Accuphase A50V with Sonus Faber Amati

If you consider Pass amps in the X600 price range, give the XA160 a listen as well. You might or might not like them better. The XA160 has a much lower output rating but it probably still provides more power than you ever need.

I personally use a Pass X350 paired with Avalon Eidolons and I am very happy with that combination.

If the X350 did not work with your system, the X600 will probably neither.