Help,

Background - I recently bought a JL Audio 300/4 amp off of Ebay (from a 100% positive buyer???). I installed it in my 2006 SCrew (I'm no pro by any means, but I am an Engineer and have installed systems in my last 5 or 6 vehicles with no problems). I ran 8AWG wire directly from the battery with a 40 Amp Maxi Fuse (probably should have been 6AWG but should meet the requirements given the length). It is grounded with 18" of the same AWG wire to bare metal near the rear seat belt bolt. New 14 AWG speaker ran to the existing wires behind the Alpine HU. The HU has been running fine for several years running off of it's own internal amp to the current speakers.

Problem - With the HU off...no problem. With the HU unit on, switched to CD, and CD paused...there is background static/noise coming from the Front-right channel only. I swapped the front and rear RCA's...no change...problem still exists in the front-right channel. I swapped front-right and front-left speaker wires at the amp and the noise moved to the front-left speaker. I disconnected all speaker wires and connected an old single speaker to each of the 4 channels, one after the other. All are fine, except the same noise coming front-right amp channel connection. The noise stays the same volume when I play a CD and turn up the volume, eventually overcoming or drowning out the static/noise.

My Conclusions - Since the noise is coming from only one channel of four, I don't think it is the ground. Since the noise moves from one speaker to the other when I swap the amp connections, I don't think it is a grounded positive lead of the speaker wire.

HELP??? - I would assume that the front-right channel of the amp...or crossover within the amp...is fried. Any thoughts or recommendations on how to resolve the issue.

THANK YOU VERY MUCH!

Ryan

 

If you've swapped RCA's and swapped speaker leads and still get it coming out of the same channel. Then yes, your assumption is right. IMO

 

I am guessing you are right. If it was a grounded spk lead the protection light would illuminate. And possibly would have the amp shutdown.

Where did you connect that old spk at? At the amp or in the door? If at amp it is the amp, if in the door it could also be radiated noise.

Buy from ebay, buy twice.

 

Thanks for the replies guys!

The protection light does not illuminate and the amp does not shut down. I connected the old speaker directly to the amp terminals. Also, when I rev up the engine, the other 3 channels are fine, but the front-right channel noise gets louder with the engine. The power of all 4 channels seem to be working equivalently, and when cranked up, the amp sounds fantastic and overcomes the noise.

It kind of sounds like there is an internal ground problem on the front-right channel. Any other thoughts?

Thanks again.

 

If you are comfortable doing this , open up the amp.. I had the same problem on an old viosonik amp.. turned out to be a loose positive connection on the inside of the amp to the terminal.. i resoldered it and all was well..