I used to do audio shows with Fritz where we used the Carreras and Carbon 7s with a 10 watt 300B SET amplifier. The combination worked just fine in a room that was 12' x 19', and we got it pretty loud, even trying to intentionally clip the amp. The smooth impedance curve and the benign phase angles of Fritz speakers makes use with low powered amps, including SET, possible. A lot will depend on the how well the amp is designed, the size of your room, and how hard you are going to push the amp.
