If you need RCA outputs, buy a set of Hosa female XLR to female RCA adaptors. They are available for about $15 at a pro-audio store or guitar center. You will need to modify them such that Pin 1 is signal ground and either pin 2 or 3 is connected to signal. It's a quick mod that I'm happy to complete for any head-fier who doesn't have a soldering iron.
For digital connection I am using a Canare LV61S coaxial cable with Canare 75 ohm RCA connectors. It cost around $20 assembled.