Remove USB Noise from Audio Output - Keyboard Waves
ziocom ground loop noise isolator [ eliminate the buzzing noise completely while playing music ] for your car audio system/home stereo with 3.5mm audio cable - Walmart.com
iFi audio iDefender3.0 USB Ground Loop Isolator 306016 B&H Photo
USB Isolator – digirig
Hifimediy USB Isolators - Made for audio to prevent ground loops