RangemasterThe Rangemaster is the most classic treble booster from the 60s, used by Eric Clapton or Brian May. This pedal produces a brighter tone and adds color to the signal.
Designators and components Step 2 of 5
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
Boost 10k-A 10K OHM LOGARITHMIC TAPER POTENTIOMETER
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
Use the following figures for the correct orientation of the transistors.
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.