I haven't read up on the C48/C50's processing, but I think there's some that goes on to 'tweak' CD quality up to something closer to the DAC's capabilities. This is maybe not the same as having higher res source files, but it should sound better than a run-of-the-mill DAC with regular oversampling, etc., that's in your CD player (unless it's high end
Also, one can certainly get 24-bit 96kHz (or whatever the DAC can accept) source files to play thru this preamp, should sound even better, if the rest of the system is up to it. 24/88 or 24/96 seems to be the new high-res standard, I am sure in the near future all digital files will be available in this resolution ... IF there's a high end market left! Otherwise ... 128kbps mp3s, anyone ???!!!