| 摘要 |
A Voss-type electronic tone control circuit in which the output of an amplifier is connected to the circuit output. An input resistor interconnects the circuit input and the amplifier inverting input and a feedback resistor interconnects the amplifier output and inverting input. One end of a first resistor is switched between the circuit input and the amplifier output. A first capacitor is connected between the other end of the first resistor and ground. A second capacitor is connected between the other end of the first resistor and one end of a potentiometer, the other end of which is grounded. The potentiometer slider feeds the amplifier non-inverting input. The capacitance of the second capacitor is different from that of the first capacitor, which enables the resistance of the first resistor to be increased, and the resistance of the potentiometer to be reduced compared with a conventional circuit. Increasing the first resistor resistance reduces loading on the boost/cut switch. Decreasing potentiometer resistance reduces the avenge source resistance presented to the amplifier non-inverting input, and, hence, the source resistance imbalance between the inverting and non-inverting inputs. The effects of the remaining source resistance imbalance are mitigated by unbalancing the input currents of the amplifier. The base of an auxiliary input transistor is connected to the amplifier inverting input. The emitter of the auxiliary transistor is connected to the second current generator to increase the current drawn by the inverting input.
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