Install Guru's! Noise problem with aftermarket amp

mooserov · Oct 23, 2009, 06:03 PM

08 evo x gsr with rockford fosgate system.

The right channel has static that pulses at about 10 hz. System plays out of both channels and Volume control does not make static louder or quieter.

I pulled out the rockford amp to put a jl 300/2 to push focal k2p's in the front. I am using a Rockford Fosgate 3sixty processor to give me control of the stock head unit's output. I found the wiring diagram for the left/right channel head unit output and my fader works correctly.

If I pull the right channel input to the 3sixty, the problem stops. If I swap right/left, it swaps to left side.

I have installed this system before without this problem.

It seems to be on the head unit side of things, but all i did was cut wires and solder on rca pigtails.

My grounds are good. Used the oem fosgate amp power and ground for the 3sixty, Sanded around the amp bolt for a lug for the JL amp. Checked with a meter about 0.4 to 0.6 ohms.

Any ideas?
Moose

mooserov · Oct 25, 2009, 12:11 PM

Sorta fixed. Started playing around with input and output gains on the 3sixty, and input gain on the JL amp and got the noise quiet, but not gone. I believe the noise is actually interference from some processor in the car because when I crank the input gain up I can hear the once a second 'tick' from the tire pressure monitors as well as the pulsing static. With gains set lower the noises are pretty much absent. I just have to have the head unit at a higher volume than before to reach the same volume output.

narkotic · Oct 25, 2009, 05:12 PM

10hz?!

mooserov · Oct 25, 2009, 05:26 PM

I'm approximating the frequency. its as if the static is getting louder and quieter about 10 times per second, only in the right channel output from the stock radio.

pips · Oct 28, 2009, 04:50 PM

Are there any uninsualated RCA's near any power wires?...either at the head unit or the RF360

mooserov · Nov 7, 2009, 11:07 AM

I don't know about the head unit, it's the stocker. There's a short (1") unshielded section where I soldered shielded rca's to the stock wiring. I shielded it with grounded foil just to see if it made a difference, it didn't. I can mitigate the noise with gain, but the problem is not solved yet.

MY08GSRX · Nov 7, 2009, 07:25 PM

try to put noise shields on the RCA (black lead core that snaps to the cable). It helps eliminate gain noise and distortion.