factory amp bypass (my way - lots of pics)

[tim eh?]

http://www.bimmernut.com/forum/attachment.php?attachmentid=6651&stc=1&d=1238283446

Well I'm honestly quite pleased this worked. Originally I tried to rewire the factory amp so my aftermarket head unit could run through the factory speakers unhindered (and also to confirm I had a blown speaker), but I trashed the amp in the process and it became necessary for me to make new crossovers out of the ones from the factory amp. Here's how...

These are the factory crossovers, they consist of coils and capacitors which work as high and low pass filters.
http://www.bimmernut.com/forum/attachment.php?attachmentid=6645&stc=1&d=1238283446

1. Remove the coils and capacitors from the circuit board (which for me was already in pieces).
http://www.bimmernut.com/forum/attachment.php?attachmentid=6646&stc=1&d=1238283446


2. I had to trace the circuits back through the circuitboard to figure out which was what. Once I managed that I drew myself a little diagram.
http://www.bimmernut.com/forum/attachment.php?attachmentid=6647&stc=1&d=1238283446http://www.bimmernut.com/forum/attachment.php?attachmentid=6648&stc=1&d=1238283446

[tim eh?]

3. Hot-glued all the pieces to a piece of plexiglass and then made the connections...
http://www.bimmernut.com/forum/attachment.php?attachmentid=6649&stc=1&d=1238283842

4. These little motomaster plugs are very handy, you'll see why later. Here are two labled for the front right mid speaker and rear left woofer.
http://www.bimmernut.com/forum/attachment.php?attachmentid=6650&stc=1&d=1238283842

Ready to go- NB there are two separate spliced cables in this photo. I made them with the intent of using the factory wiring for the speaker negatives, which worked but screwed up all the fading. In the end I had to use separate speaker negatives for all 4 corners and wire them straight to the head.
http://www.bimmernut.com/forum/attachment.php?attachmentid=6652&stc=1&d=1238283842

[tim eh?]

5. Next you have to remove all the little plugs from the amp plug, except for power, ground, and remote wires. Shogun posted a great thread (http://www.bimmernut.com/forum/showthread.php?t=40844)about this not too long ago and I finally figured out how to unlock the plug (use a knife!) BTW the B+(power) wire is on all the time so.... you know.
http://www.bimmernut.com/forum/attachment.php?attachmentid=6658&stc=1&d=1238280904

http://www.bimmernut.com/forum/attachment.php?attachmentid=6655&stc=1&d=1238280638

http://www.bimmernut.com/forum/attachment.php?attachmentid=6653&stc=1&d=1238280638

[tim eh?]

6. I used heatshrink around the exposed part of the plugs. The factory mini plug bit fits perfectly into those little motomaster plugs.
http://www.bimmernut.com/forum/attachment.php?attachmentid=6654&stc=1&d=1238280638


7. All plugged in.... hope I got it right!
http://www.bimmernut.com/forum/attachment.php?attachmentid=6656&stc=1&d=1238280683

Sounds much much much better except for the blown rear woofer of course, through the fronts it is #@$%ing amazing!


8. I had already drilled holes... my little board fits right where the amp was and I probably lost a couple of pounds...
when you drive an m20 you have to shave weight wherever you can!
http://www.bimmernut.com/forum/attachment.php?attachmentid=6657&stc=1&d=1238280683

note - jon spencer blues explosion is NOT a good band to eq your stereo to.

[ArnZ!]

mate you've have literally took the concept of 'bypass' to scary new levels!!! lol good work!

[Jeff N.]

help me - what's the theory here?

drop the amp but keep the crossover embedded in the factory amp?

[tim eh?]

help me - what's the theory here?

drop the amp but keep the crossover embedded in the factory amp?

Yes drop the amp, keep the crossovers.

The JVC head unit is supplying *12V as opposed to the stock unit 's *5V(?). Run those high output signals through the factory amp and you get a giant mid range bell curve which reduces the head units efficiency and kills the lows and highs. I (completely) bypassed the amp to the crossovers, which divide the frequencies to the appropriate speakers. So now I'm driving the factory speakers with a nice flat even 40W instead of the factory amp's massive midrange (I'm guessing) 15W or so. Who knows what it is when it's wired to 40W?

Before I did this the tweeters barely worked at all they are great and I am surprised at how much bass the factory woofers can take, they are only rated at 40W. I think they need a tiny bit of help... thinking single 8" nothing massive and just cut the very bottom out, all the speakers sound great I am really pleased!

oh yeah - Thurston Moore's 'Psychic Hearts' is great to eq a car stereo with

[bad_manners_god]

This is a good budget fix. However, what I did was much simplier....Ran new wires from head unit to new speakers individually and didn't have to cross anything over. Given it was tricky running wires into the roof for the touring.

[ladiesman217]

BMG: that is totally bollux... if you had kept the car longer, you would have blown the tweeters. And it sounds like ass. and it is redundant as hell since all the wiring is already laid in in nice twisted pair.

OP:

Nicely done tim eh! That's the way ya do it.

now drop about 80w rms on it instead of 17w and you'll be really happy.

[tim eh?]

Nicely done tim eh! That's the way ya do it.

now drop about 80w rms on it instead of 17w and you'll be really happy.

