Volume control: I think you should be able to control the volume from Roon (at least it works on MacOS and Windows on my D200 with Devialet audio drivers, no experience with Linux/Roon OS). Make sure the USB Output is configured in Roon in “Exclusive Mode” and “Device Volume”.
You can’t wake up the Devialet in USB, only Roon Air or RAAT can do this. Same for input selection. You can configure USB as the default input after power on in Devialet Configurator, if it’s the one you use the most.
Let us know whether you prefer USB over Ethernet, I have always found Ethernet better. Some manage to get better results over USB but this requires some tweaking.
No option for “Exclusive Mode”, think that’s a Mac thing as I’ve used it in the past with DACS connected to an iMac and a MacBook Pro.
The “Device Volume” in this case works on a scale from 0 to 100 but only as a percentage of the volume showing on the Expert display. It does’t show the actual volume on the Expert. I have mine start up at the default -40dB (probably like most people) so still need to grab the Expert volume control or use the app. For consistency I’ve changed the Roon setting to “Fixed Volume” so it’s at 100 all the time.
I’m currently waking the Expert using Roon by selecting the RAAT source and then switching to USB, so setting the default to USB would still require me to change source on the remote. I will set USB to default and try to condition myself to use the remote to start the Expert. Thanks for the tip.
This is the first time I’ve connect the Expert via USB so I’m still in the comparison stage as far as sound is concerned. I can’t find any settings anywhere that change USB so I’m guessing the tweaking is limited to cable choice and USB filters.
Will let you know what I eventually decide. I’ve also now got the option to isolate the ethernet using two ethernet connections but I think I’ll keep it simple for now.