I run USB from my Mac to my Douk Audio U2 which outputs a I2S signal o my Gustard X16. The Douk shows PCM but NOT DSD. I am trying to find the settings in Audio to enable DSD output but can’t seem to find the right setting
The Mac isn’t seeing anything connected to USB to output to. Nothing for the converter shows up in Roon there at all. What zones are you actually playing to as it’s not going to work without the device showing up. I think your using a route that seems incompatible as Roon isn’t seeing your DAC at all via the converter. If it did it would show up as a device to enable Roon to play to.
Please provide a link to the Douk Audio U2. My search shows this a a USB to S/PDIF converter.
Edit: You seem to have the Douk audio U2 Pro.
Incidentally, you won’t see the DAC in Roon when connected to the U2 Pro; Roon will only show the U2 Pro.
In addition, I note that this uses the XMOS chipset and requires an ASIO driver (Windows), so it is possible native DSD won’t work with your iMac. DSD over PCM (DoP) should work.