Enclosure not stated · 5 knobs
Fred Briggs Octave Ringmod Fuzzer (ORF)
Based on the Fred Briggs Octave Ringmod Fuzzer
- Category
- Fuzz
- Price
- see vendor
From the vendor
The author's own octave fuzz inspired by Tim Escobedo's Tripple Fuzz: a single op amp gain stage with a bass-shaping feedback network drives a complementary PNP/NPN transistor pair (a phase splitter) whose outputs are blended through the Intensity pot for a ring-mod-like octave. Sweet at low gain and evil when pushed; it stacks well into other gain pedals.
The author used a BC557 (PNP), a BC548 (NPN) and an LF351 op amp; any single op amp works. The optional J201 gain stage (bias its drain at 5V with the 47K trimmer) adds a lot of character; the author prefers the build with it. It connects at the point marked * and takes the Volume pot.
Schematic
The schematic is in the post. Open it at Revolution Deux. No KiCad fragment has been drawn for this circuit yet.
Parts list 27 rows
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| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 9 | ||||
| R1 | 220K | 220k | to Vr; read from the schematic by eye | |
| R2 | 3.3K | 3.3k | read from the schematic by eye | |
| R3 | 10K | 10k | PNP collector; read from the schematic by eye | |
| R4 | 10K | 10k | NPN emitter; read from the schematic by eye | |
| R5 | 10K | 10k | Vr divider; read from the schematic by eye | |
| R6 | 10K | 10k | Vr divider; read from the schematic by eye | |
| R7 | 10K | 10k | optional stage input; read from the schematic by eye | |
| R8 | 100K | 100k | optional stage; read from the schematic by eye | |
| R9 | 1K | 1k | optional stage source; read from the schematic by eye | |
| Capacitors 9 | ||||
| C1 | 47n | 47n | input; read from the schematic by eye | |
| C2 | 1u | 1u | electrolytic, bass network; read from the schematic by eye | |
| C3 | 33n | 33n | read from the schematic by eye | |
| C4 | 1u | 1u | electrolytic; read from the schematic by eye | |
| C5 | 1n | 1n | read from the schematic by eye | |
| C6 | 1u | 1u | electrolytic, output; read from the schematic by eye | |
| C7 | 10u | 10u | electrolytic, Vr filter; read from the schematic by eye | |
| C8 | 470n | 470n | optional stage source bypass; read from the schematic by eye | |
| C9 | 1u | 1u | electrolytic, optional stage output; read from the schematic by eye | |
| Transistors 3 | ||||
| Q1 | BC557 | BC557 | silicon PNP; read from the schematic by eye | |
| Q2 | BC548 | BC548 | silicon NPN; read from the schematic by eye | |
| Q3 | J201 | J201 | optional stage; read from the schematic by eye | |
| ICs 1 | ||||
| IC1 | LF351 | LF351 | any single op amp; read from the schematic by eye | |
| Potentiometers 5 | ||||
| Bias trim | 47K | 47k | Potentiometer | optional stage, set drain to 5V; read from the schematic by eye |
| Bass | B47K | B47k | Potentiometer | read from the schematic by eye |
| Gain | B100K | B100k | Potentiometer | read from the schematic by eye |
| Intensity | B500K | B500k | Potentiometer | read from the schematic by eye |
| Volume | B100K | B100k | Potentiometer | read from the schematic by eye |