Should I buy a Class A Amp.

I agree. That Krell looks like the ticket. Get one second hand, get an electronics guy to give it the once over - aka http://theartofsound.net/forum/showthread.php?27792-Krell-KSA-200-for-sale-Complete-nut-and-bolt-rebuild

you'd have a sweet amp

There's a downside of having a father who was an electronics engineer, building amps from age 12, and still designing and building them while training for four years as an electronics engineer....

Any amp, any class (a/ab/d) can be good or bad.

Electronic components are inherently non-linear over differing temperature/voltage/current/speaker load conditions, and thus all an engineer can do is compensate for these non-linearities by using all sorts of different techniques.

Class A's tend to be more linear because they reduce the number of non-linear variables in the equation. Friends of mine run 300Wpc Class A amps and frankly, they're probably the answer if you don't mind the heat and the power bill.

Personally, when it comes to amplification, I don't subscribe to "let your ears choose" unless you promise to never say "my amp is better than yours".

The technical purity of any amplifier can be measured. Perhaps start there, and then let your ears or wallet choose.