The "charactor" of pure Class A?

One of the primary things that all class A amps seem to have in common is a sense of authority. They just seem to carry more weight or body in the music.

There are so many variables in amplifier design that going beyond that simple statement gets tricky :)

Not familiar with Clayton...but pure class a amps do not switch power classifications( such as a/b amps)...run hot...as they give you all they have all the time...and are much truer to retaining an original square wave signal...however...since most general low-level listening doesnt require gobs of power or head room...class a/b amps operate in class a more than one would think....or that is my very limited understanding...sure others will chime in...happy holidays....

Phasecorrect:
Yes many A/B amps still operate in class A up to the first 1 to 3 watts, and if you've ever watched an amplifier with power meters while the music plays you are usually amazed at how much of the time the meter hangs around 1 to 5 or so watts. It's the 20 db peaks that get us...
Not all "class A" amps are PURE class A, also. I had a 50 watt per channel class A Forte model 1a which I think is a good amp and sort of has the classic class A sound, also had the original Music Fidelity A1 25 watts per channel, the sound was a bit on the rich, warm full sound, not at all harsh, strident, thin, or analytical. I believe that is the sort of thing most would agree is the "Class A experience". I would imagine an extremely expensive pure class A amp like the big old Thresholds, Levinsons, Benini, Krell, etc. would give a better representation than my Forte 1a.

"many A/B amps still operate in class A up to the first 1 to 3 watts"
Xiekitchen that's what I thought too. Then a recently read somewhere some blend class A with class B and it's not a pure switch over.
Not sure of the technicalities but it appears that some class A/B amps never operate in pure class A at all.

Stereophile said class A amps are not good for rock music. More classical, jazz, etc.

I have used several amps that were considered class A. I was a dealer for Krell and Musical Fidelity and had a pair of Stax DA 80s. The common feature was a lack of hardness in the top end. But I don't think being class A is a critical feature, it is just part of the overall design of the amp. I prefer the sound of other amps I have or have had to the sound of the above. Disclaimer, I used the earlier generation Krell , the current top end ones are much better , but at a very high cost. The current Musical Fidelity amp[M3] I use is much better than the 270 of years ago which was class A . The Meridian 605s I use are Mosfets , they sound considerably better than the KMA 100s which were their contemporaries. I think you have to review the overall performance of a given amp and how it will fit into your system rather than deciding on the basis of general design principals.