Mazda 6 Forums banner

1 - 20 of 24 Posts

·
Registered
Joined
·
1,464 Posts
Discussion Starter #1
I've put an amp in my friends vehicle before and after it runs a min or two, it cuts out due to heat and it's boiling hot. Is there any way to prevent this and/or what causes it to heat up that fast? I'm looking at this amp on ebay to power my christmas presents, a set of Infiniti Kappa 6.5" components and Infiniti Kappa 6x8" coaxials: http://cgi.ebay.com/Kenwood-KAC-8402-4-Cha...1QQcmdZViewItem

I read some reviews and I've seen several that say it overheats and cuts out very easily and basically need to know how to avoid this or if it's just an amp to stay away from.
 

·
Registered
Joined
·
1,334 Posts
Not sure what you're asking exactly but I'll try to answer your initial question. If you're not overdriving the speakers (ie. volume turned up very loud) and the amp in your friend's car shuts down after a few minutes, it sounds like the speakers are wired to the amp in such a way that the impedance is too low for the way the amp is set up.

An impedance mismatch where the amplifier is set up to drive 4ohm or 8ohm loads but is connected to a 2ohm or 1ohm load will cause excessive amounts of current to be drawn out of the amp, leading to overheating. The protection cctry inside the amp is doing what it's supposed to be doing, by shutting down the amp. If it wasn't there the output stages in the amp would have blown (shorted out) long ago.

I'd double check the wiring connections while referencing the install manual for the amp. Most amps nowadays can be configured to drive different loads depending on how the speakers are connected to the +ve and -ve terminals. Double check those connections. Incorrect connections will lead to impedance mismatches.

Also, check to make sure there aren't any stray strands of speaker wire shorting out the +ve and -ve terminals. This will have the same effect, but to a greater degree, as I describe above. Screw type terminals right next to each other on the amp make this an easy thing to do.
 

·
Registered
Joined
·
141 Posts
i'd like to add...have a fat power and ground cable(i.e.4awg.)...ventilate the amp...(mine has a built-in fan)...
 

·
Registered
Joined
·
1,464 Posts
Discussion Starter #4
so other than an impedance mismatch, what else would cause the amp to overheat and power down? Would an inadequate ground cause this? Basically I want to make sure that an amp won't just do this on it's own when it's installed properly because I want to go ahead and order this amp. If it's the amp itself that's causing itself to overheat, I obviously don't want it.
 

·
Registered
Joined
·
2,044 Posts
amps turn off out of self protection. it could be either an install problem, or problem with the amp itself. it's best to do some basic troubleshooting to figure out what's causing the problem.

remove the amp from the car and bench test. if it works on the bench, turn to your install. if you don't have the knowledge or ability to test on the bench take it to a shop and have them check it out. if the amp is bad, have it fixed/swapped out if under warranty. if the warranty is up, it's probably cheaper to replace the amp.

problems with the install could involve improper wiring of the subs or amp, or frayed improper power/ground. sounds like a problem with the amp though, so if your wiring looks right, pull the amp & bench test.
 

·
Registered
Joined
·
1,212 Posts
we would need a little more info to find out why the amp is shutting off, like pwr/grd wire size, what it's running(# of speakers, resistance).


to avoid the amp you listed heating up, the basics I used before is never mount an amp upside down. make sure the power/ground is large enough(I'd use 4 ga for the linked amp). keep the gains down (I used a line driver for a long time).
don't forget about under the hood grounds too I had 1/0 running through my previous car, added a 1ft piece of 2 ga to help the small factory ground
 

·
Registered
Joined
·
705 Posts
Defintely sounds like a install problem. And if it is a problem with the amp, it's a individual problem, not common to every one. Could even be that the gains are turned up too high causing the amp to overload, overheat and shut down. But usually immediate shutdown is more of a wiring issue. But don't let an improper use of your friend's amp, stop you from getting one.
 

·
Registered
Joined
·
1,506 Posts
Yup, it defenitely sounds like an install related problem, as has been mentioned.

That amp should have no problem running at 2 ohm stereo all day long. And generally speaking, kenwoods are known for reliablity.

Overall, use adequate power wire, do a clean install, and don't push the amplifier, and you should be fine.
 

·
Registered
Joined
·
1,694 Posts
Yup, it defenitely sounds like an install related problem, as has been mentioned.

That amp should have no problem running at 2 ohm stereo all day long. And generally speaking, kenwoods are known for reliablity.

Overall, use adequate power wire, do a clean install, and don't push the amplifier, and you should be fine.
[/b]
Don't listen to Dave, he doesn't know a thing about audio...
 

·
Registered
Joined
·
1,464 Posts
Discussion Starter #10
Yup, it defenitely sounds like an install related problem, as has been mentioned.

That amp should have no problem running at 2 ohm stereo all day long. And generally speaking, kenwoods are known for reliablity.

