You would use the 2-ch. and/or the 5.1-ch abalog outputs into your Rotel. The 2-ch. setup will be using the Oppo's awesome Sabre DACS, the 5.1 side will be using their Cirrus Logic (I think) DACs. Either way, the Oppo will be doing the DAC work, the Rotel will simply be amplifying the signal...
-RW-
-RW-