Amplifier Noise

All, It's been a while and I've left the industry... I am having a problem with a system I installed in a friend's 2011 Jeep Grand Cherokee... System: Factory CD Player to 4-ch LOC to Boston GT-42 4-ch amp. Amplified factory front speakers and bridged to fiberglass ported Boston G3 10" Subwoofer. The problem is a noise that comes and goes - about 7kHz-12kHZ that seems to grow louder at times, only in the left front speaker. The amplifier is still putting out the music and the noise is a constant volume and frequency (not alternator wine). It s a weird gremlin that I'm not sure of the source. I have not yet dug out the amplifier as it's a stealth install. My intuition tells me that it's coming from somewhere pre-amplifier (LOC or head unit). Does anyone have any thoughts as to which is the most likely culprit? I'd like to start at the place of highest probability. My process to troubleshoot will be to direct connect another audio source to the amplifier (iPhone 3.5mm to RCA). From there I will swap the LOC channels and see if the sound comes from the RF speaker. I'll do this on the input of the LOC and the output to determine if it's prior to or at the LOC. Thanks!Team Edge Audio

Basic audio system (amplified fronts from the after market Amp).Team Edge Audio

get the signal pre amp into the loc. getting it after generally causes noise.Ted

2nd Year Tier 1 Medical School

Still installing as a hobby...pays for groceries

Compustar Expert