how to notice a bad ground?

[Beatin' 10+ year member]

if your amp has a bad ground, will it not put out rated power? The signal will be clipped right?

Could you tell that you have a bad ground by the amps temperature getting hotter than it's supposed to be at rated power for a duration of time?

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[Sleeklsc 5,000+ posts]

Pretty much.

Goes into protect

More dimming than usual

Noise

Heat- Though some amps just run hot.

Popping fuses might be associated as well, though i've never had it happen.

 

[caseyarndt 10+ year member]

you should check it with a dmm

 

[Beatin' 10+ year member]

you should check it with a dmm

How would you go about doing that? I have a dmm.

where do you put the test leads?

 

[caseyarndt 10+ year member]

put the meter on ohms and put the red test lead on the neg of the battery and the black test lead on the ground that you are trying to test. you want a reading less then 0.4 ohms

 

[mat3833 10+ year member]

personally i prefer to test the continuity of the ground. not the resistance. but to each their own i suppose. and the best way to test a ground is to make it right.

Matt

 

[trumpet 5,000+ posts]

A continuity test only tells you the circuit is "on" or "off". Testing the resistance tells you part of the story, but if you're having problems with the amplifier you should do a voltage drop test.

This will require a bit of reading but, like this article says, you have to practice it for this to really make sense to you. Voltage Drop Testing | Automotive Topics

 

[maylar 10+ year member]

Measure DC volts right at the amp power terminals with the system playing. That's the only thing that matters. The symptoms of a bad ground vary greatly and there's no guarantee you'll notice them.

 

[mat3833 10+ year member]

my bad, i used the wrong word. continuity is in fact just if the wire is "unbroken". my uncle has a DMM(or something like a DMM) that plugs into a wall. you insert one lead in the wire before the ground and the other you bolt to the chassis ground up front. it gives you a reading, but its not in ohms.

Matt

 

[Beatin' 10+ year member]

Measure DC volts right at the amp power terminals with the system playing. That's the only thing that matters. The symptoms of a bad ground vary greatly and there's no guarantee you'll notice them.

how would you go about doing that? Putting the red test lead on the power terminal and the black lead on the ground terminal?

I thought that was dangerous......might damage the amp.

 

[maylar 10+ year member]

how would you go about doing that? Putting the red test lead on the power terminal and the black lead on the ground terminal?

Yep.

I thought that was dangerous......might damage the amp.

Nope. Just don't slip with the probes or you'l make sparks.