Akashic Guitar effects PCB lookup
GAINPRESENCEVOLUME

125B · 3 knobs

Aion FX

DracoAmp Distortion

Based on the Dr. Boogey

Category
Distortion· Amp emulation / distortion
Controls
Gain · Presence · Volume
Difficulty
Intermediate
Price
$12.50in stock

From the vendor

A JFET conversion of the Mesa/Boogie Dual Rectifier Solo Head that originated in the DIY community and has become a classic high-gain distortion effect.

The Draco Amp Distortion is based on the Dr. Boogey, which first appeared on the DIYStompboxes forum on January 17, 2005 as an original design by user “electrictabs”.

It uses the basic Fetzer Valve technique pioneered by Runoffgroove to convert the Mega/Boogie Dual Rectifier Solo Head tube stages into JFETs but otherwise keep the tone-shaping as close to the original as possible. Nothing can perfectly emulate tubes, but whatever the case, the result is an excellent high-gain distortion pedal.

It has undergone a few minor community tweaks since the original design, such as scaling the tone stack for lower noise and the addition of Miller capacitors on the JFETs, but for the most part it’s an excellent example of nailing it the first time. We’ve incorporated all of these best-practice changes into our version, as well as greatly improving the power supply filtering.

The Draco includes footprints for both through-hole or surface-mount (SMD) JFETs. 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.

Important note: Due to the extremely high-gain nature of the pedal, it tends to oscillate on higher gain settings. This is normal, but see the build notes in the documentation for more information as well as suggestions for how to minimize or eliminate this oscillation.

Schematic

The schematic is in the vendor's build document, page 7. Open the build document. No KiCad fragment has been drawn for this circuit yet.

Parts list 72 rows

Report a wrong parse
RefValueNormalizedTypeNotes
Resistors 27
R11M1MMetal film resistor, 1/4W
R268k68kMetal film resistor, 1/4W
R31k81.8kMetal film resistor, 1/4W
R415k15kMetal film resistor, 1/4W
R52M22.2MMetal film resistor, 1/4W
R6680k680kMetal film resistor, 1/4W
R7470k470kMetal film resistor, 1/4W
R81k81.8kMetal film resistor, 1/4W
R915k15kMetal film resistor, 1/4W
R10470k470kMetal film resistor, 1/4W
R111M1MMetal film resistor, 1/4W
R123k93.9kMetal film resistor, 1/4W
R1315k15kMetal film resistor, 1/4W
R14330k330kMetal film resistor, 1/4W
R15220k220kMetal film resistor, 1/4W
R161k81.8kMetal film resistor, 1/4W
R1715k15kMetal film resistor, 1/4W
R1810k10kMetal film resistor, 1/4W
R194k74.7kMetal film resistor, 1/4W
R205k15.1kMetal film resistor, 1/4W
R212k22.2kMetal film resistor, 1/4W
R22100R100Metal film resistor, 1/4WPower supply filter resistor.
R23100R100Metal film resistor, 1/4WPower supply filter resistor.
R24100R100Metal film resistor, 1/4WPower supply filter resistor.
R25100R100Metal film resistor, 1/4WPower supply filter resistor.
RPD2M22.2MMetal film resistor, 1/4WInput pull-down resistor. Can be as low as 1M.
LEDR10k10kMetal film resistor, 1/4WLED current-limiting resistor. Adjust value to change LED brightness.
Capacitors 24
C1100n100nFilm capacitor, 7.2 x 2.5mm
C2220pF220pMLCC capacitor, NP0/C0G
C31uF1uFilm capacitor, 7.2 x 3.5mm
C422n22nFilm capacitor, 7.2 x 2.5mm
C52n22.2nFilm capacitor, 7.2 x 2.5mm
C61n1nFilm capacitor, 7.2 x 2.5mm
C722pF22pMLCC capacitor, NP0/C0G
C8220pF220pMLCC capacitor, NP0/C0G
C91uF1uFilm capacitor, 7.2 x 3.5mm
C1022n22nFilm capacitor, 7.2 x 2.5mm
C111n1nFilm capacitor, 7.2 x 2.5mm
C1222n22nFilm capacitor, 7.2 x 2.5mm
C13220pF220pMLCC capacitor, NP0/C0G
C141uF1uFilm capacitor, 7.2 x 3.5mm
C156n86.8nFilm capacitor, 7.2 x 2.5mm
C16220n220nFilm capacitor, 7.2 x 2.5mm
C17220n220nFilm capacitor, 7.2 x 2.5mm
C1815n15nFilm capacitor, 7.2 x 2.5mm
C1915n15nFilm capacitor, 7.2 x 2.5mm
C20220uF220uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C21220uF220uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C22220uF220uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C23220uF220uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C24100n100nMLCC capacitor, X7RPower supply filter capacitor.
Diodes 1
D11N58171N5817Schottky diode, DO-41
Transistors 5
Q1J201J201JFET, N-channelSee build notes for sourcing info.
Q2J201J201JFET, N-channelSee build notes for sourcing info.
Q3J201J201JFET, N-channelSee build notes for sourcing info.
Q4J201J201JFET, N-channelSee build notes for sourcing info.
Q5J201J201JFET, N-channelSee build notes for sourcing info.
Potentiometers 5
GAIN1MAA1M16mm right-angle PCB mount pot
MID5kBB5k16mm right-angle PCB mount pot
BASS100kAA100k16mm right-angle PCB mount pot
PRES.10kBB10k16mm right-angle PCB mount pot
VOL.100kAA100k16mm right-angle PCB mount pot
Trimmers 4
TR150k50kTrimmer, 10%, 1/4"Bourns 3362P
TR250k50kTrimmer, 10%, 1/4"Bourns 3362P
TR350k50kTrimmer, 10%, 1/4"Bourns 3362P
TR450k50kTrimmer, 10%, 1/4"Bourns 3362P
Switches 1
FSW3PDT3PDTStomp switch, 3PDTAvailable from Aion FX.
LEDs 1
LED5mm5MMLED, 5mm, red diffused
Jacks & sockets 3
IN1/4" mono1/4" MONO1/4" phone jack, closed frameSwitchcraft 111X 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.