Do not misunderstand, this series is one of several series of power amplifiers that have output / low output power. This amplifier output is only possess more or less 4Watt. Or 2 X 2Watt stereo power amplifier. Minimum required voltage is not less than 3 volts and a maximum voltage of no more than 14 volts, and voltage must be rectified and filtered to obtain the maximum of the processed audio.
C9 = 0.1uF