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  #1  
Old 07-07-2007
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amps overheating

well, my amps have been overheating lately and today i started to smell burning plastic.
my 4chan amp always smells for some reason and the highs distort when it gets to hot, i have only had it go into thermal mode once or twice.
now, the 2 chan amp im using to run my sub on the other had, it has blown a few 15amp fuses, so i put a 20amp in it, back to the the burning plastic smell, it went into thermal mode today, it has done it a few times in the past so i thought nothing about it.
then i pulled into my apt parking lot and took a look at it, touched my hand to it and it burned the **** out of me, so i let it cool down, then i took the fuse out to see if it blew, nope, but it melted the side of it.
my setup is in my sig at the bottom, both amps are kenwoods.

any ideas on why they are overheating, other then me blasting my music on the highway.
any ideas on cooling?

Last edited by 5speedin2.3; 06-18-2008 at 04:12 AM.
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  #2  
Old 07-07-2007
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Looks like there not getting enough air. Maybe you could put some spacers to get them off the rear wall just a little. Nothing major just maybe a quarter inch. Other than that IDK. I know I had to space my amp off the floor since it was overheating a lot. Maybe someone else will chime in with a better idea.
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  #3  
Old 07-07-2007
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Quote:
Originally Posted by Fazda
Looks like there not getting enough air. Maybe you could put some spacers to get them off the rear wall just a little. Nothing major just maybe a quarter inch. Other than that IDK. I know I had to space my amp off the floor since it was overheating a lot. Maybe someone else will chime in with a better idea.
i was thinking about taking the backs off the amps and building something with fans blowing into it.
its really tight back there, stupid reg cab.
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Old 07-07-2007
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had to mount my jl audio amp on top of my kicker box and ride with the back glass open to keep it semi cool, it still gets warm but does not shut itself off anymore
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  #5  
Old 07-08-2007
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Where do you have your gains set at on your amps?

I looked at the specs for your hu and amps and your 4ch turned all the way down and your sub amp should be just a little above min. At these settings you should be able to turn your hu to 3/4 volume with no distortion. If at this volume and these gain settings its not loud enough you need larger amps.

Your door speakers should have just enough power with your 4ch amp. From the little info that i can find on your sub its getting maybe half the power it needs.

Another thing when choosing amps look at the RMS wattage NOT max. Every mfg max wattages are total bs.

here is the RMS wattage for your amps
Kenwood KAC-746
RMS power output - 35W x 4 @ 4ohms 14.4V
RMS power output - 50W X 4 @ 2ohms 14.4V

Kenwood KAC-5201
RMS Power @ 4 Ohms: 40W x 2 @ 14.4V
RMS Power Bridged @ 4 Ohms: 120W x 1 @ 14.4V
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  #6  
Old 07-09-2007
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ive got a pioneer head unit hooked up to 2 infiniti speakers in the front and 2 polk audio in the back, and a 1 channel 400.1x kicker amp hooked up to 2 10" comp kicker subs in custom boxes and i can blast the crap outa my subs and the amp dont ever head up... my amp is sittin right behind the seat on the right side of the truck not mounted, and as far as the door speakers with just the head unit my speakers will get pretty loud i think the pioneer is 40w rms x 4 but im not sure
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  #7  
Old 07-09-2007
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My best opinion would be you have them wired incorrectly and you have too low of an impedence which heats up the amps. That's just a guess. Use this link and see if it's of any help or applicable to you. http://www.rockfordfosgate.com/rftech/woofer_wizard.asp
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  #8  
Old 07-09-2007
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In my experience, lower quality amps tend to heat up when worked hard. I have a 4ch 600wrms Audiobahn amp that I had pushing my front door speakers off the front two channels with 75w @ 4ohm. The rear two channels were bridged to give 300w @ 4ohm to my 12" sub. Even though the amp had excellent airflow, it would still go into protect mode from heat after about 30 min of hard bumpin'. It would get really hot, hot enough to burn skin like you described.

I had my gains set correctly with a DMM and everything. I never figured out a solution and my amp even has an internal cooling fan.

The best advise is to make certain you are wired correctly and not driving the amp at too low of an ohm rating. Most amps wont do less than 4ohm when bridged.

Good luck. I know it can be frusterating.
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Old 07-16-2007
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Thats weird that it is blowing fuses, it should go in to protect mode before it blows them, i'm not positive on that though. Either you have your speakers wired wrong or the amp isn't powerful enough. You probably have the speakers wired correctly since the amp is a 4 channel and you have it wired to 4 speakers. For cooling, take the back plate off of the amps, build some type of rack, and put fans on them somehow.
I'm guessing that the biggest problem is that the amps aren't powerful enough. I have my 4-channel Alpine amp (150w x 2) wired to one set of MBQuart components up front, and it gets insane hot if I play for at least 15 min really loud. Your amp is only 35w, so it definately would get hot.

