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mikee30
06-03-2004, 08:32 PM
OKay...I can't figure this out and it's killing me. I have a 90 325i, with premium sound package. I removed the stock radio and wanted to wire up my cd player deck. After making all the connections, I test it out...everything works great..power antenna, sound etc..all perfect.
I start the car, take off...start driving, turn on radio, and begin to hear a buzzing noise. This noise increases in pitch as my tach goes higher! Ok fine..I put in a cd thinking it would not be there also..but it is! The buzzing can be heard on AM/FM and CD modes.

So I pull the radio out thinking the case was not grounded or something, or many internal wiring is affecting it...but it still does it...yet when the car is off...it works perfectly. I know the cd player is fine (had it in another car), and the stock radio never did this....so what can be causing this problem? I put electrical tape around all the wiring to ensure no crosstalk...but sitll there.

What am I connecting wrong? Speakers? Antenna?
I was told putting a capacitor on the power could solve this...but I don't understand why I'd need hat if it worked well with the stock stereo.

Any help would be appreciated.
Thanks

T.Dot_E30
06-03-2004, 08:58 PM
ok how did u run the speaker wires?

Bcus in the preium sound system for our cars there is a factory amp in the truck. If u still have it hooked up to that amp, i think thats ur prob.

what u need to do is run new speaker wires from ur deck to each speaker if u want them powered by the deck.

mikee30
06-03-2004, 09:46 PM
What if I want it powered buy the factory amp? This isn't possible?
I basically unplugged each of the wires form the stock radio, and put them in my cd player!

Anything wrong with that?

bmwm5lover
06-03-2004, 10:40 PM
U have to rewire to whole car for best results. This was done on my car just a couple of weeks ago, due to the same annoying noise...

mikee30
06-03-2004, 10:46 PM
what I don't understand is even if I do rewire the whole car and want to put in an amp, won't I be back at sqaure 1 with the same problems just a different amp?

were u getting the same noise as the one I am getting or just an annoying hum?

Also, did you install an amp and new speakers?

SourSamo
06-04-2004, 02:30 AM
Usually a better ground will help out alot. Your just gettting engine interference in the amp.

T.Dot_E30
06-04-2004, 03:32 AM
if u put an after market amp in u wouldn't have that prob.

or atleast it wont be for the same reason.

The reason is factory amp is made to only work with the factory deck.....which has only two signals going to the amp.....u see the fader knob above the deck, that actually control the fading from the amp not the deck thats why they have it seperate from the deck. + another reason is ur amplifing a signal that isn't meant to be amplified...thats why u getting all that feed back/noise

Plus factory amps are garbage, the distrotion level on them is really high.

Jus by-pass the factory amp, u wont have that prob with the aftermarket amp if u wanna put one later

mikee30
06-04-2004, 03:43 AM
Well I was hoping to put in the sound system all at once...I have a MTX amp lying around, and my deck is a clarion 35x4....should I change the speakers?

Do I need to pass new wiring to the speakers as well?

How can I eliminate the buzz without bypassing the stock amplifier? SourSamo...where do you suggest I put the extra ground? On the casing of the radio (tried that already)?

Thanks guys

Mystikal
06-04-2004, 04:42 AM
Actually Trevor, the THD on the factory premium amp is just 0.01!!. It sounded a lot cleaner than my first headunit (JVC), it just didn't have the guts to handle the volume I wanted.

mikee30
06-04-2004, 02:45 PM
So I still don't get this...everyone who wants to install a new deck on an e30 with premium sound has to remove the amp and rewire the whole car?? I find that hard to believe....

Mystikal
06-04-2004, 02:58 PM
Think about it. You're sending an amplified signal to another amp with much weaker specs, that is then amplifying it again. I had my car like that for about a week, it was hilariously bad.

You MUST rewire it.

mikee30
06-04-2004, 04:21 PM
Mystikal: Yeah I figured that was what was causing the problem, but I didn't everyone who installed a cd deck rewired everything.

I'm kinda new to audio and that kind of stuff....
Let's say I put in an aftermarket amp with my cd deck, will I still get the buzzing sound, or will it disapear due to the wiring being new?

bmwm5lover
06-04-2004, 04:27 PM
RUN SPEAKER WIRED STRAIGHT FROM YOUR DECK!!!!

T.Dot_E30
06-04-2004, 05:07 PM
Originally posted by Mystikal
Actually Trevor, the THD on the factory premium amp is just 0.01!!. It sounded a lot cleaner than my first headunit (JVC), it just didn't have the guts to handle the volume I wanted.

Really? i never actually checked out our amp, but i remember watching a show where these guys were putting a system in a Z3 and they wwere talkin about how much distortion the factory amp had, and how it was sooo shitty and how most factory ones are.

Slowered318
06-04-2004, 05:34 PM
you can bypass the amp at the trunk without re-wireing everything.. it's not exactly an easy task, but it can be done.

best option would be to run new speaker wires.. you'll need to pull back the carpet on either the left or right side of the car. keep the factory speakers for now they are pretty good..

BladeRunner
06-05-2004, 04:54 AM
I can't find my amp where is it located? Some say trunk but no amp there.

T.Dot_E30
06-05-2004, 05:20 AM
u gotta take out the trunk liner ont he left side.

Its right next to the power antena(if u have one) or the reg antena.


or actually u have an 84 318......so i donno if u have one, probably not

Mystikal
06-05-2004, 05:50 PM
Yeah Trevor, when I installed my first deck I noticed the sound really wasn't as clean (after rewiring too) compared to my stock setup. The JVC was rated at 0.08%THD, while the factory BMW one is just 0.01. No wonder.

Now my headunit isn't powering shit though, the way God intended it to be. :D

Bob Loblaw
06-06-2004, 02:58 AM
Originally posted by Slowered318
you can bypass the amp at the trunk without re-wireing everything.. it's not exactly an easy task, but it can be done.



Any hints and tips?

BladeRunner
06-06-2004, 04:26 AM
I've removed all liner and plastic no AMP anywhere, guess I should be happy. They seem to cause problems.

ZiMMie
06-06-2004, 04:54 AM
Originally posted by BladeRunner
I've removed all liner and plastic no AMP anywhere, guess I should be happy. They seem to cause problems.

Yes there is an AMP there. Completely remove the Left linning u should see it. its beside where the trunk Lid hinge is.

mikee30
06-06-2004, 03:19 PM
I found some intructions on roadfly about wiring new decks in to avoid whining noises and using the factory amp...but even after following them I get the whine.

So I'm thinking either I have a bad ground somewhere, or I might have to put some capacitors to remove the whine...just not sure how to go about it.

BMW BMXer
06-06-2004, 03:21 PM
I say the easiest way to run wires to the back of an e30 is down the middle of the car.

Of course I hafta rewire my car too, since the last person to rewire it left the factory fader in, but I wil rewire when I get a nother amp.

Jordan
06-06-2004, 04:05 PM
He has a 84 318i. None of those came with premium sound. ONLY premium sound e30's have the amp in the trunk.

chromius
06-07-2004, 03:22 AM
I had similar problems when I installed my deck...check all the grounds...even if they seem fine, cut them and redo them....and if you happen to have a premium sound system...as I did...you don't have to rewire the whole car...you can buy a wire harness that takes the wires going into the amp in the trunk and goes right into the wires comming out...it works perfectly for an aftermarket deck. Its a little bit of a pain because the stock deck uses a common ground, but once its all hooked up it works beautifully.