Tube amps and speaker ohms

Normally the tube is a self harmonic generator ( that does not exist on the original signal/recorded signal )

Raul, I would have thought you would have educated yourself better before making such an obviously false statement! You are in a lot more trouble with transistors in this area then you ever would be with tubes! Look how many tube amps can actually operate with low distortion with zero feedback, and then count how many transistor amps that do the same thing. The zero feedback transistor amps are *sorely* outnumbered!

If we run feedback on our amps, which are OTL, we can get the THD down to 0.001% at full power, but who'd want to (just like frying an egg on the sidewalk)? It is true that you reduce a lot of distortion that the ear does not care about, but you increase the distortion that the ear *DOES* care about!

Ultimately it is the rules of human hearing that are the most important factors in audio...

The zero feedback transistor amps are *sorely* outnumbered!

How do you stabilise a transistor amp circuit without any feedback at all, anywhere?

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.