Tube amps and speaker ohms

Hi Gregm, you might ask Nelson Pass or Charlie Hanson of Ayre, both of whom make zero feedback designs.

FWIW, negative feedback is a *destabilizing* feature in amplifier design, not a stabilizing one. This is a common misconception about feedback.

Direct-coupled transistor amplifiers tend to use feedback as part of their means to control DC Offset at the output- IMO an inappropriate use of feedback, as it requires a greater amount of it to do the job. It may be the traditional way to do it, but in the world of high end audio, 'traditional' is a weak excuse for a solution to a problem.

Thank you, Atma -- good point about Mr Pass or Mr Hanson.
I should have worded my question better, anyway!

>>05-21-07: Atmasphere
Anytime you are investing in tube amplifier technology, that investment will be best served by a speaker that is at least 8 ohms or more.

Tube amps, with rare exception, have reduced performance into four ohms. <<

So, it seems that in general, Tvad is correct. Even though the Atma-sphere MA 2.2 may well drive the Woodmeres 4 ohm impedance to acceptable levels, the inference is that it would drive the Defintion AFI with 30 ohms impedance a helluva lot better. Furthermore, the 60 day in-home trial of the Defintions are a huge plus. Almost essential. So now will anybody give me their impressions of the "sound" of the Zu Definition, since there seem to be divided camps on this issue?
Thanks.

This has been a very interesting thread.......

Having said that, my Primaluna PL2 with KT88's, 40wpc, has no trouble driving the Proac D15's, 88db, to louder than WAF levels in our 15 x 30 x 10 room.

Bartokfan,
Did you ever bias those tubes?.....