Does anyone know anything about grounding a computer case from a 60hz hum?

I am connecting my computer (tried an external usb soundblaster and onboard stereo out) to an amplifier (onkyo sv909pro) and im getting a significant hum.

-When i unplug the connection from the computer buzz stops. If I touch anything on the computer with the cable the buzz starts again

-There is no buzz from other sources on the amp.

-I am using a 3 prong plug on my computer, my amp only is 2 prong (ground difference?)

 

Simple thing you could try would be to add a ferrite ring (bead, core, etc) to the cord you are connecting to help filter out the noise.

http://en.wikipedia.org/wiki/Ferrite_bead

Should be able to get one at any computer shop, or DIY wiring place you might have around you. You could also scavenge one from a spare good quality USB cable you have lying around.

 

^ Sometimes it can be something as simple as your computer vibrating itself, like a fan is loose, check that, I've had a similar problem before. My CPU fan, was loose and was vibrating the motherboard a little which brought resonance to the sound card connection.

 

Thanks for the quick replies, ill try both out tonight.

 

I ended up buying a ground loop isolator (which may be a large ferrite core, i dont really know how it works) which fixed the ground loop.

No more hum