This is a simple but powerful audio amplifier with a high output power of 2x 100W RMS (not P.M.P.O.). The speaker impedance is 4 ohms. The amplifier operates in Class AB. It uses TDA7293 integrated circuits with MOSFET outputs. These are similar to the TDA7294 but have an increased maximum allowable voltage, from 100V to 120V, and are equipped with a clipping detector.

Above is a schematic diagram of one channel of the amplifier and a classic power supply for the entire amplifier (both channels).

The stereo logarithmic potentiometer, P1, is used to adjust the volume. LED1 indicates signal clipping. This may be caused, for example, by a reduced supply voltage of the amplifier, excessive ripple in the filter capacitors (if their capacitance is too small), or simply by an overly strong input signal.

Each channel has its own indicator. Clipping indicators may be omitted. The amplifier’s power supply is symmetrical, with a classic mains power transformer. 100n capacitors should be placed as close to the integrated circuits to prevent the amplifier from oscillating and causing distortion or overheating.

Mute and Standby inputs are not used. Even without their use, there are no significant impulses during power-on or power-off. If necessary, you can use these inputs to implement standby switching for the amplifier.