Tried to solve my volume issue with your above advise, but without succes.
I’ve just purchased the Hegel H390 and use my Macbook as a Roon Core. While i play over airplay to the H390, the volume control is both controllable through the amp and through the roon app.
As soon as I try to play from Macbook > USB > H390, I can’t seem to get the volume control to work the same way as the airplay way. Fixed volume seems to be the best way, but I don’t like to grab the remote of the amp all the time, mayor change in user experience IMHO.
Did you manage to resolve this? I have the same issue with my H590, was working fine but I had to reset my amp this morning and have since lost volume co trip on USB.
Thank you, I found this just after posting and remembered going through the same pain when I first set up. On another forum people have suggested not using Roon for volume control as it effects sound quality. Testing that now…