My C33 Stereo Aux Input Project [Archive] - Bimmerforums

m2pc

09-17-2008, 02:33 AM

I'm starting my own thread for this DIY because I believe I found a unique approach to this project, and because I still have some issues to work out.

ADDED 2008-09-17:

Features of this design include:

1. AUX-IN Jack in the stereo, accessible from the front faceplate.
2. RCA jacks on the back of the stereo, for hardwiring carPC/iPod/iPhone dock.
3. Switched, impedance matched, isolated audio circuit.
4. Fools the head unit into thinking a tape is inserted when it's not, eliminating the need for a "dummy" tape.

TODO:

There is an issue with the way I trick the head unit into thinking there's a tape inserted;
when you try to insert a real tape, the head unit won't accept it. If you hit EJECT and then try putting the tape in,
the head unit draws it in, but displays "TAPE ERROR" on the display.
Solution: I'm building a circuit to measure the resistance present on the AUX In jacks and automatically switch to "AUX IN"
mode. This should allow the head unit to play a tape when no AUX In signal is present.

It's only pictures for now; I will refine this post further as I get more information.

Audio switching/isolation circuit:
http://i219.photobucket.com/albums/cc200/m2pc/Circuit_Closeup.jpg

Tapping into the audio path:
http://i219.photobucket.com/albums/cc200/m2pc/Audio_Connection_Closeup-1.jpg

Leads soldered in place:
http://i219.photobucket.com/albums/cc200/m2pc/Audio_Connections.jpg

Ground and switched +12V connections:
http://i219.photobucket.com/albums/cc200/m2pc/Ignition_Power-1.jpg

Ambient Light Sensor we will be re-routing to the "security" LED spot:
http://i219.photobucket.com/albums/cc200/m2pc/LightSensor_Closeup-1.jpg

Carefully soldering wires to extend the light sensor:
http://i219.photobucket.com/albums/cc200/m2pc/LightSensor_Extending.jpg

Wires soldered where Light Sensor used to be:
http://i219.photobucket.com/albums/cc200/m2pc/LightSensor_Extended-1.jpg

Ambient Light Sensor hole enlarged for 1/8" Aux In Jack:
http://i219.photobucket.com/albums/cc200/m2pc/FacePlate_JackHole-1.jpg

Finished Product:
http://i219.photobucket.com/albums/cc200/m2pc/Installed_Final.jpg

Bris328is

09-17-2008, 06:42 AM

thats nice--good job:buttrock

m2pc

09-17-2008, 12:57 PM

Hey thanks for the kudos!

First post updated to add project features and To-Do list.

kirbykirbykirby

09-17-2008, 01:41 PM

I did this with my old C33 but did it much more ghetto :( just wired a aux in cable, and had it go to the cup holders.

kirbykirbykirby

09-17-2008, 02:05 PM

http://rides.webshots.com/album/557529812aLFABe

just4kinks

09-17-2008, 04:06 PM

Good job.

I researched doing something like this with my C43, but I wimped out because I felt like I was in over my head.

m2pc

09-24-2008, 01:52 AM

UPDATE: After much research, I decided to return my head unit to stock as far as the "tape inserted" switch goes, since disabling it was causing problems with being able to use a tape (I'd like to retain that feature).

I found a chip on the main PCB I may be able to tap into for a better aux-in signal (Thanks to dirtyguido). It's a chip marked "TDA7328D" which is a stereo audio signal processor. Datasheet is here: http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXytuz.pdf

My new plan is to intercept pins 6, 7, 16, and 17 and automatically switch my audio signal into that path when an AUX IN signal is present. That way, the head unit can be set to any source (AM/FM/WB/Tape/CD) and the AUX In will take over the signal.

I also plan to ditch the mechanical relay and employ an analog switch IC, such as this one: CD4066 (Datasheet here: http://www.datasheetcatalog.org/datasheets/105/109222_DS.pdf)

dirtyguido

09-25-2008, 11:43 PM

bascially here's what I do on them...

