Amp going into protection mode
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=54359
Printed Date: May 02, 2024 at 12:45 AM
Topic: Amp going into protection mode
Posted By: skoldspuppy
Subject: Amp going into protection mode
Date Posted: April 21, 2005 at 1:34 PM
After searching former post on the subject of Amps going into protection mode I have come to the conclusion my Memphis 16-MC500D amp in my KIA SUV is dying, it had been working flawlessly for 3 months until today when it was going in and out of protect mode at any volume So correct me if im wrong on the reasons that an amp would do this are: 1. Bad Ground?
2. Bad Speaker Wire?
3. Bad RCA's?
4. BAD HU?
5. Insufficient power?
6. Gain settings incorrect?
7. Bad Amp Did I get them all or is there anything I overlooked
1,2,3,4, and 6 do not apply I ad 2 local shops double check that
so Im thinking options 5 and 7 that sound about right for all of you Now its time for that dreaded RMA back to memphis.. oh the joy Thanks All ---Skold ------------- 2004 Honda Civic Ex 4Dr
Kenwood DDX-7015/W Nav
4 Fosgate T152C
Hifonics Brutus BX1500D
RE XXX 12 in a 4 Cube Snail Shell
Replies:
Posted By: fuseblower
Date Posted: April 21, 2005 at 3:05 PM
You could also have a bad speaker
Posted By: skoldspuppy
Date Posted: April 21, 2005 at 3:29 PM
fuseblower wrote:
You could also have a bad speaker
Elaborate please.. The speakers work fine on my Brutus 1500D in my wifes car Thanks
------------- 2004 Honda Civic Ex 4Dr
Kenwood DDX-7015/W Nav
4 Fosgate T152C
Hifonics Brutus BX1500D
RE XXX 12 in a 4 Cube Snail Shell
Posted By: KarTuneMan
Date Posted: April 21, 2005 at 8:46 PM
Use a DMM and check the impedance of the speaker. Keeping in miund how you believe it should be wired. 2 ohm, 4 ohm...8 ....etc. -------------
Posted By: kreate
Date Posted: April 22, 2005 at 12:44 AM
Could it be that something is touching on the amp...and it's putting it into protection mode? that way it won't blow out. Just an idea
Posted By: skoldspuppy
Date Posted: April 22, 2005 at 9:07 AM
KarTuneMan wrote:
Use a DMM and check the impedance of the speaker. Keeping in miund how you believe it should be wired. 2 ohm, 4 ohm...8 ....etc.
Each Speaker is 3.67ohms most commonly refered to as 4ohms, in fact out of 10 speakers including some JL , MTX and RFs that I tested at my guys shop that said 4ohms on the box read from 3.6. to 3.8 on the DMM
and yes Before anyone ask yes I know how to use a DMM Im a Computer Engineer its part of my daily work I thought of it being too low of an impedence at first and then we hooked up a speaker to it that was 4ohms one at a time and it still had the problem
Suggestions? ------------- 2004 Honda Civic Ex 4Dr
Kenwood DDX-7015/W Nav
4 Fosgate T152C
Hifonics Brutus BX1500D
RE XXX 12 in a 4 Cube Snail Shell
Posted By: skoldspuppy
Date Posted: April 22, 2005 at 9:12 AM
kreate wrote:
Could it be that something is touching on the amp...and it's putting it into protection mode? that way it won't blow out. Just an idea
Nope its a clean mount to the back of the rear seats I used 3/4 MDF under the seat fabric and its screw into that, all wiires are firmly attached with no room to wiggle The only other thing I might have thought was my relay but I disconnected it and it still goes in and out of protection mode More Ideas? Im getting a loaner amp today while I have Memphis Repair this one.. damn 6-8 weeks wait time ------------- 2004 Honda Civic Ex 4Dr
Kenwood DDX-7015/W Nav
4 Fosgate T152C
Hifonics Brutus BX1500D
RE XXX 12 in a 4 Cube Snail Shell
Posted By: DYohn
Date Posted: April 22, 2005 at 11:08 AM
Your root causes cover most of the common failure modes. If the speakers are fine using another amp, then you've eliminated the speakers. If your amp gain is set correctly, that one is out. Measure the voltage at the amplifier with the system running and see if it drops below about 10.5V. If so, the amp is shutting down on low voltage. Make sure no speaker wires have stray strands that could touch ground. But if it's not low voltage I suspect your amp has a fault. If it's only three months old you should be able to get a warranty repair. ------------- Support the12volt.com
Posted By: stevdart
Date Posted: April 22, 2005 at 11:34 AM
BTW, skoldspuppy, when you read resistance across a speaker terminals you are measuring DCR, not nominal impedance. It is always lower than the nominal impedance, usually a factor of /1.25 For example, if you get a true reading of 3.5 across the terminals, the nominal impedance would be about 4.4 ohms. This is just to save you from worrying that the impedance load might be too low.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: nam-eci
Date Posted: April 22, 2005 at 1:16 PM
The most common cause that I know for this is HEAT! 'Resistance causes Heat & Heat causes resistance' I've had a couple of Amps do that, Is it packed away in the deep dark depths of your car with NO AIR? -  You know what happens to dogs if you leave them in Hot cars! Computer Engineer!-Wire in some 12v dc Fans. Like the ones in your computer.
Posted By: forbidden
Date Posted: April 22, 2005 at 3:09 PM
^^^^ add to this to ensure that the ground return is below 1/2 ohm of resistance. This is a major leading cause of amplifier failure on the power supply and output stages.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: skoldspuppy
Date Posted: April 22, 2005 at 3:45 PM
Thanks to all who gave input to this It turned out to be the amp its self, before my dealer would send it back, he had it bench tested at a local electronics repair shop here in south florida, it just wouldn't stay out of protect mode So I got a Loaner Memphis 16-PRD500.1 for free until mine gets back from the shop, we put in in and it worked like a charm, its not as powerfull as the MC series but will at least give me some tunes I consider this matter closed and again extend my thanks to all who gave input to this Later All --Skold ------------- 2004 Honda Civic Ex 4Dr
Kenwood DDX-7015/W Nav
4 Fosgate T152C
Hifonics Brutus BX1500D
RE XXX 12 in a 4 Cube Snail Shell
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