Practical microphone equaliser circuit. - SSB TX audio equaliser
CIRCUIT DESCRIPTION. The circuit diagram of the equaliser is shown in Figure 1. The circuit is based on a fairly conventional single transistor amplifier. R1 provides a DC bias voltage for the electret mic. R3 biases transistor TR1 and R4 provides the collector load. C1, C2, C7 & C8 provide high-pass audio filtering, whilst C3 & C7 provide lowpass audio filtering. RV1 sets the low frequency response of the equalisation curve.