Dr Boogie Distortion
The Dr. Boogie Distortion is a JFET-based pedal that emulates the tone of the Mesa/Boogie Dual Rectifier Solo Head.Steps
Categories
Status: Active
Designators and components Step 2 of 5
PCB DESIGNATORS
PCB
PCB Dr Boogie Distortion
Resistors
R1 2.2M 2.2M OHM 1/4W 1% METAL FILM RESISTOR
R2 1M 1M OHM 1/4W 1% METAL FILM RESISTOR
R3 68k 68k OHM 1/4W 1% METAL FILM RESISTOR
R4 1.8k 1.8K OHM 1/4W 1% METAL FILM RESISTOR
R5 2.2M 2.2M OHM 1/4W 1% METAL FILM RESISTOR
R6 680k 680K OHM 1/4W 1% METAL FILM RESISTOR
R7 470k 470K OHM 1/4W 1% METAL FILM RESISTOR
R8 1.8k 1.8K OHM 1/4W 1% METAL FILM RESISTOR
R9 470k 470K OHM 1/4W 1% METAL FILM RESISTOR
R10 1M 1M OHM 1/4W 1% METAL FILM RESISTOR
R11 3.9k 3.9k OHM 1/4W 1% METAL FILM RESISTOR
R12 330k 330k OHM 1/4W 1% METAL FILM RESISTOR
R13 220k 220K OHM 1/4W 1% METAL FILM RESISTOR
R14 1.8k 1.8K OHM 1/4W 1% METAL FILM RESISTOR
R15 10k 10K OHM 1/4W 1% METAL FILM RESISTOR
R16 4.7k 4.7K OHM 1/4W 1% METAL FILM RESISTOR
R17 2.2k 2.2K OHM 1/4W 1% METAL FILM RESISTOR
R18 100 100 OHM 1/4W 1% METAL FILM RESISTOR
R19 100 100 OHM 1/4W 1% METAL FILM RESISTOR
Capacitors
C1 100n 100NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C2 220p 220PF 50V CERAMIC DISC CAPACITOR
C3 22n 22NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C4 2.2n 2.2NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C5 1n 1NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C6 22p 22PF 50V CERAMIC DISC CAPACITOR
C7 220p 220PF 50V CERAMIC DISC CAPACITOR
C8 22n 22NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C9 1u 1UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C10 22n 22NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C11 220p 220PF 50V CERAMIC DISC CAPACITOR
C12 1u 1UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C13 220n 220NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C14 6.8n 6.8NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C15 220n 220NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C17 33n 33NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C18 100u 100UF 35V ELECTROLYTIC CAPACITOR 6X11MM
C19 100u 100UF 35V ELECTROLYTIC CAPACITOR 6X11MM
C20 4.7n 4.7NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C21 100u 100UF 35V ELECTROLYTIC CAPACITOR 6X11MM
C22 1u 1UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
Transistors
Q1 J201 SMD SOT-23 J201 JFET N-CHANNEL TRANSISTOR
Q2 J201 SMD SOT-23 J201 JFET N-CHANNEL TRANSISTOR
Q3 J201 SMD SOT-23 J201 JFET N-CHANNEL TRANSISTOR
Q4 J201 SMD SOT-23 J201 JFET N-CHANNEL TRANSISTOR
Q5 J201 SMD SOT-23 J201 JFET N-CHANNEL TRANSISTOR
Diodes
D1 1N4001 1N4001 DIODE 1A 50V
Trimmers
BIAS1 100k 100K OHM TRIMMER POTENTIOMETER CERMET 1 TURN
BIAS2 100k 100K OHM TRIMMER POTENTIOMETER CERMET 1 TURN
BIAS3 100k 100K OHM TRIMMER POTENTIOMETER CERMET 1 TURN
BIAS4 100k 100K OHM TRIMMER POTENTIOMETER CERMET 1 TURN
Potentiometers
GAIN 1M-A 1M OHM LINEAR POTENTIOMETER
VOL 100k-A 100K OHM LOG POTENTIOMETER
PRES 10k-B 10K OHM LIN POTENTIOMETER
BASS 100k-A 100K OHM LOG POTENTIOMETER
MID 2.5k-B (5K OHM Lin POTENTIOMETER with parallel 5.1k OHM 1/4W RESISTOR)
TREBLE 25k-A 25K OHM LOG POTENTIOMETER
PCB
SCHEMATIC
POTENTIOMETER
The 2.5k-B MID potentiometer can be difficult to find. As a replacement, solder a 5.1K OHM RESISTOR to the 5K OHM LIN POTENTIOMETER as shown in the image below.
BIASING
To set the correct operating point, use the trimpots to adjust the bias voltage for each JFET stage. Use a multimeter to measure and set 4.5V at the test pads BIAS1, BIAS2, BIAS3, and BIAS4.
TRANSISTORS
You can use either through-hole or SMD transistors. The PCB is designed for JFET transistors (J201, 2N5457, 2N5458, MPF102...) with the pinout as shown in the following figure.
