This is one of the simplest stereo balance indicator circuit that you can have. The circuit will give a visual indication (using two LEDs) proportional to the difference in balance between the left and right channels of a stereo system. The circuit is based on a uA741 opamp IC. The IC compares the signals from the two channels and when both signal
s are in balance, the output of the IC will be steady and the LEDs will glow in same brightness. Unbalance in sound causes the two LEDs to vary in brightness proportionally.