Re: audio hum

Were you powering by AC supply? That could account for a hum; or perhaps the house sound you patched into was on ac. If that's the case often the only solution is to use a ground lifter on everything connected to the ac and the camera. While this increases the chance of shock it's often done to eliminate the problem. Just be sure not to operate without shoes!

You can ultimately track down this problem with a volt meter, by checking to see if there is some spurious voltage in the neutral or ground.