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Discussion Starter #1
Hey guys,

I have just installed a second amp to my car audio system to run my fusion splits. I am getting interference coming through the speakers when the engine is running. It is like a buzzing/humming sound, it is hard to explain. The noise is at a constant level and does not change with the volume of the head unit or revs of the engine. I have noticed when I unplug the RCA cables the sound stops.

This is how I wired it up:
I ran two separate wiring kits to each amp (remote, rca, power, ground). The RCA cables are on the opposite side to the power wires. The ground wire is grounded at the same point for both amps. I have also tried grounding at different points.

What could the problem be, does it have something to do with the grounding?

Thanks
 

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typically YES, these problems are ground related...

swap RCAs between amps to test, not at volume, but just to se if the noise follows... if it does, somethings up with the RCAs or HU, if not, the amp..

Sounds like HU or RCAs though..
 

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Discussion Starter #3 (Edited)
Hey mate thanks for the reply. It happens with both pairs of RCA's on the second amp running the speakers. I have a 600w amp to test with, but that will be overpowering the speakers. Can i test with that amp at low volume without blowing the speakers?
 

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Sounds like it's coming from the front... Might try a different source to test...iPod or something

Sent with Mind Bullets
 

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Discussion Starter #5
it happens with radio and ipod. My front speakers which are hooked directly to the Headunit with no amp get no interference.
 

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By different source, i mean in place OF the HU not running THROUGH it

Sent via TapaTalk with Mind Bullets
 

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I agree with Aaron, it sounds like a ground issue... I'd look at the RCA's behind the HU. The RCA barrel end could be touching metal behind the HU.

Can you pull the deck easily? Run a seperate RCA from the HU to the amp. To elliminate the HU as the issue. If the noise is still there, its prob the HU, if it goes away, there's something external of the HU.

I have seen bad RCA's before (bad solder joints) that caused issues, but if both of them cause the same buzz I'd suspect the HU or the connection behind the HU.
 

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Discussion Starter #9 (Edited)
Hmm, thinking...thinking...

Oh, is your headunit a Pioneer by any chance?
Yes the headunit is pioneer?...

and Aaron how do i run my ipod straight to my amp? without using the headunit?
Thanks :)

Adam, I am using rca y cables to split the rca outputs on the back of the headunit. When one pair of RCA's is plugged in directly to the hu i still get interference. This is when the RCA barrel isn't touching. And this is for both RCA cables.

also both RCA cables when plugged into the amp running the sub get no interferance. Is this because it is on low pass?

Thanks for the help guys.
 

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Have you tried a differect RCA cable yet? Are both cables from the same manufacturer? It's most likely not the RCA cable itself, but you'll need to elliminate them as being the issue.

Maybe the ground on the RCA out on the HU is bad? Do you amps have high level input you could try?

The ipod to the amp is as simple as running a mini (headphone cable plug) to RCA cable. you won't get a lot of gain from the amp (due to pretty low output from the ipod) but it will work for testing.
 

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Yes the headunit is pioneer?...

and Aaron how do i run my ipod straight to my amp? without using the headunit?
Thanks :)


Adam, I am using rca y cables to split the rca outputs on the back of the headunit. When one pair of RCA's is plugged in directly to the hu i still get interference. This is when the RCA barrel isn't touching. And this is for both RCA cables.

also both RCA cables when plugged into the amp running the sub get no interferance. Is this because it is on low pass?

Thanks for the help guys.
get a 3.5mm to RCA adpater. then plug the RCAs directly into the ipod. the ipod volume will control your amplifier volume, so start low.
 

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Discussion Starter #13
Have you tried a differect RCA cable yet? Are both cables from the same manufacturer? It's most likely not the RCA cable itself, but you'll need to elliminate them as being the issue.

Maybe the ground on the RCA out on the HU is bad? Do you amps have high level input you could try?

The ipod to the amp is as simple as running a mini (headphone cable plug) to RCA cable. you won't get a lot of gain from the amp (due to pretty low output from the ipod) but it will work for testing.
Okay i will buy an adapter and test with my ipod. The RCA cables are different brands, one is audioline and one is Boss. They both have the exact same problem. How do i ground RCA cables and also what do you mean by high level input i could try? Thanks

do you have daytime running lights?
No, i do not.

get a 3.5mm to RCA adpater. then plug the RCAs directly into the ipod. the ipod volume will control your amplifier volume, so start low.
Thanks, I will buy one and let you guys no what i find.
 

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Discussion Starter #14
Do you think it would be worthwhile running any pair of RCA cables over the seats or outside the car to the amp? Thanks
 

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Discussion Starter #15
Just a quick question also, Can i use a 180w speaker on a 600w 2 channel amp just to test the amp. If i have the gain down and the volume down it shouldn't blow it?
 
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