Power to the pins!

Ladies and gentlemen, I give you...

The WickVoltz Mk II:

Okay so that's not much to look at, but allow me to to elaborate...

After my previous power supply cock-up I decided the time had come to build my own. I based my schematic on (ahem...copied exactly) the schematic on Ken Stone's modular synth site and created my own PCB layout for it, which was this one:

The eagle eyed amongst you will spot that my circuit is missing two diodes that Ken Stone's has, and there is a very good reason for this; I couldn't fit them into the circuit and still have it look as nice as it does. Besides, they're only for protection in case some fool bridges the outputs, and who would do something like that?? (nervously kicks remains of old, dead power supply under the bed).

At this point I feel I need to talk about CadSoft Eagle. This is the the software I used to draw the lovely pictures you see above, and it really is a must for anyone who wants to design their own PCBs. It has a massive component library and the ability to download more component libraries from their website, and even create your own components. it can find flaws in your schematic as you design it and has a nifty auto-routing feature when it comes to the actual PCB layout stage. The only drawback I've found is that the UI is often a bit counter-intuitive. You'll find yourself scratching your head in the beginning looking for the most basic functions, butt they are there I promise you! And once you get used to it you'll find it fairly simple to create what you want.  It comes in pro and freeware versions, and I've found the freeware version pretty easily takes care of my needs.

...I don't work for them or anything, it's just good!

So yeah, I created my PCB layout in eagle, printed it onto transparency film and ironed it onto a copper clad board to come up with this:

one acid bath later I had this:

Then I drilled holes and put all the components into place, to give me the final product:

Drop in image quality due to the batteries dying in my camera.

I connected the circuit to the 2x18v ac transformer I bought on ebay and to my immense surprise and delight it worked first time!  Filled with excitement I began making a case to house the board and transformer. I don't have a pic of this at the moment, but it's basically the top part of a DVD player case bend round into something about twice the height but a third of the width. I then made front and back panels out of chipboard and fitted a switch to the front.

I connected up the circuit with the case wiring in place, ready to give a little smug smile and finish the whole assembly process, butt to my shock and horror it didn't come on properly and the transformer buzzed horribly! It seemed like there was a short somewhere in the positive regulator half of the circuit.

Long story short, I chased the fault around the whole circuit, and every time I thought I'd nailed it and the setup worked again, it would stop working straight away. My only explanation is that it was a faulty track, something I think was confirmed late in the day when I connected the transformer already switched on and the small spark this produced was enough to visibly blow a section of track off the board!

And so it is that I sit here patiently waiting for the Mk II to be etched, with fatter tracks and an extra regulator for a 5v line, it should be a winner. Also this time I'm going to tin the tracks with solder to protect them and aid conductivity. I'll post the results of this venture in the new year, along with a more detailed build guide with schematic and PCB layout and also a tutorial on etching.

Right now though I do believe the etching is done. There seem to be a couple of slightly dodgy tracks, but I'm gonna plow on regardless, maybe the tinning will save them!

Watch this space...