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Ok, I can admit when I screw up, do not know something, etc. That being said, I have a noise problem that I cannot figure out. I have never had this in almost 3 decades. The noise is not an alternator RPM dependent noise. Here's the system...

Vehicle - 2009 Jeep Wrangler Unlimited
JVC Deck
JBL MS-8
PPI Phantom Amplifiers
Dual Optima Yellow Top Batteries

Facts...

-Gains are 100% off

-MS-8 gain adjustment does not affect the noise

-1/0g ground to the frame with 1/4" nut and bolt

-I have had this noise since day one - With 3 different amp series, multiple different head units, different wiring, etc...

-The noise is only audible when source gain is all the way down - cannot hear during music, but still pisses me off!

-I have swapped every RCA possible, but the noise is STILL AUDIBLE even with no RCAs connected. That is a key fact.

-There is nothing that I have not checked, relocated, replaced, etc. It is almost as if the noise is coming through the chassis itself! I am 99.9% certain that is not due to any single component of the whole system, including wiring.

-I made a source point ground for the radio, MS-8, and all amps that goes directly to the chassis to eliminate any possible ground loop.

So, any ideas. While Joe Blow would not hear it, I can and it drives me freaking nutz! Do I have some weird sort of EMF problem? Or am I just missing something so basic that I will shoot myself right after I fix it? I don't know! I have chased down noise problems for many years and this one is new to me. I have asked friends in the industry and nobody has a clue.

So DIYMA, if you have a guess, silly or not, please lay it on me. Even us manufacturer guys need some tech support now and then! lol :confused:
 

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Have you tried eliminating the MS8 from the equation yet? I know it has to "go back in" the picture at some point, but at least knowing if IT or the vehicle is the source will help.

EDIT: I only say it or the vehicle in your case because you said you have used different amps and heads and it still occurs. Otherwise it would be an eliminate one-by-one situation.
 

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Discussion Starter #3
Have you tried eliminating the MS8 from the equation yet? I know it has to "go back in" the picture at some point, but at least knowing if IT or the vehicle is the source will help.

EDIT: I only say it or the vehicle in your case because you said you have used different amps and heads and it still occurs. Otherwise it would be an eliminate one-by-one situation.
I unplugged the RCAs entirely and the noise is still there. Is it not an audio component. I have eliminate that possibility. It is something in the vehicle itself...
 

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I unplugged the RCAs entirely and the noise is still there. Is it not an audio component. I have eliminate that possibility. It is something in the vehicle itself...
Not to sound dimissive, but I would try a Jeep forum first then. If it's a vehicle issue, the odds are good somebody else with the same car has already dealt with it and, hopefully, fixed it. Odds are greater you'll find that person on a vehicle-specific forum than here, even if it's an audio based problem.
 

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Discussion Starter #5
Not to sound dimissive, but I would try a Jeep forum first then. If it's a vehicle issue, the odds are good somebody else with the same car has already dealt with it and, hopefully, fixed it. Odds are greater you'll find that person on a vehicle-specific forum than here, even if it's an audio based problem.
Thanx, but I have yet to see a Jeep that has a SQ system in it. I want to hear from installers like, myself that have trouble-shooted a million cars. Not some hick with a jeep and a CB radio. lol :D
 

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Discussion Starter #7
If you have RCA cables that run parallel to the MS-8(near the white molex area), you will pick up some nasty noise.
Even with no RCAs installed, there is still noise. It has nothing to do with the product. It is a vehicle issue...
 

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Nope, impossible. It is a brand new custom Ohio Generator. Even with engine off and no RCAs in the amp, the noise still exists.
If the car is not running the only thing I can think of is the ellectric fuel pump. I had an 07 Jeep but never had any trouble out of noise with it.

As long as the key is on the fuel pump is running, try pulling the fuse for the fuel pump and see what it does? But if the key is in accesory mode, the fuel pump should not be on.

Good luck, this sounds like a tuff one.

LionelC
 

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If you have HID lights try un- hooking the transformer.
 

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Is the ground bolt zinc plated? (seriously)
 

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If the car is not running the only thing I can think of is the ellectric fuel pump. I had an 07 Jeep but never had any trouble out of noise with it.

As long as the key is on the fuel pump is running, try pulling the fuse for the fuel pump and see what it does? But if the key is in accesory mode, the fuel pump should not be on.

Good luck, this sounds like a tuff one.

LionelC
Nope, not that either, but thanx.
 

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Discussion Starter #15
Is the ground bolt zinc plated? (seriously)
Nope. Standard grade 5 bolt. Ground down the frame and back of the bolt and one side of the nut just to make sure I got a great ground. Measured no resistance from the amp terminal to the ground point, and then to the frame. I am about to freaking give up. This is insanity! I mean really - what am I? 17? this is ricockulous!
 

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I was gonna say fuel pump also. My ex had a Liberty that had a noise prob similar to yours. Took me 6 months to figure out it was a crappy fuel pump ground. It was super small and had no insulation. I re grounded it and all was fine.
 

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Nope, impossible. It is a brand new custom Ohio Generator. Even with engine off and no RCAs in the amp, the noise still exists.
Even with engine off and no RCAs in the amp, the noise still exists.

A couple of thoughts: 1. Then it must be inductive EMI. Are you close to power lines? A cell phone tower? Working inside under flourescent lights? Close to the fuse box? Try reorienting the car, or the amps. (Seriously...) Wrap the damn amp in sheet rubber and retest. Put it up on a block of plywood. With the amp's power wire disconnected do you still hear the noise? With the speaker wires disconnected can you still hear it?

Download a "ghost hunter" app or an EMI meter and see what happens as you move it around.

Lastly: Are you SURE it's a vehicle issue and you're not hearing something inherent to your operating environment? As in: is it a noise from an industrial park or something instead?
 

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This a long shot but what the hell. Check all the engine and body mounts anything that you think could transfer noise or vibration,grab a long scewdriver and put the shaft side on the mounts(or frame) and the handle side to your ear.Listen if you hear your noise, if you do keep moving until you find the loudest point and maybe you will find something fishy.
 

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Is that grade 5 zinc plated (like the grade 5 I bought at HD a few years ago)?
It really was the cause of my noise. Jeff (Lycan, Werewolf) gave the technical reason why it matters.
 

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Discussion Starter #20
Even with engine off and no RCAs in the amp, the noise still exists.

A couple of thoughts: 1. Then it must be inductive EMI. Are you close to power lines? A cell phone tower? Working inside under flourescent lights? Close to the fuse box? Try reorienting the car, or the amps. (Seriously...) Wrap the damn amp in sheet rubber and retest. Put it up on a block of plywood. With the amp's power wire disconnected do you still hear the noise? With the speaker wires disconnected can you still hear it?

Download a "ghost hunter" app or an EMI meter and see what happens as you move it around.

Lastly: Are you SURE it's a vehicle issue and you're not hearing something inherent to your operating environment? As in: is it a noise from an industrial park or something instead?
The noise has been there for a long time, so it is not location related. WHen the amp is off, obviously the noise goes away. So the noise is somehow entering the amplifier even with no signal cables. Through the body?
 
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