Electrical buzz coming from studio monitors?

[petrou58]

I have two studio monitors connected to a preamp, which is then connected via USB to my PC.

However, I seem to get quite a loud buzzing sound coming out of them when the computer is under heavy load, such as when I'm playing a process heavy game.

They do not make a buzzing sound when connected to my iPod, instead of my PC, so it must be because of my PC.

Any help to diagnose the problem would be appreciated

 

[entropytheory]

Sounds like a ground loop. I'm taking a probable shot in the dark here, but your speakers are probably plugged into the same electrical source as your computer, or possibly the AC plugs in your house/office are on the same circuit. When the video card starts working hard, it puts draw on the electrical line which then throws hum through the speakers. Doesn't happen on the iPod because the iPod has a battery, it's not on the same circuit, and it doesn't have a huge video card putting draw on the line. A cheap ground loop isolator off of Amazon should sort you out. For a 3.5mm connection try searching for this one: PAC SNI-1/3.5 3.5-mm Ground Loop Noise Isolator You can also test this theory out by plugging the speakers into a different power grid than your computer. In my house, the next AC outlet was sufficient, but in many houses that will still be the same circuit.

I hope this helps others. I spent a lot of hours troubleshooting this same issue.

 

[petrou58]

Sounds like a ground loop. I'm taking a probable shot in the dark here, but your speakers are probably plugged into the same electrical source as your computer, or possibly the AC plugs in your house/office are on the same circuit. When the video card starts working hard, it puts draw on the electrical line which then throws hum through the speakers. Doesn't happen on the iPod because the iPod has a battery, it's not on the same circuit, and it doesn't have a huge video card putting draw on the line. A cheap ground loop isolator off of Amazon should sort you out. For a 3.5mm connection try searching for this one: PAC SNI-1/3.5 3.5-mm Ground Loop Noise Isolator You can also test this theory out by plugging the speakers into a different power grid than your computer. In my house, the next AC outlet was sufficient, but in many houses that will still be the same circuit.

I hope this helps others. I spent a lot of hours troubleshooting this same issue.

I think you may be right, I've thought that it may be the problem and have had my monitors plugged into different sockets in the room in the past, but it didn't help. It's either a different issue or the two sockets are on the same circuit. I guess I won't know until I get a groud-loop noise isolator. It's not a 3.5mm jack though, it's RCA into the preamp, and then USB to the PC. So I'm pretty sure RCA ground loop noise isolators exist.

 

[entropytheory]

I found some but they have extra wiring coming off that you'd have to ground to something. On my rig, I went out of the sound card line output as 3.5mm through the ground loop isolator. The output of the isolator goes to a Y cable that splits 3.5mm stereo into 2x RCA L/R connectors. I plug those connectors into the preamp. Then I run 1/4 inch to the satellites. You can probably do something similar. Good luck.