Ground-Looping Issue (1 Viewer)

[Midside]

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.

 

[Parker Clack]

The test is always to try to take something out of the loop and see if the buzz goes away. Did you try plugging your laptop into an extension cord and plug it into a separate circuit not in the same loop to see if that helps? What about the M-Audio MobilePre is it plugged in? Have you tried a stereo mini to RCA cable to go from your laptop straight into the Onkyo bypassing the M-Audio?

 

[Midside]

The only thing that makes the buzzing go away is unplugging the power to the computer.

The M-Audio Interface runs off of USB power. I have bypassed it, and the has absolutely no effect on the buzzing.

I have tried splitting up the receiver and computer as far apart as I can, as well as keeping them as close as I can...in both situation the buzzing is still there

I have tried a variety of cords as well, including high-end monster cables, but nothing stops the noise.

Thanks for the reply

 

[Parker Clack]

That is so weird. It sounds like your receiver is picking up the RF off the laptop when it is plugged in. Does it have any type of wireless access turned on?

 

[Midside]

wireless? my computer connects to the internet via an Apple Airport Extreme...Wireless Internet.

I do think you are right about the RF. When the computer is SOLELY running off battery there is no noise at all. When its plugged in it's there and it's loud.

I was thinking of wrapping part of the power cable with Ferrite beads, but I am not sure if that will do the job or not.