Radio Wiring and Amp Bypass

[StereoInstaller1]

That's my problem. I understand electrical the same way. It seems to me that the speakers must ground in some way since there seem to be wires for it, but not sure how it works with only the positive wires connected at the deck. :loco:

AH HA! I finally figured out why this is kicking your ass so bad!

Pay attention here: Those wires coming from the deck are AMPLIFIER INPUT wires, NOT speaker wires...get it? Speaker wires run speakers, the wires in your dash do not, they do not connect to the speakers at all.

That is why this is kicking your ass, you are confused because they look just like speaker wires.

Those 4 positives and 1 ground are INPUT WIRES, the one negative for all 4.

Oh, and every bit of info is in the ETM, if you can't find them, you need to work on your diagram skills.

All of them are shown in clear detail, look for "HiFi Amplifier" in the ETM.

So, that being said, I need the stress this: The deck feeds the audio to the amp, the amp runs the speakers. That is why there is only 1 input ground, later E30s are wires differently. There is still only 1 input ground though.

That is why I keep telling you to read the entire "bypass" thread, the info of what to do about you having 5 wires from front to back is there.

Yet another point: Speakers do not get "ground", they get a negative signal from whatever runs them. Oh, and please start using "negative" instead of "ground" unless chassis ground is actually present on the wire. It helps clarify your questions. When I used the word "ground", I am referring to chassis ground, even when referring to the amp's negative input.

Luke

[6670charger]

I am no expert. It is my understanding that all electrical components require a circuit. That is, both a positive and a ground. I believe that speakers all require both a positive and a ground. Speakers will not work with only one conductor attached.

That's my problem. I understand electrical the same way. It seems to me that the speakers must ground in some way since there seem to be wires for it, but not sure how it works with only the positive wires connected at the deck. :loco:

[dogsbark26]

I am no expert. It is my understanding that all electrical components require a circuit. That is, both a positive and a ground. I believe that speakers all require both a positive and a ground. Speakers will not work with only one conductor attached.

I have never understood that portion of this thread discussing the low-voltage "signal" wires containing just one conductor. I get it that the signal is actually carried on just one of the conductors (unless you are using a "balanced" output/input - but that is in specialized equipment). But that does not apply here.

So I guess this response is not going to help you. Sorry.

[6670charger]

This is what I have for wiring in the trunk. There are no twisted pairs, just all of the colored wires that were mentioned in other parts of this thread going way up into the convertible boot area. Again, it seems that I have ground wires for each of the speakers, yet, I'm only connected to positive wires at the deck. What do I do with the ground wires? Are they used? If so, where/how? If they're not, then it sounds like all I need to do is connect all of the relevant positive wires together and I should be fine. I'd try this on my own, but, if it doesn't work, then I either have to re-connect everything they way it was again, or live without any stereo at all for however many days it takes for someone to help me out with this. Just need to know about the grounds and how/if they come into play at the amp.

[6670charger]

OK, found the amp. It was behind the upper trunk liner and below the convertible top boot. Only has one plug for it, and I'm pretty sure I found the positive speaker wires: RF-grey/white, LF-grey/red, RR-black/white, and LR-black/red. Again, 88 325i vert.

I assume that since there is only one plug, both the input wires from the deck and the output wires to the speakers are all in the one plug, and that my next step is to cut off the plug, and connect the positive speaker wires I just identified to the correct colored wires coming from the deck? I have all of the wires as identified below, to include what appear to be the speaker negatives:

Dash Wires-----------Speaker Wires

RF+ Blue/Red-------------Grey/White
RF- Brown/Orange--------Grey/Brown

LF+ Yellow/Red------------Grey/Red
LF- Brown/Orange--------Grey/Violet

RR+ Blue/Black------------Black/White
RR- Brown/Orange--------Black/Brown

LR+ Yellow/Black----------Black/Red
LR- Brown/Orange--------Black/Violet

Looks like BlueBMW had something similar in his car on page 13. I don't intend to run new wire to the front speakers like he did, nor do I get how to re-purpose the wiring in the rear. I understand the concept, but have no clue how to actually do it. This is the first system where I've had to do anything more than just connect the deck to the wires in the dash.

Since I seem to have speaker ground wires, do I use the negative wires too, or just the positives? What confuses me is that I don't have ground wires from the dash to the amp, but apparently do from the amp to the speakers.

[6670charger]

Any thoughts on where the factory amp might be on an 88 vert? Took out the left side trunk panel and didn't find anything anywhere near the power antenna. I know I have one as I have tweeters in the doors and a white amp wire that I had to connect behind the deck in order to get sound. Did I not look far enough back? Didn't find anything on the other side of the trunk either.

[6670charger]

Checked the wiring diagrams in the manual I downloaded from wedophones.com. I doesn't really tell me much. The diagram that shows the premium sound system with the amp doesn't show any wiring for the speakers from the amp. The other diagram without the premium system shows the speakers, but only as they're wired from the fader. What I need is the wiring from the amp to the speakers. I think I found that as posted in my previous reply. I hope this is correct, but, I'm still not certain what I'll find with regard to wiring back there since my deck is only connected with positive wires. Do the speakers connect to those wires using the positives only also?

