Ground amp under the seat

[EddieinD]

I've got amps under both my front seats that have the ground wire connected to the seat floor bolts. I'm getting some noise from the speakers when the radio is off or on but the amps are on. I've read that bad grounding can cause noise, so I'm wondering if my ground is no good. Where have others grounded their amps that have them under the seats? Under or over the seat bracket? How much did you have to scrape paint off?

Thanks

 

[sketch1]

You want your ground touching completely bare metal. If you only scraped off a little bit of the paint you need to go in and scrape more off.

Some amps will also cause interference that is just unavoidable...but you will usually only notice this with the radio. Also sometime having the RCA or Speaker cable running next to the amp's power line will also cause noise in the line. To eliminate this it is best to run the amp's power supply down one side of the car, and the RCA and/or speaker wires down the other. What kind of amp do you have? Last one I read about that was causing interference was the JL 500/1 and it was causing interferance due to it's design, so nothing could really be done about it other than moving the amp to the back of the car.

But definatly clean up that ground if you have any paint between the metal and the ground connection.

 

[ThatsRicci]

Depends on what kind of noise it is you are hearing..

is it static? or is it a hum?

make sure none of your speaker magnets are touching any metal either, all metal components that aren't supposed to be touching something should have ample room around them to avoid shorts and noise.

Run all audio wires perpendicular across wires carrying electricity whenever they have to cross.


If it's a ground loop (hum sound) you can put in a ground loop isolator but that robs some power, so try and get a solid circuit going.

 

[freezy74]

If it makes you feel any better, I have amps mounted under both of my front seats also, and I to get noise. I never used to till I cranked up the gains on the amps. It will go away if I turn then down, but so does the sound.

 

[atomic punk]

My ground cables from the amps under my seats are over 2' in length and I get 0 noise. I grounded the amps to the raised tab underneath the rear seats (pull them up and you can't miss it).

The easiest way to make sure you get good metal/metal contact is to use a dremel or other rotary tool to sand off the paint. It works VERY well and takes about 1/8th the time to strip the paint completely off the surface.

Got any pics of your ground point? Maybe we could help you more - ie, if you are grounding to the chassis through the bolt instead of directly against the metal body. I'm assuming you're using a good thick terminal lug too.

 

[EddieinD]

Thanks for the replies.

It is a hum. I've tried to keep power lines away from signal lines as best that I can. I guess the first thing to try would be to get the dremel out and see if I can clear away some more paint. I have a 4-channel Alpine MRP-F240. This actually about to be replaced - doesn't have enough power for my comps.

 

[animator]

I've got an amp that grounds to a bolt inside the driver's kick panel, and run alongside the power cable. All other wires run through the center console and I get 0 noise. I'm also using a stock head unit with an RCA convertor.


This may sound obvious, but is your ground wire the same gauge as your power wire?

 

[EddieinD]

That must be one long ground wire. I thought they were supposed to be close to the amp. So much for that. Yes, my ground wire is the same size as power wire.

 

[sketch1]

When you say power wire do you mean the wire running off the battery or the amp remote wire? They power wire off the battery and the groun wire should not be the same size....amp power wire should be 4 gauge or smaller (I used 1/0 on my mustang) and the ground wire only needs to be around a 16 gauge or so.

 

[atomic punk]

When you say power wire do you mean the wire running off the battery or the amp remote wire? They power wire off the battery and the groun wire should not be the same size....amp power wire should be 4 gauge or smaller (I used 1/0 on my mustang) and the ground wire only needs to be around a 16 gauge or so.

Where did you learn this? Just curious, because it goes against conventional wisdom. The remote turn-on lead could be around 16 awg, if that's what you meant. It all depends on the amount of current through the wire too, so a blanket statement like "amp power wire should be 4 awg or smaller" is true for certain amps, not all amps.

From: THE 12VOLT INFO

"Ground cables should be the same size (or larger) as the power cable.... we recommend using 10 gauge as the smallest wire size for any amplifier of 100 watts or more. The goal is to provide as much current to the amplifier as it could possibly need for optimal performance."

Yes, ground cables should be kept as short as possible: 1.5' or less is ideal. But if you have a beefy enough cable with a super connection to the vehicle's chassis, you can get away with a longer cable (like I said before, my 2 ground cables are 2-3' in length, but I have 0 noise due to using 4awg ground cable and a clean connection.)

 

[EddieinD]

I've got 8 gauge for the whole system battery-distribution block-amps-ground. According to all the gauge/amperage grids (like this one ), I should be fine.

 

[TimelessR1]

Just another thought also...if you are using an aftermarket radio that is putting out 4volt Low level signal to your amp, and you have your amp gains turned up (basically you are on volume 10 on your radio and the amp is at full power) this will almost always cause noise (hum- alternator whine) If your turn the volume all the way down with the car running in neutral, and gas it, do you hear the hum fluctuate with the RPM's? Try the simplest method first..work with the gains..so many people think the gain is a volume knob, while it actually is suppose to match your amp with what ever souce you plan to use. A second fix would be to get another long ground wire and ground it straight to your battery, or someplace else in the car..if the hum goes away..you know its your original grounding spot. 3rd- If you are using an aftermarket radio..it can also be the radio's ground that you are getting the hum from...try the same fix with the radio as in fix#2...or try both fixes together.

Hope this might help

 

[BANsOnLn]

so I am placing my AMP in the trunk. any recommendations on where I should ground it?