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?

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.

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?

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 :-)

I had this on mine. :grumpy:

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

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).

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

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!!

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?

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 :thumbup:

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.

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