Question Static-like sound after PC shuts down.

[nuk3snake]

Hey everyone! So I have a weird problem and it feels like I've tried everything already so here I am!
Here's the deal, I've recently noticed that after my PC shuts down, there's a barely audible static-like noise that persists.
After trying a few things I've also realized that said noise only starts after my headphone's leds turn off. The noise is not particularly loud or anything, but it is annoying me.
I've disabled quick boot or whatever from the power management options, disabled deep sleep in S4 and S5 in the bios (which is why my headphones turn off) and the noise is still there. While the PC is off however, if I plug in my headphones' led usb conector (assuming they're not disabled), the noise goes away, but then the headphones' lights turn on, which makes it impossible for me to sleep.
So, to recap:
Headphones leds enabled and plugged in via usb when PC is off = no noise, but lights.
Headphones leds disabled and plugged in via usb when PC is off = noise, but no lights.
Headphones leds usb unplugged = noise, but no lights.
The noise goes away if I turn off or unplug the psu, so I'm assuming this is either a psu or a motherboard issue? The computer itself works perfectly, and all of it's components are new so I don't know. I'd appreaciate any info, thanks!

Motherboard: Asrock Steel Legend B450m
PSU: Cooler Master MWE2 Bronze
CPU: Ryzen 5 1600 af
Case: Cougar Mx331 mesh-g

 

[Ralston18]

Make and model headphones?

Direct connection to PC USB ports or via some 3.5mm to USB adapter?

With the headphones plugged in as described are you able to cause any changes by gently twisting, wiggling, the cable especially around the headphone end and the plug end? E.g., the noise stops, the LED goes off, etc..

Try other known working headphones on your PC.

Try your headphones on another known working PC. And other audio devices if possible.

Determine if the described problems follow the headphones or stay with your PC.

Overall, my thought is that there is a short of some sort. Electricity is continuing to flow through the system until the PSU is physically powered off by its' own switch.

 

[nuk3snake]

Make and model headphones?

Direct connection to PC USB ports or via some 3.5mm to USB adapter?

With the headphones plugged in as described are you able to cause any changes by gently twisting, wiggling, the cable especially around the headphone end and the plug end? E.g., the noise stops, the LED goes off, etc..

Try other known working headphones on your PC.

Try your headphones on another known working PC. And other audio devices if possible.

Determine if the described problems follow the headphones or stay with your PC.

Overall, my thought is that there is a short of some sort. Electricity is continuing to flow through the system until the PSU is physically powered off by its' own switch.

Headphones are Onikuma K5 I think?
The mic and audio connectors don't cause any issues, the only one that seems related to the noise is the USB conector for the leds. I tried wiggling the cable and changing usb ports and stuff but there's no effect.
Had these headphones on another pc until recently with no issues.
I have yet to try another set of headphones, might do that tonight.

 

[nuk3snake]

Welp, tried:
-Different headphones
-Reseating the usb headers on the mobo
-Flashing the bios to an earlier version (as recommended by asrock)
And nothing works, so I guess I'll have to get a new psu? Or (hopefully not) a new motherboard?

 

[jxe63]

I've had a similar problem but only when the house AC power goes out. The desktop PC is connected through a UPS to mains. AC out, UPS takes over but then buzzing. AC power returns buzzing stops.

My house power is earthed with the M.E.N. system (more earth to neutral system).

Personally, I suspect my issue to be the computers PSU, leakage or a lack of or poor grounds.

Is your issue just through headphones, or through the main speakers also ??
If you unplug your headphone LED, USB does the buzzing disappear ?
I'd be looking at your PSU. Perhaps you could swap out even temporarily to verify or negate this is the cause.
I doubt it's your motherboard given it does work perfectly, as intended.