Help! Bad earth I think...

RobClubley · 23-05-2005, 21:43

Help!

I think I have earth problems with my amp. As soon as I connect it to the speakers I get a whistling sound, then it buzzes in time to the engine revs.

I have my amp installed here in my Octy estate:

So I need a place to fix the earth cable.

I connected it here:

I read that the earth cable should be as short as possible so it's about 10 inches long (careful!)

I tried relocating it to one of the rear light cluster bolts - no difference.

Any suggestions? Should I get more cable and run it to the earth point at the other side of the boot? Trouble is my speaker wirtes run across the back of the car - moght get different interference.

Not sure what to do next - any suggestions please?

macatac · 24-05-2005, 03:59

Yeah the earth should be close to the amp,that is too long,and use a bit of medium/fine grit sand paper around the screw to key it back to bare metal for a good contact,good luck.

vRS_Si · 24-05-2005, 10:57

Your earth wires the same thickness (gauge) as your power wire isn't it? Just checking! It should be!
I use the earthing point for the rear light clusters with no problems so it's likely that your picking up interference somewhere.
Where are you power and RCA wires run?

RobClubley · 24-05-2005, 11:09

Quote:

Originally Posted by vRS_Si

Your earth wires the same thickness (gauge) as your power wire isn't it? Just checking! It should be!
I use the earthing point for the rear light clusters with no problems so it's likely that your picking up interference somewhere.
Where are you power and RCA wires run?

It is the same thickness, yes.

The power runs down the drivers side of the car, other cables run down the other side. BUT thinking about it, they pass near each other behind the glovebox.

A mate has suggested getting a ground loop isolator for the audio leads - gonna try that as I'm off to Maplins later anyway and they're not too expensive :-)

**TaviaRS** · 24-05-2005, 11:58

I had this on mine.

I "created" a new earth point, drilled a hole through the boot floor, dremmeled the paint off and got a nice clean surface and put a 5 mm bolt through - cured the problem nicely

Pimpster · 24-05-2005, 12:12

The noise which you are getting is alternator whine. Can usually be fixed by using a better ground. Also check your RCAs and make sure they are not near your power cable (they should be running on different sides of the car).

Tom_vRS · 24-05-2005, 12:56

Being a lazy git, I just bought shielded RCA's and sent them down the same side of the car as the power cable. I also used the earth mounting point for the light clusters, and no problem whatsoever! Makes for a really tidy install. I will eventually use the seat mounting poing though to keep all cables as short as possible, and I think it would be a better contact.

When I order my noisekiller kit, and lashings of Dynamat (4 rolls) total £280!

I'll be ripping the entire interior out (except dash and centre console) and I'll sort all my cables out properly. I'll be running an amp for the front speakers, so there will be speaker cable running down both sides of the car... Might run the power cable down the middle for good measure.

Hope you get your whine sorted. A simple noise supressor should do the trick for a temporary measure... ?

CupraR-Rog · 24-05-2005, 18:58

Alternator whine is a pain, isn't it?

Double-check all your power cables, and especially check that ypur earth is tight as tight can be against the chassis.

Good luck getting it sorted!!

Grant · 25-05-2005, 00:32

more ideas to check,

Is the chassis to battery big enough?

Does the headunit have a good ground, if that has a poorer ground than the amp, it can make a voltage difference and make this whine, ideally all audio equipment should be commonly grounded.

Is the battery on the way out?

RobClubley · 25-05-2005, 07:26

Yaay!! It was the earth after all. I got some fine sandpaper and smoothed off the area where I'd scraped off a bit of paint (the point in the picture). Then I made sure the bolt was as tight as I could get it.

No more weird noises

Thanks for all the help guys.

From reading this section of the forum and stuff on talk audio I've learned loads about ICE and car electronics.

vRS_Si · 27-05-2005, 23:44

Quote:

Originally Posted by vRSed

When I order my noisekiller kit, and lashings of Dynamat (4 rolls) total £280!

Does it have to be Dynamat?
We (see my sig) could help

No sound proofing material yet on the website, but if you want more info pm me

23-05-2005, 21:43	#1
RobClubley Ta moko! Join Date: Jun 2004 Location: Aotearoa - land of the long white cloud Posts: 6,465 Thanks: 87 Thanked 131 Times in 105 Posts	Help! Bad earth I think... Help! I think I have earth problems with my amp. As soon as I connect it to the speakers I get a whistling sound, then it buzzes in time to the engine revs. I have my amp installed here in my Octy estate: So I need a place to fix the earth cable. I connected it here: I read that the earth cable should be as short as possible so it's about 10 inches long (careful!) I tried relocating it to one of the rear light cluster bolts - no difference. Any suggestions? Should I get more cable and run it to the earth point at the other side of the boot? Trouble is my speaker wirtes run across the back of the car - moght get different interference. Not sure what to do next - any suggestions please? __________________ Corrida Red 2004 Octavia vRS Estate - It's the bestest Skoda in New Zealand! Whaia te mātauranga, whaia te māramatanga - Pursue knowledge, pursue the wisdom of knowledge www.pimpmyskoda.co.uk www.clubley.org Facebook

