Below is an explanation by Bruno Putzeys on why people take a decent zero feedback design and add some feedback then decide it sounds worse. He agrees that can be the result, but the problem isn't that feedback was used rather than not enough was used. This quote is from a nice interview with his background and how he came to the opinions he holds.
BTW, I don't find Nelson Pass articles or products wrong. Those I owned were good, and he has used feedback in more than he hasn't. But they aren't as good as some of the better switching amps which what I currently use.
BP:Of course, the next question is how to explain that when so many people disagree with that point of view. You can’t just go around saying, “Hey, I’ve made a negative-feedback amplifier that sounds great, so you are all wrong.” You have to accept that, for those people who say they tried feedback and it didn’t sound good, they had real experiences -- they didn’t make it up or start a religion. People have really, honestly heard what they have heard, and what they heard didn’t sound good. So I had to reverse-engineer all these experiments they had been doing and work out exactly what caused that particular subjective sonic experience. The “F-word” article is, in its first part, just a rundown of feedback structures and an attempt to get terminology straight. An interesting observation identified in that first section of the article is that local feedback with a bit of global feedback is, actually, identical to full global feedback -- mathematical fact. The second part looks back at the history to see what, in different scenarios, was responsible for feedback sounding bad in those particular cases. One of those you hinted at is that, if you take a simple amplifier which has acceptable distortion (just a second harmonic is what I use as an example) and you start applying feedback, harmonics will appear that were not there originally. Higher-order harmonics, even and odd, turn up out of the blue. So if you apply a little bit of feedback, the second harmonic that you wanted to reduce drops by a little, but out of the blue you get this whole smattering of high harmonics. It is quite understandable that this doesn’t sound good. That observation has been made and published by various people over the years, but the most important conclusion was never drawn: If you keep increasing feedback, if you turn the feedback knob up and up and up, you quickly hit a point where those distortion products all start coming down again and the signal does start getting cleaner. And if you get to very large amounts of feedback, the result is just supersmooth. So that is why I say that it is normal for an experimenter to experience that if you take a good-sounding zero-feedback amplifier and add 6dB of feedback, the result sounds worse. They heard that right. But had they been in a position to add 60dB, well then, suddenly they would have been confronted with a sound that is little short of magical.
As to how this relates to cables, well it doesn't directly. Just a product of thread drift. If it bothers others too much we could start a negative feedback thread if one doesn't already exist. Of course the same Mr. Putzeys has done an excellent article measuring and explaining cables. Finding nothing there down the limits of his measuring equipment to explain a difference one would hear in normal use. But I do believe I have linked it some pages earlier in the thread. Here it is again.
At the bottom of the second page are two links to the actual measurements and additional comments by BP.