Audio Quality on Digital Out on Mac Mini

Curious to find out what type of audio quality I can expect if I use a Mac Mini's digital out to a B&K Ref 50 Pre-Amp. I'm assuming that this would be no different that feeding a digital signal from a CD or DVD player, correct. Any thoughts would be appreciated.

Also, the Mac Mini only has a mini connection. Does the adaptor to converter the mini plug to toslink degrade the signal significantly.

Thanks for the input.