Thanks - i don't think the factory speakers could take 80w rms, certainly not the woofers!!!! My JVC is old skool and really efficient, the sound is great. I will replace the rear woofers, maybe the fronts too but really all it needs is a (small) subwoofer system and to block the bottom 100 Hz out of the factories and it wil sound like a million bucks.


This is a good budget fix. However, what I did was much simplier....Ran new wires from head unit to new speakers individually and didn't have to cross anything over. Given it was tricky running wires into the roof for the touring.

Cost wasn't the issue here. It was pretty simple too, easier than tearing the car apart to run new wires, although I did have to send new speaker negatives from the trunk to the head which took me a long time. I understand what you are saying but the factory speakers are easily as good as many store bought component assemblies. How did you manage to get your door tweeters to function if you wired it that way anyway?

[bad_manners_god]

Cost wasn't the issue here. It was pretty simple too, easier than tearing the car apart to run new wires, although I did have to send new speaker negatives from the trunk to the head which took me a long time. I understand what you are saying but the factory speakers are easily as good as many store bought component assemblies. How did you manage to get your door tweeters to function if you wired it that way anyway?

I didn't reuse the door tweeters. The JBL P552 are 2 way component speakers with enough sound to not need the door tweeter's.

ladiesman217: When I did this I already had the interior apart and removed ALL the original speaker wiring, amp wiring. And ran new 16ga speaker wire, not the 18ga stock. As I said above, tweeter's were not reused!

[BMWDriver]

Tim, you could make a custom PCB. There are some where you just put your components on and use wire to link them per your design, others where you literraly trace the circuit either with a chemical acid and black lights, or with felt pen and chemical acid. It's complicated, I know, but I'd like to do that myself someday. The crossover project is really appealing.

DIY PCBs:
Wikipeidia entry on PCB (printed circuit board): links to DIY guides. (http://en.wikipedia.org/wiki/Printed_circuit_board#Do-it-yourself_.28DIY.29_guides)

I worry that the plastic could melt, although I don't know how hot a crossover gets. I may be worried about nothing. Also, my amp gets doused with oil (or whatever it is they use) when I get the car treated for rust. Or you could just box your current plate with wood and another plate of plastic on top.

[tim eh?]

Tim, you could make a custom PCB. There are some where you just put your components on and use wire to link them per your design, others where you literraly trace the circuit either with a chemical acid and black lights, or with felt pen and chemical acid. It's complicated, I know, but I'd like to do that myself someday. The crossover project is really appealing.

DIY PCBs:
Wikipeidia entry on PCB (printed circuit board): links to DIY guides. (http://en.wikipedia.org/wiki/Printed_circuit_board#Do-it-yourself_.28DIY.29_guides)

I worry that the plastic could melt, although I don't know how hot a crossover gets. I may be worried about nothing. Also, my amp gets doused with oil (or whatever it is they use) when I get the car treated for rust. Or you could just box your current plate with wood and another plate of plastic on top.

I dunno man, I think it's fine like it is. It's not going to get any hotter than it got when I was soldering it and it is glued on pretty well. There is no pressure on any of the solder points, I know it looks messy but it is just speaker wire. Actually I taped a patch of the rear panel with 1/8" thick electrical tape to make kind of a mat just in case anything wanted to jump and I moved the remaining power and ground wires well away out of there.

Yeah I had some of that stuff all over the amp! I am never letting them put that rust treatment stuff in my car again! Every time I do something now first thing that happens I'm looking at my hand going "ewww what is this crap?" From now on it is underside only!

I dunno man, have fun with the PCB but don't expect me to wait up :D.


I didn't reuse the door tweeters. I think you are missing out. The placement of the stock speakers is ideal. I don't know what the setup is in a touring but in a sedan there are 2way speakers in the rear with the same amp and they don't sound anywhere near as good as the fronts. Part of the difference is that they are only 2way speakers but the main difference is the placement of the individual speakers. The placement of the factory speakers is ideal... the footwells are perfect for bass but bad for tweeters and vice versa. I don't care what amp you are driving those jbls with but my 40W jvc head + factory speakers will kick its ass no matter what you do.



...with enough sound to not need ....
in my opinion you are addressing the wrong issue - sound waves adhere to some pretty harsh laws of physics... beyond a certain point (in a car at least) "enough sound" is irrelevant and the more common problems are efficiency and even distribution.

[repenttokyo]

BMG: that is totally bollux... if you had kept the car longer, you would have blown the tweeters. And it sounds like ass. and it is redundant as hell since all the wiring is already laid in in nice twisted pair.


why would he have blown the tweeters? You have no way of knowing what caps and crossovers he was running with his wiring.

[bad_manners_god]

I think you are missing out. The placement of the stock speakers is ideal. I don't know what the setup is in a touring but in a sedan there are 2way speakers in the rear with the same amp and they don't sound anywhere near as good as the fronts. Part of the difference is that they are only 2way speakers but the main difference is the placement of the individual speakers. The placement of the factory speakers is ideal... the footwells are perfect for bass but bad for tweeters and vice versa. I don't care what amp you are driving those jbls with but my 40W jvc head + factory speakers will kick its ass no matter what you do.

Front of the Touring and Sedan is the same for speaker placement, only difference is the rear where they put the speakers in the headliner.

My speakers werent driven by an amp, they were driven by the panasonic dvd in dash 50Wx4 and there's no way you can compare stock speakers to these. Espically at 250 a pair, you DO get what you pay for. Crisp sound, with the crossover box to an adjustible tweeter.

