Amplifier circuit is very suitable for use in subwoofer amplifier system based on IC SI1030G. Amplfier has 30W output with 8 ohm impedance. Supply voltage required minimum of 12 volts and a maximum of up to 22 volts DC. Component List : R1 = 100K R2 = 1R C1 = 2.2uF C2 = 100uF C3 = 47uF C4 = 100nF C5 = 10uF C6 = 47uF C7 = 100uF IC = SI1020GL , SI1030G