Aux-in Hacking An ’04 Subaru Radio

[Jordan] writes in to show us his hacked up car stereo. [Jordan]’s 2004 Subaru, like many of our cars, does not offer any kind of auxiliary input, and aux-in/mp3 adapters tend to run on the not so cheap side of the price scale. Even a replacement head unit was too rich for his blood. So it was time to wire something to the old head unit.

On inspecting the radio’s PCB [Jordan] managed to locate the traces that carry audio from the FM receiver to the stereo’s amplifier.  Most aux input hacks we have seen involve fooling the stereo into thinking some media is inserted, even if interfacing with the audio lines on the PCB. These require that the tape/CD functionality be altered, perhaps permanently. Even worse you may have to shlep around a blank CDR with a bunch of tracks on it! All just to fool the stereo into enabling audio output.

Instead [Jordan] targets the audio lines from the FM stereo, since radio is always enabled when active. Once the audio traces are located they are severed  and bypassed with a 1/8″ stereo plug. This setup allows the FM audio signal to pass through the connector when disconnected, and cuts off any radio audio once your mp3 player is. We have seen this same method used on a vintage stereo hack as well. Nice work!

Vintage Car Audio Gets MP3 Input

[Nali] is fixing up a 1966 Rambler Ambassador and decided to give the audio a bit of an upgrade. Instead of replacing the head unit he added a connector for audio input. The method he used is simple, inexpensive, and allows the original unit to continue functioning as a radio. He cut the feed wires going to the volume knob and patched in a headphone jack. The jack he used has an internal switch that is meant to switch off a pair of speakers when headphones are plugged in. The jack will allow the original signal from the radio tuner to pass through whenever there isn’t a connector plugged in. It seems like this is easier on older hardware than it is on modern equipment.

This isn’t where his entertainment enhancements stop. [Nali’s] working on a 7″ in-dash Linux machine so keep your eye on his thread to see what he comes up with.

[Thanks Joel383]