Hi Rob
I have a much earlier version of these speakers and have used them with a number of different amps including one of those little chip amp things that gives about 5 undistorted watts.
Depends on the music of course but you don't need much more than 1 watt continuous for acceptable levels in a large room. With a Krell 50S which lights up a bias light if power output exceeds 0.75 of a watt I was only lighting the indicator occasionally on peaks.
Current Lash Up:
TEAC VRDS 701T > Sony TAE1000ESD > Krell KSA50S > JM Labs Focal Electra 926.