I use two Aleph 5 stereo amps, 60 watts per channel in a vertically, electronically bi-amped, speaker system. This is all the power my small listening room can handle. Upper freq drivers are 50" planar dipoles; lower freq drivers are vertical arrays of equalized woofers, also dipole operated. The system gives up the bottom octave so I use two large and powerful subs when I want to listen to pipe organ or other recordings with extended low frequencies. Most of the time I leave the subs off because I don’t like to hear a lot of recorded non musical low frequencies.
The s300 arrived 5 weeks ago and has been compared extensively with the Pass amps. Performance was not identical, but comparable. The Pass are slightly darker in tone, but very expressive and musical; being old, they are also very noisy, and run hot. The s300 is very quiet and runs cool, and gives up little in musicality. It’s dynamic range is noticeably wider because of its extra power (about 5 dB).
I unpacked the m700’s and started breaking them in about a week ago. Oddly enough, at the moment, the stereo version exhibits better synergy with rest of my system; perhaps I’ve gotten use to it. It doesn’t have quite the utter dynamics of the mono, but it does exhibit greater delicacy, or micro dynamics. The monos may improve in this regard as they spend more time with me; I certainly hope that they do. However, they seem to have unrestricted dynamics; in fact they go scary loud, so much so that I fear for the health of my loudspeakers; I should probably be more concerned about my hearing.
Day by day I believe I continually hear small improvements. When they are about a month old I will do a comparison with the Pass amps. In any case my satisfaction is such that I am not returning any of the Stellars.