Use digital processor of Classe ssp-75 or SCD 777?

I own some Classe gear and would say yes. Use the digital outs on the Sony piece and utilize the dacs in the SSP-75
I would think it would make a significant difference. Choosing a digital cable is another animal all together. You should match this cable to the needs of your system. Without knowing your gear, speakers or other interconnects it's a tough call.

Musicmann, the answer is simple, try them both. That Sony sounds great, so don't count it out so soon, even if odds are 60/40 in favor of the Classe. So far, Acoustic Zen's MC2 digital cable has been the hands down winner in my personal digital cable shootout. Try it, you''ll like it.

The only way to play an SACD layer is via the SCD 777. There is no DSD digital output - only 44.1 khz from CD's.

I have used both the Analysis Plus digital Oval and the Illuminations D-60 and both are great cables, though I prefer the AP cable in my system. All very good digital cables (consitent impedance, etc) will sound much more similar than analogue cables. So stick with a high quality cable and then don't worry too much. This is NOT like speaker wire or analogue interconnects.