I may have concused this subject.
DVD-A music CD and SACD - uses the 6 analog cable set up. Don't know about regular CDs.

DVD movies and regular CDs - uses either coax or optical.

Based on what I said before, I believe you need audio connections for the optical/coax. The only reason you need/use the 6 analog cables is for DVD-A / SACD.

I'm oversimplifying this and probably not mentioning appropriate detail, but you get the jist.

TjB - take a look at the manual. The answer is in there somewhere.