In my experience the Harbeth C7 is not all that picky when it comes to amplification. They sound good with just about anything (competent, but not necessarily expensive) in front of them. Having said that, my pair did like power--at least 100wpc. I ran them with a Naim HiCap/62/140 for a while and did not really get all they were capable of until I switched to an ARC system using a 100.2 to drive the speakers. I wouldn't stress too much. If I were you I would select an amp that has adequate power and is neutral in presentation and then work on establish proper synergy between the rest of the components that appear in the chain in front of the amp. Balance and synergy is important, particularly with such a wonderfully musical speaker. Everyone needs to be dancing together or you will lose the essence of the Harbeth sound.