possible bad amp?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=133123
Printed Date: May 15, 2025 at 3:08 PM
Topic: possible bad amp?
Posted By: icebergslim
Subject: possible bad amp?
Date Posted: December 29, 2012 at 11:12 AM
I have a JL Audio slash series amp 300/4 along with another amp which I can't remember the name of off the top of my head. I have them running to a Kinetik power cell which is hooked up to my main battery. My amps and air compressors (air bags) are running off of the power cell, head unit and alarm are running off of the main battery. I have had this setup for 3 years or so now with no problems. Within the last week my battery has been getting drained until I finally had to replace it. The battery store showed me how to tell if one of the amps was draining power while the car was turned off and it looks like the JL amp is still drawing power. I have have checked both of my remote wires for voltage using a multimeter, when car is on 12-13 volts and when its off .15. This is how I've been using the ammeter: disconnect the ground from amp (so power is still hooked up, I've tried with and without remote hooked up), put one probe on the ground wire and the other probe to the negative terminal on the amp. The ammeter is set to 20 mA. The reading I get is 1.7-1.8 for the JL amp and with the other amp it stays at 0. Am I reading this correctly that the JL audio amp is drawing power when it shouldn't be (since it still does the 1.7-1.8 without the remote wire even plugged in to turn it on). I really don't want to replace the amp if I'm wrong and its still good and I can't find much on the internet about this. Oh yeah I've rehooked up the amps multiple times now and made sure that there are no loose wire strands hitting the remote wire. I did install a new head unit, Kenwood x996, about 2-3 months ago but everything was fine until a week ago.
Replies:
Posted By: DYohn
Date Posted: December 29, 2012 at 11:45 AM
The amp should not be drawing current when the remote wire is disconnected. If it is, then yes something in the amp is bad. ------------- Support the12volt.com
Posted By: icebergslim
Date Posted: December 29, 2012 at 12:34 PM
Ok thanks, I'm not doing the ammeter wrong am I? And is that enough draw to drain a battery in weeks time on a daily driver?
Posted By: DYohn
Date Posted: December 29, 2012 at 1:02 PM
Yes, you're doing it wrong. You should leave the ground connected and put the ammeter in series with the power wire. Meaning, disconnect the power wire from the amp, connect one lead of the ammeter to the power wire and the other lead to the power terminal on the amp. If it's a multimeter that you are using as an ammeter, make sure the leads are in the proper positions on the meter for measuring current. With the remote wire disconnected, the ammeter should read zero. ------------- Support the12volt.com
Posted By: icebergslim
Date Posted: December 30, 2012 at 2:49 PM
Ok, I ran the test like you said with the positive side instead of ground and both with and without remote wire hooked up to the amp. I had the probes plugged into the correct jacks on the multimeter and put the red probe to the power wire and the neg probe to the terminal on the amp. The multimeter does autorange from 0-200 mA. The reading I got was .15. I double checked with my other amp and it still said 0. Does it sound like I'm doing it right? And also that would mean there is something wrong with the amp if I am doing this correct right? .15 doesn't seem like a big draw is that enough to kill a battery in about a weeks time or is it something that just wore down the battery over a long period of time and its low enough where I didn't notice it until it was to late?
Posted By: haemphyst
Date Posted: December 30, 2012 at 6:23 PM
That's negligible current draw. My feeling is that the amp is not the issue. .15mA is what that is indicating, and the memory of your deck uses that much.
Instead of JUST checking the amplifier (as you are doing now), put the ammeter in the power lead AT THE BATTERY. Connect all your accessories. Disconnect the power cable at the battery, and check the current draw there. Either report back, or start disconnecting devices one at a time in the car, until the largest current draw goes away. THAT'S your offending device.
You could even have a bad power cell... Not out of the realm of possibility. Also not out of that realm, your battery could just be defective. I've seen it happen.
There is no way for sure that you can say it's one of the amps. You have to check all of the other loads in the car.
