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static only when engine is revved?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=106199
Printed Date: March 29, 2024 at 5:51 AM


Topic: static only when engine is revved?

Posted By: nastynate16
Subject: static only when engine is revved?
Date Posted: July 17, 2008 at 4:34 PM

Hi everyone, i recently just purchased an upgrade on my headunit the Jensen VM9512, before i had a Sony CDX-GT510. I got the Jensen because i wanted the video screen/dvd player and the 6 channel RCA outs. I have a 15' L7 Kicker playing off of a Kenwood KAC-X401M amp and an Alpine 4 channel MRV-F353 amp. These are playing Kicker KS 2007 model 6 and a half's in the back and 4x6 in the front. Now here's what the problem is, when i turn on the engine in the car i hear a small static and as i revv the engine it grows louder. however this is ONLY when the engine is on, when just the electronics are on i dont hear any static and its perfect. Also, i found that if i only use one set of RCA cables to power the 4 chan amp, and then split it with 2 spliters to fill the 4 channels i hear no static even when the car is on, but i would very much like to not use the splitters seeing as this is why i got the new headunit. Any help would be very much appreciated thanks :)



Replies:

Posted By: Alpine Guy
Date Posted: July 17, 2008 at 5:25 PM
Re-do your ground for the headunit, connect it to a bare piece of metal behind the dash securely. Sounds like you are using the ground in the factory wire harness.

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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.




Posted By: i am an idiot
Date Posted: July 17, 2008 at 8:14 PM

since you said you have no noise when using only one set of RCA cables, this can not be a problem with the grounding of the radio.  It appears as though you may have a ground loop problem.  The first thing you need to do is perform the test at the top of this page. 

https://bcae1.com/images/rca/temporaryrcashieldrepair.html

Test each set of jacks on the back of the radio.  The rca cables must be unplugged from the jacks while testing.  If you find that the problem jack is not grounded, you will need to do the temporary repair or get the deck repaired.    If all jacks are grounded, you need to call around in your area and see if you can find a shop that sell PAC products.  The item you are looking for is a PAC SNI-1.  It is a ground loop isolator.  You should be able to find a shop that will let you try it to see if it fixes your problem before you buy it.  We do it all the time.  It is a directional device, it is made to be mounted behind the radio.  Have your radio easily accesible when you get there.  If you can not easily get the radio out there, you can put it at the amp.  The only problem is at the amp it will cut your low frequency output in half.   But it will let you know if it will eliminate the noise.





Posted By: musthavemore
Date Posted: July 19, 2008 at 10:38 PM
Im not sure how this applies to i am an idiots' posting but I had a similar issue.  My car has an electric fan and every time it switched on, static would crackle through the system.  I upgraded the grounding between the battery, the chassis and the engine block.  The static disappeared. 

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Jeff





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