Noise

[donut_kng]

Heres another noise/hiss problem everyone hates which has just decided to appear in my sound system. Heres how the story goes..

Installed in my 33 is a Kenwood TV/DVD screen 6" splits at the front, 6x9's in the rear all running off a Kenwood 4 channel amp. Recently I have been doing some trialing of my Fusion sub and amp setup just to test whether the size of the box is good or if there are any leaks in my fibreglass box.

As soon as I hooked up the sub and amp, I have now found a faint but annoying hissy whining noise coming through the 4 in cabin speakers mentioned above. The amp for the sub is separate, as well as all the wiring. The only thing I have tapped into off the other amp is the remote/ignition wire, everything else is independant.

I believe that it could possibly be the RCA cable for the 4 speakers as when they are disconnected, whilst the system it on, the noise stops. Also when I put a noise filter inline with the RCA's the noise also stops. I do not want to resort to using filters as the system worked fine before and also they reduce sound quality as I have dsicover through experience. All RCA leads are out of sight of power cables even more so when the setup was working perfectly.

My next step will be to remove the complete sub and amp setup and see if the noise disappears, untill then, does anyone have any ideas on how to stop this for when I do the final fit on my subs and amps?

[frx026]

try earthing the rca's.

it sounds like the noise is being generated by them.

Strip back the plastic, earth the outher sheild and try that.

Fusion amps are clean and wont produce noise.

[donut_kng]

try earthing the rca's.

it sounds like the noise is being generated by them.

Strip back the plastic, earth the outher sheild and try that.

Fusion amps are clean and wont produce noise.

To test this, can I take a piece of 1 or 2mm wire and connect the outer sheld of the RCA's with an earth point? What would be a permanent way of doing this?

[Gazee]

If the setup was working perfectly it could be that the amp has gone faulty... (just a possibility)

If you can get your hands on another amp to try it out that would be the best and easiest way, i've screwed around for hours, re earthing the system, adding extra earths to my current electrical system, adding more earths to my head unit, filters, earthing the rca's, changing the rca's all that shit..

Then i changed my amp.. wala

If you can borrow one do that to eliminate the easiest and most likely problem (considering it was working before)

[dyken]

the noise cumin through the speakers does it get higher when the revs go up??

[RANDY]

The grounding of the RCA's.... heh...

Pretty sure that if you plug the RCA's in while the system is powered on, you can kill the grounding in the amp and/or headunit. After that, the grounding is gone and the noise comes in.

I had 50/50 luck with grounding the RCA's to the chassis. The noise went completely from one set of RCA's, and about 50% from the others. My headunit also had a blown ground track on a PCB, which I repaired, but it made no difference.

[donut_kng]

dyken: Its not engine noise, its a hissing noise that happens when the car is not running

Ok, I have completly pulled out the fusion amp sub setup and the system is now fine again. So I am assuming that the RCA's which I used for the extra amp were picking up the noise and sending it through the whole lot. Ill paly with different sets of RCA's, etc.

I'll sort it out once I have finished spraying and trimming all my fibreglass bits, as long as I know what the porblem area is now it should be easy to fix once I get to that point.

Thanks for the help

[danielr34]

wouldnt be surprised if it is a problem with the amp, you get that every now and then, even new amps can have an internal earth leak causing alternator noise through ingress. They might exchange it under warranty.

If not the amp maybe adding a condensor for the alternator might help.