Thanks for your update. You did a lot of work on those M-60s to not be able to use them with the Quads. They've been enough power in my small listening room - I can hardly push the ESL-63s before the protection kicks in. I've been getting some good hints from Ralph at Atma-Sphere and it's a work...
So I saw the M60s next to Quads in one photo. I just got a used pair of M60s to drive ESL63s, but the amount of bass energy is WAY more than any other amp, and also the amps don’t impart extra bass to any other speaker. Is that just the way those amps are with Quads?