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DRIVESAGVOLUME

Enclosure not stated · 3 knobs

Revolution Deux

Fairfield Circuitry Barbershop Overdrive

Based on the Fairfield Circuitry Barbershop· 6 other boards clone it

Category
Overdrive
Controls
Drive · Sag · Volume
Price
see vendor
Also as
Vero layout · from Revolution Deux
Tags
freestompboxes.org trace
Read the post at Revolution Deux Schematic imagefreestompboxes.org threadTagboard Effects vero layout Vero layout

From the vendor

Guillaume Fairfield's original low-to-medium gain overdrive/boost: two cascaded J201 gain stages followed by a 2N2222 emitter follower. The Sag control is a 10K pot in series with the supply that lowers the voltage reaching the circuit, changing the compression and coloring of the drive. A VP3203 MOSFET with a 15V zener provides polarity protection. The author finds it transparent and touch-sensitive, great for stacking with other dirt pedals.

Guillaume sets the JFET bias at about 2/3 of the supply (around 6V at each drain); the author suggests replacing the drain resistors R5 and R7 with 25K trimmers to set this more easily.

Schematic

The schematic is in the post. Open it at Revolution Deux. No KiCad fragment has been drawn for this circuit yet.

Parts list 27 rows

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RefValueNormalizedTypeNotes
Resistors 12
R12M2Mread from the schematic by eye
R233K33kread from the schematic by eye
R32M2Mread from the schematic by eye
R41K1kread from the schematic by eye
R58.2K8.2kadjust for 2/3 supply on the drain; read from the schematic by eye
R633K33kread from the schematic by eye
R79.1K9.1kadjust for 2/3 supply on the drain; read from the schematic by eye
R81K1kread from the schematic by eye
R94.7K4.7kread from the schematic by eye
R104747read from the schematic by eye
R112M2Mread from the schematic by eye
R121K1kread from the schematic by eye
Capacitors 7
C110n10nread from the schematic by eye
C210u10uelectrolytic; read from the schematic by eye
C3100p100pread from the schematic by eye
C447n47nread from the schematic by eye
C510u10uelectrolytic; read from the schematic by eye
C6100n100nread from the schematic by eye
C7220u220uelectrolytic; read from the schematic by eye
Diodes 1
D115V zener15Vread from the schematic by eye
Transistors 4
Q1J201J201read from the schematic by eye
Q2J201J201read from the schematic by eye
Q32N22222N2222read from the schematic by eye
Q4VP3203VP3203P-channel MOSFET, polarity protection; read from the schematic by eye
Potentiometers 3
DriveA100KA100kPotentiometerPOT1; read from the schematic by eye
SagB10KB10kPotentiometerPOT2; read from the schematic by eye
VolumeA10KA10kPotentiometerPOT3; read from the schematic by eye

Other boards based on the Fairfield Circuitry Barbershop