With the amount of equipment in home entertainment centers today the need to be able to vary the gain of the audio or video signal is needed. It can give 3 outputs from one input
Circuit operation is straight forward for amplifier circuits. The second channel for the audio amplifier is made up of the same components except the other half of IC1 is used. Pin 6 & 5 are inputs and 7 is the output.
http://home.maine.rr.com/randylinscott/jan98.htm