Well initially amplifiers will be SS PS Audio Delta 100 stereo amps, 2x120W into 8 Ohm. I have 2 available so I could biamp them using my Behringer DCX2496, but I may eventually decide to build passive crossovers for them mounted on an external rear panel so I can just use one amp or possibly dual monoblocks, or a pair of Bryston Power Pac amps in the future. Not sure what the far future would hold for them but if I build them large enough the efficiency gain might lead me to use a valve amplifier. And then again there's also the possibility to go Class D or Tripath based amp down the road.

Looking more into the design I believe the proper way to go right now is to go full hog and get another set of ribbons to stack alongside the array.