Mike C,
Thanks for responding!
We are trying to get a USB feed to the computer to live stream our church services, and we’re using OBS as our streaming software. We’re also trying to play audio back to the mixing desk, like from Spotify / YouTube / Windows Media Player
As for the transformer isolation, would something like this do? https://www.swamp.net.au/ground-isolator
What we’re using is the ST1 in on the Qu-24 from the line out on the PC, and then 2TRK out to the line in on the computer.
It helps if I use my Focusrite Scarlett USB interface but it doesn’t completely eliminate the humming.