Ground loop with Engine off & Alt Whine

[SlamminBeats]

I have never been so stumped so bare with me. I will list off how things are wired.

A couple if things to preface the situation.

1) i had the ground loop elimated, unhooked stuff and now its back and dont know how to elimanate it now.

2) rear ground is just to bare metal in tire well that i sanded down; not the best ground, but apparently good enough because it was there when the noise was gone.

3) before it was just alt whine, now its with the car off and coming through all the speakers.

4) distro blocks are just bolts lol but again they worked before when the noise was gone.

5) these crappy grounds and distros are all temp, waiting on my caps to get here first.

Headunit: Power and ground rand back to distro in back.

Amps: ran to same distro as above. So theyre grounded to same place as HU.

What should i try to figure out what the cause of the noise is? Below i will list what the causes are and will cross them out as i test.

Cause of noise:

1) amps: how should i test this, just run a y splitter and ipod as my source to see if its gone?

2) HU: how should i test this, hook up just a speaker to the connections on the back with no rcas?

3) RCAs, how should i test, use differnt RCAs?

Any help would be great. I also have a ground loop isolator which worked but after i un hooked it all and tried to re connect, it doesnt do a thing....

[never knows best]

read through this if you havent already-

http://www.termpro.com/asp/pubs.asp?ID=121

[Swordlordboy1234]

I had this situation when I tried to run a set of wires for my vm-1 that ran close to my door speaker wires. As soon as I turned the key (engine still off) I could hear a high pitched noise from my tweeters similar to an alternator whine....

This was because it was a set of wires connected to my bass amp (effectively my battery) and was giving some of that signal to my tweeters.

As soon as I relocated the wires my noise was gone.

[rockFord_Expedition]

Does your vehicle have a frame, or is it a unibody?

Do not hot swap rca's but connect your phone/ipod/anything that plays audio and has a 3.5mm output and connect that directly to your amp that is producing the noise. That will tell you if it is your rca's or not.

As you know, your ground locations sounds janky and should be moved to the frame if you have one or your strut tower if you don't.

If your grounds are good, you don't need to run +/- from head unit to amps. That is un necessary.

[bassman619]

Noise is a bitch to tackle...remember audio wires should not be ran near power wires..the power wire creates a magnetic field around it if im not mistaken ..that field can interfere with audio signal..if power has to come close to rcas best to do it at perpendicular angles. Same for speaker wires...all audio signal should be as far away from the power line as possible..everytime I have gotten whine its always because the power is too close to another wire ..so run power on one side and speaker wire and rca on the other side...even if you run it on the driver side then the fron driver door speaker wire should cross to the passenger side and run back that way instead of running next to the power.. power and gnd to the hu to the back are unnecessary. .just ground the hu to the firewall and connect the constant and ignition to the radio harness.. dont use ground loop isolators they are bandaids they dnt fix your problem they mask it. Also could be that you have the wrong kind of rca..may be an amp that needs differential rcas and youre using single ended rcas or vice versa..Im just trying to cover all possibilities but like I said its a bitch to figure out so good luck

[SlamminBeats]

Noise is a bitch to tackle...remember audio wires should not be ran near power wires..the power wire creates a magnetic field around it if im not mistaken ..that field can interfere with audio signal..if power has to come close to rcas best to do it at perpendicular angles. Same for speaker wires...all audio signal should be as far away from the power line as possible..everytime I have gotten whine its always because the power is too close to another wire ..so run power on one side and speaker wire and rca on the other side...even if you run it on the driver side then the fron driver door speaker wire should cross to the passenger side and run back that way instead of running next to the power.. power and gnd to the hu to the back are unnecessary. .just ground the hu to the firewall and connect the constant and ignition to the radio harness.. dont use ground loop isolators they are bandaids they dnt fix your problem they mask it. Also could be that you have the wrong kind of rca..may be an amp that needs differential rcas and youre using single ended rcas or vice versa..Im just trying to cover all possibilities but like I said its a bitch to figure out so good luck

havent had much time to to deal with this issue yet, but i will soon.

My power runs are all under the vehiicle, so it cant be that. I wanna say that its possibly my cheap HU.

[JEFFYBOI]

If the noise is coming through all your speakers most likely your ground shorted out or went wad on the HUs rca preouts. Change the HU out and see if it solves the problem. im like 99% sure that's the problem

[Soccerballzs]

Do you have anything connected between HU and amp? Example crossover,eq? Ground your rca outputs on HU. Run a 8 gauge ground to HU also pioneer grounds are thin!

[SlamminBeats]

HU does not have anything between amps and back of radio.

maybe th eHU is shot. its like a buzzing noise through all the speakers with car off or on, not to mention the alt whine.

the 3rd noise is like a pop pop every 2 second sor so....weird.

almost positive its not my rcas and not my amps because when i disconnect HU mand have amps on the noise is gone.

[JEFFYBOI]

Basically they ground the internals of the preouts to prevent any interference and give it a place to go. If the ground went bad on the preouts your rca preouts are basically picking up all the that interference and giving it a place to go now. Which is what you are hearing. If its a cheap Hu I would change it out. This happened on my kenwood excelon HU.