Amp issues

[Tpusich]

I know this has been covered a thousand times, and believe me I've been reading forums for hours. I'm still experiencing alternator whine. I have a 400w Rockford phosgate amp for my 4 door speakers with an alpine HU. I have COMPLETELY sanded my ground and made sure it is very clean. I have ground loop isolators on both RCA sets going to the amp and they are run on the opposite side of the car from my power cables. If both sets of RCAs are disconnected from the amp there is no whine, but as soon as the cables or even my fingers touch the RCA input ports on the amp I hear the whine. Is something wrong with my amp???? I know this is probably answered somewhere but I can't seem to find it, thanks in advance for any suggestions!

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[CSCStang]

Try to rule out the bad amp scenario by plugging an ipod into the amp. See if you get motor noise. It's possible you have bad rcajacks, or there's a short in one of the speaker wires.

 

[mylows10 5,000+ posts]

Could be amp deck or rcas

 

[Tpusich]

If I plug in any RCAs to the amp regardless of whether they are connected to anything i get alt. whine. I get the whine even if I just plug in the ground loop isolator to the amp with nothing connected to it, I have also tried multiple sets of RCAs with no luck

 

[mylows10 5,000+ posts]

If I plug in any RCAs to the amp regardless of whether they are connected to anything i get alt. whine. I get the whine even if I just plug in the ground loop isolator to the amp with nothing connected to it, I have also tried multiple sets of RCAs with no luck

The amp has a bad solder ground inside. Might be an easy fix for the right person

 

[Tpusich]

Is it easy enough that I could figure it out if I tried? What am I looking for? I can teach myself solder but I gotta know what needs to be fixed

 

[akheathen Premium Member]

the problem is, you likely damaged a path on the board that is designed as a noise shunt, from a bad ground. it's kind of like running your engine out of oil. most likely some damage is done, it's just a matter of how bad, and if there are symptoms. that's not to say that there is not something as simple as an rca jack problem, especially if you can change the noise by moving the jack around. what model is it? there are many, many years that the rca jacks were flimsy and prone to failure. what i like to do there is use a discarded resistor leg to brace a new jack some by running it allong the side of the leg and soldering in the hole, and up higher. ther should still be readily available on ebay, fyi. if you want to learn how to solder, best thing is to read, read, read, then practice, and review. it's all about time, temperature, and feel, and real easy to mess up. first, take the screw out of the middle of the rca jacks and wiggle them, while watching the legs by the board