Annoying Buzzing Noise

[supermoose1111]

I recently built a new PC.

There is an annoying buzzing sound coming from an unidentified source. I have tried turning all the fans off but the buzzing sound continues.

I am starting to think it could be the PSU (corsair AX850). A second before I shut down the PC the buzzing stops.

This is an annoying problem as one of my goals was to build a very quiet PC.

Has anyone experienced something similar?

 

[supermoose1111]

what parts do you have in the system?

Hardware:

Intel Core i5-4690k @ 4.5Ghz
MSI HD 7970 TwinFrozr III OC Boost Edition
MSI Z97M Gaming
Crucial Ballistix Elite 8GB DDR3-1600
Samsung 1TB 840 EVO
Corsair AX850

Cooling:

beQuiet Dark Rock 3
Bitfenix Spectre PWM 120mm X 6

 

[supermoose1111]

test it without the gpu in, just use the onboard.

checked that there are no cables catching on any cpu/gpu fans?

I think its one of the fans even though I said it wasn't in my OP. I plugged the fans in one by one. The rear fan buzzes. Another fan has a slight buzz, while the rest are silent. Bit surprised as the fans are brand new.

Could this mean two of the fans are faulty?