My amp (Kicker KX550.3) is starting to piss me off.

It will intermittently cut out (go into protection?) for 1-2 seconds. It happens after the amp has been on for a few minutes and will happen at random.

Background information--amp located horizontally in trunk, signal provided by speaker level output from stock head unit. Just bought and installed last week, has been doing this since day 1. Currently only driving a pair of 4 ohm component speakers (sub section of amp not used).


Things that could cause this:

1. Overheating--not likely because it will happen in the morning when the trunk is cool and the amp has only been running at low-moderate volume for about three minutes. Barely warm to the touch. Built-in fan not running (I assume it will kick in when the unit passes a certain temp. threshold). When it cuts out, it is only for 1-2 seconds. If it was overheating, it would take longer to cool down before coming back on.

2. Short circuit protection--I have double checked all my speaker connections. Measured resistance is about 4.3 ohms. Cuts out whether car is moving or parked.

3. Under/over voltage--I don't think this is the problem either. Whenever I check the voltage at the amp terminals, it is well within the acceptable range.

What else???????????

It has me stumped. Sometimes it will work all day without cutting out. I double checked all connections two nights ago, redid my ground connection and watched it like a hawk, and of course then it wouldn't act up. There is a light that indicates when it is in protection mode, but whenever I am watching it, it always works fine, so I am not 100% sure it is going into protective mode. I thought it was fixed because it worked fine all day yesterday. Then this morning, it did it again a few times on the way to work.

If you can think of anything i have missed please let me know. I am out of ideas.

I am about ready to send it back.


Thanks!

 

have you noticed if it is specifically related to a certain CD or song?

and where are your gains set?

 

Happens with many different CDs. Can't recall if it does it w/ radio as I don't listen to the radio much.

Amp gain is set very low (dial goes from 0 to 11, is set at about 2).

 

let me read the manual, and i'll get back to you....

it doesn't seem to be one of the easier things.

 

looks like you covered the big stuff --

when measuring the resistance of the speakers, did you measure to ground as well?
resistance setting on meter, red on speaker wire, black on ground screw of amp.

check all of those. none should read anything but infinite.

i don't think this is the problem, but it's on my mental list of things to check...

edit

thought about this one later... where is your ground located and what gauge are you using for your power and ground?

also, double check to make sure it's tight and has good metal contact.

 

Power & ground wires are 4 gauge.

Resistance between all 4 speaker terminals and ground is about 23k ohms (close enough to infinite?).

I think you may be onto something by suspecting the ground connection. I currently have it grounded to one of the bolts that secures the bar across the trunk (shock tower-type brace?) that runs underneath the spare tire. I did dremel off all the paint around the hole to ensure metal-to-metal contact. Do you have a better suggestion for a ground location?

The intermittent nature of the problem makes it tougher to troubleshoot. After acting up this morning, it worked flawlessly the rest of the day .

We'll get to the bottom of this yet.

 

that seems close enough to infinite for my tastes... if you had a short, it would be low...

while i'm thinking about it though -- how did you install the speakers in the door? mdf spacer? cut the basket? screwed straight into steel?

that's my ground location as well... and i didn't even dremel the paint away... (the bolt is a clean raw metal and the threads inside the hole are also clean and unpainted.)
check the crimp connector on that ground wire... see if you can play w/ it and reproduce the problem. also, is that bolt tight? (i hope you didn't and doubt you did leave that only finger tight or something.)

there is a factory ground in the trunk you could try... but i'm not sold on that being the problem.
have you noticed if it is temperature related? like, when the weather is cold is it more likely to happen? (wait, nm - you're in Cali. i doubt it gets much below 60 over there.... )

what did you use to connect to the OEM speaker outputs? (and don't say wire... )

 

The speakers in the door are mounted in exactly the same way as the stock speakers (same screws, location, basket). The Kenwood Excelons I used have a very small magnet structure, so this was not an issue.

In wiring the speaker outputs from the OEM deck, I cut the wires just past the connector, made connections using crimp-on solderless connectors (didn't have much room to maneuver a soldering iron back there). I ran 18 ga speaker wire back to the amp, 16 ga from the amp back up to the head unit and used the same type of connectors to splice back into the wires on the other side of the cut. from there, factory wiring to the doors where my crossovers are mounted.

As far as temp, you're right. When it is "cold" in the morning here it is about 60 degrees . The problem does seem to be more common when it is cool...showed up this morning on the way to work, but then again last night at about 10 pm I had no problem. Temp really seems to be a non-factor.

I suppose I could go back and solder the connections to be sure, but I'm not convinced that this is a problem. When it cuts out, it is both channels at the same time (although one is a fraction of a second behind the other??). I guess if one was intermittently shorting out, it could be causing the other to follow if the amp goes into protection. I'm thinking that it isn't intermittent short because the duration of the "cut out" is always the same. It doesn't fade out for one second one time and then for six seconds the second time. If there were wires making contact where they shouldn't be, I would expect a more random nature.

I'm just starting to ramble now.

Just throw out any ideas that come to mind. I've got some time this evening, so if you have any suggestions, I'll be pulling everything out and re-rechecking the connections to try to eliminate any potential connector problems.

Thanks for sticking with me!

 

ack... this just sounds funky...

so, the shutdown is always the same amount of time? regretfully it isn't long enough for you to check for the protection light.

*sigh*

it's done this from day one? is it grey market or legit? if legit, i'd start to vote on returning it and getting a new one.

check the connections, as it cannot hurt, but
" I'm thinking that it isn't intermittent short because the duration of the "cut out" is always the same. It doesn't fade out for one second one time and then for six seconds the second time. If there were wires making contact where they shouldn't be, I would expect a more random nature."