125B · 3 knobs
AtomFuzz Drive
Based on the ETI Fuzztone
- Category
- Fuzz· Fuzz, overdrive
- Controls
- Sustain · Filter · Level
- Difficulty
- Beginner
- Price
- $12.50in stock
From the vendor
A simple yet effective drive circuit originally designed by Dan Coggins of Lovetone and Dinosaural as a DIY project for Electronics Today Magazine.
The Atom Fuzz Drive is based on the Fuzztone, a DIY project from a British magazine called Electronics Today International (ETI) in their May 1993 issue. It was designed by Dan Coggins, who would go on to co-found Lovetone only a couple years later, and eventually Dinosaural. The PCB for the circuit was included along with the magazine. It was never available as a commercial product.
Despite its name, the Fuzztone has more in common with an overdrive than a fuzz, using diodes in the feedback loop of an op-amp to generate clipping, similar to a Tube Screamer. (Although it should be noted that the 1978 op-amp version of the EHX Big Muff does the same thing.) The tone control is a “balance” type, again similar to the Big Muff, so perhaps the fuzz vs. overdrive categorization is not so clear-cut.
The Fuzztone also bears a very strong resemblance to the Yamaha OD-10MII, a fairly obscure overdrive pedal from 1987. They sound nothing alike due to component selection, but the structure of the schematic is very close. There is no indication that Dan was aware of the OD-MII or that it informed his design of the Fuzztone, but credit where credit is due, and Yamaha’s pedal was definitely released first.
The Atom is a direct adaptation of the Fuzztone based on the schematic from the article in ETI.
Note: 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.
Schematic
The schematic is in the vendor's build document, page 5. Open the build document. No KiCad fragment has been drawn for this circuit yet.
Parts list 36 rows
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 13 | ||||
| R1 | 100k | 100k | Metal film resistor, 1/4W | |
| R2 | 560R | 560 | Metal film resistor, 1/4W | |
| R3 | 100R | 100 | Metal film resistor, 1/4W | |
| R4 | 390R | 390 | Metal film resistor, 1/4W | |
| R5 | 5k1 | 5.1k | Metal film resistor, 1/4W | |
| R6 | 1k5 | 1.5k | Metal film resistor, 1/4W | |
| R7 | 8k2 | 8.2k | Metal film resistor, 1/4W | |
| R8 | 4k7 | 4.7k | Metal film resistor, 1/4W | |
| R9 | 33k | 33k | Metal film resistor, 1/4W | |
| R10 | 33k | 33k | Metal film resistor, 1/4W | |
| R11 | 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 | |
| Capacitors 8 | ||||
| C1 | 47n | 47n | Film capacitor, 7.2 x 2.5mm | |
| C2 | 3.3uF | 3.3u | Electrolytic capacitor, 4mm | |
| C3 | 1n5 | 1.5n | Film capacitor, 7.2 x 2.5mm | |
| C4 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C5 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C6 | 47uF | 47u | Electrolytic capacitor, 5mm | Reference voltage filter capacitor. |
| C7 | 100uF | 100u | Electrolytic capacitor, 6.3mm | Supply voltage filter capacitor. |
| C8 | 100n | 100n | MLCC capacitor, X7R | Supply voltage filter capacitor. |
| Diodes 5 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D2 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D3 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D4 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D5 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| ICs 1 | ||||
| IC1 | TL061 | TL061 | Operational amplifier, DIP8 | |
| Potentiometers 3 | ||||
| SUST. | 100kA | A100k | 16mm right-angle PCB mount pot | |
| FILT. | 10kB | B10k | 16mm right-angle PCB mount pot | |
| LEVEL | 10kA | A10k | 16mm right-angle PCB mount pot | |
| Switches 1 | ||||
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | Available from Aion FX. |
| 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 | Lumberg NEB/J 21 C or equivalent. |
| Hardware 1 | ||||
| ENC | 125B | 125B | Enclosure, die-cast aluminum | Can also use a Hammond 1590N1. |