Multi-effect pedal

We had a great time at BuildBrighton with our working fuzzface guitar pedal. New member Patrick even brought along a VOX wah pedal to get some Voodoo Chile type riffs going!

Which got us thinking about embedding our effect pedal inside a guitar, and how to simplify the circuit. So we came up with this idea - it's an effect pedal combining a fuzz face and a wah pedal. Either or both can be by-passed (so you can have clean, just fuzz, just wah, or fuzz going into wah).

In a future version, we're planning replacing the potentiometer on the wah (labelled VR3) with a digital pot. This will allow us to hook the wah effect up to a PIC micro-controller and use a 3-axis accelerometer to change the wah sound. Tip the headstock towards the ground to simulate rocking the pedal back, then move it upwards to rock the pedal forward.

The introduction of an accelerometer on the guitar opens up all kinds of possibilities (imagine hooking it up to the volume control: tip your guitar skyward, a la Slash, for a volume boost while solo-ing!) Any way, here's the first version of our multi-pedal:

Multi Pedal schematic

Multi Pedal PCB

Parts list:


C1 2.2uf  capacitor
C2 0.01uF capacitor
C3 22uF capacitor
C4 0.01uF capacitor
C5 0.22uF capacitor
C6 4.7uF capacitor
C7 0.01uF capacitor
C8 0.22uF capacitor
L1 500mH inductor
Q1 BC108 NPN transistor
Q2 BC108 NPN transistor
Q3 BC108 NPN transistor
Q4 BC108 NPN transistor
R1 33K resistor
R2 330 resistor
R3 8K2 resistor
R4 100K resistor
R5 68K resistor
R6 1.5K resistor
R7 470 resistor
R8 470K resistor
R9 22K resistor
R10 33K resistor
R11 82K resistor
R12 470K resistor
R13 10K resistor
R14 1K resistor
SW1 = DPDT switch
SW2 = DPDT switch
VR1 = 1KB potentiometer
VR2 = 1KB potentiometer
VR3 = 100K potentiometer