Ground-Looping Problem

[Midside21]

I have read a lot of forums on this, but for me, all the solutions given have not worked for me. I keep getting oud buzzing noise in my right speakers. Here is my scenario. I have a Macintosh Powerbook.

The audio out of the laptop goes into an M-Audio MobilePre (Audio Interface)

From there, White/Red RCA output cables WITH a ground-loop isolator connect to my Onkyo receiver.

From there the Onkyo receiver connects to 2-sets of speakers. Speaker set A and B.

Both my laptop and receiver have 2-prong un-grounded plugs that go into the same power strip that then goes into the wall (using a 3 to 2 prong adapter for the power strip does not help at all).

Also disconnecting any TV or Antennas from the receiver doesn’t help either.

There is only one solution that clears the noise from the speakers…disconnect the power to my laptop and run on battery. But my computer is slower and I typically leave my computer on for 8-10 hours at a time so that solution is not practical.

So my question becomes what other (affordable) solutions can I try? I really don’t want to spend $100 dollars on one of those expensive surge protectors that eliminates all hum on any appliance. So what else can I try?

Any suggestions would be much appreciated.

[0239666]

What do you connect the ground loop isolator to, on the mobile pre side?