Me and my buddy are installing an amp and sub into his tC. It's a Kenwood amp, model KAC7252. (Click here, link to amp info) He's connecting it to an 12" Alpine Type-R sub. The sub's voice coils are wired in series. We ran power from the battery, and grounded to one of the bolts that the baby seat ties downs use in the trunk. Signal is coming from a preamp output on his head unit, an Alpine CDA-9856. (Click here, link to head unit info)

Now the problem is, when we switch the head unit on, the amp has power. it powers the sub (faintly, barely audible) until we turn the volume up past 10, at which point the amp goes into protect mode. The cabin lights also dim a little. We've tried it with 3 amps and gotten the same effect every time. I know the cabin lights are a sign the he needs a cap, but why does the amp keep going into protect?HELP!!

 

u have a short somewhere or the speakers are not wired up properly.

are you hooking up 1 or 2 subs? and if 1 are you bridging it?

 

Yes one sub, and we are bridging the amp correctly. We've checked and rechecked all the speaker connections, they are right. Do you know where we could be getting a short? We tried looking for one but came up with nothing.

 

ok so u did

+ from batt -> fuse -> amp

have u tried another ground point? (just to check, who knows, i've seen crazy things like that before)

 

Also try connecting another speaker (any speaker) to the amp and see if it still happens. Or else connect the sub (wired the same way) to another amp. Either test will ensure it's not the sub, as thus far it appears you only ruled out the amp being an issue.

 

i've got a cap for sale if interested
https://www.scionlife.com/forums/viewtopic.php?t=166024

 

Definitely sounds like a ground issue. Did you sand the ground spot down?

 

This is your problem. The ground is insufficient. Find an area that can be sanded down to the metal, and use a steel screw. The "rated hardware" used for seat belts, seats, etc. isn't good for audio grounds, and my guess is that the amplifier is going into protection because it can't find the current to operate at more than a few watts.

Find a new ground location. Upgrade the "big 3". Caps are overrated - don't get one. Crank it up!

 

OK so we're looking for a better ground, and also looking to use better materials for the ground. Also testing to see that the sub is working (which it should be, since it's brand new)

Thanks guys, I'll let you know how it turns out.

 

I grounded mine to where the seat belts blot in under the rear seat and it works great

 

Sweet I'll try it out. Hey you're from St.Charles, I'm in Elgin like 15 mins away :D

 

Yeah I work in Elgin. If you need any help hit me up. I have done tons of audio installs

 

Ground issue for sure.... clean the paint off the bolt and where you are hooking it up!

 

Sweet thanks!

 

You mean you have it where that metal hook thing used to be, under the flipping cover? I have it there, pushing 1000 watts and using 4awg power wire. But, I sanded mine with a dremel tool. You haven't said if you did or not.

 

Yeah that's where we grounded it. I think the consesus here is to sand down the ground area, and I think we're gonna try that.

 

Ground it where your strut is...thats what I did
but I have one of those voltage checkers..

 

I would wire only one voice coil of the sub just to see if it goes into protect mode. Don't blast it, just see if it works...I had this problem once when the sub wasn't wired correctly. when you say they're wired in series, do you mean:

pos from amp to pos on coil #1, then negative of coil #1 to positive of coil #2, then neg from coil #2 to neg on amp?

That's how mine is wired and it sounds great...I tried other alternatives and never got the others to work...

 

^ That's a good idea too. If they're wired in parallel instead of series, and if the load on the amp is too low, then it could exhibit the same symptoms as he described. Most amps can handle a lower than load than they're rated for at low volume, but will fail beyond a certain point.

 

Well, if the sub is a dual 2 ohm coil, you are fine for series wiring (total 4 ohms), but if its a dual 4 ohm coil, then you are running it at 8 ohms and not utilizing the full potential of the amp, wire it parallel for a total of 2 ohms . That is not the issue though as I will agree it sounds like a bad ground.