johnnynono57 , via OnePlus Community App , Jan 22, 2021 : I am trying to use a FiiO Q5S Type C external dac/amp with my Oneplus 7t. It connects through a usb c cable from device to device. The FiiO unit works flawlessly with every other Android device I have. I believe I have exhausted every possible option and am hoping someone has something I missed. I've tried rebooting, otg, developer options, disable/enable automatic audio usb routing. My only thing I'm not sure of is USB preference... My options just don't list "audio source"... I've tried file transfer, ptp, midi.... Etc. Hopefully someone or possibly a oneplus techie will have the answer to this... Thankyou.