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iPod Direct-connection successful! (but VERY difficult)


centerpunch

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EDIT ONE YEAR LATER: An enterprising guy has taken this idea and

developed a product they are selling to do this, see the post at:

http://www.legacygt.com/forums/showthread.php?t=18504

 

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(I will break this into several posts...)

 

WARNING! I offer this experience to help others who may have the skills and equipment necessary to make this delicate modification of the stock radio. These are not all-inclusive instructions. Your radio, your skills, and your luck may vary. And remember, if you trash your radio, you are also trashing your AC controller, and God knows how much it would cost to replace that thing!

 

WARNING #2! If you mess up, damage, or kill your car, your iPod, yourself, or anything else, it's not my fault! It's yours!

 

WARNING #3! I may not even know what I am talking about! You do whatever you do at your own risk.

 

SKILLS REQUIRED: This involves delicate cutting and connecting to a thin flex cable. Car stereo installation skills are not good enough here! You should be experienced hand soldering tiny SMD parts to have the skills to do this. (I'm not trying to knock anybody here, but trying to make sure you have the right experience, or find someone with the right experience before attempting this modification). You will be very pissed if you have to buy a new radio!!!!!!!

 

WARNING AGAIN! No guarantees, no tech support, no nothin! You're on your own!

 

STRATEGY: I was inspired to figure this out because using an FM transmitter with an iPod sucks! Period. And since Subaru has made it virtually impossible to replace the radio in these cars (those bastards!), well, you've got to do what you've got to do.

 

I actually considered putting a replacement head deck (with an aux input) in the glove compartment, and disconnecting the standard radio. But there's really not room in the glove compartment, and what a pain that would be anyway, having to open the door to control the radio.

 

But here's what I did. I connected the ipod signal directly inside the radio where the CD player signal is. That's right, both signals play at the same time. Here's the secret: You record a CD with 80 minutes of silence on it, so when you play the iPod, that's all you hear.

 

I got this idea from a Mazda RX8 fan website, where a very clever guy did a similar connection on a Mazda radio.

http://www.rx8club.com/showthread.php?t=10530&page=7&pp=15 (scroll down to ectomort's posting #95). Here's how he explained the idea:

 

"The patch signal source merges with the CD player source, and the head unit won't accept input from the CD player unless it's playing a CD, I've burned an audio CD which contains nothing but silence (I call it 4'33" extended remix, a tribute to John Cage.) When that CD plays, the iPod effectively owns the audio channel. The CD player auto repeats, so every 80 min or so I have to tolerate a 2 second dropout while CD cycles. Since my iPod has over 7200 songs on it, I won't often need to pop in a normal audio CD, but as long as I turn of the iPod, there's no problem."

 

What a great idea! Especially since the CD automatically repeats!

 

And it works!

 

I used a passive mixer to combine the signals, but you could probably also use a switch that would select the audio from either the CD player or the iPod. (But even if you do that, the CD player needs to have a CD in it so the radio "knows" to play the audio.)

 

CONTINUED IN NEXT POST

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Here are my not-guaranteed incomplete instructions: (read all of them BEFORE you start!)

 

1) REMOVE RADIO

- Pop up plastic plate with shift boot, unscrew shift knob, remove assembly.

- One screw holds each side silver trim piece in place, remove screw and snap parts off by pulling toward rear of car.

- Remove 6 or 8 screws attaching radio.

- Do not scratch radio on shift lever-- cover it with a couple socks.

- Pull radio toward you, reach behind it, and unplug the many connectors. The antenna is a small pigtail gray wire on the left side, its disconnect is about 6" from the radio.

 

2) DISASSEMBLE RADIO

- Ok punk, do you feel lucky?

- WARNING, static electricity can ruin electronics. If you don't know what you are doing, stop!

- Remove 4-way flasher switch (2 screws)

- Remove side mounting brackets (4 screws each)

(I always take a marker and mark items left or right, it helps when you're trying to put it all back together.

- Remove entire plastic front control panel (remove 6 screws, then gently pry each side a bit at a time, the entire front pops off.)

