At this time amplifier circuit based on IC KA2201, TBA820M, LM820M, and U820. You can use all ic is the series under the scheme. This amplifier circuit has a very small output power or low at 2W. Required supply voltage from 3 volts to a maximum of 16 volts. Below is a scheme of this power amplifier Part List R1 = 100K R2 = 120R R3 = 100R C1 = 100nF C2 = 100uF C3 = 470uF C4 = 220pF C5 = 47uF C6 = 100uF IC = KA2201 , LM820M , TBA820M , U820M