DIY: Line input / MP3 Player hookup to Stock Stereo!

[Panici]

Hey guys,

I wasn't able to find any useful info on soldering in an AUX input to the stock tape deck.
(My e30 is an early model '86 325E. I'm unsure if this is the original radio.)

So I spent a few hours and now have a working setup!
I take no responsibility if this fries your stereo. I've only done limited testing.

I've got CD quality sound now (a huge improvement over the tape adapters that are commonly used)

I didn't manage to get a picture of the ground I used, but it's clearly labeled on the PCB, and you can see it in the video.

NOTE:
The left/right (blue/red) wires in the video are connected to the WRONG point. See the pictures below for the proper soldering locations.

The video below is to show how to engage the Tape player without having a tape in the deck. Not having a tape in helps to reduce the system noise.

Background noise could further be reduced by disabling the internal motors, and desoldering the tape pickups. But I decided my setup is "good enough" for me.


I used a 3.5mm to RCA cable, and cut off the ends. I then soldered on the white, blue, and red wires that you see in the pictures. I chose this style of wire to clearly show the solder points to use. :)

http://www.youtube.com/watch?v=nFh__-mihSI

[Panici]

I guess the stock stereo isn't a popular choice?
Personally, I don't think anything aftermarket looks nearly as good as the stock unit.

[agent]

The stock units definitely look the best, though modern units with pre-amp outputs allow you to easily add an amplifier and a subwoofer.

Thanks for the writeup!

[Thizzelle]

how are you going to flick that little arm when it's installed? can you jab a screw driver in there when installed?

[Bronzites]

Thanks for this. I agree the stock units look the best, not to mention proper, so I bought one of these same units to replace the offensive aftermarket one the previous owner left me. I was planning on just using a tape adapter for an aux. input, but now I might try this.

Couple of questions though:
1) When you install the unit, how and where will the aux. cable fit and come out? Through the bottom of the dash above the ashtray?

2) Although I have minimal audio soldering experience, I'm still not quite sure how you did it based off of the pictures and video.. Looks like you're using the red/blue wires to just jump two points on the board - did you just solder it straight in without a switch? And forgive me, but I can't figure out what the white wire is doing there. Also not too clear on what's going on in the video with engaging the tape player and how that would happen automatically once it's installed.

Sorry if I'm too green here, but thanks.

[Panici]

how are you going to flick that little arm when it's installed? can you jab a screw driver in there when installed?

Very good question. Yes you can activate the mechanism with a screwdriver (I used the back of a pen) with the radio closed up. It's centered at the top of the deck.

Thanks for this. I agree the stock units look the best, not to mention proper, so I bought one of these same units to replace the offensive aftermarket one the previous owner left me. I was planning on just using a tape adapter for an aux. input, but now I might try this.

Couple of questions though:
1) When you install the unit, how and where will the aux. cable fit and come out? Through the bottom of the dash above the ashtray?

2) Although I have minimal audio soldering experience, I'm still not quite sure how you did it based off of the pictures and video.. Looks like you're using the red/blue wires to just jump two points on the board - did you just solder it straight in without a switch? And forgive me, but I can't figure out what the white wire is doing there. Also not too clear on what's going on in the video with engaging the tape player and how that would happen automatically once it's installed.

Sorry if I'm too green here, but thanks.

1. Not sure where the AUX cable will exit yet. When I get the unit in my car i'll update this thread.

2.
Three wires from my (3.5mm TRS) headphone cable are soldered to the red, blue, and white wires. You can solder the headphone wires directly to the unit, but I found them difficult to work with.
-Red wire connects to the right side of my headphone cable.
-Blue wire connects to the left side of my headphone cable.
-White wire connects to the ground of my headphone cable.

Red and blue connect to the solder points shown. White connects to a large solder point, labeled "GND" on the circuit board. It's towards the back of the deck.

3. If you don't want to use a blank tape in the deck, you can trigger the mechanism with a screwdriver or pen (see above)

[Todd Black 88]

I have done this to both mast e30 's.

Just get any old cassette, and rip the tape out. You will get no added noise because nothing is touching the heads.

[Panici]

I have done this to both mast e30 's.

Just get any old cassette, and rip the tape out. You will get no added noise because nothing is touching the heads.

Also a good idea.
I don't have an antenna on my car, so I'm fine with leaving it in aux/cassette mode all of the time, and it looks better without a cassette stuck in the slot :)

If it accidentally is taken out of cassette mode, a pen gives me a quick fix.

[Todd Black 88]

I am old, and I still own cassettes and use them.:)

[bmw325csi]

Next time you go through all that trouble, at least use a high quality cable. That thing isn't going to last too long. They get all bent, get distorted and stop working. Ask me how I know.

[Bronzites]

1. Not sure where the AUX cable will exit yet. When I get the unit in my car i'll update this thread.

2.
Three wires from my (3.5mm TRS) headphone cable are soldered to the red, blue, and white wires. You can solder the headphone wires directly to the unit, but I found them difficult to work with.
-Red wire connects to the right side of my headphone cable.
-Blue wire connects to the left side of my headphone cable.
-White wire connects to the ground of my headphone cable.

Red and blue connect to the solder points shown. White connects to a large solder point, labeled "GND" on the circuit board. It's towards the back of the deck.

3. If you don't want to use a blank tape in the deck, you can trigger the mechanism with a screwdriver or pen (see above)

Thanks. Having to use a pen to poke in there just doesn't seem.. adequate. I like the idea of using the empty cassette cartridge.

[brucewillies86]

very cool, does the tape player in an e38 differ much? I'd like to do this

[Panici]

Next time you go through all that trouble, at least use a high quality cable. That thing isn't going to last too long. They get all bent, get distorted and stop working. Ask me how I know.

This isn't a longterm solution for me, and I just used what I had on hand. Your right though, a better cable is in order. For that matter, a female 3.5mm jack on the faceplate would be even better.

Thanks. Having to use a pen to poke in there just doesn't seem.. adequate. I like the idea of using the empty cassette cartridge.

Empty cartridge should work just fine as well. In my case, I don't have an antenna, so keeping it in Tape/Aux mode all the time is fine, and should it accidentally come out of that mode, screwdriver/pen will do the trick.

very cool, does the tape player in an e38 differ much? I'd like to do this

I'm not sure how different it will be internally. I've seen similar mods done on other headunits though. It will probably require some trial and error to find the right solder points. Hopefully you don't blow anything up!



Wired in my stock radio today (and tested the aux input in the car)
Aux wire is coming out of the old fader switch location, for now.

It's sounds great! It's also more powerful then the little amp I had in there for testing, and it'll do the job for now (music while I wrench on the car) until I can build something custom/better.

[Todd Black 88]

This is what I did for my cab.

Get a cable with a female end, drill a hole in the spare slot plate above the deck, voila.

Get a small male to male for your phone/iPod/mp3 etc.

Cleanest solution IMO.

On my M3, I install phono jacks so I can even run a record player into it. Lol