Desolder pins 9 and 13, and connect sheilded audio cable L and R respectively to them. Connect ground to chassis ground. I disable tape function in favor of the aux in.

If you want to keep the tape function, which it seems you do, all you need is a couple relays, where you would switch between the aux in and the tape to those pins. I leave the tape mechanism alone on them and yes, you do need to insert a tape, doesn't matter if it's blank or not, because the audio is no longer coming from the tape deck pcb. If that makes sense. If you want to pickup a preamp signal,(for aftermarket amps) pins 22 - 25 would be your center conductors of your RCA cables, common ground.

Now, your plan of intercepting the audio between whatever source and having the aux override it, would require cutting in between pins 16 and 17, and pins 6 and 7 on the other channel. BUT you would need some sort of sensing circuit for the aux in to switch it. Another way to do it, look at parts express, they have certain 3.5mm audio jacks that have a built in switch in them that activates when they have a plug inserted into them,

Take care,

George

m2pc

09-26-2008, 03:06 PM

I redesigned the circuit to switch itself in and out of the main "pre-amp" loop on the TDA7318D IC. It looks like there's already some capacitors soldered on the board that lead to those pins, so I shouldn't have to do any surface mount desoldering/tapping in.

This should allow me to select ANY input (AM/FM/CD/Tape) and the AUX IN signal will take over. This means I can re-connect the tape sense switch and retain full use of my tape deck! :)

Schematic is attached.

isocuda

08-22-2009, 03:38 AM

this Brilliant setup needs a step by step...

I was gunna just solder some connections direct to the channel inputs and make an input jack...

but After seeing someone took the time to figure out the chip connections and such, which may be well over my head it would be great if I knew what parts to buy at RadioShack, and where most of the connections actually are

m2pc

05-20-2010, 12:10 AM

Hey guys, bringing this one back from the dead.

Today I cracked open my C43 stereo in the M3 and went to town.
I was able to isolate the audio signal as planned, right at the stereo processor chip.
I have a hacked setup with the stereo coughing up wires out the tape slot currently, while I put the finishing touches on my auto-AUX-in switching circuit.

Preliminary tests yielded AWESOME sound, with no "muddied" sounds like my previous design.
This bypasses the tape circuit which is designed to cut out high frequency sounds.
We're now injecting audio right into the heart of the system.

More to come soon on this project! :buttrock

m2pc

05-23-2010, 02:27 AM

Image of audio tie-ins to C43 stereo:

http://i219.photobucket.com/albums/cc200/m2pc/DSC04522Small.jpg

Dominic49

05-26-2010, 01:53 AM

hawt. let us know how it goes

theruined

11-16-2010, 09:23 PM

could you possibly follow up with any more pics/info on the C43 project as I'm trying to mod one myself but get stuck at the wiring - what I'm trying to do is a take off of Jcrowell's guide, minus the C33 part, wherein lies the problem.

I'm trying to follow the above pic but it doesn't really make any sense as I have limited experience with electrical wiring...:confused

dorkymood1

11-16-2010, 11:49 PM

Is the radio with WB an c33 or c43 ?. In your firsr post you call it a c33 and in the last post you call it a c43. My other question is what cd deck works with the radio with the WB band? Any help would be appreciated. I tried realoem to try to figure out what radio I have but could not figure it out. Thanks in advance.

m2pc

11-16-2010, 11:58 PM

Sorry, I started with a C33 (the one with the WB) but that car was totalled so I started hacking my new car's stereo (C43, the one without the WB but with RDS).

Both are similar, and the connections are almost identical. I've been running for a few months with a broken switching circuit, which only allows me to listen to the AUX input while the car is running, which is not as I planned obviously. However the sound is very clear without any of the distortion/quality degradation you get tapping into the tape deck circuit.

