Understanding E30 speaker and amp wiring

[nando]

yeah, I wondered. I think I left it attached to the radio that I ended up selling for probably $5. Doh! I see it's still available new, I should order one before it goes NLA.

I'd pat myself on the back, but I feel like I dodged a bullet. When I first looked at it again, I had no recollection of how I'd wired it originally and feared the worst (it was almost 20 years ago, lol). But earlier when I was even younger and especially dumber, I cut a huge hole in the hood of my '67 Dodge Dart to put in an ugly hood scoop. Ugh. I regretted it instantly, and ever since then I've had an aversion for permanent, irreversible mods.

It's funny because of course when I originally did this, I didn't listen to tapes - I wanted a CD player, and later MP3s were the thing. The stock stereo I didn't assign any value to. Now I mostly listen to the radio, and I don't exactly blast the tunes. I've had the blank plate for nearly 10 years now, and honestly I'd be pretty happy with a stock, unmolested sound system vs nothing at all. Now I kind of want to make a mix tape of some 1990's music, lol.

[Scottie409]

Hello, am replacing the head unit on my 91 318i Converible with a Pioneer CD bluetooth unit and removed the KE83ZBM and didn't realize there was an auxiliary amp on this vehicle.
Where is the amp located on a convertible?
thanks in advance
Scottie409

[nando]

is it in the trunk next to the antenna just like a sedan? you have to pull the carpeting off the driver's side.

also, is your KE83ZBM for sale? Does it work?

[PNWE30M50]

I wanted to try and help others in return and thought maybe a video could do that.

Luke's massive original amp bypass thread helped me out a lot. So much reading! I posted over there as well in case others are looking.

I have a 1987 325es, CM5907, premium sound, fader in dash (6 wires), and a stock amp in the trunk. Went with a Continental TR7412UB-OR, bypass stock amp/repurpose fader wires, rewire fronts/tweeters.
Please let me know if you see something I did wrong so I can fix it!!! I am also garbage at talking while filming...so sorry in advance.

Hope this helps someone

https://www.youtube.com/watch?v=lXYdEnJJVnU

[zaq123]

Maybe someone can help me to figure this part. I'm trying to connect stock CM5908 stereo to aftermarket amp. My late e30 had no stock amp. I'm connecting CM5908 speaker outputs to hi-level inputs on the amp and for some reason amp doesn't like it (it shuts off after a few secs). I discovered that even though CM5908 has 4 chan. 8 wire speaker outputs, all 4 speaker "-" are actually connected to the chassis ground internally in the stereo and as a result to the car ground. Could it be that the amp doesn't want to see hi-level input signal with"-" leads on every channel being grounded?

[zaq123]

Maybe someone can help me to figure this part. I'm trying to connect stock CM5908 stereo to aftermarket amp. My late e30 had no stock amp. I'm connecting CM5908 speaker outputs to hi-level inputs on the amp and for some reason amp doesn't like it (it shuts off after a few secs). I discovered that even though CM5908 has 4 chan. 8 wire speaker outputs, all 4 speaker "-" are actually connected to the chassis ground internally in the stereo and as a result to the car ground. Could it be that the amp doesn't want to see hi-level input signal with"-" leads on every channel being grounded?

figured it out. My Kicker KEY amp didn't like to be turned on by only hi-level speaker input signal from the CM5908 (one of the Amp's options where remote turn-on wire can be left taped off and dip switch set on DC). Connected amp's remote turn-on blue wire to 12V, switched the dip switch to +12V and all is good. Actually sweet little amp, fits into the Airbag ECU bracket perfectly and even mounting holes on the bracket work with a little modification). Just had to extend LF blue wires from the middle of the dash to the amp (mounted in the airbag module location, LH side of the dash), the rest of OEM wiring worked perfectly as they all go through the left side of the dash. Basically , CM5908 speaker outputs to the AMP hi-level in, AMP speaker outputs to stock wiring. AMP is only 200 W so fits perfectly for premium sound speakers without straining the amp (45W/ea.)

https://www.kicker.com/app/manuals/47KEY2004.pdf

[jhaurimn]

Hi, coming out from retirement to post a correction on the original post. For the picture of my car for the older 2 channel amp bypass, make sure you only connect the speaker negatives together. (the right most bundle in the picture) In my example, I had the radio ground paired up with this, which was causing my headunit to overheat and volume would eventually go down and silent after a few minutes as it heated. Youll want to remove the ground from that bundle and either cap it, or attach it to a nearby ground location.

[bradnic]

Hi, coming out from retirement to post a correction on the original post. For the picture of my car for the older 2 channel amp bypass, make sure you only connect the speaker negatives together. (the right most bundle in the picture) In my example, I had the radio ground paired up with this, which was causing my headunit to overheat and volume would eventually go down and silent after a few minutes as it heated. Youll want to remove the ground from that bundle and either cap it, or attach it to a nearby ground location.

updated the original post. need to be clear on which grounds you're talking about though - it's easy to get confused. The speaker ground connections on the actual speakers vs the radio and amp grounds. with a no-amp system the speaker grounds are the same as the output ground connections on the radio. that's not the case on a BMW SOUND SYSTEM setup with trunk amp. you can see all of this in the schematics:

1) in a no amp system, the speaker grounds are connected to the radio outputs, not to the radio chassis. the radio chassis itself is grounded separately.

