Even I can connect to standard android marshmallow device (haven't checked with older android version) and stream audio properly. And strange thing is USB AUDIO WORKS DIRECTLY WITH CUBIEBOARD 3 which is having even older android version.
When I look into cubieboard android source - in device/softwinner/kylin-common/hardaware/audio/audio_hw.c
I think audio out put device - 'AUDIO_DEVICE_OUT_USB_DEVICE' is not taken care. I tried to make some changes in source but no luck. I believe it should work directly.
Anybody who has come across same issue and got solution?