I have tended to always to drive them hard and use them as farfields (even the small ATC's play loud) - so big beefy SS amps have been my preferred choices in the past - something like Bryston 4B. If you listen nearfield at quite low volumes at a mixing desk then a Bryston 4B is certainly not going to be as refined as a Class A amp. For a near field application I don't have personal experience with ATC. My guess is that ATC's SIA 150, which operates to two thirds power in Class A, would be a great bargain compared to something like a Pass Labs X60.5 (pure class A). I imagine it has the similar MOSFET type designs in their active speakers...probably not the last word in an amplifier but solid performance that exceeds what the speaker can do and good value.
