本电路图所用到的元器件：

BC109C

Based on the classic Baxendall tone control circuit, this provides a maximum cut and boost of around 10dB at 10K and 50Hz. As the controls are passive, the last transistor provides a slight boost. The output is designed to feed an amplifier with input impedance of 10k to 250k.

ImgLoad(document.getElementById('BodyLabel'));