AUX in on a Stock '05 Head Unit w/o Silent CD (The Project)

[mcwiggin]

Ok so this thread is results and findings on coming up with a way to get AUX in on a Stock 2005 Subaru Legacy Head Unit.

 

Thanks to drcaveman in finding the service manual for the 05/06 headunit which has complete circuit schematics for the head units.. To download the manuals:

 

Manual 1 can be downloaded here (0505cqef1561l.pdf)

www.mcwiggin.com/subaru/0505cqef1561l.pdf

 

 

Manual 2 can be downloaded here (0505cqef1560l.pdf)

www.mcwiggin.com/subaru/0505cqef1560l.pdf

 

I had been posting under that topic but I think that it would be best to start a new topic to keep this information and my progress organized.

 

So here is what I have so far.

 

// COPIED FROM OTHER TOPIC

 

Ok I think this is going to pretty easy actually! I looks like we can do this without and board mods at all! If we bring pin 2 on CN402 to ground that should enable satellite signal according to the main CPU. Audio comes down pins 4 and 8 and I am not sure yet how the left and right channels are deciphered. From there I think the satellite selector button should probably work to select satellite as a source. The button does exist (its that blank spot on the input selector switch that goes 4 ways.) You can make it work by opening the stereo and removing the piece of plastic that prevents you from pushing the button. I haven't tested this yet.. but it should work!

 

I will post results as soon as I test it!

 

 

If someone gets a chance let me know what they think is going on with the left and right audio signals signals (C402 - C405 are 1uf caps)

 

 

http://www.mcwiggin.com/subaru/SatInput.png

 

Block Diagram showing the connections to CN402... As you can see there is more here than just the steering wheel controls.

 

http://www.mcwiggin.com/subaru/Block.png

[mcwiggin]

Update... I removed the radio and tried grounding PIN 2 of CN402. To my surprise the radio displayed CALL on the screen and it cut out the music. I double checked that I was grounding pin 2 and not 3 which is for telephone and it was definitely pin 2. Connecting Pin 2 to Pin 6 is my next step. This may allow the radio to go to satellite mode.

 

 

With call on the screen it appears as though audio sent down pins 8 and 4 would probably play through the stereo. I will check this when I get time. I am still concerned with how left and right channels are derived from this jack.

 

Worst case scenario it may requiring soldering onto the volume controller where they do arrive as separate channels. Hopefully that can be avoided.

[rpm6500]

I don't know for sure as its a bit difficult to judge without a searchable PDF or the board in front of me but it looks as though its a simple filter setup near CN402. I think CN402.4 and CN402.8 are mono (P and N) inputs. Then filtered and split near CN402 before heading over to IC206.

 

Could these be for a phone kit install which would only have one channel?

 

I'm still looking but it seems that the sat switch will want a jumper between CN402.2 (through resistor to IC601.24) and CN402.6 (Digital GND) to begin working.

 

If I can help let me know. I'm by no means an DE but I'm not bad in my profesion as a PCB designer.

[rpm6500]

Well, it looks like I was half right.... just looked at the other thread... If I get time to check the schematics this afternoon I'll see if I can find the audio input for SAT radio.

 

Quote from Jon

Attached is the Audio wiring diagram for the 2005 Legacy. In that diagram, connector i85 corresponds to CN402, but the pins are numbered backwards. So,

i85 #1 = CN402 #4 (SIGNAL +)

i85 #2 = CN402 #3 (TEL ON)

i85 #3 = CN402 #2 (SATEL SW +)

i85 #4 = CN402 #1 (WOOFER +)

i85 #5 = CN402 #8 (SIGNAL -)

i85 #6 = CN402 #7 (WOOFER -)

i85 #7 = CN402 #6 (SATEL SW -)

i85 #8 = CN402 #5 (N.C)

 

The two SATEL SW pins connect to the remote (i.e. "satellite") audio switches on the steering wheel. The two WOOFER pins connect to the "Super Woofer" in the station wagon cargo area. And the N.C pin is connected for some reason to the Body Integrated Unit.

 

I suspect the remaining three unused pins (TEL ON, SIGNAL +, SIGNAL -) were designed to support a handsfree phone kit. Applying a voltage to the TEL ON pin would cause the headunit mute whatever it was playing and put the audio from SIGNAL +/- on the speakers. If you're content with mono sound, that'll get you AUX IN.

