Fuzz Face (with DC inverter)

COMPONENT LIST (for PNP transistors)

PCB
PCB                 FUZZ FACE WITH DC INVERTER PCB

Capacitors        
C1       2.2u     2.2UF 35V 105C RADIAL ELECTROLYTIC CAPACITOR 5X11MM
C2       22u      22UF 50V 105C RADIAL ELECTROLYTIC CAPACITOR 5X11MM
C3       10n      10NF 0.01UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C4       10u      10UF 50V 105C ALUMINUM ELECTROLYTIC CAPACITOR 5X11MM
C5       10u      10UF 50V 105C ALUMINUM ELECTROLYTIC CAPACITOR 5X11MM
C6       100u    100UF 35V 105C RADIAL ELECTROLYTIC CAPACITOR 6X11MM

Resistors        
R1       1M     100K OHM 1/4W 1% METAL FILM RESISTOR (Optional)
R2       100k  100K OHM 1/4W 1% METAL FILM RESISTOR
R3       33k    33K OHM 1/4W 1% METAL FILM RESISTOR
R4       470    470 OHM 1/4W 1% METAL FILM RESISTOR
Bias     50k    50K OHM TRIMMER POTENTIOMETER

Transistors        
Q1       PNP 2N3906 / NPN  2N3904, BC108 or BC109
Q2       PNP 2N3906 / NPN  2N3904, BC108 or BC109
Sockets     40 PIN DIP SIP IC SOCKETS ADAPTOR SOLDER TYPE

IC
U1      TC1044SCPA   TC1044SCPA TC1044 VOLTAGE REGULATOR IC

DIODES
D1      1N4001    1N4001 DIODE 1A 50V
D2      1N4001    1N4001 DIODE 1A 50V

Potentiometers        
FUZZ  1k-B         1K OHM LINEAR TAPER POTENTIOMETER
VOL    500k-A     500K OHM LOGARITHMIC TAPER POTENTIOMETER

PCB

SCHEMATIC

INPUT IMPEDANCE

For a classic Fuzz Face build, omit resistor R1. The resulting low input impedance interacts with passive pickups to attenuate high frequencies, smoothing the fuzz effect and making the circuit highly responsive to the guitar's volume knob.

The 1MΩ resistor at R1 acts as a pull-down resistor. Adding this resistor helps eliminate "switching pop" noise when engaging the effect and prevents high frequency attenuation.

PNP AND NPN TRANSISTORS

The PCB is designed to work with both PNP and NPN transistors. Select the transistor type by placing a jumper on the corresponding PNP or NPN pad.

The original Fuzz Face uses germanium PNP transistors (AC128 or NKT275). Use a low gain for Q1 (β=70-80) and a high gain for Q2 (β=110-130). Germanium transistors tend to have leakage current and a varying gain value. For the PNP silicon version, use 2N3906.

For the NPN silicon version, use transistors such as the 2N3904, BC108 or BC109. Flip the polarity of electrolytic capacitors C1 and C2, and there's no need to mount C4, C5, D2, and U1.

BIASING THE CIRCUIT

Adjust the trimmer until the voltage at the "Bias" pad is 4.5V. Note that if you are using germanium transistors the biasing will be influenced by temperature.