Build and install your own AUX Cable!

[craig3.2]

well.. as I've now returned to the world of BMW.. it's only fair I offer my services building these again
Prices are still the same, but I can now offer iPod/iPhone connectivity and charging for an extra tenner.
it does NOT provide control from the headunit (yet.. still working on that).. but it does provide audio as well as charging.
Works fine on my iPhone 3Gs, iPhone 4 and iPod Classic it is NOT tested on anything else!

Welcome back,ian..glad to see u back posting again. have u got a diffirent z4 now?

 

[Marius]

Marius how do you charge it? (don't just say plug it in...!) What with it being there?

No charging option, but it's not a problem to me

Sent from my LT18i using Tapatalk 2

 

[Woody]

Ok cool, so when battery gets low you just remove from its position and give it some juice right?

 

[Marius]

i guess :lol:

i could fit in car charger, but i'm not exactly apple fan , only bought the ipod so i could play Flac. files on my old setup , now it's useless as oem system sounds crap anyway

 

[ITAG]

I couldn't be bothered making my own cable and living two mins from a BMW garage I just ordered the OEM lead for £40.
I asked for an install price too and they quoted 1.5 hours!!!' £208 all in!
Holy #%*!
They said as I had the CD changer this would need to be disconnected, but from what I've read this is not actually the case?

Anyway the cable arrives this week and I shall try and follow the instructions and install this myself. Anyone in Hook Hampshire?

 

[bcworkz]

If the cable has the complete connector, in order to use it instead of the one already there, you would loose nav audio and bluetooth, not CD. You obviously don't want to lose those if you have them, so you would in that case either swap connectors or simply splice wires if they are in place. It's hard to remove the individual connectors without damage unless you have the proper release tool.

Overall the only other tricky part is removing the centre vent to access the head unit, but easy once you know the trick. The rest is simple.

 

[SaveTheKakapo]

Hi Guys,

Having just acquired my (2004) Z4, an aux in was high on my list of things I wanted to add so I was glad to find such useful info here. As I'm soon to embark on the project I wanted to just ask a few quick questions in case anyone had any thoughts.

Is there any specific reason to use tantalum capacitors, would using ceramic capacitors not avoid the polarity issue?

Did anyone get to the bottom of the 0.22uF vs 0.22 F capacitance issue mentioned by Delboy691 on page 12? Which one is correct?

Also does anyone know if (and how) you can pop out the little cone (and or the clear plastic square near the bulb) from the ashtray? I would like to mount the female jack plug in the gap but am worried about breaking it.

Cheers, and thanks for the info!

SaveTheKakapo

 

[SaveTheKakapo]

Hi again,

Always impatient I have duly soldered and installed the circuitry and am pleased with the result - thanks again to all for the info.

In case anyone else stumbles upon this thread with questions similar to mine I thought I might as well post what I found.

On the issue of tantalum and polarity, I have read lots of comments from people suggesting that tantalum makes for a poor coupling capacitor due to degradation if exposed to a reverse voltage (apparently they "can handle only a few percent of rated voltage"). I'm not sure exactly what voltages the caps will be exposed to from an audio source, presumably small enough for this to not be too big of an issue (I couldn't even measure it with my standard multimeter). Electrolytic capacitors seem to be commonly suggested for audio applications instead. Wikipedia also has some interesting info on thermal runaway in tantalum caps.

Regarding the capacitance value,

http://diy.ecpaudio.com/p/some-notes-on-coupling-capacitors.html:
Coupling caps, together with input and output impedances, create high pass filters. This means that frequencies above a certain point are passed while those below are not...capacitors will also induce phase distortions in frequencies up to about 10x higher than the 3db point.

Presumably this is the root of the bass loss. I understand that the larger the capacitance the lower the cut off frequency with 4.7uF being a commonly chosen value.

From:

http://headphonehaven.com/topic/7120097/1/
the 2.2uF fairs better for instrumental pieces while the 4.7uF fairs better for most music especially vocals.
I would take the 2.2uF for my classical or instrumental songs and the 4.7uF for any other genre.

Although my cable sounds OK, if I were building the circuit again I would be keen to try a pair of 4.7uF electrolytic capacitors to see how the sound differed.

Finally regarding the little cone in the ashtray, you can remove the metal plate on which it is installed by simply pulling it vertically out of the ashtray tray. It is held in by two little metal barbs which clip into the plastic tray at the sides. I found that this allowed me to run the cable under the tray and through the bulb window (without any drilling) and to store the 3.5mm jack in the ashtray cone when not in use.

Apologies for the lengthy post but I hope it may help someone else. If any electronics buffs have any thoughts on the above I would be keen to read your thoughts.

SaveTheKakapo

 

[robjonaldo]

So something strange happened to me when I tried this mod...

The cable would not work in port c pins 3,4,10 (or any other combination I tried)

As I was about to give up I tried it in port b removing the CDC changer plug and plugging my cable into the same pins the CDC was using. (2,8,9 I think it was) this then works on the CDC setting fine with the iPod.

So why does it not work in port b as an aux? I would like to be able to keep the cd changer and have the ability to make the audio louder using aux mode as someone said was possible. I know the cable works fine but just not showing up as aux.
Any ideas?

The only thing I have not tried is plugging it in the aux and leaving it for a long time to give the car chance to recognise the new lead? I didn't think this would make a diffrence but not sure

 

[Toe-side]

Completed my installation today. Business head unit with CD changer .2003 Z4
3,4 and 10 worked for me in the 'C' socket.
Bit of a pig getting the connectors onto the pins (Eye sight!). I butchered some connectors of an old PCZ 8 block from a previous head unit fitting kit took the connectors out of the block and heat shrunk over them. Worked well.

