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Grounding Two Amplifiers

2dee11

2dee11

Member
hey everyone i have realized that the grounds on my amps are not the best therefor i plan on fixing this very soon. however in my research and reading i have found mixed results. some say to ground both amps to the same location to avoid ground loops, however some say the complete opposite. Do any of you guys have opinions on this? in my set up, i dont believe that the short 18in however short ground wires are long enough to touch each other in order to be grounded together i do have them grounded decently far apart for this reason... so my first question is with two amplifiers do you ground them together or seperate or does it matter? my second question would be your opinions on the best way to ground. the ring terminals are too small to fit on my seatbelt bolts i also dont believe they will reach or fit on my strut tower, therefore i have them grounded under the back seat in my 05 gp. i have heard that using a self tapping bolt/screw and a star washer is the best way to go after removing all the paint. thanks for the responses guys!
 


If it matters, that would be news to me. I drilled some, sanded, and used a screw I found laying around. Didn't give me any trouble.
 
The best way to ground it would be running grounds straight to the front battery negative terminal and doing the "Big 3". Get a battery bolt extender and ground both amps to it.
 
i agree with slow, i also heard shorter grounds were better and that you could also run into issues grounding to a battery
 
I have ALWAYS grounded to the battery up front. Regardless of if it was for my extra batteries or for my 4 channel amp and NEVER had a problem with it. The best ground is the negative terminal of the front battery hence why the big name audio guys run distribution blocks off the front battery positive and negative.
 


Look at me, learning!

zoidberg.jpg
 
I'm probably making things complicated...

What is a proper ground?

A poor ground connection or high resistance reading may seem trivial under no load, but once you are pounding your nice new amp and it is drawing large amounts of current, this little reading has become a monster reading that has caused many an amp to fail for no apparent reason. It may be noticeable as a extremely hot running amplifier in a short time period, poor output levels or diminishing levels and of course a blown power supply or output section in the amplifier.
Click to expand...

If we had CSI go back and look at majority of amp failures...this is it.
 


It doesn't matter if you have them grounded to the same spot or not. All that matters is that it is a good ground. Strut or seat belt bolts are generally the best. You don't need to worry about anything else. Unless your doing a big system, don't waste the money or time running another wire to the front battery.
Make good grounds and be done with it. If it won't fit over the seat belt bolt or strut bolt, put a bigger terminal on it
 
a good ground can be check with a dmm, As with the ground run up to the main batt, you can do this if you serious pulling some rms. I Just have big three and have 2 grounds that will run to batt in rear. They are connected to strut towers and paint has been sanded away. i had no issues on 1500rms stock alt and big three. All wire is 2/0 knu. I went and up my rms to 2500 and now have seen voltage drop. thus i orderd batt for rear. OP just make sure your ground is secure and used a bolt, i repeat make sure its a bolt not a sheet metal screw or the seat frame bolts.
 
Reason you probably haven't found it is because metal is a ground source. Period. The entire metal of the car is a ground. There are several grounding spots stock, so obviously it's not bad to ground to different places. The more the better the way I see it. There's no real theory you need to learn other than metal is the ground. And being that these are unibody, you dont need to worry about trying to ground to the chassis. Did you know that electricity flow starts at the ground and not the power haha
 
barnettimpala said:
Reason you probably haven't found it is because metal is a ground source. Period. The entire metal of the car is a ground. There are several grounding spots stock, so obviously it's not bad to ground to different places. The more the better the way I see it. There's no real theory you need to learn other than metal is the ground. And being that these are unibody, you dont need to worry about trying to ground to the chassis. Did you know that electricity flow starts at the ground and not the power haha
Click to expand...


I'm not so worried about a different format/reasoning for myself, but the average reader. When talking about this to people in general it's very easy to misunderstand. If people knew as much as they proclaim we wouldn't have so many failure rates due to poor install, poor grounds, or poorly set gains.

Electricity isn't as simple as touching wires and I'm always trying to help people recognize poor installation of grounds. Outside of hardware failure, poor wiring can be extremely dangerous.

Just because you are "touching" metal doesn't mean you have a good ground.
 


Which is why I said just ground to the strut tower or seat belt bolt. They both are relatively close in any circumstance to wire an amp up in the trunk and have been proven to be good grounds, so long as you make sure to remove the paint for metal to metal contact.
Your right and especially about the gains. That's a whole nother discussion in itself
 
Seat belts and seat bolts aren't a good idea. They're typically coated in zinc, subsequently causing ground noise. Lots of people have good success with a strut tower bolt but it's not my first choice. Another general rule is to keep the ground a max of ~18 inches in length.

Here's some ideas...

Seat Belt Bolt for Ground Attachment? - DIYMA Car Audio Forum

Electrical Conductivity of Metals, including some alloys

* At 20º Celsius, based on copper as 100.
** Per degree C at 20º C.
Note: The conductivity of various metals is subject to variation according to processing and alloy composition.


Aluminum 59
Brass 28
Cadmium 19
Chromium 55
Cobalt 16.3
Constantin 3.24
Copper:
Hard drawn 89.5
Annealed 100
Gold 65
Iron:
Pure 17.7
Cast 2-12
Wrought 11.4
Lead 7
Manganin 3.7
Mercury 1.66
Molybdenum 33.2
Nichrome 1.45
Nickel 12-16
Nickel silver 5.3(18%)
Phosphor bronze 36
Platinum 15
Silver 106
Steel 3-15
Tin 13
Titanium 5
Tungsten 28.9
Zinc 28.2
Click to expand...
 
I have a setup with 2 amps.

1800w Mono Kenwood and 1200w SPL 4-channel.

I sanded a spot down in the trunk, screw one ground into that, and then split that one big ground into a distribution block to both amps.

I have had no problems with this.
 
DanPrixGTP said:
I have a setup with 2 amps.

1800w Mono Kenwood and 1200w SPL 4-channel.

I sanded a spot down in the trunk, screw one ground into that, and then split that one big ground into a distribution block to both amps.

I have had no problems with this.
Click to expand...

i did the same running an alpine mrp-m1000 and a infinity 475a and had no issues
 
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