I can confirm that an external DAC should work fine with the output of a 208. Suggest feeding your DAC from an alternative SPDIF source in the first instance to make sure your DAC and cable are all working OK.

808v6, M60, MC200, HD621, Lumagen XE, 504, SB Touch, 563, 201, 204, 208, MPMAX 221, M80, Explorer, Explorer2.