Thanks for the original post and all the supporting work an info

 

[EddyC]

Hi again,

Always impatient I have duly soldered and installed the circuitry and am pleased with the result - thanks again to all for the info.

In case anyone else stumbles upon this thread with questions similar to mine I thought I might as well post what I found.

On the issue of tantalum and polarity, I have read lots of comments from people suggesting that tantalum makes for a poor coupling capacitor due to degradation if exposed to a reverse voltage (apparently they "can handle only a few percent of rated voltage"). I'm not sure exactly what voltages the caps will be exposed to from an audio source, presumably small enough for this to not be too big of an issue (I couldn't even measure it with my standard multimeter). Electrolytic capacitors seem to be commonly suggested for audio applications instead. Wikipedia also has some interesting info on thermal runaway in tantalum caps.

Regarding the capacitance value,

http://diy.ecpaudio.com/p/some-notes-on-coupling-capacitors.html:
Coupling caps, together with input and output impedances, create high pass filters. This means that frequencies above a certain point are passed while those below are not...capacitors will also induce phase distortions in frequencies up to about 10x higher than the 3db point.

Presumably this is the root of the bass loss. I understand that the larger the capacitance the lower the cut off frequency with 4.7uF being a commonly chosen value.

From:

http://headphonehaven.com/topic/7120097/1/
the 2.2uF fairs better for instrumental pieces while the 4.7uF fairs better for most music especially vocals.
I would take the 2.2uF for my classical or instrumental songs and the 4.7uF for any other genre.

Although my cable sounds OK, if I were building the circuit again I would be keen to try a pair of 4.7uF electrolytic capacitors to see how the sound differed.

Finally regarding the little cone in the ashtray, you can remove the metal plate on which it is installed by simply pulling it vertically out of the ashtray tray. It is held in by two little metal barbs which clip into the plastic tray at the sides. I found that this allowed me to run the cable under the tray and through the bulb window (without any drilling) and to store the 3.5mm jack in the ashtray cone when not in use.

Apologies for the lengthy post but I hope it may help someone else. If any electronics buffs have any thoughts on the above I would be keen to read your thoughts.

SaveTheKakapo

Has anyone experimented with different capacitors? I listen to a lot of bass music and am slightly concerned by the filtering that the 0.22uF might do. Thoughts or views welcome!

 

[EddyC]

Well I decided to answer my own question. After having a bit of a slow start (Maplin gave me a 56k resistor) I got my cable up and running. I started with a 0.22 and as reported bass was lacking, so after some research I opted to go for a 2.2. I think there is maybe a small improvement but nothing great. I'm going to try via a line out tomorrow which might offer a better improvement and will report back.

On a side note, my channel numbers don't appear to make the aux input any louder.

 

[bcworkz]

so after some research I opted to go for a 2.2. I think there is maybe a small improvement but nothing great. I'm going to try via a line out tomorrow which might offer a better improvement and will report back.

Well, I for one appreciate your testing and feedback, keep me/us informed how you get on.

 

[EddyC]

so after some research I opted to go for a 2.2. I think there is maybe a small improvement but nothing great. I'm going to try via a line out tomorrow which might offer a better improvement and will report back.

Well, I for one appreciate your testing and feedback, keep me/us informed how you get on.

On Sunday I tested my cable with the line out from my Creative Zen and it did sounds a little better (better than my S3 with the volume turned up max) as it cut out the hiss from having the volume set to max, however it didn't appear to help with the level of bass. I have trialed a number of EQ settings on the phone and Zen and they help but still nothing at the same level of CD or even radio.

Bottom line is this is a great cheap fix but I think it's left me wanting more and having previously has a connects2 in my old car I might go back down that route fairly quickly.

 

[tonlaan]

Tried all night to install mine but didn't get is working :headbang: .I installed it as shown in the picture where yellow is the ground. Now I did not use the capacitor and I only used a 220kohm resistor. I though the capacitors were only for the sound quality or are they need to fool the Z4 system. Let me know If it makes sense to try it in the exact same setup as explained here or if I made some other stupid mistake. Oh well at least I learned how to disassemble the dashboard.

 

[EddyC]

Tried all night to install mine but didn't get is working :headbang: .I installed it as shown in the picture where yellow is the ground. Now I did not use the capacitor and I only used a 220kohm resistor. I though the capacitors were only for the sound quality or are they need to fool the Z4 system. Let me know If it makes sense to try it in the exact same setup as explained here or if I made some other stupid mistake. Oh well at least I learned how to disassemble the dashboard.

Hi Tonlaan,

You need to use the correct resistor, I was given a under powered one which stopped my cable from working, got the right one and boom, all working.

I have tried with a few different value caps but not had much difference, haven't tried without thought. ..

 

[k31ron]

forgive my ignorance in electronics, but why do you need the capacitors?

 

[k31ron]

Built mine very easy and cheap solution but as others have said devoid of bass...sadly looks like refitting an aftermarket head unit is your best bet if you want decent sound quality and flexibility.

 

[casualbob]

Thanks for all the info guys.

I found an easy way to pop the air vents out after messing around with screwdrivers, I'll do a writeup when I can. I couldn't see the clips. Just need a paperclip!

My wire doesn't make the stereo register aux on the mode button. Everything looks OK. Continuity checks out. I'm out of time now but theoretically, for testing, if I wired a resistor across pins 3 and 4 would that be enough to register the aux on the head unit just for peace of mind?

Cheers all.

 

[casualbob]

Oops, 4 years late to the party!