Is this a ground loop problem?

[chaoliang]

When I connect a projector to a notebook (thinkspad t42 or t60) using with VGA cable and then connect the notebook with an audio amplifier, I hear only a loud and lower frequency noise out of the box which lasts several seconds even after the anmplifier is shut down.
No problem if it is connected to an active computer sound box or earphones. Also no problem if the projector is not connected to the notebook but only with the amplifier. Am I expierencing a ground loop problem and what can help?
chaoliang

[chaoliang]

Hi,

I found the solution in a Hi-Fi-Forum: I just drew out the cable of radio antenna and that's it. It seems that how the radio antenna line in this house was layed did not meet the standard.

[VJ]

Glad to help!

[chaoliang]

It was really a strange solution though. I had never come to that idea! Maybe I had tried an isolator or something. But radio anntena cable?

[az]

You can also get something like this: Mantelstromfilter and leave the antenna cable plugged in.

[chaoliang]

Thanks for the tip, az!