Acoustats have a synergistic love affair with MOSFET amps. If you want to make those panels sing in a manner you will not believe find an old Sumo Andromeda II or IIA, or better yet biamp with them. Run 1 channel to the panel and the other to a bass module or sub. Add a tube pre and heaven.
Acoustat model 22/2200
Totally awesome in my 20x12 audio only room. Granted they dont play loud and need gobs of current/power. The Spectra Series gets it right. Too bad they had to close, from a few disgruntled reviewers, sales dropped because of it. The power of the Quill is deadly...One of only a slew to feel it! The panels damn near indestructable, not like the newer stats or panel speakers today. These are Classic"s