This is the diagram of simple portable amplifier circuit. This amplifier circuit build based on IC TEA2025 that is a monolithic integrated audio amplifier of 16-pin plastic dual in line package built by UTC manufacture. The circuit has an internal thermal protection. The circuit designed for portable cassette players and radios. You can also use as PC audio amplifier.
Here the amplifier diagram for stereo audio input/output:
and here the amplifier with mono audio input/output (bridge):
Stereo per channel
VCC=9V; RL=4 ohm/3W
VCC=9V; RL=8 ohm/2W
VCC=9V; RL=8 ohm/5W
VCC=9V; RL=4 ohm/8W