Distortion pedal #1

Category: Pedals

2016-01-28 11:11:17

This is my first guitar pedal build - I've gone with what looks to be a pretty simple single transistor plus diodes distortion circuit.

Not knowing where to start, I basically typed 'distortion pedal' into my favourite search engine, and went from there. There are some really bad places to start if you don't know what you're doing.

(Later on I found many more excellent pedal building web resources, which I'll use in future builds...)

All of the diodes, resistors and capacitors for this build came out of old electronics that I had sitting around. I basically went nuts with some pliers and a soldering iron, pulling likely components out of broken toys, old answering machines, etc. I think the only things I needed to buy were the transistor (used a PN100), and the potentiometers, jacks and switches. The only place I knew to buy electronics was Jaycar, which has an OK range, but I didn't know which transistor to buy so ended up with a generic one.

I started with a breadboard version, and experimented with different diodes for clipping. In the end I decided on a soft clip pair of diodes and a hard clip asymmetric trio, each controlled by a switch. The hard clip is three 1N914 diodes, and the soft clip has a 4001 diode in there, but I've got no idea what the other diode is - it came out of random bits of electronics and I don't know what the coloured markings mean. I also tried LEDs as the clipping diodes, but couldn't get much difference out of them.

I put a switch in to change the input capacitor between 100nF and 6.8nF, to vary the amount of bass cut.

Soldering was done onto a perma-proto board, because it meant I could simply move everything straight from the breadboard on to the PCB.

For the enclosure I used an old iPhone plastic packaging box. After putting it all together I then read about the benefits of a metal enclosure for cutting outside interference. With this pedal, if you touch the switches on the top you can hear the local radio stations through the amp. Not ideal!

[video width="640" height="360" m4v="http://graybloomfield.com/guitar/wp-content/uploads/2016/10/dist1.m4v"][/video]

The sound is not bad - I prefer the soft clip sound.