Enclosure not stated · 4 knobs
Keeley Fuzz HeadVerified
Based on the Keeley Fuzz Head· 2 other boards clone it
From the post
Over a decade ago Robert Keeley was kind enough to share this design with the DIY community. It's a fairly unique fuzz, with a germanium treble booster at the beginning, a differential amplifier in the middle, and a basic buffer at the output (this is so it will play nice with other effects). Robert's full explanation of the circuit can be found here, however note that the schematic in that document isn't what I used. I used this later one with a tone control, and ended up laying it out with all controls externally. The PreGain control originally was a trimmer because it has a tendency to crackle when turned, but for ultimate tweak-ability I moved it externally.
The switch is a SPST on/off, by the way.
Schematic
This is a board layout, a drawing of where each part goes, and the post may link the schematic it was drawn from. Open the layout at Effects Layouts (blog). No KiCad fragment has been drawn for this circuit yet.
Parts list 28 rows
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| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 12 | ||||
| ×3 | 33K | 33k | read from the layout by eye | |
| ×3 | 10K | 10k | read from the layout by eye | |
| ×2 | 100K | 100k | read from the layout by eye | |
| ×2 | 470K | 470k | read from the layout by eye | |
| ×2 | 220Ω | 220 | read from the layout by eye | |
| ×2 | 100Ω | 100 | read from the layout by eye | |
| ×1 | 51Ω | 51 | read from the layout by eye | |
| ×1 | 22Ω | 22 | read from the layout by eye | |
| ×1 | 620K | 620k | read from the layout by eye | |
| ×1 | 56K | 56k | read from the layout by eye | |
| ×1 | 1M | 1M | read from the layout by eye | |
| ×1 | 3.3K | 3.3k | read from the layout by eye | |
| Capacitors 6 | ||||
| ×3 | 220nF | 220n | read from the layout by eye | |
| ×1 | 33nF | 33n | read from the layout by eye | |
| ×1 | 27nF | 27n | read from the layout by eye | |
| ×1 | 220pF | 220p | read from the layout by eye | |
| ×3 | 47uF | 47u | electrolytic; read from the layout by eye | |
| ×2 | 10uF | 10u | electrolytic; read from the layout by eye | |
| Diodes 3 | ||||
| ×1 | 1N4001 | 1N4001 | read from the layout by eye | |
| ×1 | 1N4148 | 1N4148 | read from the layout by eye | |
| ×1 | 1N34A | 1N34A | printed 34A, germanium; read from the layout by eye | |
| Transistors 3 | ||||
| Q1 | AC187 | AC187 | read from the layout by eye | |
| Q2 | MPSA18 | MPSA18 | read from the layout by eye | |
| Q3 | MPSA18 | MPSA18 | read from the layout by eye | |
| Potentiometers 4 | ||||
| PreGain | B10K | B10k | Potentiometer | read from the layout by eye |
| Gain | B2K | B2k | Potentiometer | read from the layout by eye |
| Tone | B100K | B100k | Potentiometer | read from the layout by eye |
| Volume | A50K | A50k | Potentiometer | read from the layout by eye |
Other boards based on the Keeley Fuzz Head
- Keeley Fuzz Head Dirtbox Layouts
- Keeley Fuzz Head Tagboard Effects