Actually difference between class A and AB?

Liguy, I have to disagree, despite Nelson's paper. The designation of 'AB' **already** "denotes that the amplifier operates in Class A up to a certain power level then switches over to Class B. This switch point is determined by the bias.", as you put it above.

IOW, Class AB already meant this; it could be class A to 0.5 watts or class A to 35 watts with clipping at 40 watts, either way that is what AB is... Putting another 'A' in front of it thus has no meaning, and is not found in the textbooks. That's why I say its a marketing term.

The Latest issue of The Absolute Sound has an artical that goes through all the different types of amps.
Just got it yesterday, have not read the whole artical yet. Looks like it has some good infromation in it.
Joe Nies

Newer Class Ds done well may be the emerging holy grail for most in terms of overall performance, efficiency, and cost of ownership. Maybe even just on performance alone, the rest aside.

I am not a Class A/B fan anymore in general.

Class A is good but practical for most only in certain cases.

I've had older Class G rail switching amps also. Those were smaller and more efficient also but also very mediocre with a compromised design, like much Class A/B perhaps.

Mapman, I suspect that that is sort of true, at least I have hope for it but have yet to see a class D amp come anywhere close to what I expect out of an amp. I think the technology has more to offer than we have seen available so far though.

Joenies, when you read that TAS article, you may also want to read this:
http://www.atma-sphere.com/Blog/