battery supply ground noise audio board

[danixdj]

Hi, i have a problem with noise when i use a battery for supply my teensy + audio board.

If i use audio line in input and battery supply (vin pin) i have a great noise to output.

Without line in i2s1 there isn't noise and if I use the supply from usb there isn't noise.

3.6 volt batt. (3 x 1,2 AA).

Thank you.

Dani

 

[danixdj]

SOLVED: i must disconnect "G" ground input and output of audio board from ground of input and output signal and connect to negative of battery.

Now it works fine!