Once I get the openOBC project done, I will go back and focus on this more. It has huge potential.

DerekVa

08-29-2011, 03:16 AM

gte619n

09-28-2011, 06:56 PM

I'd also love to wire directly into my C33's audio circuit. Any chance we could get an update on this? Thanks!

NJDave

11-15-2011, 08:36 PM

Yes, "M2PC" ... please update us on your final Alpine C33/C43 AUX modification (going through the main Audio Signal Processor), with full schematic, photos, and text description of what worked.

I've had my C33 apart ... just waiting to be AUX modified through the Audio Signal Processor (TDA7318D)!

Thanks
:(

JDStrickland

11-15-2011, 08:59 PM

I installed a wired FM Modulator. I was excited when I buttoned everything up, it sounded good and I put the Aux Jack where it makes good sense. Now, as I drive around town, the modulator is showing its failings.

I would like to get my Aux Input to go directly into an audio channel, or get a FM Modulator that actually works. The one I have was only $16.40 -- I won the auction on eBay. I think this is a product where spending more money leads to greater satisfaction.

How come one could not piggy back on the audio from the CD Changer Input? Then one would only need to unplug the Aux source to listen to the CD, or empty the CD changer to use the Aux source.

MParallel

11-15-2011, 09:13 PM

...How come one could not piggy back on the audio from the CD Changer Input? Then one would only need to unplug the Aux source to listen to the CD, or empty the CD changer to use the Aux source.

That solution has been used for years through an interface like Dice or Dension. You can get an extra module that even makes you switch between the original changer or the aux channel.

JDStrickland

11-15-2011, 09:25 PM

I was in my local BMW dealership today, and the guy behind the counter said there is no interface for my car because it is too old. If you have a link, I'd appreciate it...

NJDave

11-16-2011, 03:16 AM

flyfishvt

11-17-2011, 08:38 PM

I just finished this mod. I soldered a headphone jack onto the tape player board just like the picutes show. Then with the cover off I pushed on the mechanism that grabs the tape (no tape actually inside) and fooled the unit into thinking there was a tape in it. Then I ran a headphone extension cord to the cup holder and BINGO. I just plug my MP3 player into the cord and use the cassette tape player circuit as if there was acutally a tape in there. I can switch it back and forth from tape to CD to radio and the sound quality is excellent.

The only thing I have left to do is install a female headphone jack in the cup holder like I did on my 325. Everything is now completely out of sight under the arm rest. No cords getting tangled in the shifter or running all over.

NJDave

11-18-2011, 05:40 AM

[QUOTE=flyfishvt;23119172]"... I just finished this mod. I soldered a headphone jack onto the tape player board just like the picutes show ... I can switch it back and forth from tape to CD to radio and the sound quality is excellent.

Could you explain further the term "tape player board"? Does this mean you wired up to the larger main circuit board (to the TDA processor chip), or you wired up to one of the smaller circuit boards mounted to the separate tape drive mechanism on top of the main circuit board?

Also by mentioning you can "switch back" from tape to CD to radio ... does this mean you've incorporated a relay set to do this? Please explain this "switching" method more.

Thanks.
:)

flyfishvt

11-18-2011, 07:28 AM

If you look at the second pic in the original post you'll see the Tape Output board. In the actual unit it's under a thin metal shield. Remove the shield and solder onto the board just like he did.

Once everything is installed you fool the player into thinking there is a tape in it. Then you can use the buttons on the unit to switch from cd to tape to radio. The only difference is when you switch it to "tape" it will use the input from you mp3 player or whatever you have plugged into the aux port. If you decide to actually put a bank tape in it will still work but you'll hear the clicking of the tape spinning and sound quality will be reduced.

NJDave

11-21-2011, 06:35 AM

"If you look at the second pic in the original post you'll see the Tape Output board ..."

Got it ... but did you hook wiring up to the top Tape Output Board, or the Head Unit "In" terminals on the side board?

