Sorry, can't speak to the SET 120, but drive my Daedalus Muse (96 dB) with either AVA Ultravalve tube (35wpc) or an older FetValve 550 Hybrid (250 wpc) with ease & fine presentation. Also use an older Insight 250+ with my Dahlquist DQM-7s (not sure on their efficiency, need to dig out the manual, couldn't find online) excellently. Depending on what you are listening to, the room, and the volume, most all of Frank's gear gets the job done with ease & excellent presentation.