For a similar preamp/power amp set-up (Adcom 500 & 545), I did very well with EPOS ES 11, which are now EPOS M12.2 ($800 range new). I used the combination for quite a number of years. Good smooth sound. The system was primarily digital ... a Magnavox 630 CD player and then later a Proton 500 series CD player.
Regards, Rich
Regards, Rich