So the other day my speakers started to have very bad background noise. I power off my speakers and I heard a buzzing sound from the back of my case. So I unplugged my power supply and it stopped. I removed my power supply and plugged it into the wall and it still made the noise. While I told myself I'll just RMA it and I proceeded to install my original power supply an Antec 380w but before I completely installed it, I tested it out with only the power connected to the motherboard. And to my surprise it started to do the same thing but at a lower buzzing sound. I've tested the power supplies on a different outlet and it still made the same buzzing sound. Could my motherboard cause this problem or just bad luck and both power supplies going out at the same time?
In the process of typing the message, the background noise and buzzing sound stopped.
What country do you live in? Antec has said that a stepped sine wave UPS will cause their power supplies to buzz, and it appears to happen with many brands of high efficiency power supplies just to a lesser extent. If you live in a place that has very dirty power then it will create a strange buzz similar to what the stepped sine waves do.
Buzzing or humming is caused when the stack of laminations used to make transformers is loose. The air gap between the laminations must be minimized, and sometimes the lams are not assembled well enough in the packeting press.