- Remove top cover (2 screws).

- Remove rear heat sink (7 screws).

- Looking at the large metal faceplate (where the controls used to be), remove the 4 highest screws (they hold the CD player.)

- Carefully lift CD player out, disconnect 14 conductor flex cable from socket in lower (radio) PC board.

 

CONTINUED IN NEXT POST

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3) MAKE CONNECTIONS

a) Stereo cable #1: audio from the CD player

- The flex cable has 14 conductors, the 3 nearest the driver's side of the car are Audio 1, Audio Ground, and Audio 2. (I'm not sure which is left or right...)

- Remember, you want the 3 conductors nearest the driver's side of the radio. Double-check before cutting!

- So, take an x-acto knife and PRECISELY split the flex cable. You want to separate the 3 audio conductors from the other 11 that manage the CD player. Split it as far back as practical, so you'll have room to work with it.

- Ok, now you want to connect a stereo shielded wire to those 3 conductors. (This will be hard, and I can't help you! And sorry I didn't take any photos of this part!). The middle conductor of the 3 is the ground. When you're done, this cable is the wire with the audio signal from the CD player. Make this wire long enough to run out the back of the radio, at least.

b) Stereo cable #2: Input to the car radio

- I actually used a small 3 conductor flex cable to plug into the socket (next to where you will plug the remaining 11-conductor flex cable), but that is a huge pain in the ass.

- Here's a better way: The 14 pin socket (that the flex cable plugs into) is a thru-hole design, meaning there are 14 holes through the lower radio circuit board. It will be easier to connect to them on the bottom of that PC board.

- I don't have detailed instructions for this part but you need to do whatever is necessary to remove the lower radio PC board, and then solder a stereo shielded wire to the correct 3 pins. I actually cut a hole in the bottom of my radio case (you don't need to do this, I did it so I could probe the signals with the radio playing), so if you look at the photo you will see the bottom of the 14-pin connector. Note that I used a marker and drew a diagram of the connector pins on the bottom of the radio, with the 3 correct pins noted.

- So, connect your cable to the appropriate 3 pins, and run the cable out the back of the radio somehow.

 

So now you've got the CD audio outputs on a wire that comes out the back of the radio, and the input to the radio on a wire that comes out the back of the radio.

 

CONTINUED IN NEXT POST

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4) REASSEMBLE RADIO AND TEST ORIGINAL OPERATION

- Reinstall the bottom PC board.

- Reinstall the CD player. Don't forget to plug the flex cable into the socket! The cable is narrower now, be sure you insert it exactly aligned with the correct side. You may want to cut a piece of your business card the exact width of the 3 conductor part you separated off, and insert that in the socket to help you align the remaining 11 conductor cable properly. Press it firmly in place.

- Reverse the steps in section 2 above to reassemble the radio.

- Now let's test the radio and make sure we didn't mess anything up.

-Connect the stereo wires that are now sticking out the back of the radio to each other. This connects the CD player back to where it was originally.

- Plug the large connector from your car into the back of the radio, turn the key on, and make sure the CD player still works. (You should hear it, Einstein!)

- If it does, good job!

- If it does not, you are in big trouble now! Why did you even think you could do this! Your mom/wife/girlfriend/boyfriend will kill you!

 

5) IPOD CABLE

- I made a cable to power the iPod and connect to its line outputs using a Belkin cord and great instructions found here:

http://www.mindspring.com/%7Epmbenn/iPod/cable.htm

- I use my iPod mostly in shuffle mode, and decided to keep it in behind the flip-up door at the top of the dash. It works great here, because I can reach in with a finger and easily press the play/pause button, and the button that skips to the next song.

 

EDIT HERE OCTOBER 22: This little spot in the car gets VERY hot in the summer or when the heater is on, I'm not sure if I'd locate the ipod here if I was doing this again! Maybe I'd put the iPod in the center console between the seats, then connect the Apple remote and mount it on the console or even in the ashtray.......

