Question Speakers making high pitched noise

[Tornado77]

Hi, I'm using a monitoring 30w amplifier as my speaker. The sound quality is amazing, but when I connect it to my computer, the amplifier is making a very high pitched noise. The pitch depends on the CPU usage, higher CPU usage makes higher-pitched noise. When I connect my guitar, my bass or just my smartphone in it I have no problems. I tried to connect my 100w bass amp to see what's happening, but there's no noise, just the sound from the computer.

 

[americanaudiophile]

If the powered speaker has a three prong AC cord then try using an 3-2 adapter which will lift the ground. Sounds like you have a ground loop.
http://web.mit.edu/~jhawk/tmp/p/EST016_Ground_Loops_handout.pdf

 

[Tornado77]

If the powered speaker has a three prong AC cord then try using an 3-2 adapter which will lift the ground. Sounds like you have a ground loop.
http://web.mit.edu/~jhawk/tmp/p/EST016_Ground_Loops_handout.pdf

The amplifier is plugged with a 2 prong AC cord. Might it be a problem with the cables I am using?

 

[americanaudiophile]

Possible but not likely if they work with other sources.
Does the noise vary when you turn the PC volume down? If so then just turn the speaker up to compensate.
Try plugging the speaker into a different AC outlet.
It may need to be grounded since it doesn't have a three prong AC plug. If you can a place to ground the speaker that might help.

 

[Tornado77]

Possible but not likely if they work with other sources.
Does the noise vary when you turn the PC volume down? If so then just turn the speaker up to compensate.
Try plugging the speaker into a different AC outlet.
It may need to be grounded since it doesn't have a three prong AC plug. If you can a place to ground the speaker that might help.

No matter what's the volume, no matter if the speaker is activated or not(in the windows audio manager) it makes a high pitched noise. It doesn't do it if I plug my phone or anything else.

 

[RigPa]

If it is the CPU frequency you can hear you probably need a better audio interface. Mobo audio isn't always that great.