you got your situation solved but it appears you have a problem with your electrical wiring...I would check or have an electrician check proper grounding of your fuse box...or you possibly have a loose ground in one or more of your electrical outlets...in any case it could cause other unwanted problems down the road.
sometimes just reversing the cord in the outlet will eliminate the hum...
In any case it is always wise to find the source of the problem and fix it or get it fixed.
Register for free to join our community of investors and share your ideas. You will also get access to streaming quotes, interactive charts, trades, portfolio, live options flow and more tools.