Audio Adapter Cable - Upgrading Car Audio with MP3 Player

Modifying the MP3 player into the car audio system has a good effect. The circuit is shown in the figure. The MP3 audio signal is taken out from the headphone cable, attenuated by the resistor voltage divider, and sent to the conversion switch to select different signals (MP3 signal/tape, radio signal). Finally, the selected signal is sent to the car's power amplifier circuit for amplification.

Modification method: First remove the tape player part of the car, find the output end of the preamplifier and the input end of the power amplifier (these two ends are connected, as long as you find one end, you will know the other end. They are generally connected by a two-core shielded wire and a connector. Turn on the power, and when you touch the input end with tweezers or other metal objects, the corresponding speaker should make a strong "click" sound), disconnect the original preamplifier output and the input end of the power amplifier, and connect according to the circuit in Figure 1. The switch can be a double-pole double-throw toggle switch or a push button switch, and fix it in an appropriate position in the cabin with small screws. It is best to use a four-core shielded wire for the connection. The headphone cable for picking up MP3 audio signals can be obtained from waste headphones.

Test machine: Make sure the wiring is correct before powering on the machine for test. Turn the newly installed switch to the tape/radio position, and the tape playback and radio should be normal.