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Ground loop? Need audio/ electrical expert

3K views 14 replies 5 participants last post by  PreLudite 
#1 ·
Thought I'd ask.. Been wasting money trying to solve this little issue of mine that I need more often now than ever.

So If I plug my aux cable from aftermarket head unit to phone and charge the phone at same time I can hear my car's heart beat. Revving, interference, all kinds of whine and noise.

I only have aftermarket component speakers in front two doors and rear speakers are stock and still using AFS stock.

Now my question is since I cannot find the answer...
If my system sounds very good to my ears at all volumes when I am not charging my phone and the problem only occurs when I connect the charger same time.. Does this in fact mean yes, there is a problem with my wiring to create this interference? Or is this completely normal to happen and I need to use a band-aid (ground loop isolator or something similar) to fix the problem.

Is there something I'm missing here? Because this sounds like a ground loop issue, but some others seem to have problematic grounding issues without even having a charger connected to socket like me, like slight noise in the sound or interference but is it in fact a ground loop issue in my case? Where I need to look for issues in wiring?
 
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#4 ·
yes, it's your typical ground loop described issue that people talk of (alternator noise or engine noise as you drive). It's like hearing the cars heart beat as you drive and it whines louder the more you throttle.

Ryevin, chime in. Is your sound system or car bone stock? Is it an aftermarket head unit (audio deck)? If so, did you install yourself or give to a shop to do it? Wiring harness or no? Anything else sitting in that little space behind the head unit that we should know about? I want to know more just to see if the stock wiring the way the car came out of factory can still get this issue.
 
#5 ·
Now I've seen ground loop isolators, people call them in line noise filters... Theres tons of junk, there are stereo audio ground loop isolators, otherwise known as ground loop isolators for 3.5mm which means you can plug this little device into your auxiliary jack on your head unit and plug your auxiliary extension cable (what you regularly use (male to male audio cable)) into that thing and then plug that into your phone and it eliminates interference.

I hear a lot of people have had this similar issue and most of those devices only partially fix the problem by taking away bass noise and audio quality while some others claim they fully work 100%.

Question is, is there a problem with my/our wiring or is a band-aid the only fix for charging phone and playing music same time?
 
#6 ·
I have the same issue and ive read you should wrap the rca signal outs with wire and ground it to the head unit if thats where the problem lies but i dont have an amp wired up so my next idea would be to try a new ground location for the stereo and make sure the gauge of wire is the same size or larger than the +12V. If anything you can also buy a ground strap that bolts to the bottom of the chassis and grounds the car to the road.
 
#7 ·
I dont know what to do. I used regular wire probably around 12 gauge or that could be 24 lol I dont know. I wrapped it like you said last week and it didnt do anything to the cause. I could take a picture if I get back in there.

I also spliced a wire into the head unit wire harness wire to ground directly to a chassis screw to try and I dont know if that increased the ground loop or if it helped the cause lol.

So is this a wiring problem right now or is it normal that this happens with charger and AUX to same phone? I need to know. (android by the way)
 
#12 ·
silly question but did you use a bare wire to wrap the rca outputs? And yes I would directly ground the ground wire to chassis just make sure its a thick enough wire, your connection is solid, and you have a bare metal chassis ground. Sand off a little paint if need be and use a ring terminal.
 
#8 ·
Definitely not normal, and probably annoying as hell. I'd make sure your head unit is getting a solid ground connection. Sand it down if need be, you want metal on metal with no paint in between.

If you've got the radio out anyway and some extra wire, temporarily run a ground wire from the radio and out the window to the battery ground terminal under the hood to see if that gets rid of the noise. That will either confirm the radio ground is the source of the noise, or rule it out.

It could be that you are using a crappy/damaged aux cable that is picking up interference and feeding it to the radio's amp.

It could also be a bad ground on the cigarette lighter circuit.

Honestly, you've just got to troubleshoot connections one at a time until you find it.
 
#9 ·
I think it has something to do with the circuit or something.
My AUX cable is actually damaged, bent a bit so that sound wiggles out of left or right speaker where I need to get it in perfect position to hear all channels, but it actually works as it should when I'm testing it, it shouldn't be the cause.

I think there could be something wrong with cigarette lighter ground maybe but also my black wire or ground coming from factory harness doesn't seem to branch off and ground anywhere nearby or in that little cabin area, it just plugs into wiring harness and into audio deck.

I'm never using the radio obviously but that stock antenna cable that we plug separately from car to audio deck can that produce any kind of interference even though I never use the radio? Since it's plugged in can it cause a ground loop like this?
 
#10 ·
my noise is constant only when I turn my H.I.D.s on and only when listening to the radio (FM,no idea about AM but why would I check). My radio is stock. The static does not get loud with RPMs, its the same at idle as it is at 7k.

I would assume it has to do with where I grounded the H.I.D.s (right under the radiator stays). I'm not sure the best place to ground them would be.

It would seem our issues are separate. I should probably start my own thread as to not derail this one.
 
#11 ·
Your issue is separate. Each ballast should have a ground of its own I presume? Should be grounded on a nice chassis screw or where a previous wire is grounded to on the chassis even.

It's often normal to get a little noise on the Radio. Maybe check that wire I was previously talking about for the antenna that plugs into an audio deck, they are a little short, see if its fully connected and not loose.

3rd, don't listen to the garbage radio.
 
#13 ·
any connections or installing my fog lights etc ive done myself, im sure everything i grounded was always to a nice brass screw area or not touching any paint or trim at all. I can always double check..

The 6 rca plugs on the back of audio deck I used a many threaded wire. Looked like old speaker wire or something of the sort. Extremely thin strands that make up the wire and yes I skinned the whole thing. Its just the bare copper wrapped, no plastic.
 
#15 ·
HISTORICAL REPLY for future searchers:
This is a common problem but the fix can be a bit complicated until diagnosed.

Phone chargers are notorious for electrical noise and spurious RF output. I've detected these over a block away in parked cars that were causing high noise in my shortwave radio. Buy a better/different charger.

Figuring out the general noise issues: Audio Grounding Schemes
 
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