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amp wiring problem

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=105118
Printed Date: May 14, 2025 at 1:04 AM


Topic: amp wiring problem

Posted By: 1mmort4l
Subject: amp wiring problem
Date Posted: May 29, 2008 at 10:38 PM

Thanks for looking.. posted_image

I have a JVC KW-AVX800 installed. It has 3 amp pre outs. Front, rear and Sub. I installed an Amp up the back which is an Alpine MRP-F240. I didn't mark the RCA's (Front and rear) when I ran them under the carpet and to the back, so I am not sure which is which. No biggy there, but here is my problem.

I just want to run my stock speakers, until I get the correct aftermarket ones to put in. I initially just hooked one of the factory speakers to the amp, and nothing happened to start with. I plugged the other rca's in different slots, and eventually the speaker worked. Very poor quality, and was only with the White RCA cable, to the red input of the amp..??? Any other config did not work. I left it at that for now, as I just wanted some tunes for driving. I started my car later, and there was no sound from that speaker... I switched the RCA's but couldnt get a sound.

Today, I tried again, and ended up getting really good sound out of the speaker, I turned off the ignition, and again there was no sound when I turned it back on. I decided I would hook the other speaker up.

I tried all configs with the RCA's, but I get no sound at all...

Firstly,Is switching around RCA's bad?

Second, what am I missing?
I have no idea what the switches and dials on the amp do, so should I have them in a certain way?

Here is a picture of what I am talking about.

posted_image

Thanks for any input..



Replies:

Posted By: 1mmort4l
Date Posted: May 30, 2008 at 1:45 AM
Ok.....
Here is my cool diagram, just to be more clear....

posted_image

That is basically what I have connected now and is not working.
Here is what worked a couple of random times.. Note the incorrect RCA connection.

posted_image

Any suggestions as to the potential problem?

Thanks alot guys.




Posted By: 1mmort4l
Date Posted: May 30, 2008 at 1:47 AM
Pictures are back to front.. I cant edit the post, but the first image, is what works sometimes, the second has not worked at all..




Posted By: stevdart
Date Posted: May 30, 2008 at 2:25 AM
No use getting too deep into all these diagrams and stuff just yet.  What you need to do is start over.  You need to know what input wires are what.  Use some extra length of wire, a meter to check continuity, and the help of a friend to test and mark all the RCA wires.  Make a temporary connecting wire by soldering a small alligator clip to each end, clip onto the middle prong to test continuity.  Keep wires out of the head unit while testing.  Label the paired wires at each end. 

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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: 1mmort4l
Date Posted: May 30, 2008 at 6:52 AM
Thanks for the reply Stev.

I tried installing a different amp, a 2 ch Alpine and it worked straight away. I changed the fuse in the 4 ch, and tried it in the exact same config as the 2 ch was, but got no sound at all. Is this definately a faulty amp?

I have now installed the "working" 2 ch for now, but the sound isnt very clean. I turned the volume up, and it was very bassy, so i turned the bass off. It was ok, for a while, but then when i turned a corner the volume seemed to go quieter, and the sound was "unclean" again. Sounded like it was running only one speaker, but when I checked, they were both running. Another strange problem was that when i adjust the balance, the right speaker stays on when the selector is all the way on the left, but the left turns down, and off as it should when I slide the adjustment to the right..

This is very strange to me..




Posted By: stevdart
Date Posted: May 31, 2008 at 2:52 AM
And it will continue to provide confusing results until you start over, label all wires and make 100% positively certain and correct connections.  Ensure, as well, that there are no shorted conditions.

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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.





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