Tenma 72-10495 Power supply

An excellent value power supply except for the fan noise!

This explains how I quietened the fans

Original PWM output to a fan at idle. Note the voltage levels. This is 12V fan!

Replace the original fans with quieter more efficient TB Silence UCTB8 fans

To stop the fans running too fast until required, connect a thermistor strapped to the heatsink,

in series with the PWM drive to each fan

Fan plug and socket on front panel

EPCOS B57236S800M thermistor shrink wrapped and sleeved.

Thermistor tie wrapped to heatsink. Wired in series with new fans

The difference in noise was really significant.

Most of the time I use the power supply at low currents and to have the fans running fast for this, was extremely irritating.

With the new arrangement, I can have the power supply on at low currents and the fans are only just audible.

They still get noisy at full power, but that because they need to dissipate a lot of heat, so no problem