[Derek A.]

I don't get it..

Why go through all the hassle of ripping the factory amp apart. It takes all of 15 minutes to remove the amp side and solder in wires.

I ran the headunit output - through an electronic crossover to soften the bottom end, then fed it to two a/d/s amps - which in turn run through the factory crossover - to the factory speakers. I also added a 10" sealed sub, which is fed by another amp .

The system is super clean, super loud and was a very cost effective upgrade. I am thoroughly amazed at how much power the factory speakers can handle.

[tim eh?]

I don't get it..

Why go through all the hassle of ripping the factory amp apart. It takes all of 15 minutes to remove the amp side and solder in wires.

I ran the headunit output - through an electronic crossover to soften the bottom end, then fed it to two a/d/s amps - which in turn run through the factory crossover - to the factory speakers. I also added a 10" sealed sub, which is fed by another amp .

The system is super clean, super loud and was a very cost effective upgrade. I am thoroughly amazed at how much power the factory speakers can handle.

Nice setup. So the 10" is plenty? I'm thinking of trying an 8" woofer I have on the back shelf. I know that is really small but it is such a nice speaker. Yes the factories blow me away.

I still can't figure out why it didn't work through the amp, but I did it from scratch 3 times. And then I took it to a 'pro' who screwed it up more so I had to try something else.

BMG your $250 got you decent 55W 2-way component speakers. Put them in the dash you lose your bass. Put them in the footwell and you lose your highs. The amp that is driving them is in the panasonic. They would be a good choice to replace the rears with.

[ladiesman217]

why would he have blown the tweeters? You have no way of knowing what caps and crossovers he was running with his wiring.
He himself said "none"

that is the meaning of DIRECT.

;)

BMG: those panasonics are anything but clean, and you had a grand total of 15 clean watts to them. they are bright though!!!

I'm going to push the hell out of the Nokias with an active setup, then I'll start swapping drivers for home theater stuff (peerless 2" domes are looking very nice right now) when they eventually blow. so far they have not... passive with 80w rms (or 200wx4 in headunit makebelieve ratings) :(

[repenttokyo]

He said "none"

that is the meaning of DIRECT.

;)

i guess we were both making ASSumptions.

[ladiesman217]

Dang MainE :)

[filmy540i/6]

This thread is a very interesting read. Not that I would try to bypass any of the stock components on my own, but I'm sure there have been myriad upgrades to our audio systems since my '95 was built and I need some improvement.

Do any of you stereo gurus have a link that explains what all of these components do (HU, amp, crossovers, etc)? I'm talking generalities, not BMW-specific. I would love to have a better understanding of what's involved when I upgrade my HU.

Great post, OP!

[tim eh?]

This thread is a very interesting read. Not that I would try to bypass any of the stock components on my own, but I'm sure there have been myriad upgrades to our audio systems since my '95 was built and I need some improvement.

Do any of you stereo gurus have a link that explains what all of these components do (HU, amp, crossovers, etc)? I'm talking generalities, not BMW-specific. I would love to have a better understanding of what's involved when I upgrade my HU.

Great post, OP!

Thanks! Upgrading the head unit a bit problematic because of the e34's design. (I'm no guru though, I just know a bit about acoustics)

Sorry I don't have any links except maybe here are some good examples of what people do.
http://www.diymobileaudio.com/forum/diyma-build-logs/

But, ahem, in a nutshell, in the e34 the head unit is just a signal selector (ie. cd/radio/etc) and sends 4 (FrontRight, RearRight, FL, RL) low current signals to the amp in the trunk. The amp boosts each of these signals to a level that will 'drive' the speakers (which basically work like resistors except instead of creating heat they move the cones in and out which is what makes the soundwaves). The amp sends this signal through the crossovers which split the signal up so that the low bass goes (for example) to the big speaker in the footwell, the 'mids' to the dashboard and the high stuff (eg the tsst tsst of the highhat) to the tweeter in the door. This is necessary because sound waves vary greatly in size, which is why the speaker placement is important too. The waves that make the 'tsst tsst' sound have a wavelength of a pinhead, but low bass waves are bigger than your head, so you can try and make one speaker play them all but it won't be as efficient, and will invariably lose out on both extremes when you boost the volume a bit. The 'component speakers' in typical home and car audio systems are made up of 2 or more speakers and the speakers have the crossovers built into them. The 'speaker ground' completes the circuit back to the amp.

But in the e34 the crossovers are inside the factory amp. Which is a pain, because the amplifier is the weak link in the factory system... it's just weak is all, if you want to improve the sound it is the first thing that has to be replaced. Pretty much all of the typical head units sold in stores have an amplifier built into them so you can just get anything that has a 4x?0W output and it will be an improvement, but if you just connect it to where the factory head was then it runs through the weaker (4x+/-15W?)factory amp before going to the speakers, which really kills the sound. But it's the only way to use the factory speakers without doing a bypass. Normally you should be able to do what's in the photo below but for some reason as I mentioned this didn't work for me.

http://www.bimmernut.com/forum/attachment.php?attachmentid=6633&stc=1&d=1237242683

I don't know if any of that makes sense, but that's my understanding of it anyway fwiw. It's a bit more complicated than your average car. When I bought it the (aftermarket) head didn't work and I though 'no problem, I can do car stereos easy' but it turned out to be a real bitch and it took me forever to get it working. I don't know, this kind of technology hasn't changed much since '95, and unless something breaks or you need to hook up an ipod or something I wouldn't mess with it... I never heard a stock e34 system actually, I imagine they sound pretty decent even with the feeble amp.

