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RE: Yeah, I get that- seen it in spades.

I have heard ultra high feedback amps (mola mola for example) that still sound relatively dead dynamically. Sure they play loud and clean but not dynamic.

If you feed a large % of the signal back you are in fact combining fedback signal with "fresh" incoming signal...this must create some kind of phase shift and "noise".

In fact, Norman Crowhurst noted that one of the most insidious aspects of feedback was a signal correlated "noise" floor. Which is another way of saying a myriad of distortion products, that covers the whole spectrum none of which is large enough to stick up as a clear harmonic peak. What it does do though is modulate with the signal level because, as you know, true noise is not correlated with the signal.

This is why you can easily hear "below the noise floor" on a recording with tape hiss, which is uncorrelated with the music signal. Your brain can pick out the correlated signal and reject the uncorrelated signal (a bit like an organic lock-in amplifier).

What happens though with a correlated "noise floor" though is that you can no longer hear below that noise floor because it is correlated with the signal, which has the effect of truncating low level information and I would argue probably has a deleterious effect on the dynamics as well.

An amp with huge amounts of feedback would also have a very strong and correlated response to the noise floor and this has negative impacts on perception...I can't see how adding even more feedback would magically take you out the other side for this particular problem.

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