Noise on speakers - RCA not connected to amp

[feelinhipp]

I have an 88 Honda CRX. In my car I have two amplifiers, one powering four speakers and the other powering my sub. My problem is as follows: I hear noise on my four speakers.

I have unplugged the RCA wires going from my deck to the amp that powers my four speakers. With the deck and 4-channel amp on I hear noise in the four connected speakers, although the RCA cables are not connected. If I disconnect the speaker cables from the amp, there is no more noise. Any advice would be appreciated.

[clayton]

You might want to check your ground wire. Also make sure that your power wire is not being ran together with speaker wires. These two items can cause the noise. Mainly when the engine is running. If it does it without the engine running, you might have something wrong with the amp. Hope this helps.

[feelinhipp]

Which ground wire are you referring to. I have checked the ground on the amp, it seems good. I was thinking the ground on the head unit may need to be moved. As off now it is attached to the chassis of the car. What do you think? I have yet to begin facing the issues when the car is on. As of now, I am trying to trouble shoot issues when the engine is off. This is a brand new amp so I HOPE it is not the amp =) Thanks for any more information you can provide. I will change the ground and will let you know how it works.

[Jean]

Do you have noise in all speakers including your sub ?
What type of noise is it , static, hiss , other ?

Disconnect rca cables (one end) from the amplifier side, do you still have noise ? If no, then reconnect it and disconnect the end on the headunit side. Do you still have noise ?

You can also check if the noise is coming from your headunit rca outs or not . Turn your headunit off, then turn the amplifiers on by connecting the remote turn-on wire . IF you don't have any noise then, then its not your amp or wires.

[Jean]

You know I just realized, are you using stock headunit with speaker level inputs on the amplifier ?

[pape]

the first step would be to make muting plugs for the amp and see if you still get wine. Basically they are just RCA plugs with the shield and center pin shorted. You plug these into the amp and if you still get noise, then it is something with your amps.

http://www.davidnavone.com/index.htm


there is videos on the bottom of the page that explain muting the amps.

[feelinhipp]

Thanks for everyone’s help! I will try and answer everyone’s responses below.

Jean:
As of now I do not have the sub connected to the "sub amp". So no, there is no noise on the sub. The sound I hear is that of a hiss. This sound is coming from the other four speakers that are connected to the 4-channel amp. If I turn the volume of my head unit from 0 sound to 1, there is a slight pop coming from the speakers. I hear the hiss when the volume is 0 or higher. This is not a slight hiss but a noticeable one. I am even hard pressed to call it a hiss. I hear the hiss when the RCA cables are connected to the head unit and NOT the amp. O yeah, the head unit I am using is NOT stock. Thanks for any advice and for your help.

pape:
Should I take the step of making muting plugs? As of now I am hearing the hiss when the RCA cables are not even connected to the amp. Thanks for any advise and for your help!

[pape]

hmm you could try it for a hiss.
What kind of amp is it?
Where are the gains on the amp at, you may try lowering them.
The amp itself could be defective...

[feelinhipp]

Pape:

I have the USG4080 by US Acoustics. The gains are currently set at 50 percent but I hear the "hiss" at all levels except when gain is set to 0. At this level the "hiss" is not heard.

I also thought the amp could be defective but this will be the second amp I will have heard this on. So I thought I could rule out bad amp. Thanks for the help any more would be appreciated!

[Jean]

That's not a bad amplifier at all , nothing extra ordinary but a good car amp for the $. Question, just how bad is this hiss and also do you hear it when the Engine is off ?