[repenttokyo]

how bad do standard head units sound when plugged directly in? Is it 'worse' than the factory head?

[repenttokyo]

Ah - just saw that you have never heard the factory system.

[tim eh?]

He himself said "none"

that is the meaning of DIRECT.

;)

BMG: those panasonics are anything but clean, and you had a grand total of 15 clean watts to them. they are bright though!!!

I'm going to push the hell out of the Nokias with an active setup, then I'll start swapping drivers for home theater stuff (peerless 2" domes are looking very nice right now) when they eventually blow. so far they have not... passive with 80w rms (or 200wx4 in headunit makebelieve ratings) :(

:D are you sad because you haven't blown your speakers yet? I wish I hadn't... there is one screw in the rear speaker assembly that is impossible to get at! I wish they were in the roof!

[tim eh?]

What do you mean though by standard... you mean stock or aftermarket? Now that I have heard the speakers properly I have a pretty good idea of what stock would sound like.

edit - oh i see what you mean - your average sony or whatever head unit would sound worse than the stock unit when running through the factory amp. if the new head unit has line level outs (ie rca) you could run those and might see a small improvement over the factory head but the main problem in the factory system is the amp. 'amping' the amp makes it worse. I think Derek A.'s head is a factory head if I understand it.

[Derek A.]

My head units is a blaupunkt unit - that no longer uses the speaker level outs:
http://www.opus45.com/pics/blau_xm.JPG

I have an rca that runs to the trunk and feeds en electronic crossover:
http://www.opus45.com/pics/e34_amps.JPG

Which in turn feeds three amps - one for the front 6 speakers, one for the rear 4 speakers and one for the sub.

Here is the diagram I used for the amp wiring:
http://www.opus45.com/pics/amp_wiring.jpg

Here is a shot of the factory amp section removed from the enclosure:
http://www.opus45.com/pics/e34_famp.jpg

The system really sounds great - I am very happy for the minimal investment. Nothing to crazy from an engineering perspective.

[tim eh?]

That looks great, I wish I could afford to give up some trunkspace.

Where (hz) do you crossover to the sub Derek?

I'm trying to figure it out, I want to use an 8 ohm speaker... does that double or half the frequency of a 4ohm crossover? anybody know?

*- ok i figured it out - on a low pass filter, the cutoff frequency with an 8 ohm speaker will be half of one with a 4 ohm speaker, ie 200hz @ 4 ohm = 100hz @ 8ohm.

**- check it ... soon...
http://www.bimmernut.com/forum/attachment.php?attachmentid=6663&stc=1&d=1238618175

***- and to clarify... upgrading just the head is fine just be sure to get a unit with line outs and use those instead of the speaker outs, although it will still work using the speaker outs just not sound so good.

[Derek A.]

Not really sure what the crossover point is. I basically did it by ear.

[BMWDriver]

I see wires soldered to the crossover board, but what are they connected to at the other end ? I'm starting to guess the speaker terminals of the amp box. What gauge ?

And Tim, I see black and blue wires on Derek's pic, were they missing in yours or are they already there ?

I'll soon be opening my amp later this week or this weekend.

[BMWDriver]

Huzzah for this thread Tim btw !

[tim eh?]

Thanks, glad to be of some use.


I see wires soldered to the crossover board, but what are they connected to at the other end ? I'm starting to guess the speaker terminals of the amp box. What gauge ?

And Tim, I see black and blue wires on Derek's pic, were they missing in yours or are they already there ?

I'll soon be opening my amp later this week or this weekend.

The soldered wires are the speaker level outs (black is +, green is -) from the head. You can solder the + to the plug input board or run the wires directly. The '-' is the real question mark. There is something I don't understand about how the factory system does the Front/Rear fade and it involves the way the speaker grounds are shared L and R. I would try splicing each side together first and using the factory wires but if that doesn't work you have to run new wires to the head for the speaker grounds.

I think 16 ga wire is good- use speaker wire, not power wire.

I believe the black and blue wires are part of that factory amp and mine is slightly different - I don't know what they do.

And now that I have tried it three times, I would suggest it might be easier soldering to the underside of the board, not at the pins.

Anyone else have this technicolour equalizer?

http://www.bimmernut.com/forum/attachment.php?attachmentid=6670&stc=1&d=1238671975

http://www.bimmernut.com/forum/attachment.php?attachmentid=6669&stc=1&d=1238668376

http://www.bimmernut.com/forum/attachment.php?attachmentid=6667&stc=1&d=1238671975

...this diagram comes in very handy...
http://www.bimmernut.com/forum/attachment.php?attachmentid=6668&stc=1&d=1238671975

good luck buddy!

[filmy540i/6]

I don't know, this kind of technology hasn't changed much since '95, and unless something breaks or you need to hook up an ipod or something I wouldn't mess with it... I never heard a stock e34 system actually, I imagine they sound pretty decent even with the feeble amp.
Again, great explanation and visuals, Tim.

