Why do audiophiles shun feedback in amplifiers?

Charles1dad, It is possible but perhaps not very common. Everything depends on definition since even single unbypassed cathode resistor is NFB.

Kijanki,
I believe your right in that the vast majority of amplifiers use some degree of NFB.I think DHT SET amps are a small niche that can be the exception.
Regards,

Thanks everyone for the informative responses. In regards, to speaker/amp pairing, I have three sets of speakers, two pairs are dynamic and one pair electrostatic. In all three of these, overall I liked feedback over none.

As for DHT amp using no feedback, I have yet to hear one that has the dynamics, bass extension and tightness of a KT88/6550 using feedback...that is after taking account power output of the amp. But good DHT no feedback amps have glorious midrange, though not accurate IMO.

Regarding odd order harmonics being irritating and having increased perceived loudness, this is very difficult to pin down in one's audio system among all the other forms of distortions inherent down the chain, unless you are willing to deliberately increase the odd order harmonics in your amp and listen for the change. What I thought was irritating odd order harmonics arising from my amp using feedback was actually distortion arising from the source and boundary effect from room acoustics.

I have two push-pull class AB amplifiers. One is 40 watt/ch with EL34 tubes and the other is 100 watt/60 watt(UL/Triode).The bigger amp is one of the best PP amps I`ve heard it uses 6550/KT 88/KT90 etc. This was my main amp,top choice for driving my Coincident speakers. Three years ago I purchased my 300b SET 8 watt amplifier.From day one fresh out of the shippng carton this SET put the others into storage. It was simply better across the board.

The 100 watt amp has more bass weight and impact(the gap is`nt large however).In terms of tone,harmonics,noise floor,presence,3 dimensionally,nuance and dynamic ebb and flow the SET is superior.When playing high energy big band jazz ,the ability to clearly seperate and hear the individual instruments is extraordinary.The scale,energy and dynamics completely fill my room, it really as if the walls vanish(I`m right there at the venue,spooky real). In the sense of realism,believability and natural sound it`s the best I`ve heard so far.Some SET amps are better than others.The better quality DHT SETs are the most live-like,realistic and trueful amplifiers I`ve ever experienced. This was a profound moment for me as it put me into a different sonic realm,there`s no going back.I`ve own SS (Symphonic Line amplifier) it was`nt close to this.My 100 watt PP was better than it in terms of live flesh and blood presence.The 300B SET is a new standard however.

Just an example of how people have different experiences and impressions. The good news is there`s an amplifier topology out there for everone. SET,PP,OTL,SS,class D, take your pick.What I have discovered with SET I know others have experienced with other types of amplifiers also.
Regards,

"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?"

I don't see why you would say that 0 feedback components better SQ is a myth. If you can, try to audition some Ayre products. That will probably change your mind. (There's other great sounding 0 feedback electronics other than Ayre. I recommend Ayre because I feel that they are the best example.