Amplification for Wilson Audio Sasha on the cheap

That one Krell FPB-300c is Class A? 

That one Krell FPB-300c is Class A?

Sort of, without the big heat penalty.
As it has what’s called sliding bias or plateau biasing (class-A), which in layman’s terms, means it monitors the input music signal and raises and lowers the class-A bias automatically of the output stage accordingly.
So there no wasted time and heat in class-A when there’s quiet passages, low volume or no music signal.

Cheers George

It plays always in Class A then, can it ever switch to Class AB ?

It always tries to stay in Class-A without the heat penalty, unless you play Black Sabbath for the whole album at max level then it's going to get hot. But if you play quiet Chamber music, it's going to stay lukewarm. 

Cheers George 

I run my Sophia,s with a Proceed Amp5, i love the fact that the proceed doubles wattage at 4, and assume beyond, it has decent power supply, ive been eyeing the HPA2 version.