Hi Morrow, beautiful system. I have an earlier version of the Acapella Violon. I love the speakers, but have had trouble finding a suitable amp to drive them with. At the moment I am using Cary CAD-211's, which are adequately powerful (110W) but lack sufficient drive to get the woofers pumping. I have tried a powerful SS amp (300W) which shows that the woofers actually have plenty go give ... but the top end sounds tinny and horrible.
Given that Acapella themselves frequently demo the speakers with an Einstein 60W OTL amp, which are not very powerful and known not to like low impedance loads ... I am wondering how you are going with your Atma-Sphere M60's. Have you had issues with your bass?
I have put in a lot of effort to get my system sounding right. There is a small club of Acapella Violon owners here on Audiogon, we should get together to share our experiences with this intriguing but challenging speaker :)