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Old March 26th 06, 02:20 AM posted to rec.audio.tubes,uk.rec.audio,rec.audio.opinion
Andre Jute
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Posts: 720
Default The Catch-22 of Negative Feedback aka NFB

Trevor Wilson wrote:
Here are a few of your lies (some of which you have backtracked on):


And then this nutter Wilson lists:

-- a set of incontrovertible facts agreed by all parties, without
explaining how the facts straight out of the RDH can be a lie

-- a set of my opinions on matters of taste, without explaining how a
cultural taste can be a lie

-- and so on into astounding subdivisions of irrationality and
stupidity

Let's take just one example of what Wilson declares a lie. I wrote:

"Let me say that again: after NFB, third and higher harmonics will make up a
greater part of the distortion than before."


According to Wilson that is "a lie". Really? It is in fact a fact
(heh-heh) agreed between all informed parties that the NFB, while
reducing the *total* amount of distortion, by its very nature alters
the frequency distribution of the remaining distortion so that the odd
and higher harmonics make up a greater proportion of the recombinant
residual. That is several times spelt out in my original article which
causes Wilson to foam at the mouth. So tell us, Trevor-baby, how is my
statement lie?

I can't resist. Here's another statement (a rhetorical question,
actually) this blockhead Wilson singles out as "a lie":

"And they still use Negative Feedback?"


Uh, duh, Trevor-baby, are you now claiming that the entire audio world
has stopped using NFB? Amazing.

Below my signature I reprint Wilson's entire hysterical (and
hysterically funny) letter in full for connoisseurs of audio
fruitcakery.

What a blockhead.

Andre Jute

"Andre Jute" wrote in message
oups.com...
Trevor Wilson wrote:
Incorrect and innappropriate application
of NFB can damage an amplifier's performance.


Now you're getting it, sonny.


**Then say so. Stop telling half-truths. There is NOTHING wrong with NFB, as
long as it is appropriately applied.

Next, try not to describe as a liar
anyone who doesn't instantly subscribe to your fanatical faith in Blow
Jobs from Transvestites (BJTs) and soon the rest of us might take you
seriously.


**I only tell it like it is.

Here are a few of your lies (some of which you have backtracked on):

"Negative feedback, shorthanded as NFB, is the instant response of the audio
engineering fraternity to all ills, real, perceived, non-existent."

"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."

"Negative feedback is what gives all those 'blameless' transistor and big
PP tube amps their chillingly unnatural sound."

"(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..."

" Suppose, for the sake of simplicity, a superbly designed ultrafidelista
amp with some second harmonic and zero odd harmonics before NFB."

"Let me say that again: after NFB, third and higher harmonics will make up a
greater part of the distortion than before."

"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."

"And they still use Negative Feedback?"

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

"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."

"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."

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

"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."

"They sneer that low level listening, which 99 per cent of us prefer"

"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."

"Almost everyone listens at low level most of the time."

"Negative feedback is a bodge."


Would you care to amend these lies and state PRECISELY what you mean?


--
Trevor Wilson
www.rageaudio.com.au