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Discussion Starter #1
Im triying to figure out why my amp cuts out at high voulme levels and one of the suggestion from a member was to check for proper ground. Visualy the connection looks good and tight ,it is made with a 8" piece of 4gauge wire from the amp to bare metal on the floor of the truck using a terminal a washer and a metal screw. I checked the resistance from the ground lug in the amp to the negative terminal on the battery and got 27.9 ohms, that tells me the conection is good but beeing new to car audio i dont know what the proper values should be.
 

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Grab a multimeter set it on ohms place one probe on the neg term on the battery and place the other probe where your desired grounds is. I am not exactly sure what would be a acceptable limit but I assume it should be pretty close to 0
 

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Have you switch out your fuse?i had a similar problem, turns out the fuse looked good but
was bad internally and kept sitting off my amp on bass hits

Sent from my LG-MS910 using Tapatalk
 

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27.9 ohms is extremely high, and the floorboard is only sheet metal. You have to ground to something "beefy."

Even 1 ohm would be too high for that measurement. (Seriously.)
 

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eehigg, are you sure your woofer/s voice coils are wired properly and equipment is adjusted properly?
Since we're on the topic, how does one check the amp/s ground?
 

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Im triying to figure out why my amp cuts out at high voulme levels and one of the suggestion from a member was to check for proper ground. Visualy the connection looks good and tight ,it is made with a 8" piece of 4gauge wire from the amp to bare metal on the floor of the truck using a terminal a washer and a metal screw. I checked the resistance from the ground lug in the amp to the negative terminal on the battery and got 27.9 ohms, that tells me the conection is good but beeing new to car audio i dont know what the proper values should be.
that is not good at all. I would expect to see less than 1 ohm.
 

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Something is definitely wrong.
Touch the 2 probes of your meter together and you should get 0 ohms if calibrated properly. However, whatever numbers you get use that as your reference point. If you’re using a piece of wire to extend one of the probe leads include it and use that as reference. Now check the grounds again. Should be less than .5 ohm difference.
 

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Discussion Starter #11
The dmm is a fluke, when i touch the to leads together i get 0 ohms, but the intersting thing is that i checked ground from the battery's negative terminal to the conection point on the body of the battery terminal wire and i get the same reading 27 ohms
 

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There is only one sub a fosgate svc 10" 150rms 4ohm and the amp is a kappa 5 stable to 2ohms.

Oh ok, let us know how it goes after you check your ground again. Hate to say this, but hopefully your amp's PCB is in working order, i had an amp that would cut out and i had sent it in for repair and the problem was that the PCB was damaged. Just thought I'd throw that in there since it could be the case...
 

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The dmm is a fluke, when i touch the to leads together i get 0 ohms, but the intersting thing is that i checked ground from the battery's negative terminal to the conection point on the body of the battery terminal wire and i get the same reading 27 ohms
then I would suggest replacing the stock ground wire. it is corroded or has bad connection. 27ohms is no good.
 

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27 ohms is too much resistance. Check from battery negative post to several different spots on the car and engine. If it’s more than half an ohm it’s probably a bad connection at the battery post or the other terminating end of the cable; check for rust.
 

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Discussion Starter #15
Thanks guys i think i will start by replacing the stock ground wire to try to get as close to 0 ohms as possible, then if that doesnt solve the problem the amp is still under warranty, infinity sent me a return authorization so we'll see. As far as the charging system i get voltage to the amp positive between 14.4 and 11.9 depending on the volume the amp is playing at, but it definitly always cuts out at the lower voltage reading
 

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Do you think this voltage drop could be because of a bad ground.

No, it does have a small affect to voltage drop, but you are expiriencing alot of voltage drop. Start off by having a good ground. Then, you can check the voltage of your battery with the car/accessories off and then turn on the car (motor running) and check the voltage off the battery. When checking voltage when the music is cranked up, it's always good to check the voltage off the amp's power supply. the Big3 upgrade will also help your voltage.
Edit: improper head unit/ amp adjustments can cause voltage drop.
 

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if the ground is 27ohms, then it is certainly not helping. ohms * current = voltage. if you have a high ohm path in the power or ground system and then pull current through it, you will see a voltage drop. simple ohms law.
 
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