How Can I Eliminate Humming Sound?

[ddouglass]

Originally Posted by captnkarl

I had the same problem and the answer I got was "get a 3prong to 2 prong thingy"...That worked great and have used it since. If you unplug your power supply to the laptop, that will eliminate it also (battery won't last for a whole show). I doubt that it is the club because I had it at every club and in my house and I know that everything is grounded right in the house because I wired it myself. Dell told me that unless lightning strikes the club I will be fine running the way I do now.

So do you shut down the show if there is lightning in the area? Did Dell also tell you that your warranty will not cover that damage?
Just because it does it at every club does not mena that it still isn't their ground setup. Lowes, Home Depot, etc. all sell a simple small 3 prong tester that will tell you if their outlets are correctly wired.
Another thing that can cause this is if all of your equipment is not on the same circuit in the building. Such as using powered speakers spred out across the room. If the circuits are not all grounded to the same buss bar in the panel there is a potential for a difference in the two separate grounds which will read as a voltage across them.
When you go to strictly battery on the laptop you now are using straight DC voltage with no AC voltage present. AC voltage in this country uses a 60HZ (cycles per minute) sine wave signal to carry the voltage to whatever item is plugged in. The sine wave signal is what causes the hum.