Author Topic: did it myself and failed. little help? (Read 6446 times)

babolimp · « **on:** Jul 26, 2007, 03:55PM »

so a friend and i put a new sound system in my '94 U13 bluey sss. BOSS amp, 4 xplod speakers and a panasonic head unit.

rear speakers came out fine. the amp is in the boot so we just directly hooked in some new speaker wires from rear speakers -> amp. there was an issue with alternator noise, but i later seperated the RCAs to go along the drivers side, with the remote and power wire going along the passenger side, which fixed the problem. we only did the rears because the front doors are a bitch to get off. i later got the front doors off on my own and put in the new xplods. i just connected in the existing front speaker wires (bluewhite,blueyellow;brown,brownwhite) and rendez-voused them at the boot and into the amp.

that's where the shit hit the fan and i'm currently at a loss. i'm getting alternator noise again (only in the fronts though) wtf! AND there's an on-off pop/thump. the on-off thump and the alternator noise ONLY come from the front speakers. go figure. i've had a look around the web and the consensus on alternator noise is either rcas being too close to the power wire, or shitty grounding. as i said, i already seperated the RCAs from the power, and if it was due to shitty grounding, wouldn't the rears also experience the alternator noise? i even switched the RCAs around on the amp to see if one of them was picking up the alternator noise somehow and not the other. no difference.. alternator noise only in the fronts. as for the thump, if i remove the speaker cables for the fronts, thats that only cure i've found so far

the rears have an off thump sometimes, which is so mild it's negligible. does anyone have any idea what's going on? maybe something to do with the stock front speaker wiring? or maybe running the remote+power together is bad?

JelloBello · « **Reply #1 on:** Jul 26, 2007, 06:12PM »

remote + power together is fine, I would recommend running new speaker wires from your front speakers to the amp - stock wiring can have many issues (can't remember if the speakers share a common ground in the u13's? i know they do in the u12's - this can cause all sorts of headaches). Just make sure that the new speaker wires go along the drivers side away from the nasty power cable.

Also, when you say "rendez-voused them at the boot and into the amp." I assume you're using stock wiring which went into a stock amp? It's generally best to remove/disconnect stock amps as they can also cause funny things to happen.

babolimp · « **Reply #2 on:** Jul 26, 2007, 06:25PM »

ya the stock amps are in the bin - where they belong. i just mean't that i butchered up the harness at the boot (which has the stock front speaker wires in it) and connected up some new wiring from that into the new amp. i guess i'll have to get some new 2m long speaker wires for the fronts and see if that does the trick. but is it OK to run the speaker wires alongside the RCAs? i don't want to shoot myself in the foot afterall.

JelloBello · « **Reply #3 on:** Jul 26, 2007, 06:54PM »

Yeh, it's only the power wire that you really have to worry about... unless your head unit is grounding out through the RCAs but that's a whole other bag of problems and i don't think applies to you

Kranzy · « **Reply #4 on:** Jul 26, 2007, 09:42PM »

You wont find any issues running speaker cables with power cables as its a high voltage output so will pick up next to no noise. But because RCA are a low voltage signal they are more sensitive to power noise.

Jono · « **Reply #5 on:** Jul 26, 2007, 10:08PM »

Check the ground at your head unit too, U13s don't have a ground wire in the loom so screw the ground wire of the head unit to the body of the car. Or a metal part of the dash or something.

Using the factory speaker wires shouldn't cause any problems.

My next move would be to swap the front speaker wires from the front output of the amp to the rear output. If there's still noise then there's a problem with your amp and you should take it back for warranty (if you bought it new).

rathies · « **Reply #6 on:** Jul 26, 2007, 10:27PM »

you failed when you bought a boss amp. I personally would've thrown it in the bin and left the stocko amps in place. Thats the cause of your on/off pop.
The alternator whine is either due to grounded speaker wires (replace them), rcas too close to power which you've narrowed out or your amp not grounding properly and trying to ground through the rca's, which in turn means through the chassis of the head unit.
If the rca quality is as good as the boss amp i guess you could blame those too.

get a multi meter and see if your front speaker wires are grounding. if so try switching the polarity at the amp end it might stop the whining noise. or better still just switch the polarity and see what happens.

Sticky · « **Reply #7 on:** Jul 27, 2007, 09:22AM »

Quote from: rathies on Jul 26, 2007, 10:27PM

you failed when you bought a boss amp. I personally would've thrown it in the bin and left the stocko amps in place. Thats the cause of your on/off pop.

This is true...

I could be so many things, get a better amp and go from there

Jono · « **Reply #8 on:** Jul 27, 2007, 07:36PM »

Boss amps still shouldn't have any significant engine noise when they're connected up properly.

They are shit, but they work.

babolimp · « **Reply #9 on:** Jul 28, 2007, 04:19AM »

lol relax. it's an old boss amp. those are built alot better than the newer ones thats for sure. i wouldn't touch any new boss shit. it goes alright and cost next to nothing (ebay). even at ear bleeding levels the distortion is minimal.

Jono · « **Reply #10 on:** Jul 28, 2007, 03:41PM »

Quote from: babolimp on Jul 28, 2007, 04:19AM

ebay

Ah. There's ya problem!

JelloBello · « **Reply #11 on:** Jul 28, 2007, 04:46PM »

Leave ebay out of this!

borgtj · « **Reply #12 on:** Jul 28, 2007, 11:48PM »

Install a ground loop audio isolator and that should fix your issue,it worked for me and it was like 7 bux at radio shack.I just hope you folks has an Aussie version of Radio Shack.