In fact, I do want to upgrade to a BlueTooth- and iPod-capable HU, but I understand there's no way I'll be able to integrate my (factory) trunk-mounted 6-CD player. Which means I'll need a single-slot CD Head Unit. OTOH, I don't want to spend $500 on it so my choices (and options) are limited - especially if I'll have to get it all professionally installed by someone who is familiar with the E34 amp/crossover box. :(

[genphreak]

Front of the Touring and Sedan is the same for speaker placement, only difference is the rear where they put the speakers in the headliner.

My speakers werent driven by an amp, they were driven by the panasonic dvd in dash 50Wx4 and there's no way you can compare stock speakers to these. Espically at 250 a pair, you DO get what you pay for. Crisp sound, with the crossover box to an adjustible tweeter.

I disagree. My 535's 10 speaker stock setup sounds great with the OE crossover/gutted amp driven by 4x100W. I run it at nuetral (maybe +2db treble) and have 100W worth of sub cutting out at 90Hz. I don't cut the frequencies to the stock crossover at all.

It sounds great and can hurt anyone's ears, except perhaps the guy I saw throw up in a bass bin at the front of a Killing Joke concert where my ears were about to burst at the back. (I used to do PA work).

Seriously, with clean 20W of power x5 in a confined space, there is no need for anything more... the crumby car stuff marked 100W is (in reality) abut that in real terms as it is mostly 4 ohm, runing on crumby 12VDC supply... etc.

BTW; I like the total guttedness of that setup. Only problem is the hot glue, I know in Oz, the sun and a warm day would see the components all dribble off the board by the time u got back from buying ur girl an ice cream...

Whilst we're on this... Does anyone know... in a 525 touring, how hard is it to replace the rear speakers? Mine are blown as the PO fitted a Pioneer head unit which has far too much bass adjustment and causes the output to clip like hell. I reckon the rear is not going thru a crossover - and that's proly what saved the fronts.

Has anyone ever had to pull them before?

[tim eh?]

Again, great explanation and visuals, Tim.

In fact, I do want to upgrade to a BlueTooth- and iPod-capable HU, but I understand there's no way I'll be able to integrate my (factory) trunk-mounted 6-CD player. Which means I'll need a single-slot CD Head Unit. OTOH, I don't want to spend $500 on it so my choices (and options) are limited - especially if I'll have to get it all professionally installed by someone who is familiar with the E34 amp/crossover box. :(

You can upgrade the head for functionality pretty easily. You can get head units that control an external cd changer (sold seperately :))and have all the options you mentioned. Just be sure to get one that has line level outs for all 4 channels and use those instead of the powered speaker outs. No amp gutting required, just your basic head install, I believe you can get a plug adapter too, someone will know here. You would have to alter the plug slightly to use the line level outs instead of the speaker outs. The sound quality won't change, although you'd probably get better radio reception. You wouldn't be using the the new head unit's superior amp (:(), so don't worry about watts.

this would work -> http://www.jvc.ca/en/consumer/product-detail.asp?model=KD-ABT22

...just happened to have jvc bookmarked, any brand will sell heads like this.

[tim eh?]

It sounds great and can hurt anyone's ears, except perhaps the guy I saw throw up in a bass bin at the front of a Killing Joke concert where my ears were about to burst at the back. (I used to do PA work).

BTW; I like the total guttedness of that setup. Only problem is the hot glue, I know in Oz, the sun and a warm day would see the components all dribble off the board by the time u got back from buying ur girl an ice cream...


that is funny - you can't hurt those ears! :D

That is a really good tip, the car is black and can get pretty hot in the sun, although maybe not Oz hot. I think I'll eventually put my sub amp in that space actually, so I will need to redo that board anyway to move it somewhere else and also to add some more crossovers (I'm going to run another passive setup at 125hz for the sub now that I know how) so I will take that into account about the glue when I do that, maybe I'll build a box after all like bmwdriver says. Good to know it works though.

***-
I reckon the rear is not going thru a crossover - and that's proly what saved the fronts.

hey... you know... do you think this could maybe relate to the common speaker grounds and how the factory amp and head do the fading? Do you use the factory grounds or separate ones? Before I did this I had the speaker outs of the jvc wired into the factory amp using the factory grounds. The fading seemed disproportionate, with too much power going to the rear before. And the rear woofer also blew on me. Now with all 4 grounds running seperately it actually seems a little soft in the back (will soon change :D), although I had a passenger ask me to move the music to the front yesterday... didn't like John Coltrane wtf? Anyone else blown a rear speaker with their aftermarket head?

[BMWDriver]

I fixed both of my rear speakers with glue. The big black rubber rim was partly loose, making bad bass quirks, so I made it entirely loose and glued the thing. Problem solved, no issues.

[BMWDriver]

Well... just opened my amp, and I've certainly got a bird of a different kind in there. There's still coils and capacitors, but I have no clue how to bypass that one. Looks like a custom PCB will be simpler for me. We shall see. First I'll have to figure out many things like the cirucuit's design.

Unless anyone here has pointers to bypass that particular amp to the crossover.

I'm charging up my camera's battery, so pics up later.

[genphreak]

I simply ran low level Canare shielded 3mm dual core and terminated the ends using RCAs. That way it was easy to go down the console, under the rear carpet and rear seat to the amp. I stuck the amp under my parcel shelf as it was too long to go in the quarter panel. Also, better for heat and tweaking the amp's tone controls. All dodgy amps need accessible tone controls ;)

Speaker outputs goto the crossover and avoid that silly fader up front. It will only add distortion and noise into your system, so is best bypassed anyhow. It occupies a good place for a more interesting gadget anyhow.

