DIY Guitar Fuzz Effect Box

I received a message from a youtube viewer suggesting that I do a “Fuzz Face” guitar effects box as a project.. It seemed like a good idea so after a bit of scouring the interwebs and looking at schematics (there are plenty) I put together a three transistor distortion box that’s not too difficult to put together.

It’s a two stage amp with the first stage boosting the signal and the second stage creating the distortion and clipping. The distortion comes from the two BC547 NPN transistors going into saturation and the clipping is done by the two 1N4148 diodes. Although I didn’t include it in the final build video, a bypass switch can be added as shown in red on the schematic. Use a push on/push off DPDT switch.

The “Fuzz” potentiometer controls the level of the signal from the 2N3904 and as the level is increased, so is the distortion and clipping of the output signal.

Guitar effects boxes are fun to build and experiment with while in the bread board stage. Play around with C2 and C5 values to change the frequency response and gain.

Have fun and…
Keep on hackin!

Parts list:

Capacitors:
1 – 100 uF electrolytic
1 – 1 uF ceramic
1 – .01 uF ceramic
2 – 10 uF electrolytic

Resistors:
1 – 100 K
1 – 10K
1 – 220K
1 – 5.6K
1 – 150 ohm
1 – 2.2K
1 – 500K potentiometer, audio taper

Diodes:
2 – 1N4148

Transistors:
1 – 2N3904 NPN
2 – BC547 NPN

Misc:
1 – Push/Push off DPDT switch
1 – 9 volt battery
1 – 9 volt battery clip
1 – perf board
1 – plastic or metal enclosure
2 – 1/4″ phono jacks, one with a switch that has continuity when a plug is inserted. This will serve as a power switch.

Schematic:

3 thoughts on “DIY Guitar Fuzz Effect Box

  1. on the diagram, does R2 connect to the top of the transistor or does it just pass over and connect to the capacitor?

    • R1 and R2 are both connected to the collector of the transistor. This arrangement is called a voltage divider.

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