Hi everyone. Just installed a 4ch amp for the 4 interior speakers in my L and I have that annoying engine noise in the speakers. I have no problems with the other amp for the subs. How can I fix this?????? Isn't there something you can install on the power wire to stop this? Please help!

 

Generally engine noise comes from a bad ground. You say you have no other noise in any of your amps, so my guess is its a bad ground with your amp; however, you may have noise in the subs and just not know it, its harder to hear in the subs than the other speaker. Try regrounding that amp, and that most likely will fix it. If that doesn't work re ground the HU and then move under the hood. Generally you only have to move under the hood in extreme cases.....

Now that most likely is the case, you could possibly have induced nosise from the RCAs. Running RCAs next to power wires can cause this, along with overly shielded RCAs.

 

Your best bet is to have a really good ground for all of your equipment in one spot for both amps and head unit.If you don't your creating a ground loop(BAD!).....Also make sure your useing quality RCA'S..I've never heard of an overly sheilded RCA ,but maybe Hazard has run into this problem?As for seperating the RCA's from power ,I think thats a matter of opinion i've seen arguments for both sides of the case(I seperate mine)..The noise killer device usually doesn't work very well,plus it doesn't FIX the problem it just muffles it a bit...

 

There is such a thing as over shielded RCAs. An unshielded twisted pair is about as good as it gets in the mobile audio world. When one starts adding foil covers, drain wires, teflon...these things have the capability to stop noise but they also can attract it.

Power wires should always be away from signal wires. It is a simple fact that noise can be caused by having the wires too close. It is not as great of a concern with the 12v world but if you ever have an RCA wire near a 110v power wire in your house you will definitly know.

 

Thanks for all your help! I will run a new ground wire to the frame. I have it grounded to a seat bolt. one of the big torx ones. That should keep me busy tomorrow.

 

firemx220 -

I wouldn't waste a bunch of time and effort running a new wire to the frame of your ride.

The seat bolt should provide a good ground. I have both of my amps grounded there.

Before you go through all that, try running a new ground for your head unit, and tie it into that same seat bolt as the amp is using.

As far as the RCA cables go, the only way a cable is "over shielded" is if BOTH ends of the shield are connected straight through. One end should not be grounded, it should be left to "float".

Any RF designer worth their salt knows that a shield running the entire length of a cable effectively turns it into an antenna...

 

I have the same problem. I installed two amps yesterday and used the stock head unit. I never had noise before yet I get a bad whine in the front speakers when one of the amps is turned on. I am just using the stock radio with the speaker level inputs going directly into the amp. Will that cause this whine? I had a stereo with amp a couple of years ago in the same truck and never had this whine. I am using the same ground as the amp before...

 

I called the tech guys at crutchfield and he told me I had to ground the head unit to the same spot as the amp. He said something like the amp was trying to ground itself through the the head unit and that is why I am getting that noise. so I ran a wire from the head unit's ground wire to where I grounded the amp and most of the noise went away. there is still a low whine, but not as bad as before. Any Ideas on how to get rid of that low whine?

 

Turn down the gain a little on the amp and use more volume on the head unit...

 

my amp is grounded just to the right of the passenger seat and towards the back it involved cutting a hole in the floor rubber but there is no noise what so ever.....works great!!!!!!!!!!!!!!

 

priddyboy

do you have any pics of the ground?

 

no,but i will try and get some a.s.a.p

 

thanks a lot!

 

MX, What HU and amp are you running? Are you using any speaker lead to RCA adapters? Tons of things can cause the engine noise but like everyone has said previously most of the time it is a bad ground. If all else fails you can check the ground strap from frame to body, battery to body, and battery to engine. Just remove and replace making sure it has good clean metal to metal contact. Also I have seen noise induced from RCA cables crossing over or near the vehicles electrical wiring. Make sure that your RCA cables are clear of all higher voltage wires, especially if they are just entry level cables.