10. What should I do if no sounds when using the BTA30 in USB in, TX mode?

1. Please check whether you have connected the BTA30 to the Bluetooth headset/speaker successfully first.

2. Please check the samping rate of BTA30 from 'playback device'-'FiiO BTA30'-'Properties'-'Advanced'. Is the sampling rate shows'16bit,48000Hz' only at that time?

 If the '16bit,44100Hz' is shown at the same time, please try to unistall the driver of BTA30 in the computer and reconnect again for check: 

How to unistall the driver of BTA30 in the computer: 

3. If the sampling rate is shown correctly, please try to clear the pairing record in both the Bluetooth headphone and the BTA30 to check again. 

How to clear the pairing in BTA30:
Keep the device on (not in pairing state) and switch it to RX/TX mode, hold the POWER+PAIR button simultaneously for about 5s.