Class A Watts

However, there are A/B amps with no switching distortion and much quicker than lots of class A amps. Just because it's class A doesn't mean it's better than any other topology. Conceptually, it is ideal with regards to this issue. As far as tubes go, you're not going to get there without mosfets in an ss amp.

Going class A is a method of reducing distortion. In a high end amplifier that is supposed to sound like music, this can really help in a lot of cases.

Class A is not the defining criteria though. There are all kinds of design considerations that affect the way an amplifier can sound.

A watt is a watt unless you are comparing ss watts to tubes watts. Although many people feel that Class A amps sound tubish and it might hold some water but honestly I think they have their own particular sound and would definately give a favorable nod to the pure Class A designs over Class AB. I have heard some digital switching amps that come very close to the tube sound but in the end they still sound more like very good solid state.

06-16-13: Csontos
However, there are A/B amps with no switching distortion and much quicker than lots of class A amps....

Csontos, such an amplifier is, then, not class-ABl it's a class-A amp with some very low off-state bias current. I believe this amp is in the fuzzy region of amplifier classification - what I mean is that, traditionally, pure class-A power amps have their rated output current running thru their output stage whether there is a music signal or not hence they get very (, very) hot just idling. And, traditionally, class-AB amps do not have any bias current running thru the output stage meaning that only one output transistor operates at any given time & the other is off as in totally shut-off. This is what gives the cross-over distortion.
If an amp is running some bias current so that the output transistors are always on but the bias current is (very) low then essentially the amp is biased into class-A. I think that they call these power amps 'sliding class-A power amps' meaning that they have some very low bias current during off-state & the bias increases proportional to the input music signal when it's present.

06-17-13: Phd
A watt is a watt unless you are comparing ss watts to tubes watts.

Phd, a watt is a watt is a watt, no matter what! what say?
that includes tube watts.
From Ralph's many posts on the 'voltage paradigm' vs. the 'power paradigm' I'm made to understand that ss amps output a constant voltage & modulate output current as the speaker impedance varies. Tube power amps, OTOH, output a constant power & modulate both voltage & current as the speaker load varies (while keeping the product of voltage times current = output power constant). So, you "feel" that tube watts go a longer way than ss watts.
But 1 watt is 1 watt & will always be so, whether tube or ss.