How does digital input sounds in Rotel RSX-1065/67

I'm currently running Rotel RSX-1065, and this very receiver appears to have good 2ch analog input/output.
but what about digital inputs?
how does "digital source coming into digital coax input" sounds in 2ch? I cannot find which DAC unit/chip is used in this receiver.
If anyone has knowledge on this piece of gear or RSX-1067 under digital conncetion, let me know your opinions or any infos.