devices, including Directly
Heated Triodes, the most linear devices known to audiophile man
(duck!). There is negative feedback inescapably inherent in many
goodsounding topologies popular with the ultrafidelista tube
fraternity. (The ultrafidelista love me as little for saying so as the
cramped, unimaginative wing of the cost engineers love me for pointing
out that their beloved NFB has a downside. Read the outraged tone of
Arny's comments. The less intelligent ultrafidelista when they abuse me
for consorting, as they see it, with cost engineers like Arny and
Pinkerton, who to them are Beelzebub.)

My case is that one should choose devices which require the least
additional, added, fat and sugar, high cholesterol, nasty, sound
artery-clogging, negative feedback. Any added NFB is bad, but loop
feedback is worse than local feedback.

NFB used properly is not bad, used to much it can be.
It simply makes everything better when used properly.



"Andre Jute" wrote in message
oups.com...
I agree with you wholeheartedly. I have been saying the same things for
years.

I'm starting to wonder if Arny isn't thick and sly rather than
intelligent and obstructive. The evidence is building. For instance,
how can a guy who tells the whole wide world he's a Christian active in
the affairs of his church, as Arny does, on the same day, and for years
on end, perpetrate the slimy immorality of Arny's viciously dishonest
debating tactics, amply demonstrated by Patrick's analysis of Arny's
reply to my NFB article in the current threads. An honest, intelligent
man would go nuts trying to reconcile Christian beliefs with such
deceitful behaviour. A fool would not notice that his expressed beliefs
and his actions are opposed to each other. Other fools on the tube
conferences often make the same mistakes of comprehension Arny makes.

Andre Jute

Robert Morein wrote:
"Andre Jute" wrote in message
oups.com...

Sander deWaal wrote:

Just look what Arny had to say to one of your posts about the use
of
NFB ....the original was posted to RAO by our friend Brat Ludwig
:-)

Ludwig is a thief. The material is copyright and clearly marked for
use
on RAT only.

This was my reply to Arny. Your comment is invited:

The above reply by Arny Krueger is garbage. There is no legitimate
reason
to
draw from other fields to either justify or demonize negative
feedback.
The
question under discussion is negative feedback applied to audio
amplifiers.
These nonsequitur references are trademarks of Arny's dirty debating
tactics.

I will give the same answer I gave regarding turntable design. How
good
an
amplifier is cannot be determined by looking at the feedback loop, or
any
other single element of the design. The only valid test is how it
sounds.

There seems to be some concern by hifi purists which is based on the
following:
1. The number of iterations within a feedback loop is infinite. How
long
is
the total transit time, through multiple interations, until
inaudibility
is
reached?
2. Feedback causes a relative increase in the proportion of higher
harmonics. There is no psychometric for this effect.

These two questions, which are, in fact interrelated, remain current
because
amplifier measurement techniques are not sufficiently valid to predict
how
an amplifier will sound. The only universally accepted fact seems to
be
the
established threshold of harmonic distortion. The regimes of amplifier
operation are a multivariate affair in the extreme.

On 7 Dec 2005 15:25:11 -0800, "Andre Jute" wrote:

Unfortunately there are a lot of posts about that time, as Patrick
Turner was indulging his St Francis passion for salvaging lame vultures
and trying to teach poor Pinkothicko, who had challenged me to a design
contest, the basics of electronic design and making a ****ing awful
meal of it because Pinko isn't called Thicko for nothing.

I did no such thing, that's just more of your usual pathetic
self-aggrandisement. And I'm not called Thicko at all, not be anyone
with a functioning brain..........
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Wed, 07 Dec 2005 17:49:23 GMT, wrote:


"Andre Jute" wrote in message
roups.com...

A Google search for the exact phrase 50db negative feedback and Stewart
Pinkerton as the author came back with nothing.

What would be the best search phrases?

Try Jute Munchausen - that should get some hits........
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Stewart Pinkerton" wrote in message
...
: On 7 Dec 2005 15:25:11 -0800, "Andre Jute" wrote:
:
: Unfortunately there are a lot of posts about that time, as Patrick
: Turner was indulging his St Francis passion for salvaging lame vultures
: and trying to teach poor Pinkothicko, who had challenged me to a design
: contest, the basics of electronic design and making a ****ing awful
: meal of it because Pinko isn't called Thicko for nothing.
:
: I did no such thing, that's just more of your usual pathetic
: self-aggrandisement.

: And I'm not called Thicko at all, not be anyone
: with a functioning brain..........

agreed
your style is reasonable adequate, just the repetoire
needs working on,
lot'sZ :-)
Rudy
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

On Thu, 8 Dec 2005 17:37:05 -0500, "Arny Krueger"
wrote:

wrote in message
news
"Andre Jute" wrote in message
oups.com...

A Google search for the exact phrase 50db negative
feedback and Stewart Pinkerton as the author came back
with nothing.
What would be the best search phrases?

"jute" and "imagination" ;-)

Arnold, in case you haven't noticed, your system clock seems to be a
day ahead.

Just thought you should know.

Rudy wrote to Pinkothicko:

your style is reasonable adequate, just the repetoire
needs working on,
lot'sZ :-)
Rudy

I think you got it, Rudy. Lots of restful sleep will settle down
Oinkerton into something (possibly? nearly? approximately?)
recognizably human. Instead, every time I appear on RAT, poor old Pinko
sets his alarm an hour early in order to fire off rubber suckers. They
don't stick because I am entirely teflon-plated but Pinko has this
obsession with me that will not let him sleep.

I correct a few of Oinkerton's lies in this post in separate mails.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"an unbelievably comprehensive web site" -- Hi-Fi News & Record Review

Ruud Broens wrote:
"Stewart Pinkerton" wrote:
: On 7 Dec 2005 15:25:11 -0800, "Andre Jute" wrote:
:
: Unfortunately there are a lot of posts about that time, as Patrick
: Turner was indulging his St Francis passion for salvaging lame vultures
: and trying to teach poor Pinkothicko, who had challenged me to a design
: contest, the basics of electronic design and making a ****ing awful
: meal of it because Pinko isn't called Thicko for nothing.
:
: I did no such thing, that's just more of your usual pathetic
: self-aggrandisement.

: And I'm not called Thicko at all, not be anyone
: with a functioning brain..........

agreed
your style is reasonable adequate, just the repetoire
needs working on,
lot'sZ :-)
Rudy
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering