Hardware Insights Forum

Today I made an EMI filtering outlet by myself (well, sort of). I found an old ATX2.03 power supply at home. An idea popped into my mind at the moment I opened it.

The power supply has two stages of EMI filtering. The stage 1 was connecting to the receptacle and the stage 2 was soldered on the main pcb. The stage1 has a little piece of PCB with 2 y capacitor, 1 x capacitor and a coil soldered on it. I was thing if I could make use of the stage 1 to DIY an EMI flitering outlet/socket.

I pulled the stage 1 out of the PSU and coupled it with an outlet. Then I connected my speaker to the EMI filtering outlet and amazing happened. The speaker used to make loud annoying sizz noise (probably coil whine), but now the noise is so low that it even isn't audible unless you stick your ears to the speakers!:clap::clap:

update: I think my EMI flitering outlet doesn't work that well... The sizz noise got louder this evening...

well, it was a brilliant idea

shovenose wrote:well, it was a brilliant idea

if only it worked.

try it again

Aah the 50hz hum. You must try and centralize one ground and plug your devices into it.

Thanks Klinc. The GND is a problem cause the place where I live doesn't have GND at all. I thought the noise maybe have some connections with the absence of GND, but I can't prove it.