Amps - Class A-A/B reality

polkatese

For those amps which are rated to be Class A and A/B, is it fair to say that its presentation and slam while in the class A level is the reason why it is coveted? When I said slam, I meant also the micro-details.

From design perspective, is it considered to be in different class together, sort of the best of both worlds of pure Class A (too hot to handle) and Class A/B (lack of slam in lower volume)?

EE in the house, please educate me...

Thanks.

disneyjoe7

Part EE in the house here, why would an A/B amp have less slam at low volume over an A class amp in the first place? Do you have amp names / models that you're comparing?

McLoki

Here is a pretty good (and technical) paper on class a amplifiers.

polkatese

DJ7, not comparing any amps, but wondering about amps slam at lower volume, and its relation to the operating mode. Most of the amps in the 200+ watts are class A/AB (i.e. B&K Ref200.7, Gemstone, etc.)

Michael, thanks for the linky. I am reading it right now.

disneyjoe7

Ok so what am I missing here, I know for the most part class A amps can be cleaner sounding (less distortion) but what are you talking about less slam at low volume where did you hear that?

polkatese

From what I read and experienced, class A has more slam at lower volume compared to class AB. But, I am not sure if it is absolute or really it's a function of amp design.

F1nut

Class A/B runs Class A at low wattage, some up to as much as 30wpc or so. If you run 90dB speakers, you're using 1 watt to achieve 90dB, so regardless of the amp being Class A or A/B, both are Class A at that point.....at least until you hit a big transient.

beardog03

I hit a transient once....but he had no class..!!



sorry....carry on..!!

I would actually like to learn what you are talking about...I`m just kinda tired

tonyb

F1nut wrote:

Class A/B runs Class A at low wattage, some up to as much as 30wpc or so. If you run 90dB speakers, you're using 1 watt to achieve 90dB, so regardless of the amp being Class A or A/B, both are Class A at that point.....at least until you hit a big transient.

BINGO!!

zombie boy 2000

beardog03 wrote:

I hit a transient once....but he had no class..!!

WAAAAAAAAAAAA!!!!

Thanks Bear for the milk which speweth from mine nose onto our blessed computer screen fortwith says I verily. Amen.

As for pure Class A, it's my understanding that the most notable perk is that of less distortion.

Deadof_knight

Oh man Class a , class a/b has to do with design. Class A is cleaner sounding and will typically handle transients better thus CLEANER. Class A runs hot as hell Class a/b is more efficient less heat with a lil sacrifice in the distortion percentage. But less slam at low volume , what amp are you speaking of or comparing?

Burnt

Class A- A/B amps are a good combo of low level dynamics and loud and cooler when needed.