So about 3 months ago, maybe more, I started looking into designing a modular synthesiser. I started off building a simple VCO, and ran into problems straight away with that, which needed a solid power supply with multiple rails. So I looked into building one. It didnt take long for me to design one, based around the LM317 and LM337 linear regulators, however this has really been put on a back burner with life and several other projects getting in the way (including moving the hackspace to a new premises!), but today I knuckled down and made the PCB in the garage.

power supply pcb
the final pcb, pre drilling

Now my workflow for PCB’s does need a bit more work, and the actual equipment does too… This one was done with the toner transfer method as it previously failed with the UV exposure method. It actually failed with toner transfer as well once, but using a clothes iron instead of a Laminator made the difference. I need to upgrade my ‘etch tank’ to something more than a glass baking dish and a tray heater, to a bubble tank. Heating is optional, it just speeds up the process. Will also be looking into the Edinburgh Etch method as well, which uses Citric Acid to improve results.

Anyway, back to the power supply. With the PCB made, I can finish off mounting everything into the case I bought for it – a plastic 19″ rackmount case. May seem a bit overkill, especially as this is only rated at 1Amp per rail, however I am trying this case out for other projects as well, and seems to be quite a good choice.

The case, buried under a few other boxes of projects

Here you can see the main power switch, 5 output rails, and possibly the green LED in the middle. The transformers are already mounted inside the case to a large sheet of aluminium, and just need all the connectors putting in. I will post more pictures of this when I finish the project off, and also go into upgrades I hope to do, such as microcontroller control, current limiting, and a more powerful output. For now though, need to wait until tomorrow to finish this off…

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