USB to SPDIF question

[graben]

Last year I was interested in getting a USB to SPDIF convertor to use instead of the coax out of my motherboard. Currawong kindly lent me his Audio Gd Digital Interface. It worked perfectly for him but my 1990s Stax DAC Talent couldn't lock on to the signal, and acted like it does if I try to feed it something higher than 48khz . Even when I set the DI to use non upsampling it didn't work.
 
So my question is why do you think this was? Mismatching output voltage, or was it really was upsampling? I am worried if I try another convertor it will have similar problems. Should I just buy something like a used V-Link and sell it if I can't get it to work?
 
Looking forward to what you think.

 

[K3cT]

It's possible that the A-gd unit S/PDIF output voltage is too low for the DAC Talent to lock properly. Have you tried contacting Kingwa @ Audio-gd to check its specs?