Saturday, 11 February 2012

Building A Guitar Pedal

Building or creating something is always fun; there's a magic in separate, inanimate, bits being combined to make something that comes alive through having a purpose and being used.

I've been eyeing up building a guitar effects pedal for a while, but worried that my soldering skills would leave me with a smoking useless heap of resistors and solder. Luckily you can buy kits which come with detailed instructions, which increases the chance of having something working at the end. It does make it more a paint-by-numbers exercise until you are confident enough to strike out on your own, but a good way of building some confidence. It also takes the hassle of having to buy a pack of three hundred resistors just to use four or trying to find some of the more obscure components.

Which pedal to build for your first clone is an easy; a Tube Screamer overdrive. This is probably the most cloned pedal and is an easy first build. It is used by a huge number of guitarists and considered a classic pedal by almost everyone. It's also a nice balance to the distortion pedal I already have, a very high-gain no subtlety monster. A tube screamer softly distorts the signal and keeps much of the original sound intact while and giving a mid-range boost. The originals were famous for the JRC4558D Op-Amp chip used, which wasn't present in later models until Ibanez started selling re-issues.

The most arduous part of the entire process was wet sanding the bare aluminium enclosure to a nice smooth finish. As it came the enclosure had some very deep grooves around the edges which needed a lot of sanding down with 80 grade sandpaper. After that going through increasingly finer grades was easy.

Soldering all the components to the PCB went very smoothly and was not as fiddly as I'd feared, even with the very tip of my cheap Wilkinson own-brand soldering iron falling off. Sometimes you get what you pay for, and for eight pounds that's not a lot.

Originally I wanted to use hydrochloric acid to etch a pattern into the top, but I don't have anywhere safe to do that. I thought a well sanded and clean metal finish would look good with a decal added to the top. Once I saw it in place on the floor it looks very unassuming, the bare metal just appearing grey, so I think a coloured painted finish is called for. Sadly painting will have to wait, I can't do it indoors I'm going to need something warmer and drier than the 1ÂșC that February is currently offering.

The trickiest part of the build was balancing the three loosely screwed in potentiometers in their holes while trying to solder them to the board and keeping the unsoldered LED in the right place. I'll have to de-solder the DC power supply in the future to paint the enclosure which might cause some problems.
Once installed on my pedal board the result is very nice, producing a rich, creamy sounding subtle distortion; a very satisfying way of spending a day.