Which BNC-BNC coaxial

Better price than Nordost is: http://www.cabledyne.com/rca-digital-cable.html

The Black Cat Silverstar 75 would be an excellent choice and has bnc on both ends.

I have a Nordost Heimdall2 and an Avanti digital cables. I also have a Naim UnitiServe. I had a Naim nDac and XP5XS p/s. The Avanti is a faster sounding sounding cable and sounds a bit like you turned up the volume a notch too. The Heimdall2 on the other hand is a little warmer sounding. The vocals have a bit more 'soul'. Big difference in price too. Heimdall2 retails for $700 @1M and the Avanti retails for $160 @1.5M.

I use a $22.00 True 75ohm 1 meter coax cable from Digikey. Sounds fabulous. It's digital.

Blackcat Silverstar 75 was an improvement over Blue Jeans cable in my system.