125B · 3 knobs
SynapseResonant Drive
Based on the Systech Overdrive· 1 other board clones it
- Category
- Fuzz· Resonant filter fuzz
- Controls
- EQ · Distortion · Volume
- Difficulty
- Beginner
- Price
- $12.50in stock
From the vendor
A rare fuzz pedal that combines hard-clipping distortion with an extreme resonant filter that lends a vocal “stuck wah” quality.
The Synapse Resonant Drive is based on the Systech Overdrive, a fuzz pedal released in the early 1970s before the idea of “overdrive” had become distinct from “distortion” and “fuzz”.
Today, Systech’s most well-known circuit is the Harmonic Energizer (available from Aion FX as the Parsec), which is similar in its frequency-sweepable filter but lacks any of its own clipping. The Harmonic Energizer was most notably used by Frank Zappa.
It’s not known whether the Overdrive was derived from the Harmonic Energizer or the other way around—but either way, they’re similar in concept, and the Overdrive is very unique among drive pedals. It doesn’t have the Zappa association, but it’s interesting enough that it’s worth your time.
The resonant filter can be tuned from 133 Hz to 900 Hz, but unlike a wah, its Q is very sharp, and it has a definite “tuned” quality that can either complement the notes being played or collide in a dissonant way.
There is no way to disable the filter or reduce its gain, so it’s definitely not an always-on tone stap;e, but very useful as a quirky effect to get some spaced-out filter tones are hard to come by in such a small package.
The Synapse is a straight clone of the Systech Overdrive with no changes except changing Systech’s standard polarity protection for a simple Schottky diode as in other Aion FX projects.
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 48 rows
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 20 | ||||
| R1 | 10k | 10k | Metal film resistor, 1/4W | |
| R2 | 10M | 10M | Metal film resistor, 1/4W | |
| R3 | 3k3 | 3.3k | Metal film resistor, 1/4W | |
| R4 | 15k | 15k | Metal film resistor, 1/4W | |
| R5 | 300k | 300k | Metal film resistor, 1/4W | |
| R6 | 220R | 220 | Metal film resistor, 1/4W | |
| R7 | 5k1 | 5.1k | Metal film resistor, 1/4W | |
| R8 | 2M | 2M | Metal film resistor, 1/4W | |
| R9 | 100k | 100k | Metal film resistor, 1/4W | |
| R10 | 22k | 22k | Metal film resistor, 1/4W | |
| R11 | 300k | 300k | Metal film resistor, 1/4W | |
| R12 | 100k | 100k | Metal film resistor, 1/4W | |
| R13 | 10k | 10k | Metal film resistor, 1/4W | |
| R14 | 5k1 | 5.1k | Metal film resistor, 1/4W | |
| R15 | 1M | 1M | Metal film resistor, 1/4W | |
| R16 | 10k | 10k | Metal film resistor, 1/4W | |
| R17 | 10k | 10k | Metal film resistor, 1/4W | |
| R18 | 100R | 100 | Metal film resistor, 1/4W | |
| RPD | 2M2 | 2.2M | Metal film resistor, 1/4W | |
| LEDR | 4k7 | 4.7k | Metal film resistor, 1/4W | LED current-limiting resistor. Adjust value to change LED brightness. |
| Capacitors 12 | ||||
| C1 | 1n | 1n | Film capacitor, 7.2 x 2.5mm | |
| C2 | 10uF | 10u | Electrolytic capacitor, 5mm | |
| C3 | 22n | 22n | Film capacitor, 7.2 x 2.5mm | |
| C4 | 22n | 22n | Film capacitor, 7.2 x 2.5mm | |
| C5 | 10uF | 10u | Electrolytic capacitor, 5mm | |
| C6 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C7 | 10uF | 10u | Electrolytic capacitor, 5mm | |
| C8 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C9 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C10 | 47uF | 47u | Electrolytic capacitor, 5mm | Voltage reference filter capacitor. |
| C11 | 100uF | 100u | Electrolytic capacitor, 5mm | Power supply filter capacitor. |
| C12 | 100n | 100n | MLCC capacitor, X7R | Power supply filter capacitor. |
| Diodes 3 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D2 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D3 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| Transistors 2 | ||||
| Q1 | 2N5457 | 2N5457 | JFET, N-channel, TO-92 | Substitute. Original uses 2N5458. |
| Q2 | 2N5088 | 2N5088 | BJT transistor, NPN, TO-92 | |
| ICs 1 | ||||
| IC1 | LM1458 | LM1458 | Operational amplifier, DIP8 | Consider substituting for a lower-noise IC. See build notes. |
| Potentiometers 3 | ||||
| DIST. | 50kC | C50k | 16mm right-angle PCB mount pot | |
| EQ | 50kC | C50k | 16mm right-angle PCB mount pot | |
| VOL. | 50kA | A50k | 16mm right-angle PCB mount pot | |
| Switches 1 | ||||
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | |
| LEDs 1 | ||||
| LED | 5mm | 5MM | LED, 5mm, red diffused | |
| Jacks & sockets 4 | ||||
| IC1-S | DIP-8 socket | DIP-8 SOCKET | IC socket, DIP-8 | |
| 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 1 | ||||
| ENC | 125B | 125B | Enclosure, die-cast aluminum | Can also use a Hammond 1590N1. |
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