When making home discos, this can be very useful. This simple audio mixer allows a smooth transition from one audio source to another, or mixing them in a selected ratio (potentiometer P1), so called crossfader. It also allows a transition between the sound of a voice input from the microphone (potentiometer P3). It has a headphone for DJs, in which you can the input, which actually does not enter the power amplifier. An audio source that will go to the headphones, is selected by the switch. Furthermore, this audio mixer has simple "echo" effect. This effect is using the difference of the two channels (left and right). You can also switch between stereo and mono signal. The mixer has a bass setting (P2) with a wide range, allowing you to remove the bass in the far left position and leave only high notes. It can also reduce the bass to avoid overloading of the subwoofer or reduce the annoyance to people who do not want to listen to your music and would rather sleep :) (deep tones, unlike the high onec, can spread over the wall). Wide range of bass control is achieved using the choke. Inductors L1, L2 I salvaged from power saving lamps (those ballasts which are in series with the fluorescent tube, about 2 - 4mH).