I just use the fader on my (replaced) head unit. Couldn't bear the factory one... tho alright for its time and easy to use when driving. Dumb ass Asian units are just so horrible to use. Oh the price we pay to break out to an mp3, phone or iPod

Tip: If you have an antenna integrated in the rear window, the latest JVC head units seem to work quite well. Many others I've used seem to dislike that antenna... :) search about it (keyword: reception) and you'll SWIM...

[genphreak]

You'll need an older style amp- e34 535 ones are probaly ok (at least to '90 but maybe even to '93?)... the later ones like yours are no good for this as far as anyone has worked out (to date).

I think someone has retrofitted the old amp and done 'a gut-job' to get the ultimate setup in a later model e34, not sure who though. You should check the pin-outs are compatible- I think they are different, if so the positions might need to be changed around... BMW's privte catchcry must have once been; "Always making it different, ya! Because we can" LOL

[BMWDriver]

The diagram Tim shows matches what the PCB says for the harnesses. So it seems though the amp is different, it's the same layout for the cabling.

Pics :
Here's the monster:
http://www.quebecman.net/e34/e34 amp 09b.jpg

Here's the back of the PCB of the harness connection:
http://www.quebecman.net/e34/e34 amp 05b.jpg

As you can kind of see (letters are blurred out of focus) A6 is FRM and so on as per the diagram Tim showed. There are coils, and plenty of capacitors. I wonder that the writings on the coils are a standard thing or just part numbers. So in making a custom PCB, I might be able to re-use a lot of these parts.

EDIT :
Found an invaluable resource : Understanding Electronics Components (http://www.mikroe.com/en/books/keu/00.htm)
There is even an example of a crossover.

[tim eh?]

Yikes! That is different.

OK - like I mentioned I'm not an expert in this, I've soldered patch cords before but this was the first time I've gotten this 'dirty' when it comes to car audio. I was lucky plan 'b' worked... I suggest you should have a plan 'b'... I even had a plan 'c'.

What genphreak suggests about getting an old style amp is your best plan 'a' I think - it's a lot less work doing the bypass in Derek A's pics, your plugs are compatible plus you would have your amp as a backup.

That said, I can help you a bit to identify the components if you want to try a complete gutting like I did. The coil inductors are easy - those are the low pass filters (ie they block high frequencies) so almost without a doubt 'W03' is for the front low speaker, 'W02' for the rear low speaker and 'W01' will be combined with a high pass filter (capacitor) for the front mid (dash).

The capacitors could be difficult. Sometimes they are combined to make a different xover point, so it's not certain you are only looking for 3 of them. There will be one filter for the rear tweeter, one shared between the front mid and tweeter, and one extra for just the front tweeter. It's just they could be in pairs or worse so make sure you follow all the circuitry. Use this diagram (http://www.bimmernut.com/forum/attachment.php?attachmentid=6648&stc=1&d=1238283446) and work backwards from the plug.

*- The circuits should trace through the capacitors/coils and meet up at the pin connectors to the amp section. This is the amp output, each row is probably for a separate channel ie LF, RL, LR, RR. In each row of pins there should also be a pair of pins for the head unit output/ amp input and a pair for the speaker ground to the head also. This is normally where you would solder the hu output. It might be easier to work with if you remove the amp section. Follow me?


I fixed both of my rear speakers with glue. The big black rubber rim was partly loose, making bad bass quirks, so I made it entirely loose and glued the thing. Problem solved, no issues.

Interesting and nice fix, so you blew your rear speakers too! What kind of glue did you use?

[tim eh?]

I never had the factory fader... ? Where is it located?

Actually I do have the rear window antenna and it works very well with my old skool jvc... eventually I'll go looking for the antenna amp and play with that some :).

Sorry - still curious - I don't quite get... how are your speaker grounds set up?

And I don't have an ipod but I do have a line in anyway. Actually I can't stand most mp3s even in a car - cassette sounds better even.

[BMWDriver]

Automotive Goop. That's the glue I used. The P.O. had blown them a bit. But I got it with right rear channel problems too, where it would come on and off. The HU was to blame, so I got me a new one three years ago.

I've taken out the inductors, mapped out where they go, and I've come to a diagram similar to yours, except for the RR+ and FR+. So thanks for the missing clue. On the amp, all feeds go right through some chips and capacitors like there's no tomorrow. Of course, it's for signal processing. Not much use figuring that out.

I've measured the inductors :
W01: 0.4 Ohm
W02: 0.7-0.9 Ohm (one gives 0.7 and the other 0.9)
W03: 1.0 Ohm (one gives 0.9)

Capacitors linked to the inductor coils go as :
22µF 16V
33µF 25V

Diagram :
http://www.quebecman.net/e34/CrossoverDesign.jpg

Now I have a bit of shopping to do :D

[genphreak]

Oh sorry, I wasn't clear. I run the factory wiring from the crossover to the speakers; made the job a snap... factory fader is beside the steering column on my 88 535. It is a high level fader- and work on the outputs of the radio before the signal is set down the back to the booster amp.

Since I laid low level wiring, to do this from my new head unit, there was no need for using any of that.

Noone wants to use high level outputs of course, but I beleive you can use that same twisted pair instead. But if you have the fader, you'd want to bypass that. With low level signal, common ground is no problem (but chassis is), however I don't think the stock twisted pair is common ground after the fader. Check the pin-outs on the booster amp plug to see.

