# JL amp noise, not your normal interference



## Whitet231 (May 25, 2016)

Hey everyone, I'm new here. I've had an issue that is driving me crazy I'm hoping someone here can help me with. First, the setup is in a boat, Not a car. Hope that doesn't get me in too much trouble lol. 

Anyways, I am getting a noise through my speakers and the amp itself. It is a JL M800/8. It's the second one that has done this. It's a static like noise through the speakers, rcas connected or not. The amp itself makes the same noise internally if you put your ear up to it. First amp did it after a day. Took it back, second amp, same thing. This is without the engine running. I checked resistance of each speaker at the amp, everyone was 3.8_4.0 ohms. Protection light never came on. 
I have a positive and negative 1/0 wire running from the batteries. Voltage is anywhere from 12-13 volts. I've redone all connections, never finding any issues. I've newly installed this amp, I've had a sub amp running off the setup for a year with zero issues. Not sure why two jl amps would do this? I can take the amp out, power it from a battery not connected to the boat, and I can hear the same noise from the amp. 
Please help, I have no idea what's causing this. 
Tia


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## Locomotive Tech (May 23, 2016)

Yikes man that's a tough one, can you make a diagram of the B(+) & B(-)? It doesn't seem to be from the Head Unit because you disconnected the RCA's. I'm curious of the mounting of the Amplifier, is the mounting location also grounded that could cause an issue. Is the Amplifier in a location that has exposed it to water. I know its a "Marine Amp" but too much or direct contact could be it too. 

JL has always provided me great tech support, have you contacted them?


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## Whitet231 (May 25, 2016)

Thanks for the reply. Tech support says they've never heard of this. 
It's mounted on piece of plywood. See upload. 

I was wondering if a bad rca wire could fry something and cause this?


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## Whitet231 (May 25, 2016)

The b+ and b- is simple. From battery to junction block on the amp board.


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## Locomotive Tech (May 23, 2016)

Good Picture, It could be your RCA's, what brand are they? One thing I would do is separate your signal and power wires, they seem to be all bundled together. It could be interference (EMI) from the other amp. wiring too. Try to separate signal (RCA's), speaker and power wiring. Are there any sources of EMI running near your amps? pumps motors, etc?

I would bet its just the wiring is all too close


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## Whitet231 (May 25, 2016)

That wouldn't make the amp go bad, you think? 
Whatever it is, it's causing amps to get a permanent noise internally, even when removed from the boat and hooked up to a different power supply


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## jb4674 (Jan 29, 2015)

That's an interesting one... 

OP, you mentioned that you hooked up the amp to a battery separately and the same noise emanated from the amp?

I would re-position the amps so that the distro block is on the top left corner or on the left edge in the middle and mount both amps so that the power and ground are basically next to the distro block. Run the RCAs and speaker wire on the other side just to ensure that the audio signal is isolated from the power. 

What has JL said about it?

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## Whitet231 (May 25, 2016)

JL didn't have much to say except to return it.


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## jb4674 (Jan 29, 2015)

Whitet231 said:


> JL didn't have much to say except to return it.



I'd return it and get a different one. 


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## Locomotive Tech (May 23, 2016)

If JL will replace it, definitely do that, it won't hurt. But you are saying that BOTH amps have noise and the noise is the same for the most point? and they both do it while on a bench supply?

That leads me to something common between the two. Head unit, power supply or the wiring itself. Not sure of anything definitive that could cause an amp to get noisy but that doesn't mean that one of the RCA's didn't 12 Vdc or higher and cause some trouble there. I'm guessing that you have a 4 channel for the mids/twt and mono for a sub?

If it were me, and this is only the approach that I would Take.

Isolate the components as best you can. Try hooking your mids/twt directly to the head unit and see if the noise persists. If it doesn't I would then disconnect them from the head unit. Keep in mind, when you hook the head unit directly to the speakers, don't turn up the volume, just listen for the "noise". Protect you speakers. I would then focus on the wiring between the Head Unit and the amps. Use a multimeter and check for shorts between (+) & (-), Be sure to disconnect the (+) & (-) from the battery as the battery will show continuity between the two.

Check the RCA's for continuity from the (+) & (-) of the Batt. and the Spkr wires. Not sure which Head unit you have but that could be the source too. Would start there if it were me.


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## 06gtmike (Sep 30, 2009)

Where is the gain set? If it's cranked up too high you could get some noise.


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## Whitet231 (May 25, 2016)

Amps were damaged. I replaced head unit. I think it was taking out the low level inputs of the amp. Sounds way better now with a new amp and new head unit


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## dsw1204 (Mar 23, 2015)

Whitet231 said:


> Hey everyone, I'm new here. I've had an issue that is driving me crazy I'm hoping someone here can help me with. First, the setup is in a boat, Not a car. Hope that doesn't get me in too much trouble lol.
> 
> Anyways, I am getting a noise through my speakers and the amp itself. It is a JL M800/8. It's the second one that has done this. It's a static like noise through the speakers, rcas connected or not. The amp itself makes the same noise internally if you put your ear up to it. First amp did it after a day. Took it back, second amp, same thing. This is without the engine running. I checked resistance of each speaker at the amp, everyone was 3.8_4.0 ohms. Protection light never came on.
> I have a positive and negative 1/0 wire running from the batteries. Voltage is anywhere from 12-13 volts. I've redone all connections, never finding any issues. I've newly installed this amp, I've had a sub amp running off the setup for a year with zero issues. Not sure why two jl amps would do this? I can take the amp out, power it from a battery not connected to the boat, and I can hear the same noise from the amp.
> ...


