I got the typical whine that varies with rpm only when the engine is on. The weird thing is that it only happens on the front preouts the rear and sub preouts are fine and have no noise. I've also tried another pair of rca's. It all happened after changing moving the ground to a diffrent location. I've since then moved the ground to two other places and its now back in its origonal spot where it was perfectly fine. Still whines. I've also regrounded the head unit. No go any suggestions? :blowup:
One amp at the moment. One ground. The sound is definatly comming from the head unit. The noise goes away when I unplug the RCA's from the amp. I'm gonna try out a new ground for the head unit. Dunno what good its gonna do being as the noise is not present on any of the other preouts.
well it is either that set of cables (since you said you tried a differant set I doubt it) or an internal grounding problem with the HU
Sound goes away when you unplug the RCA's from the amp... But does the sound go away when you unplug the RCA's from the HU, leaving them plugged into the amp?
Michael thanks for getting my ability to post squared away. To me as well it indicated a piss poor internal ground plane and I am going to make a guess that it is a Pioneer head unit. Unplug the antenna from the head unit and remove the head unit from the dash, does it still make noise? Run a temporary power and ground line from the battery. Tie the yellow and red lines on the head together and attach to the power line from the battery. If you still have noise then it is 100% a head unit ground plane issue.
If the noise goes away when you unplug the RCA's from the HU, you know the noise isn't coming in through the amp itself (or it would still be there), you know the noise isn't being induced into the RCA cables (or it would still be there), so you know it is upstream of the RCA cables... ...the only thing left is the HU itself. I'd check your power connections - both power and ground. It doesn't have to be a ground issue - either would have the same effect. However, there's probably a ton of wires crammed back there.. it could be a connection that came lose - did you recently have the HU out for some reason? And it also does beg the question: When the HU was installed, was a wiring harness adapter kit used, to allow you to simply plug the new HU into the car's factory harness? I personally consider cutting factory wiring to be a sin... that fundamental. It is not only messy and opens the potential for poor quality connections and poor quality insulating, but also leads to headaches down the road when it is time to replace the HU... to say nothing of the warranty issues you'd have with dealerships for cutting any factory wiring - whether justified or not.
This all happened after moving my amps ground. I did use a wiring harness adapter. I soldered all the wires except the ground wich isnt connected to the harness. I'm gonna rip the head unit out and recheck everything this weekend I hope. Thanks for all your suggestions guys.
If this all happened after you moved your amp's ground: 1) why did you move it in the first place? 2) why do you think the problem is somewhere else? I'd say all signs point to that new amp ground.
Well, it died tonight. Looks like its a common problem with the MP919 for the face plate to open and just freeze. http://www.fuddle.org/forum_viewtopic.php?9.24 Dunno if I want to go ahead and fix it or not. I kinda doubt that the cable would cause noise in the rca's.
sounds like a ground loop... try a ground isolator and grounding deck housing to the chasis and HU ground. Your other choice would be to get a line driver and turn amp gains all the way down.
