I can't see why you wouldn't take the optical out from the D1 straight to your 568.

I've never tried it but I suspect the Dune USBs probably would not support audio out. They're there to connect USB storage and devices to the Dune.

Sooloos, Roon, G series (with LPS upgrade), 800 series (with LPS upgrade), HD621, AC200, Prime and PS, DSPs old and new.

Purdeys, Moke, Leica, 'Blad. Only the best.