Tone control circuit for higher frequencies - has negative feedback AF amplifier with two resistive voltage dividers and capacitor connected to give positive feedback

摘要

The tone control circuit for the higher audio frequencies is connected to the l.f. amplifier input. It contains a capacitor in series with a resistor connected to the reference potential. The amplifier (5) has a negative feed-back circuit (R1, R2). The tone control circuit (15) resistor (R3) is a part of a positive feed-back voltage divider (R3, R4). The reciprocal of the voltage divider division ratio is about equal to the gain of amplifier (5) with negative feed-back. The other end of the voltage divider is connected to the wiper (17) of a potentiometer (18) between the amplifier's output (11) and reference potential.