Why do audiophiles shun feedback in amplifiers?

Mapman,
In my experience the answer to your question is no. The one quality I`ve come to admire over time with my SET is honesty. What ever is the inherent sound character of the CD that`s what I`ll hear,flaws and all. Some SET amps could perhaps'pretty up' the sound but my does`nt do that. I have some recordings that are thin,brighter and in some cases edgy and that`s how they will sound.But those that are recorded well,oh my goodness.

My SET has less editorializing than all of my previous amplifiers. I reconized this aspect early on, It just seems to preserve the signal with minimal influence.The effect is heard as pure and unfiltered.
Regards,

Charles,

I'd say pretty much the same thing with the ClassD Icepower BelCanto ref1000m amps in my system, used with any of my speakers, especially the OHMs and Dynaudios.

My small Triangle Titus XS monitors, which are more efficient and known to be more tube amp friendly, are the ones where I think I could improve the sound with another better matched amp. I do not think use of negative feedback or not alone would be the main factor to determine which amps would work best with those, though I am sure some that do not use extensive NF would sound very good indeed.

I have a pair of Tube Audio Design Hibachi monoblock amps that do a very competent job with the OHMs and Dynaudios (though I prefer the Bel Cantos with those overall), but are probably a better match to the Triangles on paper.

Mapman,
I`d agree with your thoughts about appropriate amp for your Triangle monitors.My path was simplified by matching amp and speaker by the same builder. His objective was cbviously very good compatibility.
Regards,

The amp/speaker match is why I dropped this link earlier:

http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php

Mapman, if you have speakers that your class D amps are really happy with, there is the chance that those speakers may not be compatible with tubes.

Dracule1, 'tightness' in the bass is not a function of real music but is a function of an over-damped speaker. IOW its an audio system artifact.

Kijanki, I usually do not include degenerative feedback when I make my comments about the negative effects of loop feedback. This is because degenerative feedback occurs simultaneously with the signal i.e. there are no propagation delay issues.

I think it should be pointed out that the use of negative feedback to reduce IM distortion is a bad move. We get very low IM figures without using feedback- IM has a lot to do with power supply design, grounding and parts quality. I am of the opinion that is much better to design the amp to have low IM operating open loop, since IM will occur at the feedback nodes of the amplifier, resulting in a harmonic noise floor (rather than a natural hiss noise floor caused by component noise). The human ear can hear about 20 db into a natural hiss noise floor, but if there is a harmonic noise floor caused by IM (with harmonics and in-harmonc distortions extending to the 81st!), the ear will not hear below that point at all due to the way the masking principle works.

This is one way to get more detail out of an amplifier, since a harmonic noise floor will block the ear's ability to hear detail below that point.

since IM will occur at the feedback nodes of the amplifier, resulting in a harmonic noise floor (rather than a natural hiss noise floor caused by component noise).

Atmasphere, I'm not sure I understand it. IM is caused by the presence of two frequencies on non-linear element resulting in "harmonic noise floor" meaning that there will be new frequencies of small amplitude harmonically related (sum and the difference) to original frequencies. NFB reduces IM by linearizing circuit - therefore REDUCES harmonic noise floor. Very deep NFB can make it almost perfect practically eliminating IM at the cost of introducing TIM. Eliminating NFB might be possible with the inherently linear tubes but not with transistors that require linearization and regulation.

Interaction with the speaker might have more to do with the type of the amplifier - SS representing Voltage Source and Tube amp representing Power Source.