I've used Stillpoints SS on PS Audio BHK250, PSA Audio M1200 monos, and Luxman M700u amplifiers. They have little to no effect on the Luxman, a great deal of effect of the M1200 mono amps, and some effect on the BHK250. I have tended to use IsoAcoustics Orea's on amplifiers now in preference to Stillpoints. Stillpoints are great on sources, preamps, and power conditioners. There are many, many, choices now for good footers in addition to Stillpoints.