A simple mono amplifier circuit

This is a mono amplifier circuit powered by a single amplifier chip STA5100. The chip will provide a single power output of 140 watts. For stereo applications, simply build two identical circuits and then double the power supply current output by increasing the current value of the transformer. This amplifier is powered by a bipolar (symmetrical) power supply.

140W power amplifier circuit diagram:

This circuit contains all the blocks to build a mono amplifier. It is based on an output bridge power amplifier and its protection circuit. In addition, a compression function and a signal rectifier are added to complete the circuit.

The operation mode is driven by the on/off sequence module.

The Stby/mute pin sets the IC to three states:

Standby (Vpin < 0.8V), Mute (1.6V < Vpin < 3V) and Play (Vpin > 4V).

In standby mode, all circuits involved in the signal path are turned off, while in silent mode the circuits are biased but the speaker outputs are forced to ground.