This is simple portable audio amplifier circuit. This circuit built based on IC TEA2025 which is a monolithic integrated audio amplifier in a 16-pin plastic dual in line package manufactured by UTC. Circuit has Internal Thermal Protector. It is designed for portable cassette players, mp3 players and radios. You can also use it as your smartphone or PC audio amplifier. This circuit require 9V power supply to work, you may use a power supply circuit with output 9V @500mA DC current or a 9V lead acid battery.
Here is the portable audio amplifier schematic diagram for stereo audio input/output:
and here for mono audio input/output (bridge)
Portable Audio Amplifier Specification
Stereo per channel
VCC=9V; RL=4 ohm/3W
VCC=9V; RL=8 ohm/2W
Bridge Application
VCC=9V; RL=8 ohm/5W
VCC=9V; RL=4 ohm/8W
Supply Voltage min = DC3v @ 500mA
Supply Voltage max = DC12v @ 500mA
Supply Voltage recommended = DC9v @500mA
Download TEA2025 datasheet document for your project reference:
I got no sound on pin2/3