The Tiny Audio
Amplifier circuit is a good choice for battery operation. It is based on LM386 IC.
Power supply - 6 - 12 VDC
Output power - 1 W, 8 Ohm
The quiescent
power drain is only 24 mW when operating from 6 VDC
Self-centering output quiescent voltage
Onboard PRESET to adjust volume
Terminal pins for connecting power supply, audio signal and speaker
Power-On LED indicator
ON/OFF PCB mounted slide switch for power supply
Four mounting holes of 3.2 mm each
PCB dimensions 44 mm x 44 mm