Buzzing issue with new PSUs

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19 Aug 2011
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So this is a weird one but any input will be appreciated. I'm having a repeat issue of buzzing being emitted by any PSU I stick into my desktop.

I've gone through 3 Corsair RM1000x PSUs with each one emitting a buzzing sound, the first one only produced a notable buzz after two weeks (which eventually could be heard even whilst the desktop was powered off) but the next two produced the problem upon first boot. With the second and third Corsair PSU I tested them using a basic PSU tester before connecting them into the system and no buzzing could be heard, but as soon as they went into the system you could hear it.

I got the Corsair refunded and ordered a Super Flower Leadex II 1000W 80 Plus Gold which has been fine for two days but now emits the buzzing even when the system is powered down. So my first theory of there being a manufacturing fault with that brand of Corsair PSU has been thrown out. To try and eliminate the surge protector from the situation (which I bought at the same time of the first Corsair PSU) I've plugged the mains cord directly into the mains, but still a buzzing can be heard.

All the while however, I've had my old Corsair 750w PSU connected in between getting the buzzing PSUs replaced and it hasn't produced any buzzing that's noticeable, however after a long gaming session (3-4 hours) I did hear a slight buzzing being emitted, though this wasn't as severe as the other PSUs.

With the Super Flower PSU just connected to mains, no other components in the system connected, the buzzing is still audible. Which would suggest that there isn't any other component wrong in the system but at this stage I'm at a loss. I'm hoping that maybe with the PSU plugged directly into the mains the buzzing will not be as severe when the system is under load but I'm stuck on how to proceed.
I've swapped out the PSUs, the mains cords, took the PSU out of the system entirely and still can hear a buzzing.

Sorry for the long story, but it covers just what I've gone through in trying to get a new PSU. Any thoughts or comments are much appreciated.
 
5 V standby is always on when PSU gets power from wall.
That noise comes from it or input filtering components.

Makes it probable that mains voltage waveform is somehow distorted instead of being sine wave.
(square wave UPSes make PSUs buzz lot)
Would be time to check that wavefrom coming from wall.
 
Thanks for the responses. Weirdly after leaving the PSU directly plugged into the mains socket the buzzing gradually went away entirely within 2 hours. During that time I was running the system at perhaps mid-high load and found it to have disappeared by the time I powered down the system. Even double checking the PC when completely shut own there's no minor buzzing to be heard.

So, excuse my lack of knowledge with electricity, is it possibly the case that a component in the PSU was getting a distorted waveform from the surge protector, becoming 'charged' with this waveform and once this waveform was no longer being sent to it the charge eventually dissipated?
 
becoming 'charged' with this waveform
AC doesn't work that way.
Any electric charges get discharged after reaching peak amplitude of every half wave, with next half wave having opposite polarity.

Guess wiring of some coil could have settled, but it's equally likely that what ever caused some distortion/interference to mains voltage was unplugged.
And unless local power network is good especially some heavy industry could easily cause lots of interference.
Doesn't even need that...
 
AC doesn't work that way.
Any electric charges get discharged after reaching peak amplitude of every half wave, with next half wave having opposite polarity.

Guess wiring of some coil could have settled, but it's equally likely that what ever caused some distortion/interference to mains voltage was unplugged.
And unless local power network is good especially some heavy industry could easily cause lots of interference.
Doesn't even need that...

Would a UPS solve that?
 
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