How To: Add Auxiliary Input to a stock radio
I picked up an '01 Galant a couple months back from a friend and have been itching for an iPod input. I'm a bit broke right now, so purchasing a new head unit is out of the question for the next few months. The stock head unit sounds decent enough - and except for the fact that the CD player was broken it worked fine. Oh wait, CD player broken?! That means I'm stuck with AM/FM!
It took about three months of listening to the garbage on FM before I decided to do a little research in to adding my own aux-input connection. The obvious option is to pick up an FM transmitter and be done with it - however I'm a bit picky on sound quality and FM transmitters seem to compress sound and add noise. I picked the more... ..difficult route - but as you'll see it's actually not the most difficult thing to do.
Things you'll need:
1. Soldering Iron
2. Solder
3. Solder wick/desoldering braid (trust me, this helps!)
4. Phillips screw driver (large and small)
5. Sacrificial pair of headphones
6. Audio processor datasheet: http://www.digchip.com/datasheets/pa.../LC75411ES.php (or google for "datasheet LC75411ES" and download the PDF, the pin-out diagram is on page 2).
Remove the plastic bezel from around the radio / temperature controls, then remove the radio (pretty basic stuff). You'll want to completely open the radio (remove the top, remove the face plate) in order to access the sound processor.
This method will have you soldering the right channel from the headphones to the right-out on the sound processor chip, and the left channel to the left-out of the SP chip. There are two options for this, one is easier than the other:
1. You can solder RIGHT to pin 11, and LEFT to pin 24 (rather hard, as these pins are about .3mm across with about .6mm spacing between them)
2. You can solder RIGHT to pins 13+14 (bridging the pins), and LEFT to pins 21+22 (again bridging the pins).
Advantages to method 1 are the built in fader function will work (fade to front/back). Advantages to method 2 are simply that it is a bit easier (bigger solder target).
Whatever the method you pick, you must solder the GROUND from the headphones (this is usually the loose wiring wrapping the right/left wire) to the chassis ground. I soldered it to one of the metal posts that the CD player bolts to - this seems to work fine.
As you see in the pictures, I ultimately ended up soldering RIGHT to pin 11 and left to pins 21+22. I did this "combination" method because after soldering RIGHT to pin 11 on the first try, I spent 2 1/2 hours attempting to solder LEFT to pin 24. My soldering skills are rather un-developed so this was a bit of a challenge - I finally gave up and moved to a larger target - and soldered LEFT to 21+22. This worked out perfectly, but has the odd side effect of the fader working on the right channel only. I don't use the fader, so this isn't much of a concern.
Pictures of the finished product:
http://img10.imageshack.us/i/img0075w.jpg/
http://img685.imageshack.us/i/img0074e.jpg/
http://img3.imageshack.us/i/img0073on.jpg/
http://img18.imageshack.us/i/img0072iq.jpg/
Notes of interest: This method completely bypasses the audio processor chip. Volume control, bass/treble and balance do NOT work for aux input. The fader will work only if using the 'hard' method. Once you do this, the radio will work perfectly as long as you don't plug the aux cable into anything. Once you plug the aux cable into something (say an iPod), the radio will cut out 100% and you'll only hear the iPod.
Using this method so far I have not heard ANY noise or interference during normal use. HOWEVER if you plug the iPod in to a charger plugged into the accessory port you will hear noise. I suspect this is some kind of ground-loop issue, however I'm unsure as to how I can fix it. My solution is that I don't charge my iPod in my car. =P
Word of caution: I don't know if this mod will affect the CD player in any way. My CD player was already broken (displayed E01 on any CD), thus I could not test this with the CD player. In fact, as you can see from the pictures I don't even have the CD player hooked up. I can't see a reason this would affect the CD player since I'm tapping in to the output lines and not input, but your milage may vary.
I'm very happy with this mod, hopefully those of you with the stock head unit will appreciate this relatively simply mod!
Re: How To: Add Auxiliary Input to a stock radio
Get a wired FM mod. It plugs in between the antenna and deck itself. Its what is used on overhead installs on cars with factory radios. Pretty clean sound.
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