 

- After I removed the dash section (push down on the top edges while you pull, then don't forget there are a couple electrical connectors to unplug), I cut a large hole and a small hole in the top, and I ran my ipod cable through and tie-wrapped it in place. I left enough slack so I could remove the ipod and hold it to adjust settings or see what song was playing.

- I put phono connectors on, but I suppose you can just wire everything together.

 

CONTINUED IN NEXT POST

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6) CONNECTING EVERYTHING TOGETHER

- You could probably just use a DPDT switch to switch the audio from CD player to iPod. (But remember, even when the ipod playing, you've got to have a CD playing so the radio "thinks" it should play the audio.

- I used a simple circuit to connect everything together. See the scan. The resistors are necessary for impedance reasons (I tried it without them, trust me!) and the capacitors are necessary to keep DC voltage out of the ipod.

- I built all this in a hair-pie dangling off the back of the radio, then covered with heatshrink and tape. I added phono connectors to connect my ipod.

- Note, this circuit does cut the maximum volume by 6 db. So if you used to turn it up to 32, now you'll have to turn the radio up to 38. (And it only goes to 40). If you use a switch you won't have this problem.

 

CONTINUED IN NEXT POST

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7) TEST

- Connect everything, test it (remember, you'll need not a blank cd, but a CD with 75 minutes of silence recorded on it. (Of course, for testing purposes, you can use a normal CD, in which case you should hear the CD audio and the iPod audio at the same time).

 

8) REASSEMBLE CAR

- Reinstall radio, etc.

 

9) ENJOY!

- You will love it!

