For the past year I have been using my Sony NX70U solely on batteries...until the other day.

I was shooting an interview and batteries were low so I plugged it into the A/C. There was a terrible interference static / squeaky noise that can be heard through the headphones AND worst of all is recorded.

I tested it by attaching and detaching it from the A/C (also using different outlets) and unfortunately it is the cause.

Has anyone else experienced this? Can you test your camera and see if it happens to yours.

You know what, I was all ready to start typing something about non-XLR mics and it would be better with a balanced mic... but what do you know, it happens to me too.

This is with no battery in the camera, and using the stock XLR shotgun muc that came with the NX70. I'm not sure it's a "terrible" noise in volume terms, but it's there, noticeable, like cicadas at night or similar. A bit odd.

I had the same thing at work with a smaller Canon camcorder, so I wonder if it's more common than we'd expect?