This audio power amplifier circuit is simple and robust, and use discrete component available on many electronic part stores. The final transistors use 2N3055 and MJE2055. Here is the circuit’s schematic diagram:

amplifier transistor 10w circuit schematic

The MJE2055 is an npn transistor, but the configuration with TIP42A make the whole combination of TIP42A and MJE2055 are seen as pnp transistor. This audio amplifier circuit is suitable for moderate power application in home sound system.