:) Nick

[tim eh?]

Nice work! Where did you find that diagram?

Interesting your amp uses the same capacitors for all the tweeters and mine uses different ones for front and back... don't have the values handy...


On the amp, all feeds go right through some chips and capacitors like there's no tomorrow. Of course, it's for signal processing. Not much use figuring that out.


Yes that might take some time and you are bypassing that stuff anyway.


.... and I've come to a diagram similar to yours, except for the RR+ and FR+. errr... FR is same as FL and RR is same as RL... ;)

[BMWDriver]

I made that diagram by looking at the PCB. Had to take out a few items to get it right. I made many passes in order to make absolutely sure it is right. Took me some hours.

I meant I had no clue where all the positives came in at first. Your diagram clued me in on it.

I'm a bit puzzled on the negatives though. I'll get back on this later. Enough for today.

[tim eh?]

I made that diagram by looking at the PCB. Had to take out a few items to get it right. I made many passes in order to make absolutely sure it is right. Took me some hours.

I meant I had no clue where all the positives came in at first. Your diagram clued me in on it.

I'm a bit puzzled on the negatives though. I'll get back on this later. Enough for today.

oh ok haha so you figured out the symmetry already :D my bad. Nice diag :) "...many other things..." :D no kidding eh?

The speaker grounds don't even have to run through the amp although they do run through it in the factory setup. Each corner speaker group shares a speaker ground that should go straight back to the head unit. In the factory setup there are only two shared grounds that go back to the head, each side is spliced together somewhere inside the factory amp (bentley ewd-206). I tried using the shared grounds but the front/rear fading got all screwed up. I would suggest not even bothering trying that- instead I would suggest you pop the 4 speaker grounds out of the amp plug and run new speaker grounds straight to the head. A slight inconvenience but on the sunny side you can run an rca for your future sub at the same time ;). You can borrow my 'shogun extractor' (http://www.bimmernut.com/forum/attachment.php?attachmentid=6628&stc=1&d=1236970061)if you want, they are easy to make tho.

A note about speaker grounds/negatives as some people might not be aware-

They are not real grounds in the sense that you can ground them to the chassis. They work the same way, but only in relationship to the speaker+ feeds not a regular DC+ current. They need to complete the speaker signal circuit back to its origin.

Just about there, man - soon your ears will thank you - Keep at it Philippe!

***- check it out - so it wasn't the dog farting in the back!

goop you say huh?

[BMWDriver]

Yup, that's exactly it. I first loosed all of that rim, and then glued it back on with the goop. Worked out perfect.

What really stumps me though, is that there are SIX negatives listed on the PCB, contrary to the diagram you posted up. On it is printed what every pin is for. This is what it says for the negatives:

B2 FL-
B3 RL-
B4 FR-
B10 FL-
A5 FR-
A10 RR-

That's right, two sets of front negatives. Which makes sense because the tweeters are not on the same circuit as the kicks, unlike the back where everything is on the same circuit. But it doesn't specify which is the tweets or kicks.

So nothing's going back to the front by the amp. Well, that's why these wires have colors. I'll have to take out the tweeters to find that out.

My head unit is already wired in, so I don't see why I should bother with runing wire back up there. It already worked with the amp hooked in... which means it's already a closed circuit (the speaker negatives are coming in already to the HU like you said).

So we got a B+ and a couple of grounds free from the amp. I wonder how that could be used... like for a woofer amp maybe?

So far my expenses run up to less than 30$, and that includes some new tools, which is an investment. Addison Elecrtonic have good knowledgeable staff. They are quite popular I see, of late. And they are getting more square feet.

And speaking of woofers, they have a deal up right now for a 12" with an amp for 100$, but no box. I think it's a Pionner with a 100W amp, I forget. They have tons of speakers my friend.

However, that woofer project will have to wait as far as I'm concerned.

[tim eh?]

You are mistaken about the tweeters being on a different circuit. Each corner shares a single ground. These are the plugs B2, B3, A5 and A10. See bentley ewd 206.

B4 and B10 are the L and R grounds attached to the head unit. You can try to splice into these and you'll get sound but your fader won't work. With this setup it won't work unless you run 4 new separate speaker grounds. I tried splicing them already, you can see the little splice cables I made at the bottom of this photo (http://www.bimmernut.com/forum/attachment.php?attachmentid=6652&stc=1&d=1238283842).



So we got a B+ and a couple of grounds free from the amp. I wonder how that could be used... like for a woofer amp maybe?

;) it's even on a 30A fuse already. it's either for an amp or for the fridge, haven't decided yet...whichever goes in first I guess.

[BMWDriver]

Me? Wrong? Nah. It's the PCB that's wrong :p. It's at a junction point between two PCBs, and the other one says like you do.

Can't say I particularily care about fade. Right now I just want the music back.

[paul p (chi-town)]

Yikes! That is different.



Yeah, try a 94 ... oi!

http://pavlo.interaccess.com/bmw94amp.jpg

Little choice but to ‘build’ yer own crossover here..
Unlike the earlier setups, they’re active and integrated.
*sigh*
I’ve got caps on a ‘board’ to keep the lows off the tweeters, but that’s it.

Still, with only a nice Clarion HU driving ‘Helga’s’ stock speakers ... it sounds pretty sweet.



