Schematic & Wiring Diagram

Audio tone control circuit transistors based on this provides a maximum cutting and increase of about 10 dB at 50 Hz and 10K.

The first BC109C transistor acts as a buffer. It provides the circuit with an input impedance of around 250 000 has a voltage gain of slightly less than unity. As Baxendall tone control circuit is a passive design, all audio frequencies are attenuated.

The position of the controls and the ballast capacitor alters the audio response. The last transistor provides a slight increase of about 3 times. The output is designed to feed an amplifier with an input impedance of 10k to 250k. Both tone controls should be linear potentiometers type.

quick Data Transistor BC109C

Low current max. 100 mA
Low voltage max. 45 V
Collector-base voltage open emitter 30 V
Collector-emitter voltage open base - 20 V
Peak collector current - 200 mA
total power dissipation Tamb £ 25 °C - 300 mW
DC current gain (hFE ) IC = 2 mA; VCE = 5 V 200 - 800
transition frequency IC = 10 mA; VCE = 5 V; f = 100 MHz 100 - MHz