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