Amp suddenly going into protect mode.

[jjtrcka]

I have a kicker CXA300.4 powering 4 Infinity Kappa 62.11 in my 2002 Chevy 2500. It was working great for a few months. Now it is cutting in and out at higher volumes and the protect light is flashing. It appears to be getting sufficient power from the battery. If any one has any advice on diagnosing this, I would appreciate it.

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[audiobaun 5,000+ posts]

How old is your battery? Do you have the existing radio/stock radio installed or an after market??What size is your supply wiring to the amp and ground?Is it fused and if so what size fuse?What are your settings on the amplifier?A pic would help.What is your Voltage at when at Idle?what is your voltage at when radio is on and at your listening volume?Where do you have the amplifier grounded?Pics would help.Is this the only amplifier being used in this system?What size is your alternator and how old is it?

 

[Boomin_tahoe 5,000+ posts]

William!! You ask a lot of questions!!

OP, I would start with how your gain is set on the amp. May be set incorrectly, and if it is, will draw too much voltage thus cause the amp to shut down because it's drawing too much. I would also check your ground. Some amps are more sensitive to a good ground vs. others. And I mean clean metal to metal. A few scrapes may not be sufficient enough. Next up, how big is your wiring to the amp? If it's smaller than recommended size, could be the issue as well. Just guessing now...until you can report back with answers.

 

[jjtrcka]

Thanks for getting back with me guys. Finally got a new multimeter. The amp gets 14.5 volts with the HU (pioneer deh80prs) off. It reads about 13.5 volts with it on at around 20 (out of 62) volume. When I get over 30 the voltage drops to around 12.5. My gains are at about half.

My speakers are reading from 4-6 ohms. They are supposed to be rated at 2 ohms. I am grounded to where the seat is bolted down in the back (I have grounded to this spot for many years with out noticing any problems).

I appreciate any help. Thanks.

 

[los33 10+ year member]

Thanks for getting back with me guys. Finally got a new multimeter. The amp gets 14.5 volts with the HU (pioneer deh80prs) off. It reads about 13.5 volts with it on at around 20 (out of 62) volume. When I get over 30 the voltage drops to around 12.5. My gains are at about half.
My speakers are reading from 4-6 ohms. They are supposed to be rated at 2 ohms. I am grounded to where the seat is bolted down in the back (I have grounded to this spot for many years with out noticing any problems).

I appreciate any help. Thanks.

Afters so much time clipping an amp it will start to lose the capabillity of handling over its limits aka the caps start to swell.
Lower the gain till it stops going into protect mode.

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[jjtrcka]

Thanks for the response. Why would the amp clip with the gains set halfway?

 

[los33 10+ year member]

Thanks for the response. Why would the amp clip with the gains set halfway?

The gain setting does not matter until you factor in the headunit pre-out voltage.
The prs80 outputs 5v at full volume so setting the amp at half is possibly clipping it.

If you had a headunit that only did 2v then i doubt it would clip at half but you really need to learn the basics of tuning a amp.

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[shredder2]

Thanks for the response. Why would the amp clip with the gains set halfway?

Because gains are not volume knobs... they are meant to match the input signal... lol... that's a common misconception

 

[BOOMINGRANDPA 5,000+ posts]

Thanks for the response. Why would the amp clip with the gains set halfway?

yeah if u had 2v pre out 1/2 way probably be fine, try 1/4 way up and u be able to turn hu up louder

 

[jjtrcka]

I gotcha. So, yeah, sounds like I definitely messed up. Live and learn, I guess. I went ahead and turned the gain all the way down, and the amp will still protect at high volume. Did I damage the amp, or possibly a different problem?

Thanks again for the response guys!

 

[shredder2]

I gotcha. So, yeah, sounds like I definitely messed up. Live and learn, I guess. I went ahead and turned the gain all the way down, and the amp will still protect at high volume. Did I damage the amp, or possibly a different problem?
Thanks again for the response guys!

Where is the amp mounted?... just a thought

 

[jjtrcka]

Under the seat in the back of the truck.

 

[TheFiverMan 10+ year member]

Check for loose wires. Power, Ground, Remote wire.

 

[jjtrcka]

Ok. I'm an idiot. I checked it before, but didn't look close enough to the inline fuse coming off the battery. The amp side of the fuse block is partially melted and the prong burnt. The fuse never blew.

So, I'm

 

---------- Post added at 05:56 PM ---------- Previous post was at 05:55 PM ----------

 

Now needing to figure out why the block would have melted. Not thick enough wire?

 

[Boomin_tahoe 5,000+ posts]

lose connection will cause that. Seen pics of it before.