This circuit equipped with 2 switches that are useful for loudness and filtering, on SW1 as the loudness , SW2 as a filter. It also equipped with direct adjust of sound on Potentiometer 10k , but only useful as a master volume.
Minimum Voltage : 8 volts
Maximum Voltage : 18 volts
Maximum Power : 2 X 13 Watt stereo
Impedance Power : 4 Ohms