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SUSTAINFILTERLEVEL

125B · 3 knobs

Aion FX

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

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RefValueNormalizedTypeNotes
Resistors 13
R1100k100kMetal film resistor, 1/4W
R2560R560Metal film resistor, 1/4W
R3100R100Metal film resistor, 1/4W
R4390R390Metal film resistor, 1/4W
R55k15.1kMetal film resistor, 1/4W
R61k51.5kMetal film resistor, 1/4W
R78k28.2kMetal film resistor, 1/4W
R84k74.7kMetal film resistor, 1/4W
R933k33kMetal film resistor, 1/4W
R1033k33kMetal film resistor, 1/4W
R11100R100Metal film resistor, 1/4W
RPD2M22.2MMetal film resistor, 1/4W
LEDR4k74.7kMetal film resistor, 1/4W
Capacitors 8
C147n47nFilm capacitor, 7.2 x 2.5mm
C23.3uF3.3uElectrolytic capacitor, 4mm
C31n51.5nFilm capacitor, 7.2 x 2.5mm
C41uF1uFilm capacitor, 7.2 x 3.5mm
C5100n100nFilm capacitor, 7.2 x 2.5mm
C647uF47uElectrolytic capacitor, 5mmReference voltage filter capacitor.
C7100uF100uElectrolytic capacitor, 6.3mmSupply voltage filter capacitor.
C8100n100nMLCC capacitor, X7RSupply voltage filter capacitor.
Diodes 5
D11N58171N5817Schottky diode, DO-41
D21N9141N914Fast-switching diode, DO-35
D31N9141N914Fast-switching diode, DO-35
D41N9141N914Fast-switching diode, DO-35
D51N9141N914Fast-switching diode, DO-35
ICs 1
IC1TL061TL061Operational amplifier, DIP8
Potentiometers 3
SUST.100kAA100k16mm right-angle PCB mount pot
FILT.10kBB10k16mm right-angle PCB mount pot
LEVEL10kAA10k16mm right-angle PCB mount pot
Switches 1
FSW3PDT3PDTStomp switch, 3PDTAvailable from Aion FX.
Jacks & sockets 4
IC1-SDIP-8 socketDIP-8 SOCKETIC socket, DIP-8
IN1/4" stereo1/4" STEREO1/4" phone jack, closed frameSwitchcraft 112BX or equivalent.
OUT1/4" mono1/4" MONO1/4" phone jack, closed frameSwitchcraft 111X or equivalent.
DC2.1mm2.1MMDC jack, 2.1mm panel mountLumberg NEB/J 21 C or equivalent.
Hardware 1
ENC125B125BEnclosure, die-cast aluminumCan also use a Hammond 1590N1.