New power supply clicks

[Matthew Renna]

I just bought a seasonic focus 550 watt. It replaced a corsair CX 500.
Whenever my pc boots or wakes up from sleep, the power supply makes a click. It also does this when it turns off or goes to sleep. The old power supply never did this.
What is this?

 

[getochkn]

https://linustechtips.com/main/topic/902656-seasonic-focus-plus-gold-750w-single-click-sound-when-pc-is-onoff/

Some reading there. Basically it uses a relay inside to control voltages with is very efficient and safer than other methods.

 

[Matthew Renna]

hmm, so it's actually bad that the old one didn't click?

 

[Dark Lord of Tech]

http://forum.corsair.com/v2/showthread.php?t=127387

Newer PSUs do this because you have a relay that essentially switches power from the +5VSB to the normal +5V between the off and on modes of the PSU.

So.. you have things like keyboard, mouse, etc... anything that's USB based, that uses +5VSB when the PC is "off". Once you turn on the PC, that is switched over to the +5V rail. Problem with the sound is that it also uses +5V, but not +5VSB, so it's getting a bit of juice that jumps from one rail to the other as you're shutting down and that causes some residual sounds in your speakers.