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INPUTBODYSUSTAINOUTPUT

125B · 4 knobs

Aion FX

ArgusSilicon Fuzz

Based on the Roland AD-50 Double Beat

Category
Fuzz
Controls
Input · Body · Sustain · Output
Difficulty
Easy
Price
$12.50in stock

From the vendor

An obscure silicon fuzz that originally comprised half of a fuzz-wah combination unit, featuring three unique “wave shape” tone modes.

The Argus Silicon Fuzz is based on the fuzz section of the Roland AD-50 Double Beat, a combination fuzz-wah pedal originally released in 1973. The fuzz section is unique and was never released separately from the wah, though the fuzz and wah circuits are independent and fully functional on their own.

The main unique feature of the AD-50 fuzz is the 3-position “wave shape” selector. By filtering the signal in different ways, it can be transformed into a square wave, sine wave, or triangle wave. There is no tone control other than these three fixed modes.

This sounds interesting and unique until you understand a little about how wave shapes correspond to more traditional descriptions of signal characteristics. A square wave is full-frequency with heavy clipping and low dynamics—the classic fuzz tone, and the qualities that distinguish fuzz from overdrive or distortion. A sine wave is rounded and balanced, more like a natural instrument, midrange-focused without too much bass or treble. A triangle wave is piercing, brittle and treble-heavy.

In prototyping the AD-50, we found that the triangle (treble) mode was virtually unusable. (Check out some YouTube demos of the Double Beat if you want to hear it for yourself.) Because of this, the Argus has the option to trade out this mode for a mid-scoop with the center frequency around 1kHz, similar to a Big Muff with its tone control in the center position. It doesn’t have a catchy waveshape description like the other two modes, but it’s a whole lot more useful.

In addition, we’ve added two more controls: an Input level control (similar to turning down the volume knob on the guitar) and a Body control that blends between a small and large input capacitor, which sets the amount of bass going into the clipping stage. Together with the mid-scoop mode, it transforms the AD-50 into a much more versatile fuzz machine.

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 49 rows

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RefValueNormalizedTypeNotes
Resistors 21
R110k10kMetal film resistor, 1/4W
R2820k820kMetal film resistor, 1/4W
R31k21.2kMetal film resistor, 1/4W
R422k22kMetal film resistor, 1/4W
R52k22.2kMetal film resistor, 1/4W
R6120k120kMetal film resistor, 1/4W
R7470k470kMetal film resistor, 1/4W
R822k22kMetal film resistor, 1/4W
R91M1MMetal film resistor, 1/4W
R10220k220kMetal film resistor, 1/4W
R111k1kMetal film resistor, 1/4W
R1222k22kMetal film resistor, 1/4W
R131M1MMetal film resistor, 1/4W
R144k74.7kMetal film resistor, 1/4WUse 150k for stock triangle wave mode. See build notes.
R1539k39kMetal film resistor, 1/4WOmit for stock triangle wave mode. See build notes.
R1610k10kMetal film resistor, 1/4WOmit for stock triangle wave mode. See build notes.
R17100k100kMetal film resistor, 1/4WJumper for stock triangle wave mode. See build notes.
R18330k330kMetal film resistor, 1/4W
R19150k150kMetal film resistor, 1/4W
R20100R100Metal film resistor, 1/4W
LEDR4k74.7kMetal film resistor, 1/4WLED current-limiting resistor. Adjust value to change LED brightness.
Capacitors 14
C14n74.7nFilm capacitor, 7.2 x 2.5mm
C2100n100nFilm capacitor, 7.2 x 2.5mm
C31uF1uElectrolytic capacitor, 4mm
C447pF47pMLCC capacitor, NP0/C0G
C51uF1uElectrolytic capacitor, 4mm
C610n10nFilm capacitor, 7.2 x 2.5mm
C7100n100nFilm capacitor, 7.2 x 2.5mm
C8470pF470pMLCC capacitor, NP0/C0GOmit for stock triangle wave mode. See build notes.
C93n33.3nFilm capacitor, 7.2 x 2.5mmUse 250pF for stock triangle wave mode. See build notes.
C1018n18nFilm capacitor, 7.2 x 2.5mmOmit for stock triangle wave mode. See build notes.
C116n86.8nFilm capacitor, 7.2 x 2.5mm
C126n86.8nFilm capacitor, 7.2 x 2.5mm
C13100uF100uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C14100n100nMLCC capacitor, X7RPower supply filter capacitor.
Diodes 1
D11N58171N5817Schottky diode, DO-41
Transistors 3
Q12N50882N5088BJT transistor, NPN, TO-92Original uses 2SC1000-GR. 2N5088 will perform identically.
Q22N50882N5088BJT transistor, NPN, TO-92Original uses 2SC1000-GR. 2N5088 will perform identically.
Q32N50882N5088BJT transistor, NPN, TO-92Original uses 2SC1000-GR. 2N5088 will perform identically.
Potentiometers 3
INPUT500kAA500k16mm right-angle PCB mount pot
BODY500kCC500k16mm right-angle PCB mount pot
SUST.10kCC10k16mm right-angle PCB mount pot
Switches 2
TONEDPDT on-on-onDPDT ON-ON-ONToggle switch, DPDT on-on-onSee build notes for correct switch configuration.
FSW3PDT3PDTStomp switch, 3PDTAvailable from Aion FX.
LEDs 1
LED5mm5MMLED, 5mm, red diffused
Jacks & sockets 3
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.