My RPi Zero W does not play nice with Airplay. From the airplay sending device (iPad) I see that Volumio is connected as source, also in Volumio GUI, and that it streams. But no sound. Connecting to another Airplay device works. Any advice appreciated.
Depending on the type of HAT it is required to choose a mixer type. Some support hardware mixer (which is preferred, as there is no quality loss in the audio stream), or software (less optimal, but rather theoretically, as one hardly can hear the difference, which depends mostly on the quality of your audio gear). Did you try that?
I just tested what you suggested, doesn’t change anything.
I do see the source information and time counter counting down in the Volumio GUI, so by the look of it all works well, even my receiver switches to the optical input I attached the Justboom toslink to. But no sound, not even distortion.
So, I attached my old Chord Gem DAC to the mini usb of the RPi Z W and connected the analogue out to my receiver. I could hear the sound via Airplay with a very low volume. Next I tried again via the Justboo toslink and when I cranck up the volume of the receiver to 100% Its just about normal listening level.
So, question is, why is the volume so low? When I look in alsamixer the volumes to both usb dac and just boom hat are already on 100%.