Since the installation of my last amp I have had nothing but problems. The setup that I have is as follows

Kenwood X879 Headunit
Kenwood 4 channel amp
JBL tweeters in factory location
Mobile Authority 4 x 6.5 speakers
Mobile Authoriy 4channel amp bridged
10 inch Punch Stage 3 sub with dual voice coils.

I Used to have no sub and no second kenwood amp, I was just running the MA amp with the MA speakers and it was working great, now since adding the second amp, I am hearing engine noise sometimes and crackling through the speakers. I took the car back to the stereo shop 3 times, but the sound is intermittent and hard to troubleshoot. They have redone the ground and made it shorter and turn down the gain a bit, it's better but I just got back from a 4 hour trip and it was driving me crazy. What else can I do to get rid of the noise? Could it be a faulty AMP?

 

I'm not sure what all the shop has checked when you have taken it back or exactly how they have things hooked up but is sounds like they grounded the second amp in a different location than the first and created a ground loop. If this is the case it can be easily solved by using a grounding block.

 

They are both grounded to the same spot on the chassis.

 

if you disconnect the 2nd amp does the noise stop?

 

that's a good question, I have not tried it. I will try it shortly.

 

Yep try disconnecting the second amp like TwardOZralli said and see if that does it. If not and since you didn't have any noise when using the MA amp on the 6.5's and tweets and now you do I would definately say something is up with the Kenwood amp.

 

and make sure your connections are clean...sometimes pieces of wire cross over from pos to neg, and that causes the sound to distort. also..u runnin 2 amps without a cap? you may want to look into getting more power to your system........

 

Is your power/remote run on the opisite side fo the car as your RCA's?

 

Just mute hte input of the Kenwood and see if there is still noise. Take an RCA cable and cut it a few inches froom the connectors. Strip the cut end and short the posetive and negative shield wires together. Plug the RCA's into the amp and turn it on. If you hvae noise it's being caused by the amplifier. Any decent shop should have a muting plug and know how to test for noise. Wives tales like (running power near signal) or (voltage too low) are complete BS and usually start to get people to buy more stuff.

 

the noise is constant and does not get louder with volume. It does get reduced when I turn down the gain. It only happens on the Kenwood (atleast I can't hear it comming from the SUB and the other amp) the Remote power comes from other side of the car. I can hear the noise even with the stereo muted.

I am tired of this shop they have no clue, I will redo all the grounds with a grounding block myself. I don't need a cap, these are small amp's (30x4 and 40x4) and I only run 50% gain at the most, I looked at the voltage and it never drops much. I might swap the MA amp with the Kenwood amp and see if it makes any difference.

 

I'd say you're on the right track. I would first take the Kenwood amp out of the loop to isolate the problem to that amp. I would then look at it as a grounding problem first. If you have a known good ground, then it may just be a faulty amp. Good luck with it.

 

Don't mute the stereo, mute the amplifier the way I described. Odds are the amp is hte problem.

 

sorry to go OT for a sec...but I PMd you BillAce

 

even if they are oppsite he can still get interferance from the RCA cables to where they go to the amp.


a cheap set of RCA cables will cause the exact noise you described.


Can you give me a model number on your RCA cables?

 

No idea on the brand of the RCA's they don't look too cheap. What are some good brands for cables? might as well replace them anyway.