Hi peeps just wondering if you can help me out with a problem i have on my S2 Turbo...

basically when i connect my stereo up (using 1 amp) there is a BAD earthing noise coming through the speakers...thought it was the headunit so its away getting repaired....in the mean time i put in another headunit which i know is working fine...but its still doing the same thing...

The other night i was driving home and noticed the voltmeter going funny....so i pulled over and checked the alternator...looked fine but could see some sparks....wasnt far from home so drove it home....5mins into driving home...problem cured and alt was/is charging fine again!!

today i wired up the headunit to a seperate battery and the earthing noise disappeared....connected it back up to the cars wiring...noise is back...wired headunit direct to the cars battery, noise was still there. Thought the alternator might be causing the noise, so disconnected it and the noise is still present. connected a new battery to the car, noise is still there!!!

by the looks of things, the amp is earthed fine and the problem is before the headunit as if it were the amps fault or the speakers fault, the noise would have been present when the headunit was running off a spare battery...

Also the earthing point from the battery to the car was uprated a while ago along with the battery to gearbox with 4 gauge cabling....

also tried another earth to the body with no avail

what else can i try and have you ever come across a problem like this before?

am thinking of taking the dash out and checking the wiring behind there but would like to know what u all think should be the next step...

bassboy

 

Have you tried a ground loop isolator?

I know that it's not solving the cause of the problem but it will definitely get rid of the noise.

Apart from that, sounds like a floating earth problem, have you got anything else in the boot sharing the earth?

Cheers,

Andy

 

Oh, another thing to try would be to Earth the Chassis of the Head Unit to the chassis of the Amplifier - this kind of problem can be caused by the voltage differences between the two units.

Cheers,

Andy

 

andy...this only happened all of a sudden though :S could something have burnt out or something?

all the amps are earthed to the same point in the boot however only one amp is connected...

need to get this sorted as LOADS of people want demo's of my sound at FITP

bassboy

 

Strange one mate - had a similar issue with a carputer system recently though, couldn't find the source and even earthing the chassis of the system to the car seperately didn't solve it (it reduced the noise but it was still there). In the end I used a Ground Loop Isolator from Maplins for £8.99 - completely solved the problem.

I guess you don't want to try that because it will remove some of the lower frequencies of the sounds?

Cheers,

Andy

 

where do u think i should install a supressor?

bassboy

 

just tried a suppresor inline with the headunit and still no luck

bssboy

 

Bummer! I'm at a loss mate - sorry I can't be of any more help!

Cheers,

Andy

 

no worries andy...gonna try running it off a second battery which is earthed to the chassis same place as amp and see if that helps when i feel a bit better....

if not...looks like no sounds at FITP for me bummer as this was gonna be my first year might just shove a battery in the passenger side and run it off that for the day PMSL

bassboy

 

Do it mate - it's a shame I won't be there this year!

Andy

 

take it was supressor for the rca leads and there not running down the same side of the car

does the hissing noise increase when u rev the engine also tick louder when u indicate

possibly bad earths each amp should have its own earth

also earth the rcas out aswell that thin blue wire that joins the cables together

if not then could be the supressor on the coil or alternator

 

if it were a bad earth on the amp would it not have the same problem with 1. the rca's disconnected, and 2 when the headunit is powered from an independant battery?

reason i say this is coz when the headunit is ran off another battery which is not earthed against the chassis, the system runs fine?

which makes me believe its on the wiring side of the headunit...

the suppressor i used went on to the power supply to the head unit...but i will try to find one for the RCA's tomo.

i earthed the rca's out and the problem is still the same also earthed the headunit chassis to the amp and still the same

if it was a suppresor on the coil or alt, would the problem still occur with the engine switched off? i.e on first click of the key i can hear the laser moving around the headunit through the speakers, when the ignition is on, a constant low pitched buzz, then when i start it i can hear engine revs fairly loud through the speakers?

thanx for input peeps....

bassboy

 

if it runs fine off a battery thats ot connected to the car

then give all your main body earths a clean aswell

on of them could be broke but unsure until you take a look lol

try whats powered off the amp aswell

also what rca leads are you running

 

i will remove all earths - chassis to bat, bat to engine, engine to bonnet, tomo and see how they look...give them a thorough clean and put them back...

what do u mean by try whats powered off the amp aswell?

the RCA's are Rockford Fosgate White Wolf....again, if there were a proble, with these it should do it regardless of what battery the headunit is powered off?

bassboy

 

tell u where all the earths are that go all the time are behind the drivers side speaker pod! a bunch of brown wires give all them a clean up and even make a fresh earth fixing and new screw!
hope that helps

 

HORNETS7 thats the next area of attack...just a b1tch to get to as i have components down there...but i suppose i would rather do that than give someone £££ to find the problem lol...wanna try everything i can before i give up

also are there any other earthing points i should check out?

bassboy

 

well usually interference is caused by rac to close to power cables

i done a system in my old escort and the only time the power cable was near a rca was when it was going into the amps, they were on the opposite side of the car

i fitted a pioneer 6200 which was new a couple of yrs back and it hada major interence, so i put supressors in the rca and still had slight interference so had each amp have hits on earth and all was sorted

what i realised was it was the headunit causing the interference, i put another head unit in and it was fine with no supressors



just a thought of try a different headunit if you have one

 

prety sure if uve got a earth problem it will be down there! as that area earths all the clocks dash stereo electric windows fuel computer etc..........

 

xr4x4rs the power and rca's and speaker cables are all routed different areas of the car so i know its not this...

i know what ur saying about each amp having its own earth but there is only one amp in the car currently so technically has its own earth?

tried a new headunit also and still does the same thing

also earthed the headunit direct to the battery and still doing the same thing...

i will give the engine earths and the footwell earths a good check tomo or friday and let you know how i get on

bassboy

 

right checked out the earths on the footwell and everything is ok...makes no difference when i changed their location

so basically....THE NOISE IS STILL THERE

this is p1ssing me right off now

is there anything else i can try before i give up and send it in to an auto electricians?

bassboy

 

Can you do a dummy run with a piece of wire between the chassis of the head unit and the amp - just to see if it removes the noise?

I know it's a long shot but it looks like you've removed everything else.

It's a shame you don't have a spectrum analyser with a probe - but then again they're pretty expensive!

Cheers,

Andy

 

andy done that mate still no joy

bassboy

 

try what i did to mine

i wired the steros from the always live on the cigareete lighter so i have stereo with ut ignition being on

it solved my issue a few years back

 

wired the headunit direct off the battery mate and the problem was still there

bassboy