The Xbox 360 uses a WOLFSON WM8517HCGED Stereo DAC With Integrated Output Stage for 1.7Vrms LINE OUT, which is pin compatible (and otherwise quite similar) to the WM8521 (which has 2Vrms).
This is a DAC with built in output stage and derives its clock signal from the 360's master clock, the only one of the mother board.
The output has small SMD Ceramic's presumably for DC blocking. The local decoupling on the Digital and Analogue supply pins and 'CAP' pin (reference) are also small Ceramic SMD's. Output traces are very very thin. Voltage regs are miles away and have other components deriving power from the same rail's, which also has really thin traces.