I am not quite sure. One of my good friends has Apollo. His system is MC275, PrimaLuna Prolog 3, Apollo, and Klipsch LaScala and Valodyne subwoofer. Mine is Linn AV5105, Rogue Magnum 99, NAD C541i, and Tyler Taylo 7U. We tried Apollo and C541i in both systems. The only difference we both could recognize was that a little bit warmth on Apollo, but no audible difference on base, treble, mid, sound stage, detail, dynamics, ... on either system.
the Apollo bests players I have heard that cost five times it's price.
Anyway, he was rather disappointed even though he preferred warm sound of Apollo on his LaScala. On my system I preferred C541i.