Hi guys. I'm not up to speed with which amps do and don't, but I do have lots of general Thiel experience. I have noted that current delivery capability is very important, especially in large rooms or loud volumes. If an amp doesn't double its 8 ohm current into 4 ohms, it will probably sound anemic, and its oomph into 2 ohms is relevant also. Ayre amps are good fits. Jim used big Krells. Of related importance is that cabling is more critical on Thiels than usual. One reason is that phase coherence is easily scrambled by cables. On most speakers that doesn't matter because they are already scrambling phase, but the degradation is significant on Thiels. Also, Thiels very low impedance load requires more current through the cable, exacerbating its anomalies. I highly recommend very short runs of speaker cable. Jim used Goertz flat cable in 3.7 development.