Induced noise/Ground loop trouble shooting guide.

**rumy** · 10-05-2006, 10:11 PM

Originally Posted by RedGTiVR6

can you explain how you are powering the XM off of the signal from the amplifier?

are you using a speaker level signal to power it? or are you tapping into the power BEFORE the amplifier?

I am apping in before the power to the amp

**rumy** · 10-05-2006, 10:12 PM

Originally Posted by llajumpvid

What XM receiver are you using? I had the same problem using the XMD. I got rid of it when I grounded the case of the XMD.

I am using the XMD 1000 I have mounted it ontot he chasie, but will try sanding and remounting to esure proper ground

Thanks for all the help guys. I will try to rewnforce the ground and let you know.

**RedGTiVR6** · 10-06-2006, 07:14 AM

I'm putting my money on the ground...

**WinoOutWest** · 10-10-2006, 01:43 AM

Originally Posted by WinoOutWest

First off thanks for a great article! I've eliminated almost all my noise and ground loops thanks to the original posts. I eliminated my really irritating alternator whining and uncovered/resolved 2 issues: I had to re-run the signal lines on the other side of the car and to ground the PC Case and the Inverter. I have one remaining noice and I am wondering what my options are to get rid of this noise and if changing the inverter will help.

The noise seems to be generated from DC-AC Inverter and I can't seem to get rid of it. I have the inverter mounted beside the PC which is also right beside the battery in the trunk as are the 2 Alpine V12 Amplifiers (a 4 channel driving front and rear speakers and a mono driving the sub). My head unit is an Alpine as well with now amplifiers on board just a 4v outs and the Aux line in from my PC. The noise is not present when I am using the radio or the CD on the Alpine. As soon as I switch it to the AUX I get the noise. If I run the PC directly from an AC line from the house I do not have the noise. I tried a ground loop isolator on the Line out from the PC and it seemed to make no difference. I have an Audigy 2 internal card as well as a Maya external USB sound card and it doesn't seem to make any difference in the noise.

Currently I have the inverter, inverter case and the PC case grounded directly to the battery.

I am beginning to suspect that its just a crappy inverter? Curious is I have any options. Do I need a better inverter or do I need to replace my inverter and shutdown controller with a DC supply?
Cheers!

Bump
Anyone have any ideas on this?
Cheers!
Wino

**BDVirus** · 10-15-2006, 08:23 PM

ill throw my "ground loop/engine noise" problem in

installed over the weekend, friday nite i had the car on and was able to listen fine no noise.... now my cables were run in a "how can i run em to be able to listen to it today?" type running and no noise (once i fixed gain and some other simple things)

now on yesterday i ran 0/1 ga on passenger side along with speaker wire under carpet alont the corner of the floor. on the driver side i had run RCA's, remote turn on, and speaker wire. There was a bunch of factory wires already running so i thought "hey thatll be nice to follow", well last nite checked out this thread and realized that those were power wires and running RCA's 10 ft alongside power wires probabally was NOT the best choice. now i had listened to it, but not with the engine actually ON, just in ACC.....

So this morning i re-run the RCA's along the roof (there are no other power wires except along the A-pillar up front for the lamp lights) and ran it to the amp fine (almost too short lol but luckily was not).... now i also ran the RCA's for the sub even though i do not have a sub or sub amp yet so they are sitting in my trunk not connected (gonna un-hook them from the HU tommorrow). now the only thing i can think is that its a ground issue (since i just used a small lil crappy ground point that i knew was not the best ground but thought it would work to test)

heres the problem. in ACC no noise and GREAT SQ. As soon as i turn on the engine, i get a whineing noise.... it gets higher pitched with higher RPM's (and louder), and the amplifier gain directly controls volume on it.... gain all the way down=hardly noticeable whine, but its still there gain all the way up (or even 1/2 way) gives me inaudible music and all i get is the whineing

all connections are run fine and the only 2 possible causes are 1: RCA's or 2: bad ground

any ideas?

**adorable** · 10-15-2006, 09:06 PM

Quick question (I hope!)....

I have an older (stock) stereo in my daughters 1993 Mitsubishi Eclipse. It's worked fine up until now (we've had the car about 4 yrs now), but a few months ago started making a high pitch whine. It started doing it intermittently, and in between the radio sounded fine. Now it's doing it constantly...you turn the radio on, it's playing fine for a moment or two, then starts the constant whine.

I thought maybe the plugs and wires needed to be replaced so I tuned the car up...didn't fix the problem. Any idea what could be causing this? I'm thinking about getting her a new stereo and I don't want to spend the $$ on it if it's not going to fix the problem...

Any help would be much appreciated!

**RedGTiVR6** · 10-20-2006, 01:19 PM

I had posted this thread a while back, but it recieved little attention, now that we've got a stickey, I'll throw it in here hoping someone gets some use from it:

Enjoy!

Troubleshooting: NOISE

**Skipjacks** · 11-17-2006, 10:29 AM

Originally Posted by S11D336B

You can pickup a line noise filter at advanced auto parts. They are made for car stereos, It hooks up to the +12v and filters out noise caused by the alternator on the car. They can carry around 20 amps and they only cost $10. Just connect it to the constant +12V connection on your PSU. In the past this has been the solution to line noise problems I couldn't fix by any other methods. If all else fails try getting a new soundcard. That has also worked in the past. Just my $0.02.

Until next time, drink and be merry.

This looks to be my answer except for one thing...

What 12v line do I put the noise filter on?

I've got about 400 12v lines in the car. I've got the alternator whine comming through my computer sound feed.

Do I put the noise filter on the power line to the head unit? On the 12v line between the power supply and the motherboard? On the 12v main power feed going from the battery to the inverter? (And if that's the one, does it go on the positive or negative line?)

I feel like this is the answer to my altenator whine but I don't know exactly where to put the filter.

**d_general** · 12-02-2006, 05:33 AM

hi im getting this same noise as your on about but one thing is that when i move my steering wheel (its power steering)around im getting noise and when i put it full lock it gets louder and also getting it off the rev off the engine too.
iv been to auto electrian too and he hooked a suppresser on to the back of the head unit and it didnt elimate the sound at all he cant seem to find the problem and yesterday i just hooked up a ground isolator to the amp which just quietens the sound but not really curing it fully.
aswell as that when i showed him what i did he suggest a cap should finally do the job but i dunno if this wil work cos i dont want to waste any more money if this doesnt work.
i know its not the head unit cos i bought a brand new pioneer and the same thing still happens with this one.
could any one help me with this sutiation??

**romanman69** · 12-06-2006, 01:18 AM

another noise problem.....

when i hook my labtop up to my audio system i get crisp clear perfect sound. when i hook it up to my carPC i get buzz.

I have my mobo sitting under the false floor in the trunk w/ no chassis, just attached by velcro. My guess it that since i lack a chassis my mobo leaks noise. Since im not particularly eager to get a chassis would a better quality RCA wire fix the problem (my current one is an RCA cable recycled from PC speakers)