Sorry, I know this is a really old post, but this is the top search result for Helix and Android...
@Digital_Igloo FWIW, I tested using the Helix with my Google Pixel XL phone (using the April 2017 Android 7.1 (Nougat) version) using the oem USB-C to USB-A adapter plug with the helix USB cable, and it didn't work. Phone audio still played back on the phone speaker, not the helix connected monitors. I was hoping to be able to playback music from my phone through the helix usb input (rather than having to connect and route a pair of returns for every preset i use). It would also be super awesome if I could use the Helix audio as input to my android device so when i record video it would be a direct helix signal!
As far as class compliant audio support, I've been able to use my Pixel, and before that since Nov 2015, my Nexus 6 in my car with a generic cheap Windows USB to spdif DAC to feed a miniDSP, so i think the technology exists. I also playback audio from my Android phone into my FiiO e17 DAC/AMP. I'd be happy to help with testing future Android DAC support for Helix. Thanks!