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Aux Stereo Input for MP3 Player

This hack provides an auxilury input into the stock Hi-Fi stereo system without giving up use of the trunk mounted CD changer. I found that if I shut off 12V power to the changer, I could then share that input circuit. So all you need is a panel mounted SPST switch to shut down the changer and a mini stereo input jack to take input from any portable device. There are a couple of operating restrictions, but they are simple. As I'm sharing the CD changer input with the changer, the aux jack should only have something plugged in if the CD changer is powered down. Nothing blows up if you forget, but the portable device seems to load down the changer output if its playing. Conversely, though, when the changer is completly powered off, it doesn't cause the portable any problems. The proof is in the final results. It works fine with no problems.

Of course, to be of any use, you need an input device. I went with the Nomad II, as it is very small and light. It has 128M ram, so it holds over 2 hours using full CD quality sound MP3 files. Maybe someday I'll go with one of those full trunk mount systems that hold weeks worth of music. However, 2 hours of hand picked, programable music is enough for most drives, and when you get where you're going, you can take the music with you wherever you go. And, if you have your laptop, you can reprogram it from the many gigabytes that you could store on that hard drive. Don't forget you still have 6 CD's in the trunk and one in the Becker head unit.

 

 

You'll need a few other things too. Not to mention wire, a variety of hand tools, and of course your handy Becker radio removal keys.

After removing the radio, you'll need to tap into pin 18, 19, and 20 (the three cut wires). These are the CD changer inputs. Red is right channel in, Yellow is left channel in. Brown is common ground. Pin 8 (also red) is the 12V power to the changer. You need to insert a switch into this circuit in order to stop the changer from playing, so you can "borrow" its inputs to the radio/amp system. Refer to the radio manual for the location of these pins on the back of the head unit.
With all connections made, and the wires run to the CD shelf section (red for changer on/off, 2 conductor shielded for the mini input jack), we are ready for re-assembly.
Radio back in place. ready for the next step.
CD on/off switch all wired on the left, input jack all wired on the right. Ties downs on the back of the shelf for neatness. Ready to remount the shelf.
All reassembled and ready to go. Here's how it looks without the player installed. With the power switch to left of the CD shelf in the down position, and nothing in the input jack to the left of the CD shelf, all stereo functions are stock, and function normally.

Next, program the 220 to run in Aux mode when it doesn't detect the Changer. Turn the radio on, hold down the TP button until Becker 1 is displayed. Turn tuning knob until AUX OFF is displayed. Then arrow down and change it to AUX ON. Turn the radio off.
Using my utility shelf to hold the Nomad II (with velcro), and with the input jack plugged in. The player is in reach to change tracks or make other changes.

It works like this:

If you want to use the MP3 player, turn the new changer power switch to off, plug the portable into the new input jack, turn on the stereo, change to AUX mode, and its ready to go. Turn on the portable and pick your music.

If you want to use the CD Changer, turn the new changer power switch to on, unplug the portable device from the new input jack, turn on the stereo, change to CDC, use normally.

In other words, the Becker 220 now "wakes up" in the AUX mode, or CDC mode, depending on whether or not the CD Changer power switch is on or off.

It should also be noted the ANY device with a mini stereo jack can be plugged into this setup, so any walkman, TV, laptop, hard disk MP3 player, or future device will work here.

Good Luck with yours. --------- J.R.
 

 

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