diagram ingram

This stereo balance indicator circuit diagram is designed using few common external components .The schematic circuit is very simple to build and will provide an visual indication with LEDs for left , right and center balance . 

Outputs from each channel are fed to the two inputs of IC1 connected as a differential amplifier . Output of the IC1 is connected to the noninverting inputs of the IC2 and IC3 . If the outputs of the IC1 approaches the supply rail , the outputs of the IC2 and IC3 will go high illuminating the LED 3 , this will show that the right channel is dominating . If the sound is balanced to the left channel , the Ic2 and IC3 will go low and the LED1 will light . If both channels are equal in amplitude the outputs of the IC2 and IC3 would be low and high respectively , lighting up LED2 .