The Rogers are quite inefficient, but, the very high impedance makes them a very easy load for tube amps. I heard a pair in a large room driven by fairly low-powered amps (somewhere around 18 watts). The MC275 should work quite well with the Rogers, It has been a while since I heard the Electa Amator so I won't say which I prefer. I will say that I was quite surprised by how good the Rogers sounded in my recent encounter with them.
