Firewire to Balanced XLR Bridge

I've got a very nice Audio Research DAC (DAC7), but am not happy with the sound via USB input via PC.

Coax input from my Pioneer Elite BDP-09FD to the DAC7 sounds fantastic!

So I would still like to keep my ripped CD's (.wav) and download Hi-Res files to playback through my DAC7, but the DAC7 has a limitation of 16/48.

My question is, what can I buy that uses Firewire as the source input and has a balanced output and also handles 24/192? If nothing exists that has balanced out, the next best for me would be firewire in and coax out.

Product suggestions would be appreciated!

Thanks,
Joel