Kranzy · « **Reply #13 on:** Jul 29, 2007, 11:32AM »

Quote from: borgtj on Jul 28, 2007, 11:48PM

Aussie version of Radio Shack.

http://www.jaycar.com.au/

Jono · « **Reply #14 on:** Jul 30, 2007, 01:17AM »

A ground loop isolator also cuts out the extreme highs and lows of the sound... the highest pitch treble and lowest pitch bass.

babolimp · « **Reply #15 on:** Aug 5, 2007, 02:46PM »

ok so i finally got around to tinkering with the system again (been a little busy as of late). as jono suggested, i swapped the front speaker wires from the front output of the amp to the rear output, but the problem still existed. then i just decided to just disconnect the front wire inputs and have the front speakers offline as the thump and alternator noise is irritating to me. but then the alternator noise was still there! in the rears, that is. i found that removing the front RCAs from the amp solved this problem. does that ring any alarm bells for anyone? if not, i might just end up running the fronts off the head unit to avoid all these problems...

rathies · « **Reply #16 on:** Aug 5, 2007, 10:44PM »

yup removing the rca's can indicate a few things that i already outlined above:
-rca's too close to power cables or not insulated. are they good quality?
-amp is not grounding properly and trying to ground through the rca's which are grounded to the head unit. try sanding the paint back to bare metal where you have grounded your amp.

you might be able to stop your on/off pop by swapping the neg and pos wires over on the amplifier end (speaker outputs not power). give it a shot and let us know the results. of course you'd have to do the same on the speaker end. i am assuming that if these are stock speaker wires that are grounded then only the negative will be grounded.

P-Unit · « **Reply #17 on:** Aug 5, 2007, 10:46PM »

The easiest way to fix a problem you cant find is to start from scratch, run fresh speaker cable up the centre of the car and into the front speakers from there, all new no crossing with power or rca = no problems.

rathies · « **Reply #18 on:** Aug 5, 2007, 10:47PM »

yup i was about to edit my post when you said that P-Unit. I always suggest running new cables when someone tells me about an intermittent problem like this.

babolimp · « **Reply #19 on:** Aug 5, 2007, 11:17PM »

Quote from: rathies on Aug 5, 2007, 10:44PM

yup removing the rca's can indicate a few things that i already outlined above:
-rca's too close to power cables or not insulated. are they good quality?
-amp is not grounding properly and trying to ground through the rca's which are grounded to the head unit. try sanding the paint back to bare metal where you have grounded your amp.

you might be able to stop your on/off pop by swapping the neg and pos wires over on the amplifier end (speaker outputs not power). give it a shot and let us know the results. of course you'd have to do the same on the speaker end. i am assuming that if these are stock speaker wires that are grounded then only the negative will be grounded.

rcas are good quality. they came from an expensive amp kit. the amp power cable is running on the opposite side of the car to the RCAs. the only power cable the rcas come anywhere near is the tiny one at the back of the head unit. i will try to see if i can ground it better at the boot, as it is using a painted spot. is there anyway to test if it's a good ground without a voltmeter?

also i will try switching the speaker wiring around a bit again, though i think ive tried this earlier. i don't know why you said "of course you'd have to do the same on the speaker end." because switching the neg and pos wires around there would just negate switching pos and neg at the amp in the first place.

as for running a whole new set of wiring through for the front speakers. i have no idea how to "run them down the middle of the car". i have a feeling its going to be alot harder than it looks. getting the damn doors off sure was. the only place i know to put wiring is under those plastic panels by the doors =/

P-Unit · « **Reply #20 on:** Aug 5, 2007, 11:40PM »

Go to a woodyard, get one of those yellow sticks from in between sheets of chipboard. Use nitto tape and tape the cable to the stick, then jam it under the carpet from the boot to the centre console. Thats how you run a cable through, jaycar have some nice flat cable designed to run freely under carpet.

if ur in Vic i can give you a hand, otherwise there are plenty of others out there who can give you a hand or advice on how to run fresh cable, because fresh cable is the best way to do a stereo. In my car the only stock cables im using are the 12V for the head unit and the ACC for the head unit, everything else is fresh cable.

borgtj · « **Reply #21 on:** Aug 6, 2007, 12:19AM »

My problem was also @ the RCA jacks and the isolater took it right out.

rathies · « **Reply #22 on:** Aug 6, 2007, 12:35AM »

as a quick test you could run some alternate (spare or borrowed) speakers straight from the amp with a short piece of wire and see if you get the on/off pop you've been experiencing. This will help you to see if its the wiring or the equipment giving your grief.

Quote from: babolimp on Aug 5, 2007, 11:17PM

i don't know why you said "of course you'd have to do the same on the speaker end." because switching the neg and pos wires around there would just negate switching pos and neg at the amp in the first place.

because some idiots don't know that and thier front speakers would be running in reverse phase, which still works but not well. Not suggesting you are an idiot, just covering all areas

also how many amps are you running on this setup and what sort of wire did you run? not enough available power can also be a problem in regards to the whining noise.

Jono · « **Reply #23 on:** Aug 14, 2007, 07:53PM »

Firstly, sand the paint from under your amp ground connection. Yes you do need a voltmeter or a multimeter to check a ground.

Try running a spare set of RCAs down the middle of the car from the head unit to the amp... don't worry about running them properly, just plug them into the head unit and into the amp to see if you still have the noise.

If you do still have the noise with the temporary RCAs plugged in, the front speakers disconnected and a good ground then there's a problem with your amp. A ground loop isolator might help but it's just a band-aid fix for a bigger problem.