Hi Brian
I had the TC 60's for about 20 yrs. I had them on Sumo Electronics. A Polaris amp and Athena preamp. For some context I worked for hi end dealers, so I heard a lot of stuff, and that combination was great. On the TC 50's I heard a Klyne sk5 preamp and B & K ST 140 and that was really a fine set up. Of course that is old stuff. Newer I imagine there are many other good combinations. I did hear the Angelus's sound superb. I always felt the Adcom 555 comparatively speaking, was grayish and hard sounding so I could see the Angelus speakers not sounding good with it.