Hello @Brian_Breneman,
I’ve been able to do some more testing with the UD-501, and I believe I have found a workaround that gets the device back into a functional state. When the device becomes unresponsive as you’ve explained, I’m able to get playback restarted by opening the DSP engine in Roon and enabling then disabling Sample Rate Conversion with the drop down set to “Max PCM Rate (Power of 2)”.
Let me know if this works for you!
-John