Most digitals outs a brand/style specific. Plus why would you want to bypass the DAC's in a H/U like the 9255, Mac or Denon. That is one of the main things that makes them such great SQ H/U's and one of the reasons they cost so much.
I'm looking at temporarily replacing the 9255 because it stopped playing CDs, so I need to have it sent in for service and I want to try another SQ H/U while the 9255 is out. It also gives me the option to have another great H/U. The only down fall is I need an EQ because none of the other H/U's that I'm looking at have them built in.