I have Magneplanar 1.7's and power them with a Jolida 502 P with KT 150 tubes. This is a 60ish watt per channel amp and I find no problem at my normal listening levels (70- 75 db with peaks up to 90 db or so according to my radio shack db meter) I also have a Conrad Johnson MF 2300 amp (240 watts into 8 ohms, tested at 400 watts into 4 ohms). Of course, the CJ will play louder but I find the Jolida very satisfactory at the loudness I like and with the music I listen to mostly - Jazz, classical, earlier rock and such. Room size is 14X24 and I sit about 10 ft from the speakers. The speakers are run full range with a sub set at a very low level for bass augmentation only.