Well,
First off sorry for the long title of this thread.
I went out and got what I thought would be a low cost line conditioner to get rid of the 60cyle garbage which does not always appear, for my last job I used the ac adapter on the GL2 and the Marshall monitor into the ac line and no problem.
Anyhow...
I have a 12 volt power pack (cigarette lighter socket) that I normally used as a source for my video light.
So I figured why not use it as another source of battery power for my GL2.
Now I do not have the 12volt adapter that Canon sells for the GL2 so you can power from your car battery. I do have a powever inverter I have used on long trips for my laptops and other items that need ac power.
So, I plug in the power inverter to the small 12volt battery then plug in the ac adpater to the inverter NO GO. huge buzz.
So I plug in the GL2 into the conditioner, one you plug into the ac line, to the inverter that is plugged into the battery. Buzz still there but why down.
Here is the chain:
1: 12volt battery
2: Power inverter
3: Line conditioner
4: GL2 with ac adapter into line conditiner.
Humm is less but stll there.
So I put the GL2 on its own battery, which really defeats the purpose of the above jerry rig in the first place.
I plug in my Marshall monitor to the GL2 and the Monitor into the above rig AND you guessed it HUMMing. I remove the video monitor and the hum is gone. Oh well I will use the GL2 builting monitor.
Now the following was really strange.
Just for kicks I put the GL2 whith its own battery ontop of the 12volt power converter . . . . HUMM! WITH THE CAMERA OFF!!!!!!
It seems that the power converter was the culpret, unless of course I touched the converter and then the hum was gone.
Now I know why when electricity was first discovered it was considered witchcraft.
Very confusing! I just thought I would pass on the experiment.
Yours,
Tom

Witchcraft, agreed.

I was doing these interviews this summer. I have a lav mic with xlr plug that I put into an xlr -> stereo mini jack so I could plug it into the mic jack on the GL2. Well, sometimes I would get this horrible hum, and other times it was fine.

On first experiment, it was always fine with the battery. Only sometimes fine with the ac adapter.

Turns out, it depended on the age of the house. Really old houses and apartments didn't have proper grounding in the wall sockets. I have no idea. I just know that it's suppsoed to work, and when it doesn't, it's the work of the devil.

The low/moderate cost power inverters use electronic switching methods to approximate a sine wave output - they are very noisy electrically speaking, with lots of harmonics and spatter. And they provide minimal to no power conditioning to remove the noise.

The Canon power adapter/charger does not provide full power conditioning, and electrical noise can leak through to the output. Not a problem for battery charging, but can be an issue with camcorder use if the power source noise is excessive.