[zmarko]

I'm eagerly watching these threads. I don't understand all the 'pin' talk and whatnot, but if someone provided detailed pictures of what to do where (on the boards and stuff), I could pull it off.

 

:subscribe:

[2furious]

Clever...!!!

 

Subscribe..

[Andyjo]

Just check out IC 206 i believe, both Radio & CD signals come together there, so you could just tap the AUX in there, and trick the HU into muting the radio & cd at the same time, and you'd be golden, which looks like what you're doing... hmmm...

so wire up the sat button to the 'tel on' and blamo.... looks good to me! i'd do it if i brought my soldering iron back to school...

oh yeah, and the 'pin' talk... whenever you have a chip, or something on a PCB, it has 'pins' which are connected to the PCB... those pins are how the data/signals are transfered throughout the HU... just soldered joints really...

[mcwiggin]

Ok here is my game plan. Looks like the stuff about the satellite switch is true :-( The good news is bringing the unit into call mode is easy! Tapping in the audio in stereo isn't quite as simple but is totally doable.

 

Looks like I need to remove the resistors (this is pretty easy and can be done with a nail clipper) R251, R252, R351, R352 (doing this will untie the right and left channels from each other) the next step is to solder right ground to the upper pad for 252 and left ground to the upper pad of 352 then connect audio for the right to the upper pad of 251 and audio for the left to the upper pad of 351

 

http://www.mcwiggin.com/subaru/resistors.png

 

http://www.mcwiggin.com/subaru/audioplan.jpg

 

 

I will let you know how it goes... I may do it tonight or tomorrow depending on my schedule.

 

I will take pictures

[zcarmob]

Here is IC206 where the audio goes in. Pins 4 and 33 are inputs from the cd and radio. Pins 2,3,34,35 are coming from connector CN402 pins 4 and 8. Pin 6 on connector cn402 looks like a ground.

[kp1095]

Got an ipod and sat now i have to do this, just so it looks sanitary.

 

susbscribe.

 

maybe i could just send someone my stocker and exchange it for one already done!!!

 

for a fee of course.

 

K

[zcarmob]

mcwiggin,

 

While you are testing try this.

 

With and ipod or some other audio device.

Connect Right + to pin 4 on connector cn402.

Connect Left + to pin 8 on connector cn402.

Connect ground to pin 6 on connector cn402.

 

Now ground pin 2 and try to play the audio.

 

I was looking at the pc board and capacitor c402,c403,c404,c405 all have seperate. traces to resistors r251,r351,r352, and r252. So that means if you run the right side to one pin 4, left side to pin 8, and the negative ground to pin 6 then that should work.

 

The only problem i see is that both left and right will be mixed together, because pin 8 on cn402 connects to both pin 3 and 34 on ic206. Also pin 4 on cn402 connects to pins 2 and 35 on ic206.

[Andyjo]

So, in order to use the 'call' feature to grab a audio signal, you'd have to ground pin 6, on cn402, and pull the resistors, and dump in your audio signals, via pins 2,3,34&35?

If you were to just jump off the FM / CD and mute either of those units, you'd just have to tap into pin 4, and 33 on IC206..

i guess what i'm wondering is what's different between pins 2 & 3 and 34 & 35.. i see it says L+,L- and R+, R-

what does that really mean for connecting an audio connection there?

it seems to be that those resistors are there too... what drop down the signal?

[mcwiggin]

Because when moving to call mode it changes the input on the volume control chip. so adding audio where the FM + CD connect won't work. The call feature has its own volume / bal / fad / ect.... that are diffrent from the other modes... removing the resistors stops the audio from traveling back to where the 2 channels are linked together.

[mcwiggin]

Ok just looked at the Chip Diagram and looks like your suggestion may be a possibility... I will look into it..

 

Hopefully I will have time tomorrow to do some experimenting

[mcwiggin]

mcwiggin,

 

While you are testing try this.

 

With and ipod or some other audio device.

Connect Right + to pin 4 on connector cn402.

Connect Left + to pin 8 on connector cn402.

Connect ground to pin 6 on connector cn402.

 

Now ground pin 2 and try to play the audio.

