This is an audio amplifier circuit based on IC, and IC were used that MPC563 with minimal output 6W, with impedance of 4 Ohm. Supply Voltage Minimum 4 Volt DC and a maximum voltage to 20 Volts DC. See him under this Scheme.
Electronic Circuit is a good site for hobbyist also who would like to try DIY because it shared good circuits. If you have a personalized circuit requirement you may feel free to request it through the comment box or contact me.