[6670charger]

After going back, is this the info? Just use the Dash wire to speaker wire part? Also, I didn't have twisted pairs; only positives. I assume that will hold true in the trunk as well. Do I connect both speaker wires to the single positive wire, or no? As I said once before, I understand the absolute basics of electrical wiring, and I'm extremely new to stereo wiring. Some of the simplest of things to others are baffling to me until I work with it a bit. Right now, my assumption is that since all the factory wiring already goes where it's supposed to, this should just be a matter of disconnecting the amp, and then connecting whatever wires go from the amp to the speakers to the correct wire coming from the deck to the amp. I also assume that the amp in the deck will power everything just fine, and that the factory amp combined with the amp in the deck is either putting out too much power, too little power, or interferes with the deck amp in some way which is what is causing the spitting in my speakers at higher volume. Since I already have the deck connected correctly, now it's just a matter of determining which wires from the amp go to which speakers.

Dash Wires-----------Speaker Wires

RF+ Blue/Red-------------Grey/White
RF- Brown/Orange--------Grey/Brown

LF+ Yellow/Red------------Grey/Red
LF- Brown/Orange--------Grey/Violet

RR+ Blue/Black------------Black/White
RR- Brown/Orange--------Black/Brown

LR+ Yellow/Black----------Black/Red
LR- Brown/Orange--------Black/Violet

[StereoInstaller1]

Anyone have any information with regard to which wires go to which speakers from the amp to the speakers? I'm sure I can probably figure it out on my own, but, if someone else has already created this wheel, there's no sense in me trying to re-create it. I've been doing some looking on-line and haven't found anything that I understand yet.

Yes, there are charts and diagrams and all sorts of documentation, plus you can download the BMW Factory Electrical Technical Manual (ETM) at www.wedophones.com.

Dig through the threads in my sig, either the amp bypass or the $500 killer stereo should have the chart.

[StereoInstaller1]

Is it not possible to use the existing speaker wiring from the amp to the speakers? Can't believe the existing front speaker wiring can't be used on an unhacked harness.

Here is the story, which has been covered about 1100 times: there are only 5 wires from the deck to the amp in a fader equipped Premium Sound car.

Let me say this again: THERE ARE ONLY 5 WIRES, YOU NEED 8!

So IF you plan on bypassing your factory amp AND your car came with a fader, you have 2 choices: Run 4 pairs of wires from the deck to the trunk OR re-purpose the 4 input wires as rears and run new wire to the front speakers.

NO MATTER WHAT, IF YOU BYPASS THE AMP, YOU NEED TO RUN WIRES.

So, what this means is a you need to make a choice. If you KNOW you are gonna do a real stereo SOON and not just deck power, don't bother bypassing, just deal with the shitty stock amp until you finally get the time/money/balls to upgrade.

If you have a properly functioning stock amp, you will not have crackles and noises. You may have a little "hiss", but no bad/shitty noises. Assuming, of course, that you followed my wiring instructions properly.

I hope it is obvious that it is easiest to work with the stock amp/speaker wiring intact when installing an amp, right? It means that all 4 corners of speaker wires are already in one place, so it is as simple as running RCAs and power wires at that point.

Hope this helps, man...hard to watch some obviously intelligent people struggle with what is a fairly simple job. I know it is only a case of overthinking, just relax and understand what the electronics want to see.

Luke

[6670charger]

Anyone have any information with regard to which wires go to which speakers from the amp to the speakers? I'm sure I can probably figure it out on my own, but, if someone else has already created this wheel, there's no sense in me trying to re-create it. I've been doing some looking on-line and haven't found anything that I understand yet.

[agent]

OK, so if I understand you correctly, after I disconnect all the wiring from the amp, and probably remove the amp itself, I should just be able to locate/identify the speaker wires coming from the amp, and connect them to the speaker wires coming from the dash?

Yes, though since your plans are now to bypass the factory amp, you're really going to want to put an aftermarket amp back there. In addition to greatly improving the sound, it makes the installation exponentially easier.

[naomiswanson]

I already had an experience regarding this matter actually I am using z3/318ti this stuff is very easy to use and it is also provides for improving your car. However, thank you for your great information about E30 wire maybe next time I try to use it.

[6670charger]

The speaker-level inputs to the factory amp are not used, though the speaker wires from the (factory) amp are.

OK, so if I understand you correctly, after I disconnect all the wiring from the amp, and probably remove the amp itself, I should just be able to locate/identify the speaker wires coming from the amp, and connect them to the speaker wires coming from the dash?

[agent]

I
Unless I missed something, the only instructions I've seen in this thread with regard to bypassing the amp have involved running new wires to the front speakers.

I don't believe that's the case. The factory amp has speaker level inputs. What most folks are doing (and what I did) is replacing the factory amp with an aftermarket amp and running RCAs from the deck to the aftermarket amp. The speaker-level inputs to the factory amp are not used, though the speaker wires from the (factory) amp are.