[9uman9y]

Originally Posted by biterror

Is the noise affected by volume control or signal source (bluetooth / something else) or any other audio setting? If it is always the same, the problem might be with the power amps or the DACs.. if the noise level changes with audio volume setting, then the noise comes from earlier stages in the system.

Thanks for the clues. No, it does not depend on either volume or source.

The noise can be heard even if I press the volume button to turn the sound system off altogether (but sit in the car, so that the power is still on).

I also think it is quality of the power supply, or some interference, but can't test it.