Range Master (with DC inverter)

PCB DESIGNATORS (FOR POSITIVE GROUND PNP VERSION)

PCB
PCB              RANGE MASTER WITH DC INVERTER PCB 

Capacitors        
C1    4.7n     4.7NF 0.0047UF 100V POLYESTER FILM BOX TYPE CAPACITOR
C2    22n      22NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C3    100n    100NF 100V POLYESTER FILM BOX TYPE CAPACITOR
C4    10n      10NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C5    47u      47UF 25V 105C RADIAL ELECTROLYTIC CAPACITOR 5X11MM
C6    100u    100UF 35V 105C RADIAL ELECTROLYTIC CAPACITOR 6X11MM
C7   10u       10UF 50V 105C ALUMINUM ELECTROLYTIC CAPACITOR 5X11MM
C8   10u       10UF 50V 105C ALUMINUM ELECTROLYTIC CAPACITOR 5X11MM

Switch
SW    SPDT ON/OFF/ON        MINI TOGGLE SWITCH ON-OFF-ON

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

OPAMP
U1     TC1044SCPA   TC1044SCPA TC1044 VOLTAGE REGULATOR IC
(Socket    8 PIN DIP IC SOCKET ADAPTOR)

Resistors        
R1    470k   470K OHM 1/4W METAL FILM RESISTOR
R2    3.9k    3.9K OHM 1/4W METAL FILM RESISTOR
R3    1M      1M OHM 1/4W METAL FILM RESISTOR
Bias  100k   100K OHM TRIMMER POTENTIOMETER 1 TURN

Potentiometer        
Boost  10k-A    10K OHM LOGARITHMIC POTENTIOMETER

PCB

PCB SCHEMATIC

PNP/NPN VERSION

The PCB is designed to build both positive and negative grounds. To create the positive-ground (PNP transistor) version, simply place a jumper over the PNP/NPN pads as shown below.

For the NPN version, do not mount components C7, C8, and U1. Make the jumper over the PNP/NPN pads as shown below.

BIASING

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.

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

TREBLE SELECTOR

Select the input and output capacitors (C1, C2, C3, and C4) to adjust the amount of low frequency amplification. A higher capacitance value will result in more low frequency amplification. Experiment with values between 2.2nF and 100nF.

The toggle switch lets you select between three treble configurations:

• Center Position: Uses capacitor C1 (e.g., 4.7nF)

• Up Position: Combines C1 and C2 (e.g., 4.7nF + 22nF = 26.7nF)

• Down Position: Combines C1 and C3 (e.g., 4.7nF + 100nF = 104.7nF)

If not frequency selector is required, dont mount the toggle switch, C2 and C3.