nagging possible electric gremlin

[Firesong]

In the L300 I run 2 amplifiers. One powers two sets of speakers
and the other powers a subwoofer. It's been set this way for
about a year or so. Now, Im having an issue where the one
sub is blowing fuses. It takes a 25 watt and it cracks them.
I tried a 30 amp but still it blew. I undid the wiring and redid
it to make sure that nothing was shorting. The same huge gauge
wire powers the other sub with no issues.

Sub - older Kenwood KAC-649S 4/3/2 channel amp.
Any ideas?
There is a larger inline fuse before the 2 amps and it's solid.

Firesong

[Meanman]

does it blow instantly? or does it take awhile to blow? Instant= short to ground on power side. Slow burn = excessive draw.

[jessef]

Did you put in new wiring from start to finish for the whole system ?

The stock wiring in many places is quite thin.

[lopar]

Does it pop at low volume/gain? Can you temporarily slave in a different sub? Voice coil could be starting to go (short). Take cover off of amp, only a few screws, smell for "burnt" and check for corrosion (internal shorting). Sub protesting poor music selection? Give up on Britney Spears.........

[Firesong]

It's blowing immediately.
I traced the power back and made sure it was intact with
no grounding. The other amp isn't having issues with that wiring.

I can hook up the power and ground. No sub connected. Put the
wire in from the deck (which connects both amps). Turn the ignition
on. Deck fires up, signal goes to the amps and pop.

That's without the sub wires connected.
No smell from the amp, took off cover and it looks pristine inside.

Firesong

[lopar]

Well that narrows it down to the amp or wiring to the amp.
This is not to insult, but: recheck the wiring for + and - to the amp(it happens), and make sure there are no bits of wire across output terminals shorting.
If that is all good, your amp is shorting internally and it is now a paperweight.

Good luck!

[Tinytoy]

I have a pretty decent multi-meter here for you if you need one.Sounds like something has gone south in the guts of the amp itself if its popping fuses with nothing attached. Would that not be a dead short that could be checked by a continuity check?
Phone me if you want the meter.
TT
Lopar beat me to it

[mararmeisto]

From your description, it doesn't sound like it's the fuse in the vehicle that's popping, it's the fuse in the amp. If that's the case, it's the amp.

Also, it's REALLY never a good idea to see if a bigger fuse will keep the circuit from tripping - that leads to fires.

[Firesong]

Yah, I was figuring the amp.
It's seen it's day.
When I say I put a larger fuse in the amp is was from 25 to 30, not
a big difference. Just wanted to see if a slight increase was enough.

Tiny, we should get together now that I have my van back.

FS

[Tinytoy]

Are you going to the fireworks? Give me a shout if your out and about, mabey we could meet up. I finaly got the pyro completed

[FalcoColumbarius]

Fire the two amps and get one amp that can do the job properly with less impedance issues, besides it will save you space. Does your sub not have it's own pre-amp?

Falco.

[Firesong]

I have a top of the line excelon kenwood deck with multi preamp outs
and running 2 kenwood amps to power Infinity speakers and a 12"
phoenix gold sub.

I run a separate amp for the sub for obvious reasons. Not worried about
space. Everything is secured and hidden as is.

I like decent quality sound, not so much volume but quality.

Silly stuff

FS

[thedjjack]

Pull the power wire off the amps then power up the system. If it does not blow with the amps unhooked you have an amp with a problem. If it still blows your wiring must be shorting.

Cheers

[Firesong]

lol
It's the fuse in the amp. It won't blow without power :)

Im pretty sure at this point the amp is down for the count.
FS

[yojimbo]

Normally it will be a power device that fails, and if its blowing a 30 amp fuse without smoking it must be something hefty like the output transistors have gone short, usually they would blow open, but, not always, it's probably not even worth the time for a tech to fix it, though if it was mine I would open it up and see. There is also the slight chance that one of the output transistors cases is touching the chassis somehow, the cases are usually +ve and are bolted to the -ve chassis as a heatsink, with a thin insulator in between, and a bolt through a sleeve, if any of that fails, then you will have a dead short between two parts capable of carrying a high amperage long enough to blow a fuse without even smoking or getting warm. It's probably an easy fix if you know your way round it, I'd open it and play.