Bong noise when system shuts down or while turning on from PSU.Corsair 750 RM

I have a Corsair RM 750 that makes a single click sound (like a switch going off) after the computer turns off or turning ON or going to sleep mode. Anyone else with the psu that experience this? Is this common to Corsair 750 RM or i should get another one? It sounds like a loud bang.







Here is the video with similiar noise but on model HX Corsair :

http://ift.tt/1tFUFyK

Is this normal?