Hi

We recently purchased a Panasonic AG-HMC71 video camera.

Connected to our PA systems is a basic mini mixer for which the right channel feeds audio to a pc for recording purposes and the left channel feeds sound to the camera.

Previously this worked fine with our old camcorder but with the new camera there is a 'hiss' in the background of the audio.

If I plug headphones in to the socket that feeds the camera I can't hear the 'hiss' but it's there when the sound is fed to the camera. I know the camera is fine because if I plug a mic directly in to it there is no hiss.

The reason we take sound from the PA system to the camera is that sometimes we may have 3-5 people sitting on the stage speaking so this makes it easier to get the sound to the camera.

How can I get rid of this 'hiss'?

I tried connecting from the 'tape out' on our main mixer as this is the only spare output but there was a buzzing noise there.

I don't know if it makes any difference but I have been using the jack plug audio input on the camera and not the XLR input.

Thanks

I suspect you've put your finger right on the problem there ..... there are a number of reasons why the method you are using could be causing you this problem, but I would say that the most likely solution is to come out of your mixer at line level and into the XLR sockets on the rear of the camera (ensure they are also switched to line input). Additionaly, ensure that you have set the record levels on the camera so that you are recording at the proper level.

My thoughts turned to AGC (Automatic Gain Control). If you only have one input to the camera, is the other input channel turning itself up full looking for a signal?

I'll try the XLR input & check the agc settings. Thanks.

Also check to see if the 3.5mm input doesn't have a ploarising voltage superimposed on it to power a condenser mic, and this reverse voltage, is not appreciated by the mixer. Simple solution, of course is just to make up a new cable with an XLR on it, and try that!

Checking the spec on the camera, the 3.5 mm jack is for a mic level stereo feed only. You should definitely be using the XLR inputs on the back with the selector set to "Line Level".

The control panel on the side of the camera near the viewfinder gives you a choice of auto or manual audio levels plus knobs to adjust the level in manual. To avoid pumping, I'd go with manual and do a line-up prior to shooting so you know levels you see on the mixer will be right on the camera.

Bob