I don't see any mystery here, either. The case when it comes to resistors isn't quite so clear cut. The problems start to happen when you're putting a lot of them in the signal path - in early experimentation, I put about 10 or so per channel in the signal path, and the extra brightness in the sound was obvious from the first note. Not as much as you'd think, apparently. I would have thought that amps would benefit most, since the large transformers do have a tendency to rattle and hum.
Some companies pride themselves of making no use of feedback.
Feedback is where you feed the amplified signal back into the circuit to improve distortion characteristics, among others. Unless I ever get the chance to do a comparison, I'll remain undecided. It is a fact that coax connections usually suffer from less jitter than optical ones. The jitter in an optical connection isn't induced by the transfer, but the conversion to and from light at each end. 6 The only real problem with digital interconnects is the impedence issue.