Do I buy a Krell KSA-80b ?

A Threshold SA3 is a much better value and is a pure class A unit like the Krell. Power difference between 50 and 80 watts of good power is not really that material in real usage. Both amps will drive speakers with difficult loads. The Threshold goes for 800 usually; wonderful buy.

I have heard a lot of people compare different amps (Threshold or Aragon) to the Krell gear. On paper they all look good, in the listening room thay all fall short. See my review of the Krell FPB 200 if you are interested in more details.

err...excuse me Krell KSA 80B is pure class A same as KSA 50 MKII and KSA 200. The rest maybe heavily biased towards class A.