Hi @Phil_Knowles,
Please let us know what the solution was as I am having similar issues with my other DAC(S.M.S.L M8).
Haha…ok got my SMSL M8 to work…linux decided to “mute” it in the mixer. So if your system detects the DAC fine(aplay -l shows your device), and you’re not getting any sound open the mixer with alsamixer, make sure you select your dac with f6, and then make sure all the outputs are un-muted(it must NOT display MM). You can toggle mute with the m key.