125B · 2 knobs
OctagonOctave Fuzz
Based on the Tycobrahe Octavia· 3 other boards clone it
- Category
- Fuzz· Octave fuzz
- Controls
- Sustain · Volume
- Difficulty
- Easy
- Price
- $12.50in stock
From the vendor
The very first octave-up fuzz effect, originally invented by Roger Mayer for Jimi Hendrix and later copied by Tycobrahe for a commercial release.
The Octagon Octave Fuzz is based on the Tycobrahe Octavia, a transformer-based octave fuzz pedal originally released in 1973.
The circuit itself was designed by Roger Mayer for Jimi Hendrix and dates back to 1967. He designed somewhere between 15 and 20 iterations for Jimi between ’67 and 1969, some of which only lasted a week before being tweaked again. The Octavia was never sold commercially, so there was no final or standard version of the circuit, but units were made for several other guitarists such as Syd Barrett and Peter Frampton.
One of these units was sent to the Tycobrahe Sound Company in California for repair. (Accounts vary as to whose unit it was, but it wasn’t Jimi’s.) They traced out the circuit and later released a commercial pedal in 1973, also called the Octavia since Roger had only used the name informally and never commercially. It was accompanied by a wide advertising campaign, but it ceased production sometime around 1976. According to Roger, the specific unit Tycobrahe copied was intended for 24V operation, but they dropped the power supply 9V without scaling any of the values, so the transistors are biased improperly.
Roger Mayer was never satisfied with any of the transformer versions and by 1970 he had redesigned the circuit to use all silicon transistors with no transformer. Jimi did play one of these new versions before his passing, but it has not been linked with any actual recordings and may have just been for evaluation and feedback. Roger has produced versions of the transistor Octavia ever since, but has never reissued the transformer version because he felt it was inferior.
Because of this, the transformer Octavia is more closely associated with Tycobrahe, and the transistor Octavia is called the “Roger Mayer version” even though he invented both. But since the transformer version was almost the only version Jimi ever played, it still lives on as its own circuit in the pantheon of early guitar effects.
All in all, it’s a complicated history that has caused a lot of confusion in the past fifty years. The two Octavias don’t have much in common and don’t sound alike, but both are worth building if you like octave fuzz. The transistor Octavia is available as our Octahedron project.
The Octagon is a direct adaptation of the Tycobrahe circuit, with the only addition being a toggle switch that disables the octave for a more traditional fuzz effect.
Schematic
The schematic is in the vendor's build document, page 6. Open the build document. No KiCad fragment has been drawn for this circuit yet.
Parts list 38 rows
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 13 | ||||
| R1 | 820k | 820k | Metal film resistor, 1/4W | |
| R2 | 180k | 180k | Metal film resistor, 1/4W | |
| R3 | 680k | 680k | Metal film resistor, 1/4W | |
| R4 | 220k | 220k | Metal film resistor, 1/4W | |
| R5 | 220R | 220 | Metal film resistor, 1/4W | |
| R6 | 22k | 22k | Metal film resistor, 1/4W | |
| R7 | 470R | 470 | Metal film resistor, 1/4W | |
| R8 | 1k | 1k | Metal film resistor, 1/4W | |
| R9 | 47k | 47k | Metal film resistor, 1/4W | |
| R10 | 1k2 | 1.2k | Metal film resistor, 1/4W | |
| R11 | 100R | 100 | Metal film resistor, 1/4W | Power supply filter resistor. |
| RPD | 2M2 | 2.2M | Metal film resistor, 1/4W | Input pulldown resistor. |
| LEDR | 10k | 10k | Metal film resistor, 1/4W | LED current-limiting resistor. |
| Capacitors 9 | ||||
| C1 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C2 | 150pF | 150p | MLCC capacitor, NP0/C0G | |
| C3 | 33uF | 33u | Electrolytic capacitor, 5mm | |
| C4 | 1n | 1n | Film capacitor, 7.2 x 2.5mm | |
| C5 | 220uF | 220u | Electrolytic capacitor, 6.3mm | |
| C6 | 100uF | 100u | Electrolytic capacitor, 6.3mm | |
| C7 | 33uF | 33u | Electrolytic capacitor, 5mm | |
| C8 | 100uF | 100u | Electrolytic capacitor, 6.3mm | Power supply filter capacitor. |
| C9 | 100n | 100n | MLCC capacitor, X7R | Power supply filter capacitor. |
| Diodes 3 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D2 | BAT46 | BAT46 | Schottky diode, DO-35 | The original Octavia used Ge diodes, but BAT46 will perform better. |
| D3 | BAT46 | BAT46 | Schottky diode, DO-35 | The original Octavia used Ge diodes, but BAT46 will perform better. |
| Transistors 3 | ||||
| Q1 | 2N3906 | 2N3906 | BJT transistor, PNP, TO-92 | |
| Q2 | 2N3904 | 2N3904 | BJT transistor, NPN, TO-92 | |
| Q3 | 2N3904 | 2N3904 | BJT transistor, NPN, TO-92 | |
| Potentiometers 2 | ||||
| DRIVE | 1kC | C1k | 16mm right-angle PCB mount pot | Reverse audio (reverse log or antilog) taper. |
| VOLUME | 500kA | A500k | 16mm right-angle PCB mount pot | Audio (log) taper. |
| Switches 2 | ||||
| OCT SW. | SPDT center off | SPDT CENTER OFF | Toggle switch, SPDT on-off-on | |
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | |
| 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. |
| Other 1 | ||||
| XFM1 | 42TM022 | 42TM022 | Transformer, 1.5KCT/600RCT | |
Other boards based on the Tycobrahe Octavia
- Tycobrahe Octavia Experimentalists Anonymous
- Retrograde Madbean · 125B · $11.00
- Octavius PCB Guitar Mania · 125B · €9.90