My main listening is done with a vinyl rig, but I do have CDs and Files, I use an old Pioneer DVD player a 676A as a transport and stream files from my NAS to SB Touch, I bought an Audio-GD NFB2 DAC for $450US plus post from china (another $50). I plug the DVDP in via the RCA and the SBT via the optical i/p using the selector on the DAC to switch sources. The DAC also has a USB input which I have not used. There is a choice of receiver chips but for an extra $22.50 you can have both, the DIR9001 only does 96K while the WM88xx allows 192.
The differences I have found are that the soundstage is much improve and I can hear more detail in the music than without the DAC. It takes about 30 mins from switch on to come on song, but it's worth the wait.
I still believe that my Viny rig sounds better but the digital is getting there.
Steve
Steve.
Kit I have:
CD player, TTs, Phono stages, Pre amps, Power amps, Integrated amps, DACs, Streamers, Speakers and a bunch of cables.