by janui » 02 Dec 2017, 11:06
Hi MikeC,
You have quite an old kernel with 4.1.20-1-ARCH, Frank's test kernel is 4.1.33-1-ARCH or similar. It is still important that the manufacturer tells you which version supports the DAC.
But from what I see in you debug is that the USB dac is not detected as a USB device. It’s a two-step process, first detection as USB device then detection as an audio device. You Dac is just not seen! Not sure what this means exactly, maybe Frank can add his wisdom.
But I would first check: 1. the USB cable, 2. the power supply requirement for the dac (if self-powered, or under 350mA via USB should be ok), 3. Check that the 'max_usb_current=1' line in config.txt is uncommented.
janui