Overall, use adequate power wire, do a clean install, and don't push the amplifier, and you should be fine.
[/b]
that's basically all i needed to know. Here's my setup, let me know if this is ok. I have a 4 guage wire running from the battery to the rear of the car, it splits to two 8 guage, one for a 760w (380 RMS) Pioneer amp, one for a Kenwood 720w (360 RMS and yet to be purchased) amp. The ground wires are 8 guage. Remote and RCA come from my Pioneer AVIC N2. On my Pioneer amp which is bridged and pushing my Alpine Type R 10" sub, I am using 14 guage speaker wire. What guage wire should be used on the Kenwood for 90w RMS at 2 ohms per channel?
 

·
Registered
Joined
·
705 Posts
14 guage would be fine. Nothing smaller than 16 though.

I can't remember how much speaker wire it took to go from the front speakers to the amp in the rear, but if you find yourself needing more than 25ft on any one speaker, then you need at least 14 gauge. I would just use 14 gauge to be on the safe side, or even 12 if you think you can run that big of wire into the doors, it's possible, I've done it, but it's not fun.
 

·
Registered
Joined
·
1,506 Posts
Don't listen to Dave, he doesn't know a thing about audio...
[/b]
haha...dick.

What guage wire should be used on the Kenwood for 90w RMS at 2 ohms per channel?[/b]
16 guage is more than adequate for the door speakers. Also, if you're not up to running new wires into the door, the stock wiring should be sufficient for those power levels.
 

·
Registered
Joined
·
1,320 Posts
You cant wire a regular speaker at different ohms than its already at. Subs are a different story. As long as you have them hooked up correctly to the amp it shouldnt be a problem. Make sure that all the power and grounds are tight. You most likely have a loose or inadequate ground.
 

·
Registered
Joined
·
2,664 Posts
I've got a question since we are on the topic of door speaker wiring.

On an installation I did on a Mazda6 I simply soldered the speaker output on the amplifier (JL 300/4) to the vehicles stock wiring harness. I used 12awg speaker wire because that's all I use for speakers. But how do I run 12awg wire all the way up to the speaker.

Now on previous installations all I would do is run the wire between the door panel and the vehicle's interior panels. You can see the wires when the doors are open but not when shut. I really didn't want to do this but I didn't think there was any other way other than drilling a hole in the door and chassis.

If drilling is the only option how do you do it without having corrosion issues later on.

Thanks.
 

·
Registered
Joined
·
1,464 Posts
Discussion Starter #15
I've got a question since we are on the topic of door speaker wiring.

On an installation I did on a Mazda6 I simply soldered the speaker output on the amplifier (JL 300/4) to the vehicles stock wiring harness. I used 12awg speaker wire because that's all I use for speakers. But how do I run 12awg wire all the way up to the speaker.

Now on previous installations all I would do is run the wire between the door panel and the vehicle's interior panels. You can see the wires when the doors are open but not when shut. I really didn't want to do this but I didn't think there was any other way other than drilling a hole in the door and chassis.

If drilling is the only option how do you do it without having corrosion issues later on.

Thanks.
[/b]
you would have to run the wire through the rubber boot that already exists in the door jams. I haven't done it yet, but I've heard and can imagine that it's a pain to do.
 

·
Registered
Joined
·
2,664 Posts
I tried doing that but the connector inside the rubber has no holes to pass the wires through. Unless you drill that and fish the wires through. If it is indeed possible it would be great to see a how-to on this. I've done just about all kinds of installations but this is the only part that has me puzzled on which solution is best.
 

·
Registered
Joined
·
705 Posts
This has been covered a few times already on this forum. It is a major pain, but well worth it once you are done. You will have to fish the wire behind the side panels. Then you will have to dremel the plastic moelx connector on both sides where there are no wires. Then fish the wires through both connectors, then put everything back together. I know thats kinda a rough way of saying it, but it's almost midnight where I am, and I have to work in the morning. If you want, send me a PM, and I'll try to send you a lot better walkthrough.
 

·
Registered
Joined
·
1,464 Posts
Discussion Starter #18
i have a friend that has this amp: http://www.crutchfield.com/S-hi1cM5GU7kl/c...amp;search=501x

He never used it, it sat in his closet since he bought it about a year ago and he'll sell it to me for the same price that I could get the Kenwood amp for. Is this a pretty good match? I think it is, but just want to make sure. I would have to turn the gains down, but then again I wouldn't have to run the amp hard. opinions?
 

·
Registered
Joined
·
705 Posts
You could set the gains down and it would work. But when you start turning up the volume, even with the gains down you'll still probably push more than 90W and potentially cause damage. You'd have to get multimeter out and make sure you are setting your gains low enough not to cause damage, but then high enough to hear the music. If they are the same price, I would just go for the other amp, because it's a better match for those speakers. Cause they are already @ 2 ohm, so not a lot of resistance, easier to damage with over powering.

Just my .02

That and I really just don't like Rockford n' Fosgate
 

·
Registered
Joined
·
1,506 Posts
I'd be less worried about the extra power, and more worried about the selectable crossovers. 120hz is pretty high to cross your door speakers at. Although, running them full range wouldn't be the end of the world, it's defenitely not ideal.

and for everyone else, here's a tutorial I saw on running wires through the molex for the 3, very similar to what you'll run into on our cars. This is exactly how I did it in my car.

http://www.the12volt.com/installbay/forum_...=78731&PN=1
 
1 - 20 of 24 Posts
Top