Well, I finally got around to trying, and the difference is staggering!
Running a digital cable from the Directv box to my ARC CD9, and when using the upsampling feature it sounds like a completely different source. The music is now alive, and bears no resemblance to running w/o the DAC.
Now comes close to that warm, detailed, musical sound quite similar to a quality recorded cd.
Quite happy with the results.