2. Can the BTR3 work as a DAC for the computer, and how?

A: Yes, the BTR3 can work as a DAC for the computer.  

Auto mode: Power on the BTR3, and connect it to the computer, then select it as the audio output device to play music; the white light will stay steadily on;

Manual mode: Power on the BTR3, and connect it to the computer,  then quickly press the Power button for 3 times; then white light will stay steadily on.

You could try to test your BTR3 with the computer with the operation mentioned on "Auto mode" firstly. If it can not work, then it should be under Manual mode. Then you could contact us by email (support@fiio.com) to get the new firmware, and upgrade your BTR3 by Windows computer, if you want to make the BTR3 to be Auto mode.

(The USB DAC mode can be switched to Auto/Maual mode via App, and this function will implement by new firmware for the BTR3)