Carver Silver 9-T monoblocks. Circa mid ‘90’s. A lot of people didn’t like them on other speakers but they sound fantastic paired with the Carver ribbons.
Yes,m I seem n to recall n that there was some controversy over these. They didn’t sound good with some speakers, but with others, there was some amazing synergy. They seemed to do well with difficult loads like electrostats and your ALS IIIs. Have you checked out Carvers Sunfire Series II amps?
Same with my ARC DSi200 aND Maggie 3.7is. From their earliest days, Magneplanars and Audio Research gear always seemed especially harmonious together. That’s a love affair that has never grown old for me. It’s a combo that utterly disappears when you turn them on. Huge soundstage and layer upon layer of detail.