Arny Krueger wrote:
Nick Gorham wrote:


No, of course you can have as many stages as you want so as much gain
as you want, however its gets harder to apply global feedback with
more stages as you start to run into problems with phase shift.


Managing this sitaution is one of those things they teach in engineering
school.

Yes,thats why I said you start to run into problems, not that you can't
do it, as you say, part of any engineering discipline is learning how to
solve problems.



The other side of the above statement, of course, is that the
rationall that goes behind the reintroduction of SE designs tends to
frown on the use of global feedback.


The goal of modern SE design is obvioiusly to design the least accurate
amplifier possible.

Don't know, I suspect the goal of a commercial SE designer would be
different from mine, so you would have to ask them.



It can be heard that increasing
feedback will tend to cause the sound to become closed and in some
way deader.


In the minds of certain delusional persons, yes.


I think the word you are thinking of there is "listeners".


The interesting question is what there is about a high-distortion amplifier
that audiophiles should prize.


Yes I agree fully, that is the interesting question.


However for those that prefer the result of SE with little or no
feedback, then the additional problems are seen as acceptable.


Think of the modern SE amplifier as a good amplifier, front-ended with an
EFX box, such as might be used with an electric guitar.


Well yes, you could think of that, or you could show me how to create
such a circuit to put in front of a "good amplifier" that will produce
the same effect in a listener that SE designs can. If it was that
simple, then please tell me how, and lets see if people can tell the
difference. Maybe they could, if so my life would be much simpler, and
yours would involve much more cash.


There is a element of fashion attached to SE design and currently,
part of that fashion is zero negative feed back.


Good choice of words - the modern SE amplifier is a device borne of fashion,
not technology.


Yep, no disagreement there.


As I said, I am not trying to convince anyone of the "correctness" of
SE designs, but just trying to give some answers to the questions
that were raised. Which got onto feedback via the fact that without
global negative feedback its hard to make anything like a linear amp
from non linear devices.


An obviously ignorant statement, given the effectiveness of local feedback.



Yes of course smaller feedback loops can do the same thing. Remember I
am not claiming to be anything but ignorant of modern designs, just
answering the questions raised about the use of triodes.

--
Nick