I use the M2Tech Hiface and BNC into the EE Tube DAC and have never experienced any problems. I did have difficulty with a cheap DVD player and CD player via optical into the EE DAC, but once I used a high quality transport I consistently got a lock. Apparently the 9018 chip doesn't handle high jitter sources as well as the old chips. However, the sound is wonderful. I see no need to think about another DAC just to have 192 USB. Especially for the price of the EE DAC. So, to answer your question.....if the USB-SPDIF is located next to the computer, how long is the digital coax? What kind of digital coax are you using? Is it possible to temporarily move the computer and EE DAC close to each other and see if you maintain a lock? If all of that fails, contact Bill at Morningstar Imports (bill@morningstaraudio.com). He has been very responsive to all of my emails and we have talked at length on the phone several times about audio and music. He is very friendly and helpful person and would want you to be happy with the unit.