 

I was looking at the pc board and capacitor c402,c403,c404,c405 all have seperate. traces to resistors r251,r351,r352, and r252. So that means if you run the right side to one pin 4, left side to pin 8, and the negative ground to pin 6 then that should work.

 

The only problem i see is that both left and right will be mixed together, because pin 8 on cn402 connects to both pin 3 and 34 on ic206. Also pin 4 on cn402 connects to pins 2 and 35 on ic206.

 

Tried the audio on CN402.... It does work. Its sounds good! It is mono :-(

 

hence working on these other mods.

[Deer Killer]

If someone gets a chance let me know what they think is going on with the left and right audio signals signals (C402 - C405 are 1uf caps)

Those are filters, so you don't need ground loop isolators, etc. Also they may filter out some audible frequencies since the input is for voice..

 

L/R is obvious tied together for mono input. However since this works you should be able to get stereo input by doing the following:

 

Cut the trace from c402 to c403 on the input side.

 

Cut the trace from c404 to c405 on the input side.

 

Now you should be able to tap in stereo audio to that side of the capacitors, however in order to have full filtering you will need two more inductors like L605 for the two new lines you have created, and add them in series to the input like how the two pins above are connected with them.

 

PS damn, now after I dropped all that cash on an 07 radio.. I don't give a crap about mp3 or srs..

[zcarmob]

Instead of cutting traces why not just unsolder one side of c403 and c405 to test then if it works just remove them all together.

 

Why would you need to add two more inductors since they are all ready there?

[Deer Killer]

Instead of cutting traces why not just unsolder one side of c403 and c405 to test then if it works just remove them all together.

 

Why would you need to add two more inductors since they are all ready there?

because you will have four wires. If those are smt caps, good luck...

[mcwiggin]

Ok here is my game plan. Looks like the stuff about the satellite switch is true :-( The good news is bringing the unit into call mode is easy! Tapping in the audio in stereo isn't quite as simple but is totally doable.

 

Looks like I need to remove the resistors (this is pretty easy and can be done with a nail clipper) R251, R252, R351, R352 (doing this will untie the right and left channels from each other) the next step is to solder right ground to the upper pad for 252 and left ground to the upper pad of 352 then connect audio for the right to the upper pad of 251 and audio for the left to the upper pad of 351

 

http://www.mcwiggin.com/subaru/resistors.png

 

http://www.mcwiggin.com/subaru/audioplan.jpg

 

 

I will let you know how it goes... I may do it tonight or tomorrow depending on my schedule.

 

I will take pictures

 

Just preformed this mod... The good news! Audio Works... Its in stereo.. The bad news... I think I need to add those resistors back as turning volume above 1% on my ipod leads to distortion. This is an easy fix. Other interesting things to note. While in call mode the stereo won't exit all mode regardless of the cars power state till you unground pin 2(3) the music stays on.. This makes sense. Like if you were on a call and turned your car off.

 

I will let you know how it goes with adding the resistors.

[zcarmob]

Now we have to figure out how to get the SAT switch to work or somehow ground pin 2.

 

But I think if you leave those resistors alone and remove those 2 capacitors it should work.

[Deer Killer]

you _need_ those resistors, you may have damaged the chip without them :O Theoretically you also need some sort of decoupling like that is going on in the official line-in.. i.e. those caps and inductors.

[mcwiggin]

Added the resistors and it sounds great..

[mcwiggin]

Right now I have the + of the op amps that the audio is feeding just danlging.. The resistors are on the - side of the op and feed the line in audio. It sounds good.

 

Made a really simple setup to switch the radio into call mode when I turn on my satellite radio using the output it provides for FM modulation. It runs 5v down this to trip the accessory which disconnects your stock antenna. I simply attached a resistor and to the +5v and then to the base of a transistor allowing it to connect the call to ground.. This could be done with a relay too.. but this was easier with what I have on hand.

 

 

I am having an issue though.. There is a hum in the background so somewhere noise is getting into the system. Its only audible when there is no audio playing but it is audible. Possibly adding back the capacitors will filter out this noise. The other issue is I am sure I am doing the wrong thing with how the audio is fed to the volume chip... If someone could guide me as to what is the right thing to do that would be great.

[CasopoliS]

waaay over my head but I am impressed

[mcwiggin]

Don't worry... once I get it right.. I will write down some simple instructions.. in the mean time... its going to be lots of electronic gobbldy gook.