Burnt voice coil

discopigg

hey all, i've just somehow managed to burn out my voice coil in at least one(of two) of my cvr 12" kickers. I'm thinking it's because of my alternator which isn't too nice atm(giving readings of up to 15v sometimes)..
My main fuse near the battery blew, along with the two fuses on my a800t amp and I got that nice burning smell from my subbies. :mad:
I've been building a box for my 2 new polk momo mm2124 and i'm thinking now is the perfect time to replace my kickers.
My main concern what i wanted to ask you all about is:
Is there any chance it was actually my amp doing the damage? i really don't want to hook up my new polks and have them die on me, the kickers i can live without but i'm looking forward to running these.
Cheers.

PolkThug

I blame it on Audiobahn.

MacLeod

I doubt its the alternator - I think youre overpowering the subs at the amp. If the alternator was spiking I dont think it would send that power spike thru the amp into the subs. A burned up voice coil generally happens over a sustained period of time when it builds up more heat than it can dissipate. A large burst of power can usually be dissipated by the VC before damage occurs so long as its not sustained. Besides, amps can easily work at 14.4 volts all day long so 15 or even 16 wouldnt hurt a quality amp. If anything, Id expect the amp to fry from power surges before the subs that are attatched to it.

My first guess was that you either had the gain set too high and pushed the amp into clipping or the amp was simply too big for those subs and you overpowered them.

ShinAce

The alternator could have bad regulation, and this won't help, but the speakers burnt from being played too hard.

discopigg

well my gains weren't properly set, had been a bit lazy there. but i wasn't actually running them hard at the time, which is half the reason why i think it might be an issue with the amp.. I'll be getting the alternator fixed anyways. but is there any way the amp might damage the new polks otherwise?

MacLeod

If the gains werent set properly you wouldnt have to crank on the volume to overload your speakers.

Gains arent a volume control, they simply match the amps input signal with the CD players output signal so for example when the CD player is at 50% volume, the amp is at 50%. If you had the gains set too high its possible that when the CD player is at 50% the amp is at 80% so all you had to do is bump it up a little more and your amp would clip which sends a signal at more than double the amps normal rated power. So a 500 watt amp can send out 1000 watts or virtually pure distortion and if you have it hooked up to a 500 watt sub, well you wont have subs for long.

discopigg

so you think i'll be right if i do my gains and crossovers properly?? I had been running them without an issue for a couple of weeks. seems strange that they'd wait that long to pack it in. i know my amp isn't top quality(audiobahn) and i'm just nervous it could be an issue with it. really would hate to waste my brand new subs.

exalted512

The only way the alternator would be a problem is if the voltage was so high that the amp started producing a lot more power. Either way, burnt voice coils are a sign of abuse.
-Cody

MacLeod

discopigg wrote: »

so you think i'll be right if i do my gains and crossovers properly??

Whether its the problem or not, having your gains and crossovers set properly is ALWAYS right.

I had been running them without an issue for a couple of weeks. seems strange that they'd wait that long to pack it in.

What am I, a mirage? You got me on a "pay no mind" list?? Didnt I just say that you burn a voice coil by building up too much heat in one for a SUSTAINED PERIOD OF TIME? Sheesh. Nobody pays attention to me. You sure youre not my wife??

But seriously folks, you can fry a VC by too much heat sustained over a few minutes, or gradually wear one down by overheating it near its breaking point for several days.

discopigg

okay, thanks heaps for all the response.. i'll blame you if my amp packs in my new speakers. :P
But seriously, appreciated the input..

discopigg

btw cody, what would you consider a large enough voltage to cause the amp to produce much more power?

raggadiman

discopigg wrote: »

btw cody, what would you consider a large enough voltage to cause the amp to produce much more power?

If the output of an alternator managed to get past the regulator there is the inline fuse, and in most cases the onboard fuse that will blow, stopping the spike from causing the amp to surge..(unless you have the wrong fuses installed.)

candaddy

If he had them wired wrong to the amp, it could cause a lot of trouble. For instance, a one ohm load could cause the amp to be way unstable and send out a very bad signal (and excess current) even at lower volumes. The gain could be fine in that case once the proper load was restored (4 ohms, or whatever the amp is designed for). That would and could cause lots of fuse popping.

Just something else to check out first.

exalted512

discopigg wrote: »

btw cody, what would you consider a large enough voltage to cause the amp to produce much more power?

If your amp is running at 16V, it can put out some major power, but on the flip side of things, do some major damage.

This is what happens when your regulator messes up:

This one was running at 18V.
-Cody

black magic

exalted512 wrote: »

If your amp is running at 16V, it can put out some major power, but on the flip side of things, do some major damage.

This is what happens when your regulator messes up:

This one was running at 18V.
-Cody

that doesn't look pretty at all

discopigg

woooh, that's some good melting.. When my kickers packed it in i was getting a reading of around 15v off my headunit, and it could well have been higher, that's its top reading. haven't tried to use the amp since, i wonder if that's toasted too..