2) if you have the trunk amp, the speaker grounds are connected to the amp outputs, not the amp chassis. the amp chassis is grounded separately. the radio chassis is also grounded separately, and only the positive radio outputs are used.

If you read the above carefully, you'll notice the speaker grounds are never grounded to the chassis directly in either setup.

so yes, on a BMW Sound System setup with trunk amp, keep the output ground wires from the radio separate from the amp output ground wires (which are also the speaker grounds).

[jhaurimn]

2) if you have the trunk amp, the speaker grounds are connected to the amp outputs, not the amp chassis. the amp chassis is grounded separately. the radio chassis is also grounded separately, and only the positive radio outputs are used.

This ended up being the issue, they werent kept separate. Apologies I didnt/couldnt clarify this sooner. The car had a bad battery which I attributed the radio issues with. Turns out it was a different issue all together. Glad it wasn't worse because the heatsink on the radio got insanely hot.

[bradnic]

This ended up being the issue, they werent kept separate. Apologies I didnt/couldnt clarify this sooner. The car had a bad battery which I attributed the radio issues with. Turns out it was a different issue all together. Glad it wasn't worse because the heatsink on the radio got insanely hot.

We should all be grateful you posted your note. I made some changes to the post to clarify the above. Honestly I didn't look at it closely enough when you first sent the pic. I should have caught it then. Glad the radio is ok.

[PNWE30M50]

bradnic/jhaurimn,

Can you please look at my youtube video that I posted (post #34)? https://www.youtube.com/watch?v=lXYdEnJJVnU I performed (what I thought was correct) an amp bypass/Continental HU install on my 1987 325es. Car is an early model 2 channel setup, has fader in the dash and premium sound system.

Everything works perfectly (HU can be used for hours) but with your recent "correction update" I am thinking I did something wrong. Looking at timestamp 7:16 in my video for reference, I simply separated the stock violet wire (ignition 12v) from the stock brown/black ground wire(s) and connected them to my new HU ISO connector accordingly.

My questions is this, the stock brown/black ground wire was actually 2 wires. Just like the schematic says but I didn't separate them. I just hooked it (them) up to my new HU ground wire?

Is this a mistake?

[andrewgrhogg]

OK people - resurrecting this slightly old and dead thread, just so i can add in what worked in my case. I have a 1985 325e, with the -2 radio - as in Fader, no amp in back, no tweeters. Not many people seem to have this set up and most of the posts here and on other forums are for the other systems.

So, here were the keys for my set up. Note that i was going for "good enough" sound, in an almost 40 year old car, that isn't the quietest machine on the road to begin with! As in, why would i spend a butt load of $s on an excellent sound system when the amount of "noise" in the environment is just going to impede on all those lovely high and low notes. I don't need thumping bass, and i don't need neighbours 3 blocks down to hear my music, but i do need clarity so i can actually hear the words and the individual notes, and i need it loud enough to hear when im driving with the windows down. And i wasn't looking to spend a fortune on a car that i could sell tomorrow for maybe $15k. So, here is what i did. Note that my stereo system was 6500-2, and everything was original including all 4 speakers and all wiring, and i had the original head unit still. No Amp!

1. Installed a new head unit - Continental TR7412UB-OR
2. Installed 4 new speakers - Rockford Fosgate R1525X2 using all existing wiring
3. Did not need to do any additional wiring, or burrow around inside the dash to unwrap wires etc.
4. All the balance and fading works fine, despite numerous people here and on other forums indicating it would not. I looked at the wiring diagram, disagreed with peoples thoughts on ground wires and shared wires not allowing different voltage drops to different speakers (Fade and Balance), wired it up the way i thought it would work, and bingo - it works fine. FYI i have a dual engineering degree, in Mechanical and Electrical engineering, so id like to think i have some idea what im doing! :-) In this case, i did...but no promises for the future...
5. The key for me was to do the following
a. Remove the Fader from the dash, and undo 4 of the 6 wires. I left the Yellow and Blue wires in the small harness, just as a way of keeping them from touching everything else. You could of course remove them and then tie them off. Neither wires is used in this configuration.
b. From the Fader, used the Yellow/Red and Yellow/Black (Left front and left rear positive speaker wires) and the Blue/Red and Blue/Black (right front and right rear positive speaker wires) and connected to the relevant 4 "positive" speaker wires from the head unit.
c. From inside the dash, from the wires that were connected to the old head unit, connected the yellow/brown (left front and left rear combined negative wires) to the two "negative" wires for the left front and left rear speakers. So this is three wires connected together.
d. From inside the dash, from the wires that were connected to the old head unit, connected the blue/brown (right front and right rear combined negative speaker wires) to the two "positive" wires for the right front and right rear speakers. Again this is three wires joined together
e. The blue and yellow solid wires from inside the dash are tied off so they dont touch anything. The yellow/brn and blue/brown are also tied off so they dont touch anything. They are NOT tied into any grounds.
f. The solid brown wire from inside the dash is connected to the ground wires on the head unit.


