Rangemaster

COMPONENT LIST

PCB
PCB             rangemaster-diy-pcb

Capacitors        
C1    4.7n    4.7NF 0.0047UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C2    47u     47UF 25V 105C RADIAL ELECTROLYTIC CAPACITOR 5X11MM
C3    10n     10NF 0.01UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C4    47u     47UF 25V 105C RADIAL ELECTROLYTIC CAPACITOR 5X11MM

Transistors        
Q1    PNP    2N3906 / NPN  2N3904, BC108 or BC109
Socket        40 PIN DIP SIP IC SOCKETS

Resistors        
R1    470k   470K OHM 1/4W 1% METAL FILM RESISTOR
R2    3.9k    3.9K OHM 1/4W 1% METAL FILM RESISTOR
R3    1M      1M OHM 1/4W 1% METAL FILM RESISTOR
Bias  50k     50K OHM TRIMMER POTENTIOMETER 1 TURN

Potentiometer        
Boost  10k-A    10K OHM LOGARITHMIC TAPER POTENTIOMETER

SCHEMATIC

PCB

PNP/NPN VERSION

The PCB is designed to build the positive ground (PNP transistor). To build to the negative ground version (NPN transistor): change to NPN transistor, invert the polarity of the electrolytic capacitors (C2 and C4) and connect the +9V where it is marked -9V.

Capacitors for PNP version                        Capacitors for NPN version

TRANSISTORS

The original Rangemaster uses a germanium PNP transistor with gain between 75 and 100 (OC44). For the PNP silicon version, use 2N3906. For the NPN silicon version, use 2N3904, BC108 or BC109.

Use the following figures for the correct orientation of the transistors.

TRANSISTOR SOCKETS

Use 3 pin headers (40 PIN DIP SIP IC SOCKETS ADAPTOR SOLDER TYPE) or a transistor socket.

BIASING THE CIRCUIT

Use the trimpot to bias the circuit. Use a voltmeter to measure the voltage on the "Bias" pad and adjust to -7 V (+7 V if using NPN). Note that if you are using germanium transistors the biasing will be influenced by temperature.

INPUT AND OUTPUT CAPACITORS

Experiment with values between 2.2n and 100n for C1 and C3. The higher the capacitance, the more low frequency is amplified. You can use a switch (toggle or rotary) to select between several values.

POWER SUPPLY CHAIN WITH POSITIVE GROUND PEDAL

A positive ground pedal cannot be directly connected to the power supply in chain with your other negative ground pedals. Use the Charge Pump PCB to build a voltage inverter and power your positive ground pedal in chain with the rest of your pedals.