Above circuit diagram is the schematic of 1W stereo headphone amplifier. The circuit is built based TDA2822, designed for use in portable players, radios and other common electronic devices which can use headphone for the audio output.
A 3V power supply/battery can be used to drive headphones providing 20mW in 32 Ohms per channel. This circuit can use 8? small loudspeaker as the audio output, but you need a 9V supply and this circuit will provide 1W power output.
The IC KA2209 is an equivalent to the IC TDA2822, you can use KA2209 if you can”t find TDA2822.
Download datasheet: TDA2822 datasheet