A simple, satisfactory Color Organ can be built with a handful of cheap components. This design features: no mains supply transformer, built-in microphone and three widely adjustable frequency bands obtained by means of very simple, passive filters for Bass, Middle and Treble. Simple Color Organ Circuit Diagram Due to the very low current consumption of this circuit, the mains supply can be conveniently reduced with no heat dissipation by the reactance of C1; then rectified by D1 and D2 and clamped to 24V by the Zener Diode D3. The music diffused by the loudspeaker(s) of any type of media player, is picked-up by the built-in microphone and the resulting signal is greatly amplified by a two-stage transistor audio amplifier Q1 and Q2. At the output of the second stage, the audio signal is filtered and split into three fully adjustable frequency bands by means of a simple (though effective) passive filter formed by P1, P2, P3, R7, R8, C6 and C7, thus avoiding the complexity of op-a...