This is a PSU modification which is meant for the Creality3D Ender 3, but may be used for other printers too.
In the first step it replaces the original PSU with a Mean Well LRS-350-24.
Then it replaces the original PSU cover fan with a specially designed partial case. This lets you use a 80 mm 12v Arctic F8 Silent fan (or any other 80 mm x 25 mm 12v fan) and reuses the original Ender 3 power socket / switch combination part. The original fan is also 12v indeed (see the photo).
It is made from three parts. They should easily print without any supports. It also will fit on the Ender 3 bed even if the resulting part is bigger than the print area.
There are multiple prepared cable tunnels at the lower side and it can be mounted just as the original PSU (I designed it to go outside of my printer encasing though). It is just slightly thicker to allow the cabling to fit well. There are also only the original screws of the PSU lid and fan needed for assembly.
The PSU operation with this case + fan modification becomes practically noiseless.
P.S.: I also added the Fusion 360 file so people can remix it for their printers / different sockets.
The flat surface is meant to go onto the bed. I printed it with 2 perimeters and solid infill for the 3 top and bottom layers.