I am currently going through something like this myself...a static noise through my tweeters in my front stage (of my car, although). I switched out a head unit, checked RCAs, even brought it to a car stereo place so they could look at it, with no results. I did notice that if I turn the volume up when the static appears, the static goes away...don't know why.

Yesterday, I was adjusting the gains and when I was turning one of the gain controls, the static started when I was moving the controls. When I stopped moving the controls, the static went away. Now, I am thinking maybe there's a short in the gains somewhere. I haven't yet brought it to somebody to look at that because I just discovered this yesterday. But, maybe look at your gain controls. Just an idea.


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## kyheng (Jan 31, 2007)

Actually JL Audio amps are quite good on noise rejections.
But, voltage must stay healthy when it is working. Try measure voltage on this state.


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## Locomotive Tech (May 23, 2016)

OP, just curious, what head unit do you have and how old is it?

@dsw1204 I have seen the gain potentiometers get dirty or just get sloppy and cause terrible noise. What type of amp are you experiencing trouble with?


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## lurch (Jan 20, 2014)

i would like to know if there is an overly aggressive battery charger being used to
keep the batteries up while the boat is not in use. 

i have seen this before, and would hate to see another beautiful JL amp ruined.


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## Locomotive Tech (May 23, 2016)

lurch said:


> i would like to know if there is an overly aggressive battery charger being used to
> keep the batteries up while the boat is not in use.
> 
> i have seen this before, and would hate to see another beautiful JL amp ruined.


Good point, I didn't think of that


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## lynchknot (Sep 27, 2014)

Locomotive Tech said:


> @dsw1204 I have seen the gain potentiometers get dirty or just get sloppy and cause terrible noise.


I was about to say the same thing.


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## What? (Jun 5, 2008)

I have experienced this with two XD800/8v2 and one M800/8v2. I remembered this thread when I heard the noise. They all did it in the car or on the bench. You only need to have power, ground, and remote connected for the amps to make the internal buzzing/static sound. The marine version also had an internal squeal sound upon initial power up.


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## dsw1204 (Mar 23, 2015)

Locomotive Tech said:


> OP, just curious, what head unit do you have and how old is it?
> 
> @dsw1204 I have seen the gain potentiometers get dirty or just get sloppy and cause terrible noise. What type of amp are you experiencing trouble with?


This is to both Locomotive Tech and Lynchknot (since I do not know how to reply to both of your responses simultaneously). My amp is an Arc Audio KS900.6. I've found that if I play the volume fairly loud (not ear-piercing loud) that I do not have my problem. But, when I play it at normal volume when I have passengers in the car, I get that static noise. Also, when I am playing it loud (I have found recently) at low passages, I get that static noise. If it is those gain potentiometers, how do I clean them up?


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## dsw1204 (Mar 23, 2015)

lynchknot said:


> I was about to say the same thing.


This is to both Locomotive Tech and Lynchknot (since I do not know how to reply to both of your responses simultaneously). My amp is an Arc Audio KS900.6. I've found that if I play the volume fairly loud (not ear-piercing loud) that I do not have my problem. But, when I play it at normal volume when I have passengers in the car, I get that static noise. Also, when I am playing it loud (I have found recently) at low passages, I get that static noise. If it is those gain potentiometers, how do I clean them up?


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## jb4674 (Jan 29, 2015)

dsw1204 said:


> This is to both Locomotive Tech and Lynchknot (since I do not know how to reply to both of your responses simultaneously). My amp is an Arc Audio KS900.6. I've found that if I play the volume fairly loud (not ear-piercing loud) that I do not have my problem. But, when I play it at normal volume when I have passengers in the car, I get that static noise. Also, when I am playing it loud (I have found recently) at low passages, I get that static noise. If it is those gain potentiometers, how do I clean them up?



De-Oxit should work. Just ensure that you buy the type that you can control and apply with a q-tip because the spray bottle has too much force. 


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## dsw1204 (Mar 23, 2015)

jb4674 said:


> De-Oxit should work. Just ensure that you buy the type that you can control and apply with a q-tip because the spray bottle has too much force.
> 
> 
> Sent from my iPhone using Tapatalk


I went to Amazon and there are a lot of De-Oxit products. Is the De-Oxit Fader Liquid the one you are referring to?

https://smile.amazon.com/DeoxITFade...93&sr=8-1-fkmr0&keywords=De-Oxit+fader+liquid


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## Locomotive Tech (May 23, 2016)

Most of them should work. It has been my experience that the "static" (that your hearing), only at low power is because the surface contamination interferes with the conduction, at higher powers, the voltage is enough to overcome the inherent impedance caused by the contamination.


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