I was hooking up my sub amp (Alpine MRD-M501) and I accidenlty connected my RCA's the the RCA out spot on my amp. I didn't think anything was wrong because my sub was working. After about a half hour drive I started getting really bad engine coming from my sub. When I got home I started looking over everything and noticed my mistake. I unplugged both RCA's and the engine noise went away. I then plugged in one RCA (to the RCA IN this time) and there was no engine noise. As soon as I plugged in the other RCA the engine noise came back. I then tried a few other combinations and if only one RCA is plugged in there is no engine noise, but if both are plugged in I get engine noise. I didn't have this problem until the mistake I made. I even tried another set of RCA's and even swapping to the rear speaker RCA's to rule out a bad sub pre-out on the radio.
What could have happened?
did you try to ground the outside terminal of the rca? also look at your ground. or maybe get a ground issolator from a local audio store.
carsolutions wrote:
did you try to ground the outside terminal of the rca? also look at your ground. or maybe get a ground issolator from a local audio store.
No I have not. Here is a complete story of the last week.
I had a Pioneer AVIC N3 to start with. Wired to the factory radio harness. Running a Pioneer 4-ch amp for the components and my alpine amp for the sub. I didn't have any engine noise on anything ever. I sold the AVIC N3 and installed my spare Kenwood HU until my new Clarion I ordered arrived. The kenwood didn't have three sets of RCA's so I left the sub RCA'a disconnected. I also disconnected them from the sub amp so it didn't pop from the RCA's touching something behind the dash. I then installed my new Clarion radio. This is when I connected the RCA's for my sub amp wrong to the line out preouts on the amp. I drove the car for a half hour and then the engine noise started coming from the sub. I did the above procedure in my first post and that is where I was last night. I now have only one RCA plugged into my sub amp and it's fine. Today it is 16 deg c out, at lunch I went to leave and I could hear engine noise coming from my front left speaker. After the vehicle had warmed up inside the noise was gone. I then tried plugging in my other RCA into the amp but the engine noise was still present so i unplugged it again.
On my new radio it has a black box on the yellow wire. I'm guessing that it's a noise choke. There was a lot of excess wire on my radio harness so i bundled it up and taped it around the black box. Could this be causing some of my problems?
I have 4ga power and ground running my amps. I also have a 1 fared cap installed. My ground is at a big seat bolt on the floor (paint scraped away and a star washer. All the amps are connected to the same point. RCA's are run down the opposite side the power cable is.
Like I said, I didn't have any problems with the AVIC or the Kenwood....Or even the Clarion until I connected the RCA's up wrong. Is it possible I messed something up in the HU from connecting the RCA's wrong?
Should I ditch the factory ground and go stright to body ground on my HU?