Given the following quote from MSB
"The other important goal is physical and electrical isolation from computer audio noise. All servers and plain computers deliver the exact same bit perfect file, so the musical data is identical. They sound different because of jitter and electrical noise (different from audible noise). This noise can come from your own network equipment and at much higher frequencies from cell towers, TV, and radio stations, etc., conducted along the Ethernet cables."
I agree 100% with this quote. Note that jitter does not apply to asynchronous connections only synchronous connections. Another statement of fact is that fiber optic cable does not carry electrical noise at any level. Notice that their Pro USB uses fiber optic cable for complete electrical isolation (their words).
So if you place fiber optic couplers between your source and DAC the only noise injected into your system will come from the second coupler.
So a poor mans directer would be two fiber optic couplers with the second coupler warped in a Faraday fabric (check amazon). This option is about 200 dollars. Just a thought.