Voltage controlled treble control. The input goes through a 30 k ohm resistor to the inverting input of an op amp, TLO74. The input also goes through a 43 k ohm resistor to plus 12 volts. The input also goes through a 22 k ohm resistor to pin 4 of the DBM. Pin 4 also goes through another 22 k ohm resistor to minus 12 volts. Pin 1 of the DBM connects through another 22 k ohm resistor to minus 12 volts. Pin 1 also connects through another 22 k ohm resistor to the output of the op amp. There is another 30 k ohm resistor connected from the output to the inverting input of the op amp. There is a 15 pf cap in parallel with this 30 k ohm. A 12 k ohm resistor connects from the inverting input to ground. There is a 20 k ohm resistor connected between pins 2 and 3 of the DBM. There is a 24 k ohm resistor connected from pin 5 to ground. Pin 14 goes to minus 12 volts. Pins 10 and 8 each go through 4.7 k ohm resistors to ground. Pin 8 goes through a 430 k ohm resistor to the wiper of the treble control pot. This is a 10 k ohm pot, it's bottom is connected to minus 12 volts, and it's top is connected to plus 12 volts. Pins 6 and 12 each go through 12 k ohm resistors to plus 12 volts. Pins 6 and 12 each go through 82 pf capacitors to ground. Pin 6 goes through a 47 k ohm resistor to one end of a 330 pf capacitor. The other side goes to the noninverting input of the op amp. The noninverting input goes through a 68 k ohm resistor to ground. The output of the op amp goes through a 470 ohm resistor to the output of the circuit. End verbal description.
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