I use a Kell FPB 600c with Maxx 2's at the moment. One thing I can say for sure is that regardless of what you may read about low power amps and Maxx's, these speakers love power and you will need it to get the full potential. I am pleased with the Krell + Maxx combo but am also looking at other options. I am seriously considering Spectral DMA 360's. Wilson uses these amps in their playback system and has for many many years. That says quite a bit about their accuracy and the wide bandwidth seems ideal for the Maxx. I have also been more than impressed with every Spectral piece of gear I have ever heard. Nothing has come close to the speed and accuracy.