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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: icebergslim
Date Posted: December 30, 2012 at 10:51 PM
Ok, I've done some more testing. I hooked everything up to the Kinetik (tested each wire before hooking up which is 2 amps and 2 compressors, there was one wire that read .02 and the rest was 0) and then tested the main battery. I disconnected the power from the main battery and let the car sit for 20-30 mins to make sure all the computers went to sleep from stuff I read online before coming here. Then I tested the main power wire and got a reading of .02 and then tested just the power wire running from the main battery to the Kinetik and got a reading of 0. Before doing all of this I also took the Kinetik into O'reillys to have them test it because I figured it probably got drained to much from the other dead battery. They really didn't know what it was but they did a load test on it (carbide I think its called) and their tester immediately said it was bad and only had a 52 % charge on it. My multimeter reads 12.?? volts on it when I brought it home.
My thinking now is that the old car battery was just at the end of its life and died, then killed off the Kinetik and thus brought me here. But I'd rather have a good educated guess before I hook everything back up and risk killing another battery so I came here. I know the Kinetik will just drain my new main battery since its bad so I'll have to replace that but I think I'll be good to go then. My other question is the O'reilly guy said I could hook up a trickle charger to the Kinetik and it would last a while longer and be just fine. Is that true?
Posted By: icebergslim
Date Posted: December 31, 2012 at 10:25 AM
Also just out of curiosity since I'm learning this, since the Kinetik is bad it should be drawing power from the main battery to recharge itself from my understanding anyway. Does the car have to be on to see that and I should be able to see how much current its take with the ammeter still right, and would 0-200 ma be the right setting or should the multimeter be on 10a?
Posted By: DYohn
Date Posted: December 31, 2012 at 12:32 PM
icebergslim wrote:
Also just out of curiosity since I'm learning this, since the Kinetik is bad it should be drawing power from the main battery to recharge itself from my understanding anyway. Does the car have to be on to see that and I should be able to see how much current its take with the ammeter still right, and would 0-200 ma be the right setting or should the multimeter be on 10a?
I would take it out of the system completely, you do not need it. ------------- Support the12volt.com
Posted By: icebergslim
Date Posted: January 01, 2013 at 10:45 AM
Thanks for the help!
Posted By: bkearney
Date Posted: January 01, 2013 at 10:13 PM
So I'm having a similar issue... i have a JL 500/1 and about two weeks ago my battery was completely drained, somewhat out of the blue,.. then after a jump it was fine for a week or so,.. then completely drained again. I ended up replacing the battery a few days ago because it was 5 years old anyway.
Now. Somewhere in the middle of all this, the 500/1 quit working. (not sure exactly when, but definitely in the last week or so)
after not using the car for a couple of days, ive noticed the new batter is a little weak so heres where im at...
I noticed the 500/1 is warm and my other amp was not (car hasnt been on in 24 hours). so im assuming the amp is drawing a current...
ive made sure the remote wire is not touching the positive lead. The amp lights turn off when the car is off, and on when the car is on, but the amp isnt working. I havent had a chance to test anything yet, but just wanted to see what everyones thoughts were, and icebergslim, is your amp warm when its been off?
sorry for the sidetrack, and long post... thanks for the help!
Posted By: i am an idiot
Date Posted: January 02, 2013 at 3:56 PM
A JL Slash series amp will light up with ground and power on the remote wire. No 12v necessary on the power terminal. It being warm would lead me to believe that the power supply inside the amp is faulty.
Make sure the signal sense switch is in the off position.
Posted By: icebergslim
Date Posted: January 03, 2013 at 1:57 AM
No my amp was cold still...I think mine was just a dead main battery and it killed my power cell. Does is still get warm without the remote plugged in (just to rule that wire out as causing the problem)?
Posted By: bkearney
Date Posted: January 03, 2013 at 12:20 PM
thanks for the responses,... i havent tried disconecting the remote wire, but the power light on the amp does turn off when the ignition is off, so i assumed it wasnt the remote wire... I also made sure the signal sense switch was set to off. For the time being, i have just disconnected the amp, but when i have a little time this weekend, i will start testing some things. My main issue at the moment is that even when its on, its doesnt play.
Posted By: fuster
Date Posted: January 22, 2013 at 12:49 AM
I suggest removal of the amplifier from the car and test for current draw on a battery on the bench top. That way there are not any other sources to interfere with finding out if the amp draws current with the power on wire not attached.
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Chronic, late stage optimist.
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