Akashic Guitar effects PCB lookup
DRIVETONEVOLUME

125B · 3 knobs

Aion FX

Peppermill

Based on the Runoffgroove Peppermill

Category
Overdrive· JFET Overdrive
Controls
Drive · Tone · Volume
Difficulty
Easy
Price
$12.50in stock

From the vendor

A super-simple drive created by boosting the signal into a J201 JFET until it clips in a tube-like manner.

The Runoffgroove Peppermill is a simple circuit designed to showcase the tube-like clipping characteristics of the J201. It’s a very minimalist design which is composed of nothing more than a MOSFET gain-boost stage into a JFET. The gain can be adjusted between the two stages to control the amount of clipping, and an output volume is present at the end, and that’s it.

The Aion FX version of the Peppermill is a direct adaptation of the original circuit, with one modification: the addition of a tone control. The original circuit has a R-C lowpass filter right before the volume, and by making the resistor value adjustable, you end up with a useful tone control without otherwise affecting the original circuit.

Since the J201 is very difficult to find in TO-92 through-hole format, and many DIY hobbyists are intimidated by SMD parts, Aion FX offers J201s in SMD format that have been pre-soldered to adapters so they can be used as through-hole parts.

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 31 rows

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RefValueNormalizedTypeNotes
Resistors 9
R11M1MMetal film resistor, 1/4W
R21M1MMetal film resistor, 1/4W
R34k74.7kMetal film resistor, 1/4W
R41k1kMetal film resistor, 1/4W
R5100k100kMetal film resistor, 1/4W
R61k1kMetal film resistor, 1/4W
R75k15.1kMetal film resistor, 1/4W
RPD2M22.2MMetal film resistor, 1/4WInput pulldown resistor.
LEDR4k74.7kMetal film resistor, 1/4WLED current-limiting resistor. Adjust value to change LED brightness.
Capacitors 7
C122n22nFilm capacitor, 7.2 x 2.5mm
C268n68nFilm capacitor, 7.2 x 2.5mm
C31uF1uElectrolytic capacitor, 4mm
C447n47nFilm capacitor, 7.2 x 2.5mm
C52n22.2nFilm capacitor, 7.2 x 2.5mm
C6100uF100uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C7100n100nMLCC capacitor, X7RPower supply filter capacitor.
Diodes 1
D11N58171N5817Schottky diode, DO-41
Transistors 2
Q12N70002N7000MOSFET, N-channel, TO-92
Q2J201J201JFET, N-channel, TO-92 or SOT-23Can use either J201 (through-hole) or MMBFJ201 (SMD).
Potentiometers 3
TONE100kCC100k16mm right-angle PCB mount pot
GAIN250kBB250k16mm right-angle PCB mount pot
VOL.100kAA100k16mm right-angle PCB mount pot
Trimmers 1
BIAS50k50kTrimmer, 10%, 1/4"
Switches 1
FSW3PDT3PDTStomp switch, 3PDT
LEDs 2
D23mm LED3MM LEDLED, 3mm, red diffused
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 mountMouser 163-4302-E or equivalent.
Hardware 2
BATTBattery snapBATTERY SNAP9V battery snapOptional. Use the soft plastic type—the hard-shell type will not fit.
ENC125B125BEnclosure, die-cast aluminumCan also use a Hammond 1590N1.