Previously, I had hooked up to the "top" Tape Output Board terminals only, and the result was a "muddled" sound, coming out of both channels ... really bad sound. Like "m2pc" I would prefer to hook-up through the main board TDA processor chip, as the sound should be 100% clean going into the Tape Player Head unit this way, instead of taping into the tape circuit board.

How's the overall sound on your hook-up?

flyfishvt

11-21-2011, 06:46 AM

NJDave

11-21-2011, 04:17 PM

I hooked onto the tape out terminals. The same ones as the top set of wires in that pic. Sound quality is excellent. After reading this thread and others I was prepared for poor sound but it's excellent. I don't know if it makes any difference but he used RCA ports on the back. I used a headphone jack similar to what he installed on the front.

In my hook-up attempt, that didn't sound great, I used a headphone jack too (but I'm sure that wasn't
the problem).

Did you use "shielded" 3 wire cable (off the tape head board terminals, or did you just use single individual
wiring (ie: covered 18-22 gauge)?

I may try re-soldering a new set of wires to the tape circuit board again, as I took everything apart, and
will need to try this all over again.

I'm thinking it might make more sense to "patch-in" through the "head unit in" side terminals shown in the photo.
This way the audio would be by-passing some of the tape board circuitry ... and making a more direct connection
to the main processor. Or it doesn't really matter, because both the top and side terminals are directly connected
to each other, and are "all-in-the-same"

Did you ever try the wiring just "patched-in" to the side board terminals (instead of the top ones like you have)?

flyfishvt

11-21-2011, 04:46 PM

I just used plain covered wires. I grounded it to the chassis of the head unit instead of soldering the ground wire onto the board. Not that it really makes any difference. It was just easier that way. If you have some phone cable that works good too. Not the white thin stuff that plugs into the back of the phone but the round grey stuff with 4 wires inside. The wires are very small and easy to solder.

NJDave

12-02-2011, 05:01 PM

So I just re-soldered the three wires to the three terminals off the main tape head circuit board (the small board one on top of the separate tape drive mechanism, with the tape out solder termainals), and tried the deck out with an iPod Touch attached .... the sound ONCE AGAIN (this being my second attempt), SOUNDED LIKE CRAP!

The sound, tapping into the tape deck circuit board is kind of "scratchy" and sounds like the speakers are being overloaded or something ... definitely not a clear sound output by any means.

"flyfishvt" ... I'm not sure what you meant by "Then you can use the buttons on the unit to switch from cd to tape to radio."
I'm doing this Cassette AUX modify with a BMW C33 Cassette/Radio unit, and the tape player only becomes active (takes over from the radio or 6 CD player in the trunk), when a tape is placed in it ... there are no "buttons" (My older C33 BMW Cassette player is out of a 1997 E39 528i).

I still haven't figured out how to tape into the "audio processor chip" on the main board, like the "m2pc" claimed to have done. I just wish he would repost his method in a full understandable "step by step" description.

Come-on "m2pc" what ever happened with getting back to us on this!

*Note: When I re-hookup my in-dash BMW Business CD player, and use the iPod Touch in the AUX mode .... the sound is awesome ... so it's not my speakers or anything that are making the older BMW Cassette player sound like crap. It's the non-working method of using the Cassette tape circuit for the AUX output.

flyfishvt

12-04-2011, 07:43 AM

I just finished a 6hour drive yesterday and the sound quality from my aux input was as good as the CD player. Don't take this the wrong way but are you using a "stereo" cable? I almost bought a mono cable to use as an extension cable. I also don't know what you have for wiring or connectors. I used plain wires (non shielded) for the ones inside the headunit. I used a plain (cheap) female recepticle from radio shack. I drilled a hole in the back of the headunit and mounted it there. Then I ran an actual headphone extension cable from there to the center console. One end of this extension cable was male and the other female. I mounted it to the under side of the center console and used a 4' male-to-male headphone cord from my i-phone to the jack. Just like you...I soldered onto the small board on the tape deck. I'm no expert on sound systems but crackling sounds are usually a bad connection or static caused by a bad ground or something like that. Instead of grounding from the female recepticle to small board I grounded directly from the recepticle to the chassis. What kind of plugs and receptilces are you using?

