Distortion Plus

The Distortion + is one of the DIY pedal classics. It has the ability to generate a great tone range between overdrive to distortion.

Steps

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Designators and components Step 2 of 5

COMPONENT LIST

PCB
PCB DISTORTION PLUS DIY PCB GUITAR EFFECT

Capacitors
C1 1n   1NF 0.001UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C2 10n   10NF 0.01UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C3 47n   47NF 0.047UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C4 10p   10PF 50V MULTILAYER MONOLITHIC CERAMIC CAPACITOR
C5   1u   1UF 50V RADIAL TANTALUM CAPACITOR
C6 1n   1NF 0.001UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C7 1u   1UF 100V 105C RADIAL ELECTROLYTIC CAPACITOR 5X11MM

Diodes
D1 1N270 1N270 GERMANIUM DIODE DO-7
D2 1N270 1N270 GERMANIUM DIODE DO-7

IC
IC1 TL071    TL071 OPERATIONAL AMPLIFIER J-FET PDIP-8 TL071CP
(IC1 Socket   8 PIN DIP IC SOCKET ADAPTOR)

Potentiometers
VOL 100k-A 100K OHM LOGARITHMIC TAPER POTENTIOMETER
GAIN 500k-C 500K OHM C500K 500KC ANTI-LOG TAPER POTENTIOMETER

PCB

PCB SCHEMATIC

MODIFICATIONS

The original circuit uses two 1N270 germanium diodes. Change the diodes to obtain different distortion tones. The germanium diodes (1N60, 1N270 or 1N34A) will produce softer distortion, the silicon (1N914 or 1N4148) harder and the leds more fuzz and crunch. You can also experiment with different combinations (symmetric o asymmetric). If you want to have a versatile pedal with a diode selector, you can use a 2PDT switch or rotatory selector.

If you are using germanium diodes and the output doesn't have so much volume, you can place 2 diodes in series to increase your output level.

GENERAL DESCRIPTION OF COMPONENTS

Resistors

Use a multimeter or the color bands to obtain the resistance value. Resistors do not have polarity, you can place them in any direction.

Electrolytic capacitors

Electrolytic capacitors have their value printed on them. The negative polarity pin is indicated by a white strip along the can. They also have a longer leg indicating the positive pin. The maximum voltage rating never can be exceeded, make sure you are using at least double voltage rating than your power supply. For example, if you are using a 9V power supply, use a electrolytic capacitor with at least 18V maximum voltage rating.

Polyester capacitors

Polyester capacitors have their value marked with three numbers. Read as picofarads (pF), the first two are the 1st and 2nd digits and the third is the multiplier code. These capacitors do not have polarity, you can place them in any direction.

Ceramic capacitors

Ceramic capacitors have their value marked with three numbers. Read as picofarads (pF), the first two are the 1st and 2nd digits and the third is the multiplier code. These capacitors do not have polarity, you can assemble them in any direction.

Integrated Circuits

Integrated Circuits (ICs) have their model printed on them. A notch half-circle or a dot indicates the correct position on the PCB.

Diodes

Diodes have their model printed on them. The polarity (cathode) is indicated by the ring near the side. This ring is also marked on the PCB.

Led diodes

Led diodes have polarity, the cathode is indicated as a flat surface on the side of the diode and also it is the shorter led. On the PCB, the cathode is marked as a flat side and anode as a round side.

Potentiometers

Potentiometers have their resistance value marked on them. They are marked with A, B or C for logarithmic, linear and reverse logarithmic, respectively.