Mac > USB > Empirical Audio Off Ramp Turbo > AES > Grace 902
Grace works great as a dac, headphone amp and passive preamp for my amp and speakers (2 channel)
Got my cable box and dvd player routed thru there as well. Bought the Off Ramp used on ebay for cheap
good quality solution for getting USB into a DAC that doesn't have it. The Grace's built in USB is 16/44.1