The circuit that has been designed here to extract the voice out of music channel is basically a differential amplifier build around an op amp. Two circuits are drawn, one with bipolar power supply and the other with unipolar power supply. Advantage of bipolar supply is that the output voltage swing will be greater and perfect quality of the audio waveform can be achieved. Still the big disadvantage is the power supply itself. Unipolar power supply can be portable but it gives a limited output voltage swing which may sometime degrade the audio waveform. So it is up to you which power supply is to use and accordingly the circuit has to be chosen.
Project Source Code
Filed Under: Electronic Projects