As far as using the buttons to control everything...its easy. While the cover is off the headunit and its turned on you manually push in on the tab that an actual tape would hit when its inserted. This will make the tape deck think a tape is inserted and it will pull pull it in then the tape carrier will hit the "tape inserted" microswitch in the back. Your deck/headunit now thinks an actual tape is inserted and you can use the tape/cd button to go back and forth from your aux input to the CD player in the trunk if you have one. I did it this way because those fake tapes with the cord on them make a ton of noise as the drive motor spins. With no actual tape inserted it whisper quiet. You only have to do it once. Even if you remove the headunit from the car the tape player stays in what I call "tape locked in" position. If you hit the tape eject button you'll have to reach inside the tape player and carefully push in on that tab again to make it pull the nonexistant tape in and lock down.

NJDave

12-06-2011, 05:51 PM

"... are you using a "stereo" cable? ... I also don't know what you have for wiring or connectors. ... What kind of plugs and receptilces are you using?

Q:
Are you using a "stereo" cable?

A:
I have been using a direct 30 pin connector to male stereo 1/8" mini
jack (a P.I.E. Universal cable, that is connected to a Radioshack 1/8"
female panel mount on the back of the C33 Cassette deck (I drilled a hole
in the heat sink and mounted the female jack to an aluminum extension
wall I soldered to the chassis, behind the "holed" heat sink opening).

__________________________________________________ _______________

I'm just wondering if you are connecting the iPhone from the internal headphone jack, or using a 30 pin connector coming off the bottom of the phone?

I may try grounding the new wiring ground to the chassis itself, but I would think the ground terminal on the Radioshack jack would be enough to accomplish a good ground.

I don't have a direct stereo male to male 1/8" cable to test if this would be a better way to connect ... rather than the 30 pin outlet. There may be something to the fact that the direct 30 pin connector may be sending a more pure unprocessed signal to the deck, and over-loading the AUX input signal (although this shouldn't really happen), as opposed to using the internal headphone jack of the iPhone/iPod Touch .... where the signal is coming from a digital signal processor that control the "processed equalizer" setting outputs.

I'll have to get a male to male connector cable and try the headphone jack off the iPod Touch ... and see if that is any better for sound.

flyfishvt

12-06-2011, 06:05 PM

I wouldn't even know where to begin with a setup like you have. I kept it simple. I use the headphone jack on my I-phone. I've also tried it with a mp3 player I have and it works with that too.

NJDave

12-07-2011, 05:17 AM

My understanding is that the audio output on the iPod & iPhone 30 pin dock connector, is that it is a "fixed" line level output, and it also can't be controlled using the volume setting on the iPod/iPhone (only the MID unit volume knob works with the 30 pin dock connector). Only the headphone jack audio output is controlled using the volume setting, directly off the iPod/iPhone.

So I'm thinking, this so-called 30 pin dock connector "fixed line level output", of the iPod/iPhone, may just be too much sound output level for the tape circuit to handle ... and some how it's distorting the input signal to the re-wired tape circuit AUX output I've done.

I get back with my results, when I've had an opportunity to just run the line from a headphone stereo jack, on an iPod Touch, to the AUX input jack.

M3C

02-26-2012, 03:33 PM

That solution has been used for years through an interface like Dice or Dension. You can get an extra module that even makes you switch between the original changer or the aux channel.

Are you saying that with Dice or Dension interface you can still use the original CD changer or the interface just by switching? Switching - plug unplug or with a switch?

