Just to report back to this helpful community. I experience a step up in sound quality listening with iem's with the Spotify extreme files that seem to be > mp3 320 kbs quality. Just have the Q1 and not sure whether the amp, the DAC, or both deserve credit for the improvement. Also nice too know that in case I will ever have a telephone with a high quality DAC, the Q1 can still function as a useful headphone amp.
Q1 works fine and plays Spotify streaming extreme quality through the phone's USB (Q1 in DAC + amp mode) with Moto G5 plus and android v 7.
- works with OTG USB on the phone's USB port. Non OTG cable didn't work for me.
- developer settings USB > audio
- Charge on the Q1 in off position