Power amp buzzzzzz..........

[Vagrant No2]

I have now fitted my amp , speakers and disc player , prob is I have a buzzing sound from speakers both amped and non amped . Also when I change discs by selecting on the head unit I get interference on the speakers . There is a single thin lead that runs with the amp cables from head unit to amp , do I need to connect this to anything ? Nothing in any instructions for amp or head unit or cable kit .
Anyone know the answer ?

[MUD MUNCHER]

the thin lead could be the power antenna lead which tells the amp when the stereo is swicthed on or off this lead is usually blue in colour so look for the power antenna lead on the back of the head unit also the buzzing noise could be that you have put the power leads to close to the speaker wires i hope this of some help
cheers shaun

[Wild Thing]

sounds like you could have a bad earth problem

[nero279]

This would almost certainly be the remote turn on wire. It should be connected at both ends. On the amp there should be a terminal marked remote, normally it's between the +12v and earth terminals. On the headunit there should be either a blue or blue with a white stripe wire on the loom it's often sleeved with a tag that says remote on it, and may or may not already be connected to something depending on how the loom is set up.

Erm.. as for the buzzing it could be any one of a number of things. The most common is running a speaker or RCA wire too close to a power cable, but that would only really explain the buzzing on the amped speakers.

Without looking myself i wouldn't like to make too many other suggestions, other than to make sure the amp has a really good earth, and no stray bit's of the copper core from power or earth cables shorting anything. Where did you get your wiring harness adapter from, as the interference when changing discs is making me think you have been sold a dud harness adapter or something sinister like that, it's uncommon for it to have that effect but it is possible.

[nero279]

in the time it took me to write that 2 people already told you in about half as many words.

[MattF]

Cr*ppy ground or interference. If the grounding is okay, try a suppressor
on the 12V supply.

[Vagrant No2]

I have a seperate amp remote which is working OK as I checked that . That wire came with the amp kit with the phono cables for output with this thin wire attached . Could it be a earth for amp to head unit like the old turntable and amps had 'back in the day' before CD's ?

[Wild Thing]

use a meter to check if there is any power on the thin wire wnen it the amp is powered up if not then try putting it to earth no harm will come by it as long as there is no power on the wire

[Vagrant No2]

use a meter to check if there is any power on the thin wire wnen it the amp is powered up if not then try putting it to earth no harm will come by it as long as there is no power on the wire

The wire has nothing connected at either end , it is just bonded to the amp leads .

[Wild Thing]

then I suggest you bond it to the amp casing ie earth then bond the other end to the head unit casing ie earth and see if it helps also put a good earth strap from the amp to the body as short as possible

[kiowa]

do you mean the wire is bonded to the side of the rca lead the one that goes from the stereo to the amp if it is that is intended to used as the remote so if you already have one i wouldent bother with it as for the buzz check the earth both on the head unit and the amp

[nero279]

Still reckon it's amp remote wire, there are quite a few kits about where the amp remote is bonded between the phono leads. If you've already connected your own i'd ignore it. I've never seen an in car system with a case to case earth between an amp and headunit.

I'd go with checking all your earths next then. How close have you run the power cable to everything else?

[Vagrant No2]

Still reckon it's amp remote wire, there are quite a few kits about where the amp remote is bonded between the phono leads. If you've already connected your own i'd ignore it. I've never seen an in car system with a case to case earth between an amp and headunit.

I'd go with checking all your earths next then. How close have you run the power cable to everything else?

I bought an amp wire kit which came with big fat power and earth cables with fitted terminals, remote amp cable and the phono ended cable with the thin bonded on cable . Due to the lack of room between seats and sills all the cables are bundled together under the sill tread trim by door aperture . Should these be seperated , I spent 3 weeks trying to find an easy route for them all and ended up like described .

[AndyLala]

earthing.. causes noise...
installation causes noise...
stereos in cars causes noise...








OK.. you could:

Earth everything to the same point...
Run a much larger earth from the head unit to ground...
You could wrap your power lines round ferrite cores...
You could disconnect the shielding in your RCA's at one end (head unit - amp)
You could route your RCA's so that they only cross you power lines at 90 degrees...
You could boost your pre-amp signal to 18v so that no electrical circuit in the car would interfere...
You could resolder the main boards in you amps, in your head unit, in your speaker connects, so that there weren't any dry joints
You could increase the size of your earth leads on the batteries...
You could electrically test all your leads so that they were 'electrically' equal at the frequencies they were going to play.
You could digitally filter out the buzzing frequencies, then recreate them on demand...

on and on and on and on (perhaps I am being flippant, I apologise)

Run a larger earth lead from the head unit to a known (tested) good earth on the vehicle.
Run the amp earth lead to the same point.
Earth and power down one side of the vehicle, signal down the other.
Increase the size of the earth leads on the batteries.
Cross power lines and RCA's at 90 degrees...
Then check that you amp isn't nadgered.

[nero279]

Keep the amp earth short, take it to a good earth, rear seat / belt mounts are normally pretty good.

Power down passenger side, RCA + remote down drivers side or on drivers side of centre console under carpet then under rear seats. Any interference on the RCA cables will be amplified by the amp, before it comes out the speakers. If they cross you won't notice the interference unless you're entering SQ comps, whether it's at 90 degrees or not. It's if they run parralel you'll hear the interference.

Try that first. Then check the earth on the headunit, although a headunit only draws a relatively small current so it doesn't need a massive chunk of metal or 0 gauge cable, it just needs a constant good connection. If it's got a poor earth the display will normally flicker a little aswell as the sound going.

If that doesn't sort things check and re-check all the connections, ensure the RCA leads are plugged into the correct output on the headunit, I couldn't work out why i had no sound from the DVD player when i put that in my escort until i realised i had the DVD plugged to the RCA out, and 1 of my amps plugged to AUX in.