Modifying my cheap Chinese power supplies...

[Big Monk]

So I’ve almost got my parts order ready. I’m going to mod on of the little supplies for my son’s board.

Basically it will get some Low ESR caps all around, the taps will get new ferrite beads to bump the mA up and I’m going to use the 24 vDC wall wart into a clean 18 vDC regulator to feed the power in to the box.

I’m also going to build a conversion box for my TrueTone CS7 so I can get an adjustable 9/12 vDC tap off the 18 vDC tap if I want for added versatility.

 

[Big Monk]

Here are a couple of boards i'm tacking onto the Fuzz 2022 order. They came out of the conversations here so this seemed like the right place to post them.

First is a LM2596 "Cleanup" box for my Chinese power supply experiments. Receives 24 vDC @ 2-3A and gives a clean 18 vDC supply to the Chinese units:




Next is a simple converter box for the 18 vDC/100 mA outlet on my CS7. Single DC input and 3 separate jacks for DC output. 78 series regulators allow me to use the 18 vDC tap to get 12 vDC or 9 vDC out depending on which jack I plug into. The 18 vDC output simply bypasses the regulator circuits:



Both will go in 1590A enclosures.

 

[jwin615]

Hopping in late here but, alas.
@Big Monk, a couple of questions, notes.
Curious what the reasoning is for starting at 24v if your max output will only be 18v? Is this purely to isolate that output from the rest of them via separate voltage regulator?

Also, if you wanted to build the initial AC to DC stage, you could start with an external AC to AC wall wart. Alesis and peavey, among others, did this a lot through the 80s and 90s. I'm sure you're aware and have thought about this. But in the event, there are wall wart that are just the transformer. If you were going this route, then 24vac makes a ton of sense re rectification.

For the group, here an idea I had:
A pcb layout to fit a common large enclosure suited to fit multiples of something like the minmax AAF-03 series
9v datasheet here
I haven't explored all series and alt manufacturers like mean well etc
But they are a 1 in x 1 in x .6in AC to DC converter with 330ma output and 70mv p2p ripple(rated through a mlcc iirc)
A pcb with a multitude of those footprints on both sides(staggered) would allow the user to stuff it with whatever modules needed with room for extra filter caps(maybe an ac line filter as well.
In a 1032l, you could easily have 16-18 dedicated outputs of your choosing in under 50 parts.
These minmax are a little pricey at $15 a pop. Meadwell has lower current modules in the $5 range. If any of those are suitable, a pcb, dedicated and isolated modules for 16 outputs, DC jacks and 1032l enclosure clock in around $100-110.
Add in another couple bucks for smoothing caps and ferrites if needed. And in building it, drilling would be the hardest part.
I think it would be a cool diy offering as users could build the power supply that they need. I also like the idea of ditching the wall wart and having ac in.
Just an idea.

Edit: meanwell itm-03 series are about 1x1.5 inch in PCB mount, 100mv p2p ripple with 3330ma capacity at around $6. Looks to have input and output filtering so maybe a couple of smoothing caps but may work.

datasheet here