125B · 3 knobs
VulcanOctave Fuzz
Based on the fOXX Tone Machine· 4 other boards clone it
- Category
- Fuzz· Octave Fuzz
- Controls
- Sustain · Tone · Volume
- Difficulty
- Easy
- Price
- $12.50in stock
From the vendor
A classic untamed fuzz from the 1970s that adds an octave-up overtone.
The Vulcan Octave Fuzz is a recreation of the fOXX Tone Machine, first released in 1971 and discontinued in 1978. The Tone Machine is a thick fuzz that uses a phase splitter and complementary rectifier to create an octave overtone.
The Tone Machine has a lot in common with the Fender Blender, but with a more pronounced octave and smoother tone, as well as the ability to disable the octave by turning off half of the phase splitter. And the tone is not unlike the Superfuzz, although it uses a different method of octave generation to get there.
The Vulcan is faithful to the original, but with two added modifications. First, the octave switch (normally just “on” or “off” in the original) now has a 3rd setting allowing you to bypass the series diode in non-octave mode. See build notes for more details on this.
The second modification is to the tone control. The tone control of the original is somewhat similar to the Big Muff, but many people find it’s difficult to get good sounds from the treble side of the rotation. By increasing the value of the treble-side tone capacitor, it improves the usability. A switch has been added to let you choose between two different capacitors in addition to the original.
Note: The PCB-only version of this project uses a type of capacitor that has been temporarily discontinued by WIMA. Please see our news article about the issue and the substitution spreadsheet for project-specific recommendations. We are stocking a limited supply in the mean time. The build document has not yet been updated to reflect this. It does not impact the kits.
Schematic
The schematic is in the vendor's build document. Open the build document. No KiCad fragment has been drawn for this circuit yet.
Parts list 63 rows
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 26 | ||||
| R1 | 1M | 1M | Metal film resistor, 1/4W | |
| R2 | 47k | 47k | Metal film resistor, 1/4W | |
| R3 | 1k | 1k | Metal film resistor, 1/4W | |
| R4 | 47k | 47k | Metal film resistor, 1/4W | |
| R5 | 100k | 100k | Metal film resistor, 1/4W | |
| R6 | 100k | 100k | Metal film resistor, 1/4W | |
| R7 | 4k7 | 4.7k | Metal film resistor, 1/4W | |
| R8 | 4k7 | 4.7k | Metal film resistor, 1/4W | |
| R9 | 12k | 12k | Metal film resistor, 1/4W | Jumper to increase maximum sustain setting. |
| R10 | 100k | 100k | Metal film resistor, 1/4W | |
| R11 | 100k | 100k | Metal film resistor, 1/4W | |
| R12 | 220R | 220 | Metal film resistor, 1/4W | |
| R13 | 150k | 150k | Metal film resistor, 1/4W | |
| R14 | 15k | 15k | Metal film resistor, 1/4W | Some variants have a 1n capacitor in parallel with R14. |
| R15 | 1k | 1k | Metal film resistor, 1/4W | |
| R16 | 10k | 10k | Metal film resistor, 1/4W | |
| R17 | 22k | 22k | Metal film resistor, 1/4W | |
| R18 | 4k7 | 4.7k | Metal film resistor, 1/4W | Jumper for more control over bass range. |
| R19 | 470k | 470k | Metal film resistor, 1/4W | |
| R20 | 47k | 47k | Metal film resistor, 1/4W | |
| R21 | 10k | 10k | Metal film resistor, 1/4W | |
| R22 | 1k5 | 1.5k | Metal film resistor, 1/4W | |
| R23 | 100k | 100k | Metal film resistor, 1/4W | Modification to prevent popping when switching the octave mode. |
| R24 | 100k | 100k | Metal film resistor, 1/4W | |
| R25 | 100R | 100 | Metal film resistor, 1/4W | Power supply filter resistor. |
| LEDR | 10k | 10k | Metal film resistor, 1/4W | LED current-limiting resistor. Adjust value to change LED brightness. |
| Capacitors 17 | ||||
| C1 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C2 | 1n | 1n | Film capacitor, 7.2 x 2.5mm | |
| C3 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C4 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C5 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C6 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C7 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C8 | 22uF | 22u | Electrolytic capacitor, 5mm | See build notes for capacitor value. |
| C9 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C10 | 1n | 1n | Film capacitor, 7.2 x 2.5mm | |
| C11 | 2n2 | 2.2n | Film capacitor, 7.2 x 2.5mm | |
| C12 | 15n | 15n | Film capacitor, 7.2 x 2.5mm | |
| C13 | 47n | 47n | Film capacitor, 7.2 x 2.5mm | |
| C14 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C15 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C16 | 100uF | 100u | Electrolytic capacitor, 6.3mm | Power supply filter capacitor. |
| C17 | 100n | 100n | MLCC capacitor, X7R | Power supply filter capacitor. |
| Diodes 5 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D2 | BAT46 | BAT46 | Schottky diode, DO-35 | Substitute. Original uses 1N34A or other germanium. |
| D3 | BAT46 | BAT46 | Schottky diode, DO-35 | Substitute. Original uses 1N34A or other germanium. |
| D4 | 1N34A | 1N34A | Diode, germanium, NOS | |
| D5 | 1N34A | 1N34A | Diode, germanium, NOS | |
| Transistors 4 | ||||
| Q1 | 2N5089 | 2N5089 | BJT transistor, NPN, TO-92 | Modern substitute. The original used 2N3565 or 2N5133. For best results, sort for hFE (gain) of 400 or more. |
| Q2 | 2N5089 | 2N5089 | BJT transistor, NPN, TO-92 | |
| Q3 | 2N5089 | 2N5089 | BJT transistor, NPN, TO-92 | |
| Q4 | 2N5089 | 2N5089 | BJT transistor, NPN, TO-92 | |
| Potentiometers 3 | ||||
| SUST. | 50kB | B50k | 16mm right-angle PCB mount pot | |
| TONE | 50kB | B50k | 16mm right-angle PCB mount pot | |
| VOL. | 50kB | B50k | 16mm right-angle PCB mount pot | |
| Switches 2 | ||||
| MID | SPDT | SPDT | Toggle switch, SPDT on-on | Modification to improve usefulness of tone control. See build notes. |
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | |
| LEDs 1 | ||||
| LED | 5mm | 5MM | LED, 5mm, red diffused | |
| Jacks & sockets 3 | ||||
| IN | 1/4" stereo | 1/4" STEREO | 1/4" phone jack, closed frame | Switchcraft 112BX or equivalent. |
| OUT | 1/4" mono | 1/4" MONO | 1/4" phone jack, closed frame | Switchcraft 111X or equivalent. |
| DC | 2.1mm | 2.1MM | DC jack, 2.1mm panel mount | Mouser 163-4302-E or equivalent. |
| Hardware 2 | ||||
| BATT | Battery snap | BATTERY SNAP | 9V battery snap | Optional. Use the soft plastic type—the hard-shell type will not fit. |
| ENC | 125B | 125B | Enclosure, die-cast aluminum | Can also use a Hammond 1590N1. |
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