5.1 connection vs coax

I have both 5.1 analog input and coax output on my pioneer elite dvd player and 5.1 input on my B&K reference 30 preamp.I dont know which connection would give me better sound.Whats your opinion??
Try them both. It will come down to two issues. First, which device has better bass management (if needed) and, second, which device has better D/A conversion.

Kal is right. I have Denon 5910ci and a McIntosh MX135 that I pass two channels thru a LS26. And I find that on certain codecs I get better diminsion on 6 channel input and others I do better using the MX135 processor. I would use both if possible. On SACD and DVD-A 6 channel is best hands down.
thank you for the advise.I am going to purchase some Signal cable analog 2 cables next week and give it a try.