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I didn't say OTL's sound bad

The point is, most OTL's use negative feedback, yet the sound is usually described as very good. These seems to indicate that fear of negative feedback is unnecessary. As Aczel points out,many audiophiles have a phobia about it.

I think your example shows why it's a good thing;1.75 ohms seems high to me, though I suppose it's reasonably low compared to an SET. Transcendant gets down to 0.4 ohms with the T-8 by using 33 dB of negative feedback. I think that's quite a bit, even by 1970's standards. They indicate typical PP NFB as 25 dB.

I don't remember listening to an OTL, except at a NYC show in 1983. Most of what I know about them I learned from the Ultimate Hi-Fi Bull Session series in The Audio Critic (Aczel included Futterman in the session;I think the H-3a was one of his favorites), and what I read on the Transcendant website.

I quote from Bruce Rozenblit's article,"So it is absolutely essential that negative feedback be employed in the design of OTL amplifiers and tube amplifiers in general. There is simply no other way to reduce output impedance to acceptable levels."

I know high output impedance amps (say 1 ohm plus) aren't good matches for my speakers;even the Josephs drop to about 5 ohms impedance and none of my speakers are real efficient. The Infinities have an impedance curve that looks like the Himalayas. At the same time, I know that a DF of 100 does not by itself mean you've got a great amp.

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