Why do audiophiles shun feedback in amplifiers?


I've owned several very highly regarded tube amps. Some of them allowed adjustment of the amount of negative feedback. I've always found some degree of feedback improved the sound...more realistic with tighter bass, dynamics, better defined imaging, etc. I have found amps with less or no feedback sound loose and diffuse with less dynamics... I know you should design am amp with excellent open loop gain before applying feedback. I can see the use of no negative feedback for low level amplification (eg, preamp and gain stage of CDP or DAC). So why this myth perpetuated by audiophiles and even many manufacturers?
dracule1
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.
I listen to all sorts of music and even play electronic keyboards in my band.

'Tight' to me in its simplest definition is an artificial coloration imparted by overdamped speakers. You get a fast attack, but not so much body behind the initial thump. Depending on the amount of overdamped issues (no speaker is made that needs more than 20:1 BTW) this amount of body is variable. What I find is the low frequency ambient signature of the room is the first fatality to this problem.

Any tube amp can be made to have a 20:1 damping factor or more with enough feedback. Most transistor amps have considerably more. What I am talking about here is not really saying that the amp can't play bass right, but if there is no speaker that is not overdamped with that amp then its a moot point.

The head engineer of EV wrote a 2-part article about this back in the late 50s. You might think that somehow the physics that he was writing about went away in that time, but they didn't... about the only thing that is really different is that there are 4-ohm speakers now. If we are talking about a 4 ohm speaker, then the damping factor of the amp can be up to 40, as damping factor relates to 8 ohms only during measurement, whereas any speaker can be overdamped if its impedance is more than 20X that of the amp.
Ralph, My previous speakers had smaller woofers and smaller cabinets but bass extension was 5Hz lower. Bass quality wise it is much better now with more natural attack and decay. It sounds more even, resonating less with the room (same amplifier). I read that speaker bass can be tuned for max extension (it sells!) or for the lowest distortion. Bass now seems to be very melodic, natural and effortless while before it was a little congested. As for damping, my amp has DF=4000 at low frequencies, but it doesn't make much difference since xover inductor in series with the woofer is usually about 0.1ohm limiting DF to 80.

Dracule1, on p4 of the Stereophile article they test Cary amp with adjustable feedback and describe sound change. At the end no feedback sounded the best. It doesn't mean that amp had zero feedback. There could be still a lot of local and perhaps even some global feedback left.
Hi Kijanki - yes I realize this is semantics; I do now understand what you were talking about - however, your use of terms is very bizarre to an orchestral musician. Orchestral string players do not speak of the length of their strings as "scales" (and neither do they use the term "tight" to describe their sound, as I explained in my earlier post). The use of the term "scale" in the way you do must be a guitar thing. Probably because the length of the string on an orchestral instrument is always the same, whereas in a guitar it would not necessarily be.

I also fully understand the way in which some audiophiles use the term "tight" - I just disagree that it is a good term. I could see the term applied to an amplified string bass or acoustic guitar sound, but this would be because of the amplification, not because of the instrument itself. The term is simply not used in describing live, un-amplified, acoustically produced music (certainly not in the classical world, anyway), and therefore doesn't really have anything to do with Harry Pearson's "absolute sound" concept, if one agrees that that should be the standard for what a system should ideally sound like. If one doesn't agree, then by all means use the term. Dracule's definition of the common audiophile way of using it is as good as any, though I have never heard a pianist use it. Drummers, yes. Even timpanists, though they generally use the term to describe the tightness of their drumheads and the effect this has on the sound, which is somewhat different, I think, from Dracule's description.

Charles1dad, I agree with your post in response to mine completely.
Learsfool, Term "Scale" applies to all string instruments. Please read here: http://en.wikipedia.org/wiki/Scale_%28string_instruments%29

Upright basses have 10" longer scale than bass guitar. It makes for much higher string tension* resulting in (as Dracule1 called it) "initial fast transient attack followed by natural decay and rich harmonics".

*Since string tension goes in square of length 43.3" upright bass has twice the string tension of McCartney's 30.25" Hofner bass that in comparison sounds flabby with lack of definition - poor attack, muddy overtones. .