Besides designing awesome sounds for Toontrack, our very own Ulf Edlund has a thing for building stuff – in particular guitar pedals. Here’s his own step-by-step guide to making one from scratch. Enjoy!
Some people do knitting, others fly tying or models of classic cars or airplanes. I build stomp boxes. Over the last few years, I have put together a bunch of different overdrive, phaser, tremolo, reverb and compressor pedals. The aspiring DIY pedal builder can find tons of info on the internet. Anything from schematics and layouts to various kits. For a first build it’s recommended to go with a kit. Then you get a printed circuit board, all needed components and usually an easy-to-follow step-by-step description.
After putting together a few kits, I eventually took the step to building from scratch using stripboard. A stripboard is a board with perforated strips of copper used in electronics prototyping where you cut and link lanes to create the desired circuit. This time, I was aiming for an overdrive with that little extra push. Something to deliver thick, creamy and dynamic distortion. Often referred to as Dumble-style overdrive after the super rare and legendary amps that sell for prices few mortals can afford.
Scouting the schematic.
There are tons of resources on the internet and one of my personal favorites is Tagboardeffects. A non-profit blog housing a huge selection of stripboard pedal layouts. After some scouting the choice fell on the Wattkins RF Drive, originally published at the Wattkins Amp Forums site.
Sourcing the parts.
There are plenty of sources for parts and electronic components on the web. Being located in Europe, I got mine from German based Banzai Music.
This is going to be a four knob pedal in a BB-sized box, meaning 119x94x34 mm. To save some time, I will use a pre-painted box in a nice deep blue sparkle finish. First it needs to be drilled for jacks, pots and LED. This requires a fairly steady hand and pretty exact measuring. Actually, this time I did it in a hurry and came a bit close between the jacks and the two top potentiometers. I barely managed to fit the jacks but made it by half a hair.
Maybe this is my favorite step. Coming up with a design for the box. I like to try to achieve a plain but stylish look on my builds. The box graphics are created in Photoshop Elements and printed on transparent inkjet decal paper. It’s wise to do a test print on paper and check that everything fits before printing the actual decal. Applying the decal requires caution. It’s quite tricky to get it straight and centered. It’s also very easy to get air bubbles. I try to keep the decal a little smaller than the box, simply to make it last longer without peeling off around the edges.
Once the decal is in place, it’s time for the spray box. Use a well ventilated space for this and avoid the fumes. I have found that it takes at least four good layers to protect the decal and give a nice shine and depth to the finish.
Preparing the board.
While waiting for the paint to dry between the layers, there’s time to work on the circuit board. First it needs to be cut to size. This is 16 x 12 rows with 11 cuts and 3 links. I have a small hacksaw that i use for cutting it to size. To create the cuts in the copper strips, I use a handheld drill bit in the right size, approx 3 mm, and give it a turn or two. For links, I use a piece of wire or a recycled cut off leg from a resistor or other component. It’s important to measure out the board and count the rows and holes from the top side, meaning the side where the components will be sitting. Otherwise the board will be mirrored. I always check with an OHM meter to see that links and cuts are good.
Populating the board.
Once the cuts and links are double-checked and confirmed, it’s time to start populating the board – starting with resistors. I find it convenient to mount the components in the order of height. Resistors first, capacitors last. For two reasons I will use a socket for the IC. First, it allows for easy swapping and second, it prevents over heating the IC chip. I will sometimes use sockets for the clipping diodes too, but this time, I have no plans to experiment with different diodes, so I solder them directly onto the board. Pay attention to direction of diodes and polarity of electrolytic capacitors. Soldering a stripboard is slightly more difficult than a printed PCB. It’s important to check for spilled solder between the lanes and if necessary scrape clean with a sharp knife. Two helpful tools when checking for shortage are the OHM meter and the magnifying glass.
Populating the box.
Once the the lacquer has dried it’s time to mount the hardware to the box. I always mark the back side of the potentiometers with a sharpie to avoid confusion and mixups later. Make sure the right potentiometer goes in the right place.
Finally it’s time to wire the board to the box. I have chosen to not make this pedal battery operated, so I only have to follow this offboard wiring schematic.
I will mount the LED directly to the board and put it on a piece of foam to isolate it.
Once everything is hooked up and double checked it’s time for the first test drive. It’s not uncommon to have to go back to the work bench and check for missing or mixed up connections. Luckily this time everything worked at the first attempt so i can go ahead and close the box, mount the knobs and put a piece of velcro underneath.
Time to get on board. I managed to find a space for it. Both physically and musically. It sounds like I hoped it would, fat but clear, and very dynamic. I have a few ideas for the next build, but now it’s definitely time for some playing 🙂