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JL Audio Mono block amp getting too hot

11K views 49 replies 10 participants last post by  zeus 
G
#1 ·
Guys, i'm a bit pissed off at the moment. I was cranking my sub the other day, and it just started to go on and off, and stop completely, then coming back on.

So anyway, i openned the boot, and what do you know, the amp was hot to touch.

I am running a Clarion dual voice coil sub (dual 4 ohm coils) at 2 ohm with the amp running at 2 ohm. The amp (jl monoblock model: e1200) SHOULD be able to do 2 ohm stable @ 200wrms, which is why i bought it, because the sub is rated at 240wrms @ 2 ohm.

My mate reckons the sub is drawing too much power(hence the heat of the amp) and this makes the sub go on and off.

My questions is, can i wire the sub up differently so that it doesn't draw so much power? I just spent all this money, and it's already causing me trouble. I might have to get a whole new amp, or maybe a sub depending on what options there are.

Cheers,
Yagz
 
#2 ·
How is the amp mounted?
If its rated to go to 2 ohms then it should be fine. How long were you using it?
Is the sub wired correctly in parallel?
How hot was it? Was it burning or just warm?
Are the power wires thick enough?

Dan
 
G
#3 ·
Re: Re: JL Audio Mono block amp getting too hot

DansEdgli said:
How is the amp mounted?
If its rated to go to 2 ohms then it should be fine. How long were you using it?
Is the sub wired correctly in parallel?
How hot was it? Was it burning or just warm?
Are the power wires thick enough?

Dan
The amp is mounted in a very well circulated area. Here is a pic http://www.effalcon.com/pics/yagz/Dscf0464.jpg

I'd been cranking it. The sub, i'm guessing is very thirsty if it's causing this jl troubles. But, if the amp is rated at 2 ohms, i should be able to run it at 2 ohms without any hassle.

The sub is wired according to this diagram http://www.rockfordfosgate.com/rfte...Voice+Coil+-+4+ohms+x+2&image.x=24&image.y=10
The wiring diagram number 1 is how it's been wired.

The amp was very hot. I could touch it, but it was extremely hot.

I'm running a 4 gauge power wire to a dizzy block, which then splits up into 2 8 gauges, which are run to both amps.

Cheers,
Yagz
 
#4 ·
Hmm that is weird?
Maybe the heat is normal, I know my amps get pretty warm but i havent had a chance to put my monoblock to use yet.
They are spose to be more efficient so less heat should be generated?
When it turns off is there a overload light that switches on or is there just no power?
Maybe your ground is faulty? Or your remote turn on lead
Other than that i cant think of anything.

Dan
 
G
#5 ·
There is an overload light known as 'protect' mode, but the times it's happened, i've been driving, so i can't see it.

I'm running it at half balls for a while until i can figure out some cooling methods.

This is pretty annoying as you'd think that a JL monoblock amp worth $500 should be able to power a clarion DVC sub for pete's sake.

Cheers,
Yagz
 
#6 ·
Seriously man, I'd really be lookin at the cooling fan option we were discussing earlier. It really shoudn't be shutting down like that. The heat is generated because of the lower impedence your running, I know a few amps that need to be fan cooled when wired lower than average.
 
#7 ·
Although it probably should'nt matter much , could it be the fact that the amp's mounted horizontally ? As the hot air is trying to dissipate through the heat sink , it's rising to the highest end and causing a hot spot. I know if you mount an amp upside down this will happen, Might be a little far fetched but it's not beyond the realms of possability is it ?
 
#9 · (Edited)
I wouldn't think mounting it in that fashion would be to problematic to the heat dissipation. My amp is situated the same way (running 2 Ohms) and doesn't get that hot. Out of interest what guage are you running for your ground (is it a decent ground)? Its hard to tell from the pic? :wnc: :wnc: :wnc:
Turn your gains down and see if its as bad :fraz: :fraz:
 
#10 ·
I doubt it would be the mounting orientation.
My guess is that the DVC driver dips way below it's 'nominal' 2 ohm rating. This is quite common, and an easy way to find out if it is that is to disconnect one of the voice coils and see if it still does it.

Rick.
 
G
#11 ·
4 gauge power from battery to first 40 amp fuse, then 4 gauge from first 40 amp fuse to a distribution block which has 3 8 gauge output terminals and 3 fuse holders. At the dis block, i have 2 more 40 amp fuses with 8 gauge power cables coming off it to the 2 amps. Then, i have a 10 gauge ground cable to the pioneer amp and an 8 gauge ground to the JL.

I'm going to try and run each 4 ohm coil off each channel of the amp so it runs at 4 ohm instead of 2 ohm.

Thanks everyone, i'll keep you all posted :)

Cheers,
Yagz
 
#12 ·
I'd be running a seperate power for each amp, one fuse one each of them. That way the power's not getting confused as to which way it is running and you get better performance because of the extra power.

As for the heat thing, why don't you switch two of the amps around to see what happens? It could just be the amp.
 
#13 ·
Freak said:
I'd be running a seperate power for each amp, one fuse one each of them. That way the power's not getting confused as to which way it is running and you get better performance because of the extra power.
Power doesn't get 'confused', power doesn't care whether it runs down 2 runs of 8 gauge, or one run of 4 gauge.
8 gauge has around 55amp rating and 4 gauge has around 110.

