Ground loop with TV when power adapter connected

I have a white Macbook (non-unibody) which I have connected to my TV with a mini-dvi to VGA adapter. I have done the same in the past with my Dell 1525 with no issues. When the Macbook is connected to the display whilst being connected with the power adapter, the screen has interference. After some googling I believe this is because of a ground loop. The monitor displays fine when the power adapter is removed.
Since I am using some processor-intensive applications my battery life doesn't last long, and it is incredibly inconvenient to have to keep plugging the adapter in and out.
Any suggestions on a cable to remove the ground feed or other solutions? I have already tried resetting the PRAM.

You might need an electrician to check or replace the electrical outlet or wiring, if it really is a ground loop. Try temporarily plugging the TV and Mac into the same surge strip. If the interference goes away, then the fault is likely in the outlet(s) that the Mac and TV are plugged in to. (The surge strip puts both devices on the "same outlet" thus eliminating the ground loop between outlets in your home wiring. Of course, a bad or old surge strip could cause a ground loop as well so if you're already using a surge strip, try another surge strip in case the ground loop is in the strip.)
Why don't you see it on the Dell? Likely because the Dell's power adapter has a transformer in it, which serves to isolate the electrical circuits between the devices. TVs and desktop computers often do not have this type of "isolation" transformer anymore, so ground loop interference can be more noticable. BTW, they do sell isolation transformers, but they're mostly for TV technician troubleshooting and not designed for continuous use. One that can handle a TV's electrical load can cost more than an electrician, so don't bother. You might be able to find a smaller, lower cost one to handle the Mac, but it still would mean a issue with the electrical wiring that may get worse over time. So IMO, better to spend the money on a electrician.

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