Wow! single mode!? At the very least one can feel comfy that if things went down SQ-wise anywhere in a fully funtional rig, the Tetas interface was proly not it. Single mode fiber, laser driver and laser = Hi-Crazy-End + Not-cheap.

Really two choices:

1. External converter box like an Offramp, but with ST out. Problems being in the conversion of USB to ST, and formatting (does it come out SPDIF? Likely, that's what Theta used for ST.)

I think that kind of product would be awesome, i don't know if its possible to do but many cd/dvd players has s/pdif coax out, so coax in and USB in and then ST out. I would buy two of those, thank you