Adding AUX Input to OBS Stock Radio

[capricefrk013]

Figured I would Post this here cause of the type of radio used in our trucks.

Add AUX Input To Stock Radio

I've finally decided to switch my 98 Camaro CD unit out for an aftermarket HU, and now I'd like to move it into my Grand Am. Since I don't have to worry about killing it now, I've decided to take it part and try to add an aux input (which isn't even possible with adapters in a 98). I've done something similar to an old head unit before, here's what I've found so far.

The amp seems to be on the main board board, so there isn't an easy way to tap in there like there was on my old head unit. No easy route from the radio, either. However, the CD player is a self-contained unit with a ribbon cable, so audio must be passing over it.

Here's a picture of the bottom of the CD player, with the CD connector circled:

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Now, here's a closeup of the connector. I tapped in a couple of leads to a set of powered speakers to locate the wires carrying sound. I've labeled the left and right channels. It appears that some later models may have a connector with more pins, but the 1st and 3rd pins are still correct. Use the metal stereo chassis as a ground.

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So it's just a simple matter of splicing into those three wires with a special jack. This will allow the CD audio to pass through the jack fine when nothing is plugged in. When you plug in a cable into it from your MP3 player or whatever, it physically disconnects the audio to the CD player, and instead passes along the signal from your cable. You will need to have your CD player playing for this to work, even though it's using audio from your MP3 player. I know some of the aftermarket adapters that plug in between the HU and the cd changer work the same way, the changer plays, but it replaces the audio.

A quick search of radio shack.com returns the 274-246 for $2.99

jack

However, unlike the old HU I modified, I don't think you can easily put a jack into the face of this head unit, since there is a circuit board running behind plate. You can't just drill a hole and stick it through. See here:

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So I think the solution would be to run a 6ft+ wire through the back of the HU with a jack at the end you could run into glove box or into the console. The panel mount jack from radio shack isn't really the best for that, but it would work. I'm sure one of the big online electronics suppliers have something better.

So for a couple of bucks and fairly basic electronics knowledge, splicing into three wires, you should be able to an an aux-input to any 98+ camaro HU.

What do you guys think?

Ok, I've completed this project and it works great. Although I put the jack directly into the faceplate, I'd recommend against it since it's hard to find space to install it that can be used once the stereo is installed.

The switch is radio shack part #274-246 for $2.99 link

I recommend using a piece of networking/cat5 for the wiring. I had planned to have use solid colors as circuit board connections, but switched two when I was soldering so you may want to ignore the colors. Here's a picture of the jack soldered up

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Here are the details on the connections:

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Pin 1 - Ground - connect to the stereo chassis
Pin 2 - Left Channel - wire from CD connector on main circuit board
Pin 3 - Left Channel - wire coming from CD player module
Pin 4 - Right Channel - wire coming from CD player module
Pin 5 - Right Channel - wire from CD connector on main circuit board

Here is the jack wired into the CD connector. Note my wires run into the face, you'll probably drill a hole in the back of the case and run the wire out there.

Soldered everything and taped it.

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[capricefrk013]

Just follow the link to the tee you wont have any issues. Just make sure to ground the adapter to the chassis of the radio and you wont have any noise issues.

 

[970tahoe]

Any better pics of the splice job and the wires?

 

[chevy_man]

For future reference, shrink tube works, lasts, and looks much better than tape.

Also, if you buy a smaller diameter solder, it'll melt into the connection with less heat, and you won't bubble the plastic. I know when I did one on my denali, the jack itself started to melt like yours with hardly any heat so I dug through my toolbox and found some smaller stuff and didn't get any melting after that.

 

[Sully]

dumb question.... if you arent going to run the ipod port in the stereo, why not tap into the wires between the cd player and the radio so that you dont have to rip it appart?

 

[thunderstruck]

That would work too, but only if you have the separate CD player below your HVAC controls.

 

[Sully]

ok, just thinking outloud

 

[capricefrk013]

For future reference, shrink tube works, lasts, and looks much better than tape.

Also, if you buy a smaller diameter solder, it'll melt into the connection with less heat, and you won't bubble the plastic. I know when I did one on my denali, the jack itself started to melt like yours with hardly any heat so I dug through my toolbox and found some smaller stuff and didn't get any melting after that.

Thats not me. I just brought this over from GMFS.

dumb question.... if you arent going to run the ipod port in the stereo, why not tap into the wires between the cd player and the radio so that you dont have to rip it appart?

That would work too, but only if you have the separate CD player below your HVAC controls.

You cant tap into those wires. Hence the reason for going in to the radio where you send the audio signal directly in to the amplifier.

 

[thunderstruck]

Why not? It seems like it should would work exactly the same way, the only difference is that the CD player is external rather than internal.

[EDIT] In fact, that's how the aftermarket auxiliary input adapters (PAC, PIE, etc.) feed audio into these radios.

 

[capricefrk013]

Here is a pic of the diagram for the slave CD or Tape.

Serial Data is needed to turn the AUX/Tape feature on.