AC adapter making my speakers buzz -- and it's not a ground loop.

ori — Mon, 23 Mar 2009 19:13:24 -0800

New, generic AC adapter is causing my computer speaker system to hum. I thought it was a ground loop, but a cheater plug (fitted on the jack of the AC adapter) didn't help. (The speaker system itself is not grounded.) I know it's the AC adapter, because if I run my laptop on battery power, the hum disappears. Anything I can do, short of forking out $70 for an original adapter? This adapter has been working fine otherwise.

I'm using an external Sound Blaster Live! 24bit as my sound card, but the problem persists when I switch to the on-board sound card.
The speaker system works perfectly well with other laptops.

In short -- it's the AC adapter. But what should I do?

Getting rid of the phone buzz?

kamelhoecker — Thu, 12 Apr 2007 08:18:42 -0800

My phone has a loud buzzing noise. When I touch the screw on a lightswitch plate, sink faucet or a metal lamp, the buzzing stops. What is happening – and more importantly how can I use the phone without having to ground myself? My phone service is through my cable provider. The cable comes into the house, splits into a box for internet (cable "modem") and into another box for my phone service. My phone connects into my "phone box" with a standard telephone wire.

I did some research and my hum/noise problem sounds like a ground loop – except that my phone, internet modem, router, laptop, etc. are all not grounded. (They have only 2 prongs. But maybe the cable is grounded.)

Also, confusing (to me) is the fact that the problem goes away when I am grounded. What does me being grounded have to do with my phone?

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AC adapter making my speakers buzz -- and it's not a ground loop.

Getting rid of the phone buzz?