In your situation, cobbling together BNC with RCA sounds nastier than taking advantage of the shared AES/EBU connections. Some say 75 Ohm coax is more dynamic, 110 Ohm AES/EBU more airy. Research here on Audiogon and you'll find the ideal length for coax is between one and two meters. AES/EBU offers a higher voltage connection. What really floats my boat with AES/EBU is locating the transport with my CDs and running the cable across the room to the DAC. Mogami 3173 AES/EBU cable, specifically designed for long runs, has a suggested maximum length of one thousand feet! My 25 feet terminated with Neutrik XLRs gives good results, indistinguishable from the one meter Theta AES/EBU it replaced.
Which is better - S/PDIF Coaxial or AES/EBU
I have a Moon Nova CDP that I am thinking about using as a transport,which digital output is considered the best way to go, the Nova has a BNC S/PDIF(Coaxial) and AES/EBU(Balanced).The dac that I am considering has a rca coaxial and AES/EBU connection. Thanks for all your suggestions