3rd post - adding mp3 player WITH cd changer

[thermo]

I'd like to add an MP3 player (empeg more than likely) to the car. I want to leave the headunit stock so I can run the Audi CD-changer off it with the heads up display. Is there any way to feed into the Delta headunit without using a FM-modulator? I don't particularly want a switch for it on my dash. The ideal situation would be for the headunit to run the CD changer, but change over to the mp3 player automatically when it's activated. I've seen a few circuits on this forum, but no one really has explained to me how they work in use. I'm an engineer so I'm not afraid to break out the soldering iron or read complex schematics Thanks a ton everyone -J sorry for all the questions all at once!

[SteveK-O (stock!)]

Since you have the dreaded Delta headunit, this will be hard. For later headunits like the Concert, you can feed right into the right and left signal wires (pins 19 and 20). The head unit shows Disc 1, Track 1 and you control the MP3 player separately (so I'm told).

For the Delta headunit, this is also pins 19 and 20 on the radio (blue 8 point connector) and pins 4 (green wire) and 5 (grey/white wire) on the CD 8-pin connector. By all reports, however, it does not work for the Delta headunit. This unit is running some proprietary (Alpine?) comm protocol between the headunit and the CD player. Bus data is pin 13 on radio (blue 8-point connector) and pin 1 (red wire) on the CD 8-pin connector. Bus clock is pin 14 on radio (blue 8 point connector) and pin 3(orange wire) on the CD 8-pin connector.

Apparently the headunit and CD player need to establish two-way comm before the headunit will recognize a CD player is there and use the line-in inputs. I have not been able to stand paying $500 for the CD-player so I have not played with it yet. All reported attempts to find a accessory to solve this have come up empty. All sources that was "working on this" have never produced anything.

I've about had though. I am so sick of broadcast radio. I am contemplating attacking this problem and building an interface board to convert headunit commands to commnands that operate an MP3 player. Without the proprietary protocol, this will take some work. I will need someone in the Twin Cities to let me use their CD changer and the help of my genius software comm-protocol hacker rally-partner. He's up for the challenge. We be both engineers. If we crack this, we might build interface boards for sale, but I don't know how many people would want them. The evil Delta headunit was only used for 96-97 and early 98.

Anyway, you have a problem with no solution for now. I would love to be wrong.

Steve-O (98.0 A4 2.8QMS + 01 Passat GLX 4Motion, plotting my Delta-Apline takedown move)

[JustJeff]

As long as the CD changer is plugged into the Delta H/U, the protocol is being established.

Find the line-level audio, left, right and ground, and switch this only.
This is what I do with the Concert set-up.

The H/U should not care where the audio is coming from, unless there is something really strange about how this H/U is set up.

[SteveK-O (stock!)]

I don't have a CD changer and don't want to buy one. I have read that the Delta is a tougher comm to emulate, but no details. What I can see is that the Delta head has a bi-directional comm setup (one comm wire) whereas the Concert headunit has bus data in on pin 13 and bus data out on pin 14.

If Apline was being too clever with the comm handshaking, it possible that line switching won't work even with the CD changer. Has anyone tried it yet?

Steve-O (98.0 A4 2.8QMS + 01 Passat GLX 4Motion)

[jslerner]

Someone on the A6 forum wired an ipod to the cd changer interface with a little converter wire. I'm not sure if he knows how to have both the CD changer and the MP3 player running off the same source on the head unit. Worth a search...

[thermo]

So what you're suggesting is this:

get the Audi changer for 200 bucks on Ebay, or pick up the panasonic 8-disk changer and adapter

use the CD changer to establish the handshake with the Delta

splice in some kind of AV switch so the actual SIGNAL going to the headunit can be changed between the changer and some other RCA-level input

[SteveK-O (stock!)]

The ONLY CD changer which will correctly establish comm with the dreaded Delta headunit will not cost you $200. It will cost you $400 at the least! It lists for $600 new and you can find it new for $500. On ebay, they usually top out over $400. All the CD changers currently on ebay for the A4 will NOT work with the dreaded Delta headunit. I ordered one for $250, but vwparts.com found out that they were confused and the CD changer would not work on the dreaded Delta headunit.

Even if you do shell out the dough for one, there is a possibility that it would not work. If the CD changer and dreaded Delta headunit engage in excessive comm in the proprietary protocol, the DDH (Dreaded Delta Headunit) may know that that CD is not playing. I guess if the CD changer is really playing and you switch the line inputs, it should work for sure. When the CD stops the DDH may not play the inputs. This is where some experimentation would be needed.

I'm sure that cleared everything up.

Steve-O

[randel]

Once you find the line-level path from the changer to the head unit, splice in the MP3 signal.

Then burn an entirely blank 72 min audio cd, and play it when you are using the MP3 player.

[Steve66]

I installed a portable MD player in my A4 and patched into the analog lines coming from the CD changer. I use a switch under the dash (on the passenger's side) to switch between the CD changer and MD player. I suppose you could rig up some kind of relay that would automatically do the switching for you but, for me, that would be overkill. I leave it switched to the MD player about 95% of the time, so pushing a button under the dash is no big deal for me.

I posted information on my install a while back...look here for more info:
http://forums.audiworld.com/a4/msgs/591510.phtml