Pyramid PS36KX is one of the few power supplies I have for my radios. Recently I decided to consolidate and hook up more radios to a single PSU via powerpoles, it makes everything easier.
One problem with the Pyramid is noise, it’s *extremely* loud, with just a single fan.
Pop goes the chassis, one cheapo 24V fan is the culprit, no speed control, only 2 wires.

Quick throwback to computer days, and here come TWO 12V quiet noctua fans, I used the NF-A8-FLX model which come with lots of options by default, including rubber dampeners.
Both fans are connected in series to make them work under 24V, I cut the yellow (RPM sense) wire, hooked up both fans and installed them.
One went in place of the original 24V fan, and another across the case, near the AMP gauge.

I did have to drill 2 holes in the chassis to attach the new fan, and it doesn’t perfectly overlap with the holes in the top case, but it’s good enough.

Overall cost was pretty low, some labor and cost of two quality fans, but the result is stunning, near absolute silence, makes a lot of difference listening to the radio.

Update 2024. The PSU broke at some point, seems like a common failure – the RED Overload LED was on and the buzzer was beeping.
I ended up replacing the NTE Rectifier with an NTE5556-I version and the PSU is back in business!

Cheers