Hi @Andreas_Huber,
Thank you for posting, and we’re terribly sorry to hear about these ongoing issues with upsampling and playback performance with your DACs.
The issue here is likely a PCM sample rate disagreement between RoonServer and the Vega G1 USB audio input.
Unfortunately, @BlackJack is entirely correct that replacing the USB input with a network input on your Vega is the only way to reliably prevent these issues. We’ve encountered this issue before with the Auralic Vega series on this forum and the conclusion is that the network input on the Vega series works best with Roon. The issue is outside the scope of Roon’s DSP, unfortunately. Please see the below post, from a user who contacted Auralic directly:
We’ll be watching for your response. Thank you!