Smartcam HD Pro audio noise

I’ve connected not one, but two cameras that I’ve bought at different times and different places. Both cameras give off audio interference (noise) when connected. If I hold my ear to the camera, I can actually hear the noise being produced within the camera itsself. It sounds faint hearing it at the camera, but it comes through loud and clear on my mobile when connected. It makes hearing audio from who’s at the camera less than satisfying. Is this a known problem? Is there a remedy?