What's better 100w class a or 200w class ab?

If you need the power due to inefficient speakers, lossy room and/or high desired listening levels then the higher powered class AB might be better. If you can easily reach desired listening levels in your room with your current equipment and 100 watts of power then you might prefer the lower powered class A amp. The class A amp will probably use more electricity, require more space (may require different cabling) and create more heat.

This is all very interesting, but why don't you just listen to the two ? I would imagine that this question cannot be answered theoretically since it depends on how loud you listen, what type of music, and your preference for the type of sound.

Krell's FPB series amps are designed to run at class A to full power. This might have something to so with why they named them as they did: Full Power Balanced

Richard

I would go for 200w class AB as long as you have at least 8-10w Class A....If the 200w amp has less than that it will likely sound bright after it blasts through the class A region and say a female vocalist is screaming away at the top of her lungs....We at CTC just finished a huge mono amp which runs over 25w class A and, other than running at over 50 degrees C, it measures beautifully when in the class A region with just 2nd and 3rd harmonics and starts picking up some 5th as it crosses over into past 25w up to 400+w or so.....Lots with tradeoffs in amp design and hard to get everything right so we concentrate on the area at 10w and under where most all the music, other than atomic blasts, will be played.....

I'd reckon that the biggest question is what is the impedance of the speaker? Since this fellow is deciding between two amps from the same mfr, the biggest diff will come IF the "class A" amp slides into AB because of a low Z load. In which case it might just put the same power into the load as the AB amp from the same mfr.

The circuit is likely to be identical, just the rail voltage will change - assuming the description is accurate, the 100w class A amp *ought* to have *higher* rail voltage than the 200w AB amp -as the load causes the amp to slide into AB the advantage of the higher rail voltage will be more output available than with the nominally higher rated 200W AB amp!

:- )

Of course into a calm 8 ohm speaker - go with the 200 watt AB, IF the criterion is only max output with an inefficient speaker...

It also matters what the output devices are. Mosfetters and BJTs act a bit differently in AB vs. A.

On the other hand, with two amps that use the identical circuits, I'd pick the one with the better power supply regardless... :- )

_-_-bear

.