06-06-2020, 09:10 PM
It sounds like a USB audio hot-plug issue or possibly something to do with the Pi-4B USB implementation which is quite different from earlier Pi's. IME USB audio hot-plug on Raspbian has been problematic.
Are u using the USB2 or USB3 port for the DAC?
Try swapping in a Pi-3B+
Are u using the USB2 or USB3 port for the DAC?
Try swapping in a Pi-3B+