Okay surely this topic has been covered time and again, but I'm not satisfied with the comments that touch on it...so here goes;

I've got an Intel D945GSEJT mobo with available on-board SPDIF header. Although the mobo supports USB, a fully functional music server is realized without using any USB devices, thus freeing the USB bus to move strictly audio if that is the chosen route.

My plan is to integrate the Opus DAC into the server chassis and hand the DAC analog output to a tube preamp. For example, the USB to SPDIF converter or the SPDIF transceiver, whichever is used, will reside next to DAC and within several inches of the server mobo.

Question, is a wire connection from mofo SPDIF header to SPDIF transceiver the best option for integrating off-board DAC? Why convert USB audio if SPDIF is available? Pros and cons of each?

All comments are welcomed and appreciated.

Thanks for the input. 35 feet, huh? I'd say USB Audio 2 has nothing over the tried and true S/PDIF standard. However, its clear USB will be the winner in the end cause the market says so.

My choice is very simple given all computing is performed in one chassis with no moving parts--completely isolated from EMI and other sources of noise.

MPD will output directly to S/PDIF interface (bit-perfect audio) connected to TP transceiver, wired to Opus DAC, and finally, connected via rca interconnects to an off-board passive I/V converter built into a grounded grid tube preamp.

Should be both challenging project and most audible delight in the end.