Hang up & Drive!
94 BMW 530iT&A 145K, ‘Helga’ ( Shleppen Schnell mit “Musique ... nonstop” *dances* )
92 BMW 325i 165K, ‘Rolf’ ( Euro vision equipped, ghetto Naka install *woot* )
93 Datsun NX2000 190K ‘Carla’ ( Uber heated seat & rust holes *shakes head* )
85 Toyo MR2 140K ‘Jerry’ ( Showcar/track toy, killer mpg, way more fun than a prius *grin* )

“When the going gets weird, the weird turn pro."
- Hunter S. Thompson

[paul p (chi-town)]

Oh here’s the 1st thread on Helga’s setup
The Clarion HUs do a killer bmw amber
*grin*

http://www.bimmernut.com/forum/showthread.php?t=39362

Hang up & Drive!

"I would rather be exposed to the inconveniences attending too much liberty,
than to those attending too small a degree of it."
– Thomas Jefferson

[tim eh?]

[color=indigo]
Oh here’s the 1st thread on Helga’s setup
The Clarion HUs do a killer bmw amber
*grin*

Nice to see what the pros run, thanks for posting your setups guys. Yeah so far I've dished out around $30 now that I bought some goop for the speaker. I've used that goop stuff before, it is serious, will come in handy.

Looks great! My h/u certainly doesn't match but it looks decent anyway I think. Not bling at least and it says hello and goodbye :) It, a sub amp and the ashtray are the only remnants I have of my old dodge van. Used to sound A1+++ in there, soon it will be restored to its former glory! (the stereo not the van)



Yeah, try a 94 ... oi!

Little choice but to ‘build’ yer own crossover here..
Unlike the earlier setups, they’re active and integrated.
*sigh*
I’ve got caps on a ‘board’ to keep the lows off the tweeters, but that’s it.



ouch tough task - these (http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=280177614566) would work well for the rears i think and are cheap but i didn't find anything for the fronts while i was looking. altho if yer happy why bother?




Can't say I particularily care about fade. Right now I just want the music back.
I know how you feel I was going nuts even though it was only a week! You won't be content with the sound... fade is nice to have but it is easy to run new wires another time - want those 2 splice cables I made? They fit the plugs perfect - you can have them if you want.

[BMWDriver]

Well, I've seen how the negatives are wired. B4 and B10 get divided up between all 4 negatives back at the HU.

Before any negatives get onto those two terminals (B4 and B10), however, they go through a series of capacitors and a couple of resistors, which means that perhaps this sorts out the fade. It would be interesting to examine your PCBs if you still have them Tim. I'll perhaps try to figure out my own negative circuit.

First up, I'm close to completing my build and installing it by just splicing the negatives back to the front as is.

[BMWDriver]

Well, whaddya know. It all works just fine, including fade and balance. I just have to kill the bass a bit, and treble too, and it all sounds very nice indeed. It does lack in the bass department, but that's already well known.

What I saw at Addison is a deal for 200$ for a 12 inch woofer speaker, including a 300W RMS amplifier, all Kenwood. Not bad I should think.

[tim eh?]

Well, whaddya know. It all works just fine, including fade and balance. I just have to kill the bass a bit, and treble too, and it all sounds very nice indeed. It does lack in the bass department, but that's already well known.

What I saw at Addison is a deal for 200$ for a 12 inch woofer speaker, including a 300W RMS amplifier, all Kenwood. Not bad I should think.

Cool! Congrats! Wish that had worked for me.

You certainly don't need any more than that addison package imo. Sub come in a box? You need an enclosure... that is the trick. I'm going nuts trying to figure out a box. It's a lot more power than I am going to put in myself anyway.

You can have my old pcb if you want it for research, i think i voided the warrantee on the amp -->:D (http://www.bimmernut.com/forum/attachment.php?attachmentid=6684&stc=1&d=1239365247)

topside (http://www.bimmernut.com/forum/attachment.php?attachmentid=6682&stc=1&d=1239365247)

underneath (http://www.bimmernut.com/forum/attachment.php?attachmentid=6683&stc=1&d=1239365247)

if that's too easy you can try the eq (http://www.bimmernut.com/forum/attachment.php?attachmentid=6670&stc=1&d=1238671975) ... soon to be scavenged for aesthetics!

[BMWDriver]

Thanks again for this post! I think the same as you for the sub. I'd rather go for something more subtle, like a 10 inch, or lower if that exists. I also saw a 10 inch at $130. There's so much stuff...

Right now I don't know what I'm talking about, so I don't know how much power would be enough. Likely less than 100W. Until I do more research and shopping...

I'll post up some pics of my build in a new thread later.

Cheers!

[tim eh?]

Thanks again for this post! I think the same as you for the sub. I'd rather go for something more subtle, like a 10 inch, or lower if that exists. I also saw a 10 inch at $130. There's so much stuff...

Right now I don't know what I'm talking about, so I don't know how much power would be enough. Likely less than 100W. Until I do more research and shopping...

I'll post up some pics of my build in a new thread later.

Cheers!

Happy to help - finally something I actually know a little bit about!

I already have my sub stuff I just have to decide where to put it. It is going to be very modest - a single 8" vifa home theatre woofer and a 200W amp. Kind of overkill on the amp but it is powering an 8 ohm speaker so it will really be running around 100... will draw less amps is a plus.

Won't kill the neighbours dog but I'll be able to listen to maiden at required loudness levels...