Difference between Class A and AB Amp

[here.choo]

Can anyone tell me that's the difference between Class A and Class AB amp? Do they have more class? Like C, D , E?

Thanks,

[littlephil]

There are more than just A and AB. It has to do with the way the power tubes are used.
Heres a great (and very long) article by Randall Smith describing it all.
http://www.mesaboogie.com/US/Smith/C...WebVersion.htm

But honestly, there isnt much difference in terms of tone. There may be a slight difference you can hear, but all the 'Class A is the best' stuff is really just advertising hype.

[Vim Fuego]

Briefly,
Class A has all the waveform going to each of the tubes, in fact, often there is only one tube.
Class B has opposite halves of the waveform going to each of the tubes, positive to one, negative to the other.
Class AB is somewhere in between with all the positive and a bit of the negative going to one tube and all the negative and a bit of the positive going to the other.
Many people think the VOX AC30 is class A, but it's really AB, although biased towards A, but if you turn it down it will operate as Class A.

http://www.duncanamps.com/technical/...of%20Operation
for further info

Jim

[Sickbean]

Originally Posted by littlephil

but all the 'Class A is the best' stuff is really just advertising hype.

And part of the 'older/retro is always best movement'.

That Boogie article is ace btw.