TheGuy34

09-14-2012, 03:18 PM

Hey m2pc what ever happened with the direct to processor approach? I cant get good quality out of the soldering to tape deck technique.

NJDave

10-10-2012, 04:30 AM

To follow up on my final C33 AUX conversion observations.
Probably a little late, but better late than ...

In following up on my AUX conversion of the BMW C33 Tape/Radio Cassette Player, I was actually able to confirm having the unit work through wiring to the tape head inputs on the lower circuit board. I was also able to confirm that using the Apple "earphone" jack (on my iPod Touch), was the better connection method to use, rather than connecting through the lower 30 pin connector port.

In using a standard 1/8" stereo cable, coming out of the iPod Touch "earphone" jack and connecting to the C33 "modified" AUX input jack, I was able to have the C33 AUX modification work perfectly. The sound is great, and pretty much matches CD quality (that of course considering coming from an mp3 player - iPod Touch). I also found that in using the iPod Touch "earphone" jack output, I was also able to adjust the sound quality using the internal iPod Touch Apple (EQ) equalizer settings (reduce bass, increase bass, rock, flat, acoustic, loudness, treble booster, etc.). This way, the sound output could be almost "custom set" for various sound listening/car interior situations.

With using a "blank tape" in the cassette deck, when using the AUX input, I didn't notice any real objectionable tape deck/tape noise, except the occasional tape "auto A-B side flip" (but using a long play tape of 60 minutes or more helps in this area). Also, with the BMW outer C33 "cover door" closed, there wasn't really any issue with tape noise.

Over all, this C33 AUX conversion turned out very well, and the sound quality was excellent, obviously, depending on the overall quality of your speakers and using high quality mp3 audio files of 256-320 VBR (typical lower quality mp3 audio files (128 kbps or lower) will obviously not produce sound of a higher quality).

m2pc

10-10-2012, 04:57 AM

Hey m2pc what ever happened with the direct to processor approach? I cant get good quality out of the soldering to tape deck technique.

It works fine for my setup, EXCEPT:

1) I had originally planned (and built) an auto-switching circuit using an op-amp and some relays, but it never got wired correctly and doesn't work unless the car is not running (key in "ACC" position). This was intended to detect and automatically switch the audio signal from the external device into the audio path of the C33/C43, directly to the TDAxxxx audio processor. When the AUX signal was paused or disconnected for a certain number of seconds, the relays would fall back to their default state, thus allowing the normal stereo operation.
2) As a result of #1 not working, my head unit is in permanent "AUX" mode. Meaning I have to launch an Internet radio app on my iPhone if I want to listen to any local AM/FM stations.
3) Due to #2, when the cable is unplugged from my iPhone, I get a TON of engine whine/noise in the system.

When connected to a good audio source, however, the sound quality is excellent!

flyman3456

12-15-2012, 07:17 PM

Look an empty post....

Look an empty post....

And now that I have 15 posts...

So I originally followed the diy aux install and had soldered my connections to the tape board. This resulted in really poor sound quality. Following some of the info posted in this thread I was able to make a direct connection to the TDA7328. Pins 10 and 14 are for the tape input. 13 and 9 are the CD input. Also, this method disables the ability to play tapes. (although it only takes 20 minutes to revert back)
Tools required:
- A decent soldering iron, tip cleaner, and solder (i used a $20 radioshack)
- Wire
- Heat shrink tubing
- RCA and 1/8 inch plugs or your choice
- 2 x 2.2 microfarad capicitors http://www.radioshack.com/product/index.jsp?productId=2102479&znt_campaign=Category_CMS&znt_source=CAT&znt_medium=RSCOM&znt_content=CT2032230

I now have an aux input that sounds just as good as the cd input.

