The new three output PSU is validated.

The initial idea was to replace linear power supplies which sometimes get very hot, as well as the switching power supply directly connected to the mains which can present security risks.

I therefore opted for an intermediate solution which consists in using a standard transformer to lower the mains voltage, and a triple low-voltage switching power supply to take advantage of a better performance than that provided by a purely linear power supply. The two outputs provided for supplying analog parts are fitted with linear regulators following the switching regulators for better noise rejection.

The result is this reduced size power supply (160 x 80mm):

I have already had the opportunity to perform some tests when I had not placed all the defined components, especially the output filter capacitors. I had to temporarily place models with through legs. For these tests, I used all the boards of a Korg T1. 

It works fine!

This time I used the final version of the power supply to power the board set of a Dynacord-ADS sampler, a famous vintage German samper :

www.deepsonic.ch

This sampler consumes more current than the T1. In fact, a little more than 2A for the 5V part for the version I own:

For this test I did not use the floppy disk drive which actually consumes very little on standby. I was however able to test the audio output which does not present any residual noise. The ADS has a switch on the front panel allowing the generation of a nice sinusoidal output.

Final thoughts: This power supply works perfectly and is able to deliver at least 2A on all its outputs without requiring a cooling system. Note that if the + 5V AND the + 12V should each output 2A, one of the diode bridges should be capped with a small cooling system since it should provide 4A, but this situation rarely happens. For ease of implementation, I may change the output capacitors to through-leg models in the production version of this power supply.