Question ATX PSU giving Noise to Amplifier

Feb 27, 2020
Hi everyone,
My Amplifier system gives a High pitch static noise while I play something from Computer but not from my phone. Then I switched the Power supply (ATX PSU) of my Amplifier to a normal power 12v 700mA Adapter. The noise GONE!! This noise was created by SMPS Power supply 12v 15A (ATX PSU for PC) which I purchased and separately using as my Amplifier Power supply. I don't know the reason. Would be great if any knows it. Because I really want to use ATX as my Amp PSU as it gave it better sound.
PC Power supplies, especially cheap ones or ones designed for servers or office computers typically aren't shielded all that well since EM interference isn't a big deal in computers since everything is digital. They also tend to produce quite noisy electrical output as well

You could try and shield the ATX PSU but the specifics of doing that I'm not really sure about sincethe only thing I'm pretty sure about is to shield for EM you have to know the specific Hz range and choose accordingly. Although that may not do a thing since the interference could be on the power to the Amp itself which I don't know the specifics about cleaning up.