I'm using a Focusrite Scarlett 2i2 USB audio interface to connect microphone audio to the computer for processing (Audiomulch/Ozone 5) and then output through the Focusrite to a radio transmitter. There's audible 60hz hum on the audio at the transmitter. I've been unable to tame the hum via better grounding, use of balanced connection, etc. I'd prefer to isolate the USB port and only use an audio isolation transformer as a last resort.
I purchased a ADMU4160 based isolator supposedly rated at 350ma (Focusrite draws 310ma). I've been unable to get Windows applications or Windows Sound to recognize my Focusrite when it's connected through this isolator, even though it shows up fine in Device Manager. I've also gone through a reinstall of the driver with no change.
So I'm wondering if anybody might have some advice on how to resolve the issue with the Focusrite/isolator not being recognized as an available soundcard by Windows applications. Also, can anyone recommend an alternate usb isolation product that would work reliably under Windows?
Thanks for any help.