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First of all, Great work!!!! Comments: 1. It probably would have been better to source a socket and extra ribbon cable so you didn't have to hack up the case, just plug in. It's easy enough to find those kind of connectors inside old junk laptops. I understand though that cutting the hole was probably necessary for reverse engineering it. Questions: 1. So does the signal get muted when the cd player is changing discs/tracks? Or is it continuous whenever the cd player is selected? Another option would be to use an automatic switching line driver, so no matter what cd is playing, it's just been disconnected when there is a signal from the ipod, no messing with blank cd's. (but read next question). 2. Did you confirm what level these inputs/outputs are at? It would suck to get the wrong impedance/level and eventually fry something (like the CD's drivers). (I think you forgot to post the circuit you used) 3. Did you confirm that it is common ground, or just guess? perhaps the next pin is audio2 (-)?? 4. Did you happen to probe all the other pins? I'm going to guess there's just one pin to indicate the cd is playing (not digital communication), it should be possible to fake this. I can even imagine that this will override the amplifier input even if the HU is listening to radio. Oh, and let us know if it still works in a few days ;)
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[quote name='centerpunch'](I will break this into several posts...) READ THIS! I also considered adding a power amp to the radio, and having a switch so I could switch between using the car radio signal or the ipod signal to feed the power amp. (This is probably a much easier idea, and in fact, if I was doing it again, I might do that instead.) (THINK ABOUT IT! You'd just add a power amp, which is pretty cheap, and you don't mess with you head unit at all. This would be a MUCH LOWER RISK way of adding an iPod!!!) [/quote] I don't know jack-squat about car audio, but that's EXACTLY what I was thinking on my drive home today. As I said, I do not know about car audio - do they have amps with just AUX-IN connections?
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Referring to deer killers questions: 1) I think the cable is permanently attached to the CD player. 1) With a cd with one long recorded track of silence, it only mutes at the end of the cd and then immediately starts that cd over. The audio only comes out of the car's speakers if the radio thinks a cd is playing. 2) Without the resistors the impedance of the radio sucked the ipod signal down to nothing. 3) I think I confirmed that, but I may have been predisposed by the RX8 guy's data (which of course, has nothing to do with a Subaru radio). 4) Yes, I probed all the pins, but I was only looking for audio, so I didn't pay attention to other signals or DC levels. Yes, I've only used it for 30 minutes, I'll follow up in a couple days. Or sooner, if it smokes!
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FANTASTIC, U are the MAN Deer Killer....... Well Done.. Have to agree with Stef, amazing walk thru and thanks so much for your time and effort of going to the trouble of posting it all up with pics. Now for others looking to attempt this process, I think I have a way much simplier way.... Step 1. Remove Motor Step 2. Remove Steering Column Step 3. Remove all seats Step 4. Remove Suspension...... Step 5. Loosing my head.... That is a lot of work for anyone to go thru, hmm the things we do for our music. Again, Deer Killer well done, u deserve a good old Aussie pat on the back. Now when can u come to Melbourne to do mine LOL. Adam.
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Uh, I (Centerpunch) posted the long instructions. To reply to Deer Killer's photo with green arrow: That's the connector on the lower (radio) pc board. The other end of that cable is (I think) permanently attached to the CD player. Deer Killer's green arrow shows how you unplug the cable from the lower board before you modify the cable.
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[quote name='centerpunch']Uh, I (Centerpunch) posted the long instructions. To reply to Deer Killer's photo with green arrow: That's the connector on the lower (radio) pc board. The other end of that cable is (I think) permanently attached to the CD player. Deer Killer's green arrow shows how you unplug the cable from the lower board before you modify the cable.[/quote] It's true Adam....centerpunch deserves the credit! 3 cheers! :D
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[quote name='Deer Killer'] 4. Did you happen to probe all the other pins? I'm going to guess there's just one pin to indicate the cd is playing (not digital communication), it should be possible to fake this. I can even imagine that this will override the amplifier input even if the HU is listening to radio. [/quote] The radio is pretty smart, I think there is a lot of communication coming from the CD player. For example, the audio mutes if the CD player skips. This makes me think that there won't be a simple way to fool it, and playing the CD recorded with silence is the easiest (and maybe the only) way!
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[quote name='centerpunch'][quote name='Deer Killer'] 4. Did you happen to probe all the other pins? I'm going to guess there's just one pin to indicate the cd is playing (not digital communication), it should be possible to fake this. I can even imagine that this will override the amplifier input even if the HU is listening to radio. [/quote] The radio is pretty smart, I think there is a lot of communication coming from the CD player. For example, the audio mutes if the CD player skips. This makes me think that there won't be a simple way to fool it, and playing the CD recorded with silence is the easiest (and maybe the only) way![/quote] Hmm, I think that would be a good sign. Only the cd player knows if it's skipping, therefore it must do the muting itself, somehow.
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Welll, the CD player doesn't mute its audio, rather it somehow tells the radio to mute the audio..... I found this out because my first "CD-with-75-minutes-of-silence-recorded-on-it" skipped, which (when it happened) muted the audio from my iPod. But I suppose you are right, it could be a simple hi or lo line. But I tell you, the silent-CD works great! Oh, I drove the car 30 minutes to work today, this iPod hack still works great!
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I used to be a mechanical engineer, but now I'm kind of a product development and marketing guy. But I have a lot of experience messing with electronics. After I disassembled the radio, I probed the signals with a scope, and a good friend (who is an ee) identified the correct 3 wires, and sketched up the resistor/capacitor network....
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[quote name='John M']Do you have any info on what the HVAC section shares with the radio? Is it just the faceplate, do they share a wiring harness, etc?[/quote] The entire front of a unit is a single pc board that covers virtually the entire area. After you take the assembly out of the car, you can remove the plastic front (6 screws, I think), then the plastic front literally snaps off the front of the unit, revealing this huge PC board. There are two small electrical connectors that automatically unplug when you remove the plastic front. I don't see any possible way to remove the radio by itself. But here's another idea. I didn't measure exactly, but it looks to me that if you remove the top dash module (with the ac vents, clock, and storage area), there might possibly be room (with modifications) to put a new head deck up there. Maybe the aftermarket stereo guys will work on that possibility......
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[quote name='John M']Do you have any info on what the HVAC section shares with the radio? Is it just the faceplate, do they share a wiring harness, etc?[/quote] Oh, they do have separate wiring harnesses on the back. The radio connector and antenna connector are separate from the 2 or 3 A/C connectors.
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