SMSL SU-1 DAC with Ultra?

[Modecorp]

Has anyone tried the SMSL SU-1 DAC with the Ultra and if so, what were your thoughts? Im loving my Ultra so far, but I am curious to how much more it could be improved with the addition of a relatively cost effective external DAC.

 

[NBK5LCB]

I tried to hook my SU1 to the Ultra via optical but no sound could be heard. I had my sub connected to Ultra and when I attempted to connect, I only heard the sub. No music out of speakers.

 

[Modecorp]

I tried to hook my SU1 to the Ultra via optical but no sound could be heard. I had my sub connected to Ultra and when I attempted to connect, I only heard the sub. No music out of speakers.

Does the SU-1 need to be connected to the Ultra via USB?