Hopefully these pictures provide enough explanation.

https://lh5.googleusercontent.com/-AqCYmX5oYfM/UM0O_D5CZ8I/AAAAAAAADEE/8umTjaybjkI/s704/2012-12-15

https://lh5.googleusercontent.com/-vLI7afb5eOM/UM0O7Zmo_-I/AAAAAAAADDo/bJLLsR8vJuk/s1063/2012-12-15

https://lh4.googleusercontent.com/-V9ptncZnu9E/UM0O4d-YmmI/AAAAAAAADDQ/Nux45bDhoa8/s704/2012-12-15

https://lh4.googleusercontent.com/-LfV448xCPyg/UM0PBl6LWoI/AAAAAAAADEc/LZnqPMwXciQ/s704/2012-12-15

https://lh4.googleusercontent.com/-WsNDwyBkcA0/UM0PDxzSOJI/AAAAAAAADE0/MRMv9w2pC4E/s704/2012-12-15

https://lh4.googleusercontent.com/-pkXx8N76zh0/UM0PGkUrIdI/AAAAAAAADFM/k0yHcuQHZs0/s704/2012-12-15

Reference the TDA7328 datasheet. http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXytuz.pdf

405style

12-15-2012, 07:57 PM

yeah i just use a tape adaptor for the oem look. Sub takes care of the lows, highs are fine on tape adaptor.

TheGuy34

12-18-2012, 10:56 PM

So I originally followed the diy aux install and had soldered my connections to the tape board. This resulted in really poor sound quality. Following some of the info posted in this thread I was able to make a direct connection to the TDA7328. Pins 10 and 14 are for the tape input. 13 and 9 are the CD input. Also, this method disables the ability to play tapes. (although it only takes 20 minutes to revert back)

Hey it looks good! I can't stand the soldering to the tape board technique. Ive done it and re-done it like 5 times and it just sounds terrible. I cant put my phone above 50% volume and I have to turn the radio all the way up, then it just qets all fuzzy. Anyway, I just have a few questions.

1) How do you use the input? ie; put a blank tape in?
2) In the picture, is red positive, green negative, and black ground?

Thanks,
Brian

Surfin

02-26-2016, 08:02 AM

It works fine for my setup, EXCEPT:

1) I had originally planned (and built) an auto-switching circuit using an op-amp and some relays, but it never got wired correctly and doesn't work unless the car is not running (key in "ACC" position). This was intended to detect and automatically switch the audio signal from the external device into the audio path of the C33/C43, directly to the TDAxxxx audio processor. When the AUX signal was paused or disconnected for a certain number of seconds, the relays would fall back to their default state, thus allowing the normal stereo operation.
2) As a result of #1 not working, my head unit is in permanent "AUX" mode. Meaning I have to launch an Internet radio app on my iPhone if I want to listen to any local AM/FM stations.
3) Due to #2, when the cable is unplugged from my iPhone, I get a TON of engine whine/noise in the system.

When connected to a good audio source, however, the sound quality is excellent!

Bringing the thread back from dead... :devillook

So this method would alow me to use the C33 unit with the entire tape assembly/drive off, always in Aux mode, is this correct?
If that's the case, now we have the definitive solution HERE (http://www.ebay.com/itm/Wireless-Bluetooth-12V-MP3-WMA-Decoder-Board-Audio-Module-TF-USB-Radio-For-Car-/121846311946?hash=item1c5e9b2c0a:g:7KQAAOSwNyFWeS7 h) !! :redspot

I already have all the parts, just need to confirm before the soldering starts. My plan is to remove the entire Tape unit and install this module just behind the tape door, when not in use (without a flash drive) is looks 100% OEM. With a USB unit, the door stays open and we can use the remote to operate the module, cicle between sources (including FM, just need an extension from external radio antenna), change music and all.

Surfin

02-27-2016, 03:17 PM

Update:

I removed the Tape drive and wired the mp3 module directly to the TDA, but as soon as the unit displays "Tape Error" the sound is muted.
With the tape deck on I get sound, but this way I don't have space for the module.
Sound quality was excellent in both tests.

