Hi @Grant_Munday,
It looks like there are some great next steps here that Sean suggested, I would try to verify what the behavior is like via iOS first just to confirm that it works via another endpoint with the Lightning Kit and that the DAC itself is properly functioning.
Once we establish that, we can give other computers running Roon a try (see Running Roon as a Remote Guide) and verify if this behavior is DAC specific or Core/Endpoint specific.
I would try to change one variable at a time if this starts working properly:
- Use USB + iOS adapter
- Use same USB on a PC Roon Remote
- Use the intended adapter for the original setup
- See where the issues start
Also, I would double check to make sure you have the newest firmware and I have recently seen a thread where the Pre Box S2 was a counterfeit (Pro-ject Pre Box S2 Set-Up Digital Question), might be worth looking into where you bought it from just in case this might be related.
– Noris