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One channel continually blowing

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=3959
Printed Date: May 18, 2024 at 9:47 PM


Topic: One channel continually blowing

Posted By: ih8u37
Subject: One channel continually blowing
Date Posted: September 25, 2002 at 3:07 PM

A friend of mine is having some serious problems with his system. He's tried three different amps so far, from two different companies, and the same thing keeps happening.

Everytime, something happens to screw up the right channel of the amp. The system will work fine for a while, but eventually, seemingly out of the blue, all four subs start sounding like they're bottoming out.

He has two 12" Kenwood subs wired parallel, showing 2 ohms to each channel. All of the amps used have been 2 ohm stable by two channels. We've quadruple checked the speaker wires everytime, to make sure the poloarities were correct, as well as the RCA's.

I'm stumped. Any trouble shooting suggestions would be greatly appreciated. Thanx in advance.




Replies:

Posted By: djfearny2
Date Posted: September 25, 2002 at 7:00 PM

dont bridge kenwood subs they suck. you can try to series wire the subs to one side of the amp and what it will do is take that 2 ohm load from both speaker and change it to a 4 ohm load. most amps can not handel 2ohms only good ones can. try that you should be fine especially if you are running the amps mono cause you only using the left rca input only or even on lopass crossover.





Posted By: Xplod 1
Date Posted: September 25, 2002 at 9:34 PM

posted_imageHey man, just to let you know your not alone, I had the same problem in a chevy van. I didnt have them bridged or nothing, but i have about five amps, with only the left channel working on them, I finally fixed the problem though, I got rid if the van, haha, sorry this reply is no help in solving your problem, just letting you know I know how you feel.

         Good Luck!

PS does any body know what to do with amps with only one channel working?



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XPLOD 1




Posted By: ih8u37
Date Posted: September 26, 2002 at 6:24 AM

difearny,

The subs are 4 ohms each. Currently, they're wired in parallel, creating a 2 ohm load per channel. If I wired them in series, they would create an 8 ohm load per channel greatly reducing the power going to them.

I don't get it, why would the same channel blow every time?





Posted By: AW1208Q
Date Posted: September 26, 2002 at 9:13 AM
What amps has he tried? How hot do the amps get when he is running the system? They maybe over heating and killing the right channel. I would try getting an amp the is 1 ohm stable and trying that. Most amps that are 1 ohm stable can handle alot more than an amp that is 2 ohm stable




Posted By: chasesaccessori
Date Posted: September 26, 2002 at 11:15 AM

Your overlooking some things that you  need to check.

first:

check your wires to ground.  phiysically look the wires over. 

second:

check the subs out.  I wouln't put it past that one of the voice coils are having a problem and shorting out. 

Are you sure that it is your amps or speakers that are cutting out and not you souce unit?  Flip the rca's to be sure.



-------------
(owner/installer)
Chase's Accessories
Ridgecrest, CA
in business since 92




Posted By: ih8u37
Date Posted: September 27, 2002 at 11:41 AM

The grounds have been thoroughly checked.

How could I check the voice coils of the subs for problems?

The music isn't cutting out. It plays fine for a while, then all four subs start to sound like they're bottoming out, or play as if the polarities were switched. I have flipped the RCA's, & know that it's the amp, not the head unit.

The amps have been two different Power Acoustik amps, & a Soundstream amp. All were stable at 2 ohms, but none were high current or stable at anything less.





Posted By: chasesaccessori
Date Posted: September 27, 2002 at 4:27 PM

Lets try this again..

Check the speaker wire and make sure that they are not grounded.  Check the entire run from the amp to the speaker connection.

Take the speaker out of the enclosure and carefully push the cone in and out.  It should feel nice and smooth, not gritty feeling or have a hang up point.

If he has had this happen to different amps, then I would be pretty sure that it is one of the speakers or the wires.  Make sure that he is not cranking the gains up too.  If he is that big of a rocker than he should get an amp that has a ton of watts and then keep the gains turned way down.



-------------
(owner/installer)
Chase's Accessories
Ridgecrest, CA
in business since 92




Posted By: ih8u37
Date Posted: October 02, 2002 at 12:01 PM

The speaker wires are perfect...we've checked them over & over again.

I have yet to check the cones for their "feel". What can this tell me, I haven't heard of this before. I check them w/ a DMM, & they checked out perfectly. I figured that would tell me if they were blown or shorted or something, but I could easily be wrong.

The amp he's using is a Soundstream rated at 440w RMS x 2 @ 2 ohms. His subs are (4) Kenwood 12's, each pair wired in parallel capable of handling 120w RMS each. So basically, he's showing each 120w sub 220w of power. The gain is matched exactly to the voltage of the pre-outs on the head unit.

What would make the same channel blow over & over again. Not the amp, just one channel.





Posted By: ih8u37
Date Posted: October 02, 2002 at 12:04 PM
Oh, & if the subs do feel "gritty" or have a hang up point, what does that mean?




Posted By: chasesaccessori
Date Posted: October 03, 2002 at 12:58 PM

what that means is....Your coil is damaged. Though your speaker may still play for years to come, you are continually damaging the coil.  The inner part of the coil is either out of round, Distorted you might say, and rubs on the coil itself.  This is usually caused when a speaker is played out of range, It over extends itself trying to keep up with an amp that has its gains turned up. If the rubbing breaks through the coating on the wire and two or more of the coil wires short across themselves it will couse the coil to spaz out.  The shorting out might not be constant, it could only happen every once in a while.  When it does, it changes the ohms your amp sees instantly.

I have diagnosed this type of problem many times and would almost be willing to bet that if you change out the woofers in question with a new set that the problem would disappear.

P.S.  This problem is un repairable and most speaker mfg's will probably not warrantee them.



-------------
(owner/installer)
Chase's Accessories
Ridgecrest, CA
in business since 92





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