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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
dracule1 OP
1,043 posts
 
I thought KT88s are beam tetrodes, not pentodes?

I do like the sound of DHT amps without feedback in the right system. They have a certain magic to the sound that I think is missing in tetrode or pentode amps with feedback. IMO, DHTs are more expressive than life making tetrode/pentode comparably "dull", hence I can see why they are popular. However, I don't think DHTs are as true to life...I know many feel just the opposite.
dracule1 OP
1,043 posts
 
Thanks Kijanki for the link.
charles1dad's avatar
charles1dad
6,996 posts
 
Dracule1,
KT88s are beam tetrodes as you state. They are grouped and interchanable with the power pentodes(6500,EL 34,KT 90.120 etc.). Many amplifiers(such as mine) allow use of most of these, especislly KT 88 and the 6550 tubes.DHTs are a completely seperate catagory altogether.

Push pull amps can sound excellent(my Bella Extreme 100 monoblocks built by Bill Baker and my friend`s VAC Phi 300.1 monos). There`s just a different character to the sound.
Regards,
dracule1 OP
1,043 posts
 
Ah got it, Charles1dad. May be one day, if I have the right speaker, I'll get a DHT amp. But I'm not sure if I can deal with the heat. My OTL amp raised the temp of my listening room by 15 degrees F easily in the summer. I've owned KT88/6550/KT120/EL34 and OTL amps.
charles1dad's avatar
charles1dad
6,996 posts
 
Dracule1,
A 300b SET has 'very little' heat output.There`s only 1 output tube(8 watts) per monoblock.My PP amps run much warmer with 4 6550 per side. You may never prefer a SET no NFB compared to PP with some NFB. I`m just giving my own preference(after living with both amplifier types with extensive direct comparisons) and by no means making any sort of proclamation that applies universally.I wish you continued enjoyable listening with your system.
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