Compensating multi-stage feedback (was: RE: all tranny vca+ )

[J. Larry Hendry]

OK, I am new to this game and have read this discussion with interest.  I
will have to claim that I was totally ignorant to the use of op amps until a
few months ago.  Now, I know just enough to make some op amp circuits work.
I have a couple  of references that I am using on the subject.  1 - the
simple Radio Shack booklet and 2 - the very in depth "Art of Electronics"  I
have built a few of these circuits for summing and inverting and have the
basic hang of it.

What is escaping me here is why the use of an op amp and negative feedback
in the audio path is perceived by some to be a bad thing.  For example, if I
wanted to boost the level of a line level audio signal to use in my higher
voltage modular audio path, seems like a simple op amp (one with the right
characteristics for audio) would be easy choice.

Without starting a discrete vs. op amp vs. tube all out onslaught, I would
appreciate hearing individual reasons why one would choose to build a
discrete circuit in the audio path as opposed to a good op amp.  Subjective
reasoning is really what I am after.

As always, thanks.  I don't post much here as my knowledge level is so far
below the qualified ones on this list.  But, I read almost all of it and
appreciate the great spirit of sharing.

Larry Hendry


----- Original Message -----
>100% agreed. I'd even go one step further: The complete audio path can be
>done without negative feedback. (And hence no compensation.)

From: jhaible <jhaible at debitel.net>
That's what I intended to say. Been there, done that - the audio path of my
JH-4 synth is completely built that way. The only multi stage feedback loop
is in the VCFs, to get resonance.