I think that covers all the wires, other than the power wires which people have mentioned above already. All the Fading and Balancing works fine, and even if you turn up the volume and have all the sound going to one speaker, there is no distortion etc. Note that if you have Zero sound set for two speakers using the balance or fade, that a little sound will still come out of those speakers. This is the joy of the shared negative wires for two speakers. However, you wont be able to hear it unless you stick your ear close to the speaker - so. not an issue.

This set up cranks sound, is clear on all notes, doesn't have speaker sound issues at full volume, allows Fade and Balance to work, has Bluetooth, will have the unit come on automatically when you turn the car on, and only costs $140 for speakers, and $174 for the head unit. And, most importantly, does not require running new speaker wire, or digging around in the dash unwrapping wires. The old adage stands true here - "Don't let perfect be the enemy of good enough".

[The_Glory]

Hello, colleagues.
Interesting topic.
I am going to install the original sound system with an amplifier.
There are several questions about it.
1. I have front speakers of a BMW, but from the E38 - with an additional pair of contacts for connecting a hands-free standard telephone. They do not have a coil of wire around the magnet. How critical is it? How to connect them correctly?


2. I still don't have the original rear speakers. There will be Clarion 2-way speakers temporarily. Everything is clear there with the wiring, but not quite clear with the connectors for the rear speakers on the wiring. Judging by the photo on the Internet, the same rear speakers were used on e23, e28 and e30, which had ordinary flat contacts and corresponding flat contacts on the wiring. My wiring has rear speaker connectors with cylindrical contacts. I received the wiring without number tags, with the main connector cut off and without the contacts of the front speakers - this is probably the result of the "mp3 upgrade" of the 2000s. But the rear connectors, apparently, are factory. What speakers is this wiring for? Is it not for E30? I saw the same wiring on the Internet, with the same connectors.



3. Where exactly is the ground, marked on the diagram in the ETM as G106, which comes from pin 10 of the amplifier connector, screwed? Judging by the wiring, - somewhere near the rear left speaker, but I don't understand exactly where... And also, - a separate terminal on the body of the power amplifier - is this also another ground?


PS
By the way, about the colors of the wires and the scheme. Apparently the schemes and colors for the European market are different from the American market. I (and all my other friends) have audio wire colors that do not match the colors listed in the American ETM. Also, we are completely missing the C243 connector. Is it used for an additional fader control?
It's a bit confusing, but I figured it out and de-foamed the radio and amplifier connectors. I can show it here later, but the text is in Ukrainian...

[bradnic]

bradnic/jhaurimn,

Can you please look at my youtube video that I posted (post #34)? https://www.youtube.com/watch?v=lXYdEnJJVnU I performed (what I thought was correct) an amp bypass/Continental HU install on my 1987 325es. Car is an early model 2 channel setup, has fader in the dash and premium sound system.

Everything works perfectly (HU can be used for hours) but with your recent "correction update" I am thinking I did something wrong. Looking at timestamp 7:16 in my video for reference, I simply separated the stock violet wire (ignition 12v) from the stock brown/black ground wire(s) and connected them to my new HU ISO connector accordingly.

My questions is this, the stock brown/black ground wire was actually 2 wires. Just like the schematic says but I didn't separate them. I just hooked it (them) up to my new HU ground wire?

Is this a mistake?

So sorry I missed this post. I commented on your vid. GREAT JOB.

It would be great for folks to post pics of the 4 wiring setups in the 1st post. I will continue to add pics as I find them.

EDIT: added some comments to your video, cross-posted here

@2:32 those are both positive, blue/black for rear, blue/red for front. same for the yellow pair.
The 2 channel premium sound cars used a common brown/black ground wire between the radio and the amp. That wire was then grounded to the chassis. You can see all this in the 2 channel BMW Sound System schematics showing the "digital radio" and the "amplifier". There is no "speaker ground wire" going to the radio in this setup.

@2:59 you have brown/black wires connected to the positive speaker wires so you've ended up reversing polarity on each of those speakers. if all four are reversed then you won't notice a lack of bass from phase shifted speakers. I

t would have been cleaner to just do the 2 channel amp bypass in the r3v thread.
Here's what you could have done, under the rear seat, no need to cut the trunk harness and leaving all the speaker wires alone:
speaker + to radio +
- blue red to grey white (right front +)
- yellow red to grey violet (left front +)
- blue black to black white (right rear +)
- yellow black to black violet (left rear +)

speaker grounds to radio out ground
- grey brown, black brown, grey violet, black violet from speakers can be tied together, then to a separate added speaker ground wire run to the radio

chassis ground (keep separate from speaker ground)
- thin brown black to brown

[Ducky11]

It's been asked a few times and I can't seem to find any real answers: Does anyone know the pinouts for the CM5908 CD player plug? I'm trying to make Maakbaas's bluetooth adapter work but CM5908 needs a customized cable. If I can find the pinouts I'm pretty confident I can make it work. Anyone?