In any case, it sounds like his wiring is up to scratch.

Rick.
 
G
#14 ·
Yeah, it's not the power that's the issue, as the amps are both running power to spec, but it's more of the fact that it's not running stable at 2 ohm. it's probably dipping below 2 ohm.. In which case, i will connect one channel up to one coil, and the other channel to the other coil so it runs at 4 ohm. Hope the amp can handle that :p
 
#15 ·
What I mean is, if you have 100% power heading down one wire, and that then splits into 4 different wires all of different guages. The power is not going to be 100% it will be reduced having to run on numerus wires of different sizes. Keep everything the same, it's much neater and you get a better power flow. Think of it the same as your exhaust. If it flows through different size pipes left right and centre, it will restrict the flow.
 
G
#16 ·
Current is different to exhaust fumes. It will travel down anything, as long as it has a path, and the way i thought of it, is to think of the 4 gauge that goes to the 2 8 gauges as 2 8 gauges itself.
 
#18 ·
Freak said:
What I mean is, if you have 100% power heading down one wire, and that then splits into 4 different wires all of different guages. The power is not going to be 100% it will be reduced having to run on numerus wires of different sizes. Keep everything the same, it's much neater and you get a better power flow. Think of it the same as your exhaust. If it flows through different size pipes left right and centre, it will restrict the flow.
It doesn't work like that.

Rick.
 
#20 ·
So you all think i'm stupid. The bigger the gauge, the more power that goes through the wires. That is why bigger amps should have bigger wire. My GF's amp wiring pack which is rated at 300watts only has 4 gauge wire running the power. My brother's 500watt amp pack has a 2 gauge power wire. Why? because the bigger the wire, the more power you can suck through it. At least that's what I have been told. Yeah an 8 gauge power wire can still draw enough power to run the amp, but not as much as it could. A 2,1 or 0 gauge would be better, maybe not by much, but it's still there.
 
G
#21 ·
The JL monoblocks min specs says it need a min of 8 gauge wiring. Anything more that that won't give it more power, it'll just be able to suck more. But that's the opposite of what i want to happen, because at the moment, it's sucking too much current to power the sub.

I'm going to re-wire the sub, as the amps are all fine and the power and ground wires are all ok.

Cheers,
Yagz
 
#23 ·
Freak said:
So you all think i'm stupid.
I don't think you're stupid, you just don't understand the relationship between current draw and cables.
The bigger the gauge, the more power that goes through the wires.
Only if the the amplifer is drawing more power. Anything beyond that is pointless.
That is why bigger amps should have bigger wire. My GF's amp wiring pack which is rated at 300watts only has 4 gauge wire running the power. My brother's 500watt amp pack has a 2 gauge power wire. Why? because the bigger the wire, the more power you can suck through it. At least that's what I have been told.
Whilst that's correct, it doesn't mean a bigger wire will be better again.
As I said, the wire only needs to be as big as the maximum current draw from the amplifiers.
Yeah an 8 gauge power wire can still draw enough power to run the amp, but not as much as it could. A 2,1 or 0 gauge would be better, maybe not by much, but it's still there.
No, it won't be better.
The only time it 'may' be better is when running very long cables, and I mean more than 10m. No 'typical' car install has more than 5-6m of power cable.

Rick.
 
#25 ·
This is an extract from the 'car audio Australia' website.

Q: What size power and ground wires do I need for my amplifier?


Using thicker power and ground cables will allow your amplifier to draw the juice it needs from the battery more easily.
A:Before you can decide on the appropriate gauge wire for your installation needs, you need to figure out the current demand of your system.

To do that, you must ascertain the approximate current draw (in amperes) of your amplifier (or amplifiers). First, calculate the total power of each amp (multiply the number of channels by the number of RMS watts per channel). If you have multiple amps, add up the total power figures to arrive at a grand total. Second, double your grand total power figure. And, finally, divide by 13.8 — the result is your system's approximate current draw in amperes.



Using thicker power and ground cables will allow your amplifier to draw the juice it needs from the battery more easily, allowing the amplifier to work at it's peak performance.

Q: How much air space do I need around my amplifier?

A: An amplifier produces heat, which its heat sink absorbs and dissipates. You should leave a few inches of air space around the amp so that it stays as cool as possible. When mounting an amp on a side wall (vertically), make sure that the fins on the heat sink are also running vertically so the heat escapes more easily. Don't mount an amp upside down — the amp will not be able to dissipate heat effectively, and overheating can damage or destroy your amp!


Just thought that this might help some.
 
#26 · (Edited)
Freak said:
To do that, you must ascertain the approximate current draw (in amperes) of your amplifier (or amplifiers). First, calculate the total power of each amp (multiply the number of channels by the number of RMS watts per channel). If you have multiple amps, add up the total power figures to arrive at a grand total. Second, double your grand total power figure. And, finally, divide by 13.8 — the result is your system's approximate current draw in amperes.
All good and well.....
(Though much easier to just work off the fuse which comes with the amp and add them together).
Using thicker power and ground cables will allow your amplifier to draw the juice it needs from the battery more easily, allowing the amplifier to work at it's peak performance.
.......Untill we reach this point.
Thicker than what may I ask? As I said in my above posts, if the cable being used is the correct gauge for the job, then going beyond this will not make any difference.
I can see how those quotes led you to your assumptions, as they are a little misleading.

Rick.
 
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