I also considered removing all tape deck parts and leave just the tape mainboard, but this don't guarantee that I will not get the tape error again. The tape deck works perfectly, I think it's not worth the risk, plus I would risk loosing this partial working (as I would have no more tape)

Any tip in about bypass the tape drive ok check?

For now it looks like this:
https://lh3.googleusercontent.com/mkQhbZmdb_nRujSx3Hrjw-gcHFsPbV_fwRUM4Iz77lzOK6zxBEWaJAeWeZARnplZRXxE39w-y0-GMKkv8gel0Hrj0uO9N3SnUgIm9KAbH7DZcZgXLsOO-uW1VQXVt7W7fEHw1e4tP3vsu4etiLlkHK3AR-wkkTq_Tc6Btozm1SAz8Wjfscja4KpMjzYa7N4fCKGaA3rQcX15 P-rHXEjk0x9Ot-62sCckkPaxRe8e6qIsQPcc_8QgpX3M8UdPa0RwIW2tMV4LgMlo 3ODiNkSLYuQlNdkvZDfOwm3o1J50RijCSoLH3-A2H6MaNqO_wIJySt2lJd7oNoSJHXWxxRWhSr10i9qq4rj7934w W90bSIsSp7Fkh3YUx_eSSrQQYQrYgus255qIbdO2ypivvErYfX Yl3VhSH37RU4a2OFv9pta_WhSHUGimOX_w1iSc0CfquC9GV-aqxH3nJO5nX51L5y6ohx80vn1A9aCilUPY3grUFtua1OhSh4su pzfXXT7V45gsFn4yZ_Qae4By3qP0f5gbdVzxvcpytApOPMYZoT x6Ze8MaBlvQTJAcejDx-UXHFIW=w1723-h969-no

Lukitas

05-19-2016, 09:03 PM

So right now i am tapped to the Cassette player should i do what flyman did? will i get better sound from there or should i just leave it how it is in the tape inputs.

Surfin

05-25-2016, 08:34 AM

Fix.a.ZX

10-01-2018, 12:41 AM

I soldered directly to the board using capacitors, sound was very good.
But because I could not fit the mp3 module inside the stereo unit without removing the cassette assembly (removing it causes TAPE ERROR and no sound output), I droped the project and got the specific mp3 module for the C33, C34 and CD43, that goes attached to the cd changer port, works perfect.
Looks like this one: http://image.made-in-china.com/43f34j10BOTQFLbqHGkz/-E36-E38-E39-E46-1200LT-X3-X5-.jpg
But it's not this brand nor have bluetooth. I liked and recommend.

Hey you were onto something, but the reason you weren't successful in removing the tape deck without error is because the radio expect certain trigger points to be open or closed circuit in order for the tape mechanism to work. Now those triggers are in form of micro switches throughout the tape mechanism. remove the entire circuit out from the tape mechanism (the flex board circuit) and as you are doing so, glue all of the micro switches and hall sensors you find in their resting position (the hall sensor is on the bottom gears, you might need to glue that gear onto the sensor in a certain position). I've not done this fully as I'm not so obsessed with the factory radio but I have gone so far as to open a radio and do it on a test bench.

good luck

Lukitas

10-02-2018, 07:14 PM

Hey you were onto something, but the reason you weren't successful in removing the tape deck without error is because the radio expect certain trigger points to be open or closed circuit in order for the tape mechanism to work. Now those triggers are in form of micro switches throughout the tape mechanism. remove the entire circuit out from the tape mechanism (the flex board circuit) and as you are doing so, glue all of the micro switches and hall sensors you find in their resting position (the hall sensor is on the bottom gears, you might need to glue that gear onto the sensor in a certain position). I've not done this fully as I'm not so obsessed with the factory radio but I have gone so far as to open a radio and do it on a test bench.

good luck

Can you do a quick DIY showing what needs to be removed to be able to delete the cassette module please.