2. Problems concerning A1's output sound.

A: 1. A1 can turn on but with no sound comes out.Firstly, pls check and see whether the input and output port has been plugged in the right socket and make sure the connection is firm enough. 
Secondly, turn up the volume and avoid setting at its minimum.
If the problem still exists, then it would be the problem of the product itself. In this case, pls contact us by sending email to support@fiio.net directly. We will help you handle this matter ASAP. 

2. Monophonic/ Noisy output problem.
Pls try to unplug and replug the headphone cable to see whether the problem has been solved or not. If not, then try on a new headphone cable.
If all the methods above tried in vain, it would because the headphone had been soldered falsely or been broken of false solder or broken socket. In this case, pls contact us by sending email to support@fiio.net directly. We will help you handle this matter ASAP.