Why do audiophiles shun feedback in amplifiers?

Learsfool, Upright bass has better "definition" related to fact that strings are, being long scale, at high tension. Sound of plucked string instrument can be defined by factors like Presence, Projection, Sustain, Separation and Tone. Upright bass has huge projection and great separation making for punchy tight sound, but at the same time has good presence and long sustain. Sound depends entirely on the player, that can play it to use projection and shorten the notes to kill sustain or can play softer because of good presence and use sustain "filling" the room with bass that reverberates. All I'm saying is that short scale bass guitar like McCartney's Hofner will sound flabby no matter how you play it, because it is extremely short scale bass with very low string tension. For the same reason Strat electric guitars sound punchier than shorter scale Les Pauls.

Learsfool, this is all semantics. I have been playing classical guitar since high school, and have dabbled in piano and sax. I have attended concerts at some of the finest halls in the country (Symphony Hall in Boston, etc) and listen to live unamplified acoustic music on a regular basis (Jazz, folk, and classical). By tight, I don't mean bass that has been stripped of harmonic content and sounds dry. I mean muddy bass that has been stripped of harmonic content distorting the timbre of the instrument. Tight bass has initial fast transient attack followed by natural decay and rich harmonics. This can be heard with plucked stand up bass, low piano notes, kick drum, tympani etc. There are exceptions of course such as wind instruments, like church organ, tuba, etc.

Dracule1,
I agree this is semantics, we all seem to be describing the same natural character of acoustic bass.The difference is our individual ways of achieving this sound in our systems.You chose PP tubes,Kijanki with class D and me with SET amps. Different ears ,different solutions.
Regards,

As an aside, many years ago I had LWE speakers, which provided negative feedback from the speakers back to the amp. The idea was to monitor the speakers response to the input signal and correct the differences by providing feedback to the amp. So, it was an attempt to correct the imperfections of the speaker, rather than those of the amp. As I understand it, the feedback was trying to do more of a long term, overall correction rather than a short time duration correction. I was never sure how much the feedback effected the sound, but I did like them paired with an old Dynaco SS integrated. People always asked why I have wires coming out of the top of the amp. Obviously, the idea never made the main stream, but the speakers were well reviewed at the time.

I consider both acoustic and electronic forms of music in assessing quality of sound reproduction because I listen to it all. I have heard acoustic bass sound fabulous but synthesized bass be greatly lacking at the same time, and vice versa.