I connect my android smartphone from audio jack output to my pc audio input and get a good analog sound signal. But when I connect this smartphone to the pc with usb data cable the analog sound becomes hissing e.g. music from smartphone overlaps with noises on pc.
Why does this happen?
How can I eliminate these noises? maybe I have to use some shielded cables? If yes - then audio or usb? or I need some sound direct box or something like that?

  • $\begingroup$ not a signal processing question – this is probably about insufficient noise suppression on the shared grounds. You'll be better of on electronics.stackexchange.com ; my guess would even be that very similar questions have been asked on there. $\endgroup$ – Marcus Müller Mar 16 '19 at 0:41
  • 5
    $\begingroup$ I'm voting to close this question as off-topic because it's not a signal processing question, but an electrical engineering question. However, similar questions have been asked on electronics.stackexchange.com before, which bars migration to that site. $\endgroup$ – Marcus Müller Mar 21 '19 at 17:14

The problem was resolved by adding ground loop noise filter like this


Not the answer you're looking for? Browse other questions tagged or ask your own question.