The amps are not large enough to drain your elecrical system too much, but if you do run your electrical system below 12 volts, your amps will run much less efficient and get hotter quicker. Amplifier power ratings are for 14.4 volts usually, so if you use them when your electrcal system is drained to less, they will play at a lower power thus working them harder to keep up with speaker(s).
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  #10  
Old 07-16-2007
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blowing fuses is a protect mode......if the amp trys to suck more amps off the battery than the fuses are, the fuses blow so the amp isn't overloaded......

last time i had an amplifier blow fuses it was because the amp was toast......

as far as cooling them, build a little box for them to sit on (mount the box to the back wall) and then install a couple 12v computer fans in there....leave some slits in the side/top of the box so it can draw in fresh air...
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Old 07-16-2007
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If the amp has a 'protect mode' and fuses, which it should, it should go in to protect first. I have never blown a fuse on my amps, they go in to protect first.

Your amps may be going bad if they constantly blow fuses, as mentioned.
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  #12  
Old 07-16-2007
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the amp is more then 35watts, its [email protected] and the other amp is [email protected]

i think it could have had something todo with my old battery but idk, we will see.
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  #13  
Old 07-16-2007
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that 75x4 is probably the max.....RMS is usually about half that of the max......
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  #14  
Old 07-16-2007
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Turn the gain down.
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  #15  
Old 07-19-2007
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The protect mode is for heat. It will only go in that mode if the amp gets too hot (MOSFETs start overheating) . There's probably a thermistor on the heatsink to monitor temperature. When it gets too hot it goes into protect mode until it cools down. If it's blowing fuses it's because it drawing too much current. These are two different things. If the amp was cold and drawing more then 15 amps it will still blow the fuse.

Question is, is it blowing fuses only when it gets hot??

By putting a 20Amp fuse in there isn't gonna help much. Actually you shouldn't do it. There's a reason why they put a 15 amp fuse in there. By increasing the size of the fuse you might cause internal damage to some components.

How long have you had the amps??? Heatsink compound might be drying up and not dissipating heat as it used to.

What gauge wire are you using to power you're amps??? The bigger the better. Do you know if you have 12V at the amp, because you have to remember. Voltage goes down, current goes up!!
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  #16  
Old 07-19-2007
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Quote:
Originally Posted by lifted97ranger
blowing fuses is a protect mode......if the amp trys to suck more amps off the battery than the fuses are, the fuses blow so the amp isn't overloaded......

last time i had an amplifier blow fuses it was because the amp was toast......

as far as cooling them, build a little box for them to sit on (mount the box to the back wall) and then install a couple 12v computer fans in there....leave some slits in the side/top of the box so it can draw in fresh air...
I have to agree with everything lifted97ranger said. I think the damage to your amplifier is already done. It's just a matter of time before it quits completely.

That burning plastic smell is usually electronic components on the way out. Believe me I'm an electronics tech and that smell is never a good thing. I bet if you open it you'll be able to smell around and find out exactly which component smells like that.
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  #17  
Old 07-19-2007
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im running 2g wire upto my disto block, then from there its 6or8g wire, i forgot.
i have 13.4volts at the distro block.

the small amp does only blow fuses when it gets hot.

ive had the 4chan amp apart before to repair it, one of the ground leads burned off the board, no idea why, it was like that when i got it.

i also put new heatsink compound on it when i did it, i have no idea whats causing the smell, i guess i could take it apart again to look.
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  #18  
Old 07-19-2007
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PCB Melting or capacitors leaking
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  #19  
Old 07-20-2007
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Quote:
Originally Posted by Mnemonic
PCB Melting or capacitors leaking
I have to agree here!! Look for bubbled caps. The best way is to use your nose. The component will still smell like burnt plastic. Once you find the components or components, look around at other things. Resistors, capacitors, diodes and see if any of them are starting to be black. See if the PCB is black as well.
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  #20  
Old 07-20-2007
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If you take your amp apart. Can you take pictures and post??

Might be able to see what the condition of the board is!
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  #21  
Old 07-20-2007
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could possibly be an easy fix...
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  #22  
Old 07-20-2007
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You'd be surprised how easy some of the fixes are. Sometimes a 10 capacitor will bring back a dead unit. I just fixed a 19 inch LCD computer monitor. 3 capacitors and the thing is up and running now.
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