memphis amp fades out

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=114366
Printed Date: April 28, 2024 at 2:59 PM

Topic: memphis amp fades out

Posted By: ianarian
Subject: memphis amp fades out
Date Posted: June 10, 2009 at 5:28 PM

05' Dodge Ram 1500 Hemi 4x4, (ALL)Memphis M-class 500.1, and a 400.4, 3-way(4 pass) electronic x-over, 6.5" components Front, 3-way 6.5" rear, 10" sub mounted in re-supported center console (downfire) prefab box. Yellow top batt, 1.5f cap. Pioneer/Ipod. System has worked perfect for about a year. Problem: Sub fades on and off in a random manner. Sometimes it wont play with system upon start, it fades in 20 minutes later. Sometimes fades out halfway home. Customer states light on sub amp stays on when sound fades out. The problem has become more frequent over time. There's no pattern linked to Sound Volume, Temperature or music type. Occasional 2 week spans of problem free use occur. Sound is affected only on sub. The fade out sounds like someone is just turning volume down. Suggestions? I did the install so the problem has to be electronic. I may just need to know how to narrow down troubleshooting methods.

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Replies:

Posted By: DYohn
Date Posted: June 10, 2009 at 6:07 PM

Sub amp or head unit. Pull them and test them both.

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Posted By: ianarian
Date Posted: June 10, 2009 at 6:33 PM

With the issue being random in nature, I was wondering if there are any practiced methods of rooting out the problem. Each time I check out the system it happens to play just fine. My next step would be to swap amps which would either resolve the issue or really narrow it down. Memphis has changed designs so a new amp would require a new amp rack cover to be built, resulting in a mismatching display. |HEADACHE| Before I go there, I'd like to check all other possibilities.

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Posted By: soundnsecurity
Date Posted: June 10, 2009 at 7:54 PM

ianarian wrote:

With the issue being random in nature, I was wondering if there are any practiced methods of rooting out the problem. Each time I check out the system it happens to play just fine. My next step would be to swap amps which would either resolve the issue or really narrow it down. Memphis has changed designs so a new amp would require a new amp rack cover to be built, resulting in a mismatching display. |HEADACHE| Before I go there, I'd like to check all other possibilities.

swap the radio

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Posted By: i am an idiot
Date Posted: June 10, 2009 at 8:17 PM

In order to not change equipment for the fun of it, there are a couple things you can do. If the amp is connected to the sub output jacks of the radio, use a set of Y adapters and connect it to the front or rear jacks. Let him listen to it for a few days and report back to you. If it does not happen while connected to the other jacks, you have a radio problem. Are you sure that the power light remains on when the amp cuts out? Also with the system playing, hit the top of the amp with your hand or a rubber mallet. These amps are pretty well built and do not usually suffer from bad solder joints, but it could. Also grab the RCA inputs of the amp and move them around a bit to see if you can make it cut out.

Posted By: ianarian
Date Posted: June 14, 2009 at 7:47 PM

The hell, thanks man, I guess I was brain spoogin my troubleshootin ideas. I like the Y adapter process. Muchas Gracias!

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This is what I do for FUN!

Posted By: ianarian
Date Posted: July 29, 2009 at 3:22 PM

I finally got back to this thing, the sub amp is actually 16-MCA300 - Memphis 150 x 2 ClassAB So I found that noise filters were put in shortly after a new Pioneer deck.. Hmmm The new deck was a product upgrade so he re-used the old lead adapter, which only connected Pwr, Gnd, Rem,and Mem. Gender directed him to connect RCA's connectors directly to the outputs of X/O. (Question1)Bad Idea, No?. Well coincidentally the left sub chan on the X/O blew at some point not helping the bridged Mclass-10D2/Series. I removed the X/O, and filters and the Engine noise is fierce and will require future investigation.(Or he can re-filter as he pleases) (Question2) If anyone has followed this, is it possible the filter on the X/O output blew the channel and the sub fading was the bridged amp receiving 1 input? More questions to follow-

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Posted By: ianarian
Date Posted: July 29, 2009 at 5:47 PM

Hopefully an Idiot has some time for suggestions on repair.

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Posted By: mike swanson
Date Posted: July 30, 2009 at 12:18 PM

The rca grounds on that HU are most likly to be bad

Ive seen alot like that

The thing is that the sub is 500w rms and you only have 300w ?

and when you say bridged m-class subs what are you sayin? 1 sub bridged on the amp/

The amps are mono cant be bridged

Posted By: ianarian
Date Posted: July 30, 2009 at 8:18 PM

Problem:agreed. Bridged is the wiring config of the amp. Should I fix the X/O? Question! What caused the problem? Question! FYI, Memphis claims this amp can rms 500w.

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Posted By: i am an idiot
Date Posted: July 30, 2009 at 8:27 PM

Remove the circuit board from the crossover and look for bad solder joints. Also remove the RCA jacks and look for bad solder joints on them also.

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Posted By: ianarian
Date Posted: July 30, 2009 at 11:52 PM

Check....other than sloppy work..all else appears as normal. posted_image

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This is what I do for FUN!

Posted By: ianarian
Date Posted: September 22, 2009 at 11:53 PM

Uh-HUH, can someone tell me if this is the way that Memphis rigged the terminals back then? Sorry for crappy pics.. posted_image

There is a hole drilled in the end of the threaded anchor bolt and the speakers wires are soldered on.

This is the way it was sold from MASA in San Rafael, California, United States. Look a little closer and you'll discover something odd about the nuts holding the terminals on. I watched him pull this out of the box sold as brand new and set it in the center console enclosure. At the time I did not inspect it. Why would I? I have been having non-stop issues with this sub and never thought to see if the brand new sub was actually brand new. As well as the crossover that blew the channel, when he bought a new one from some shop in Berkeley, California, the manual didnt even match the product. The box it came in indicated chrome black as the finish,(similar to the one that blew) but the actual product they sold him was some charcoal dull finish. Finally after months of ill performance he decided to remove the sub and thats when/how this came to my attention. Also what I thought was a air leak around the downfire sub, was actually the rubber surround tearing apart. We braced the enclosure, added another layer of MDF to the baffle and it has held. Now the warranty has expired, a lot of time has passed, I been cursing this brand since day 1. Now after closely investigating these problems, I've realized where things are going wrong. These things dont happen to me when I actually make the purchases. I never thought to verify the legitimacy of something wrapped as it would be straight from the manufacturer. This @$$H0l3 needs to know the trouble this has cost me, not to mention Memphis' credibility ruined, just so he could make a quick sale? The one and only Memphis system I've put in and the one and 1st system ever to have not exceeded expectation. Im bent over this matter ....Comments and thoughts please!

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This is what I do for FUN!