24-05-2005, 10:57	#3
vRS_Si Briskodian Join Date: Dec 2003 Location: Coventry Posts: 1,267 Thanks: 6 Thanked 21 Times in 21 Posts	Your earth wires the same thickness (gauge) as your power wire isn't it? Just checking! It should be! I use the earthing point for the rear light clusters with no problems so it's likely that your picking up interference somewhere. Where are you power and RCA wires run? __________________ vRS Mirror polished 9*18" Mercedes Alloys, APR FMIC, ABD TIP & CAI, Powder coated inlet manifold, Jabba Re-map, Blueflame/Pipewerx exhaust, Forge DV, KW v3 coilovers, Neuspeed ARB, S3 strut braces, bonnet lifters, Autostyl rear spoiler, Milotec rear diffuser & bumper grills, side rubbing strips removed, front and rear rubbing strips smoothed and colour coded, scuttle pannel colour coded, chrome grill colour coded, mk2 vRS badge, de-locked, tints, mk4 aero wipers.

24-05-2005, 11:58	#5
TaviaRS Dinosaur Join Date: Oct 2002 Location: North of the Watford Gap Posts: 14,917 Thanks: 19 Thanked 42 Times in 38 Posts	I had this on mine. I "created" a new earth point, drilled a hole through the boot floor, dremmeled the paint off and got a nice clean surface and put a 5 mm bolt through - cured the problem nicely __________________ A jolly sensible Mercedes E class saloon in a rather fetching bluey grey colour. No it isn't fast, no it isn't modded, and yes, it will still eat your Fabia for breakfast. Official mobile chicane for Briskoda trackdays

24-05-2005, 12:12	#6
Pimpster Briskodian Join Date: Jan 2005 Location: Leicester Posts: 428 Thanks: 0 Thanked 0 Times in 0 Posts	The noise which you are getting is alternator whine. Can usually be fixed by using a better ground. Also check your RCAs and make sure they are not near your power cable (they should be running on different sides of the car). __________________ --------- Pimpster Ex-Skoda Owner

24-05-2005, 12:56	#7
Tom_vRS Briskodaholic Join Date: Dec 2004 Location: Fenland, Cambridgeshire Posts: 10,716 Thanks: 556 Thanked 361 Times in 243 Posts	Being a lazy git, I just bought shielded RCA's and sent them down the same side of the car as the power cable. I also used the earth mounting point for the light clusters, and no problem whatsoever! Makes for a really tidy install. I will eventually use the seat mounting poing though to keep all cables as short as possible, and I think it would be a better contact. When I order my noisekiller kit, and lashings of Dynamat (4 rolls) total £280! I'll be ripping the entire interior out (except dash and centre console) and I'll sort all my cables out properly. I'll be running an amp for the front speakers, so there will be speaker cable running down both sides of the car... Might run the power cable down the middle for good measure. Hope you get your whine sorted. A simple noise supressor should do the trick for a temporary measure... ? __________________ 97/R BMW 328i in Boston Green. << Clickable for boring info. My Journal

24-05-2005, 03:59	#2
macatac Briskodian Join Date: Aug 2004 Location: LONDON Posts: 110 Thanks: 0 Thanked 0 Times in 0 Posts	Yeah the earth should be close to the amp,that is too long,and use a bit of medium/fine grit sand paper around the screw to key it back to bare metal for a good contact,good luck.

24-05-2005, 18:58	#8
CupraR-Rog Briskodian Join Date: Mar 2004 Location: Somerset Posts: 609 Thanks: 0 Thanked 0 Times in 0 Posts	Alternator whine is a pain, isn't it? Double-check all your power cables, and especially check that ypur earth is tight as tight can be against the chassis. Good luck getting it sorted!! __________________ Some people say I'm stark raving bonkers... ...the others just smile and nod...

25-05-2005, 00:32	#9
Grant Briskodian Join Date: Dec 2004 Location: Huddersfield Posts: 247 Thanks: 0 Thanked 3 Times in 3 Posts	more ideas to check, Is the chassis to battery big enough? Does the headunit have a good ground, if that has a poorer ground than the amp, it can make a voltage difference and make this whine, ideally all audio equipment should be commonly grounded. Is the battery on the way out? __________________ 51 plate Silver 1.9TDI PD100 Comfort Not that special - but it ain't broken!

25-05-2005, 07:26	#10
RobClubley Ta moko! Join Date: Jun 2004 Location: Aotearoa - land of the long white cloud Posts: 6,465 Thanks: 87 Thanked 131 Times in 105 Posts	Yaay!! It was the earth after all. I got some fine sandpaper and smoothed off the area where I'd scraped off a bit of paint (the point in the picture). Then I made sure the bolt was as tight as I could get it. No more weird noises Thanks for all the help guys. From reading this section of the forum and stuff on talk audio I've learned loads about ICE and car electronics. __________________ Corrida Red 2004 Octavia vRS Estate - It's the bestest Skoda in New Zealand! Whaia te mātauranga, whaia te māramatanga - Pursue knowledge, pursue the wisdom of knowledge www.pimpmyskoda.co.uk www.clubley.org Facebook

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