rhvix

I installed a pair of 8" subs, and an Amp, to go along with my Aftermarket deck. I now have a noise in the subs. If I turn the key to accesories there is no noise and it works fine, but if I start the car I can hear it, but it does not change pitch with engine speed, also I turn the key back to acc. after the engine was running I can still hear the noise but it changes. The noise has nothing to do with the head unit since I can unplug the inputs to the amp and the noise is still there. I tried running the ground wire from the amp directy to the battery but the noise is still present.
Get all that, any ideas. It is an 86 rx7 gxl automatic, if that makes a difference.
My only thought was something to do with the fuel pump.

Thanks

cprx7

That's alternator wine usually caused by bad ground loop or poor shielding on power or signal lines. Since you've eliminate the signal line (RCA cables) then check your grounds again make sure they are secure and clean and that there is only one ground. Try using wire loom on your signal and power lines just to make sure they are isolated. Also check if the speaker wire from your amp to the speaker is not touching the chasis at any point (torn rubber insualtion perhaps) this will create a ground loop. Also, some radios RCA outs are not grounded to the radio's chasis (you can check if they are using a multimeter ohm setting resistance should be zero) if it's not then you need to run a small wire from the chasis of your radio to the chasis of your amp. Some RCA cables come with a little wire in between the left and right channel cables, that's what it's for. If all this fails then you are fucked.. just kidding.. you'll just have to look harder and maybe get a line filter, although a line filter will not eliminate the problem, it will attenuate it though. Good luck.

rhvix

After grounding everything in my car, the noise did not go away. Then I tried bridging the two channels on my amp, and like magic, the noise went away. So something must be messed up inside the amp. Now I will try to return an already installed amp.........

swilson@assetworks.com

iTrader: (13)

Been there and fixed it as follows:

Is the amp installed so it comes in contact with the cars chassis?
If so insulate it from the car (other than the provided ground wire/post) as this can cause a ground loop.

If that doesn't work tie all of the different componenets (head unit and amps) to a single "star" ground point on the chassis.

If you still are getting ignition noise then one of the components other than the amp is contacting the chassis and creating a loop.