Induced noise/Ground loop trouble shooting guide. - Page 2

kickercivic1 · 06-21-2006, 04:27 PM

ya, but this is my third inverter and they were all different companies and I had the same problem with all three of them. I tired like 5 different grounds. I really think i have a ****ty kenwood 4 channel amp.

kickercivic1 · 06-21-2006, 08:51 PM

fixed. just got a escilpe amp all noise gone..piece of **** kenwood, made me go thru all this **** for no reason... thx will..

snoopdan · 06-22-2006, 09:49 PM

What about addressing problems from actual power supplyies on a car PC. I know I have so much trouble with noise from my M2-ATX that I no longer hook up my carputer to rest of the car's audio system, when the initial idea of getting a car pc was to eliminate the use of a cd player head unit alltogether.

Id love to find a way to fix my noise problem, im about 1/2 way ready to pull my carputer alltogether and just stick a dvd player in there and leave it at that.

RedGTiVR6 · 06-23-2006, 08:52 AM

really? you have noise from the M2? why do you think this is?

I'm running an M1 and have no issues. Before I went optic I didn't have many issues either.

I wonder what's different in the M2 that makes it nosier?

Rublex · 06-28-2006, 11:26 PM

Guys,

I just hooked my PC up and I also have the noise. What I did was instead of connecting the power and ground to the car I used another PSU I have for testing purposes and when I hook it up to the other PSU the noise disappears, as soon as I plug it back to the car the noise comes back.

I have also tried using the ground from the PSU and the 12v from the car and the noise again shows up. So it has to be the 12V from the car battery. What can I do about that?

Thanks

Will Albers · 06-29-2006, 06:21 AM

connecting to the PSU makes sense. It will clean out the noise.

You will need to list your components and follow the directions laid out in this article. Post a new question instead of adding onto this one for better results.

S11D336B · 07-08-2006, 07:17 PM

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.

alansanmateo · 07-13-2006, 08:05 PM

newbie here

I've searched the forum, and I see I may have a lot of work to do to isolate my problem, but I'm still hoping you guys would indulge me and listen to my question, which will be very simple for you guys:

I have a 2000 Sebring Convertible, with stock audio unit (CD player with cassette deck)

I play my iPod through a cassette adaptor (FM modulators are useless in SF Bay Area)

When I rev the engine, I get a whine from the engine compartment (I hear it through the heater vents - I don't believe I hear it through the speakers, though I could bw wrong). If I unplug the cassette adaptor, the whine disappears.

Yes, the whine changes pitch as I rev the engine.

I do still enjoy driving the car,though I may be replacing it within a year. I'll likely replace it if I get hit with any repair >$1000, so I don't really want to put a bunch of money into the car (such as a new/modern audio unit)

Is this likely to be "easy" to fix, or should I just buy a new audio unit?

Am I guaranteed to fix this problem by buying a new audio unit?

I really appreciate your patience in replying to a newbie question. I am not electronically-savvy enough to do the troubleshooting that folks have suggested, so I'd likely have to go to a car stereo place, and.....well, that usually results in just buying a new unit.

If you think the best route is a new unit, I'd appreciate any advice you can give on what I should look for. I'm told there aren't many units that fit in the space of the Chrysler unit, so my choices are limited. Or my installer lied to me.

Thanks, again

Will Albers · 07-14-2006, 07:52 AM

Its a ground loop between the stock head unit's power and the iPods power supply. Do you have it powered through the cigarette lighter plug? If you run the iPod on battery power do you still have the issue? I'm guessing not. There is plenty of info out there that explains a ground loop

Very common and can really suck. Unless you have the ability to add a new cig lighter plug to the wires directly at the plug behind the radio, plan on buying a ground loop isolator and a bunch of adapters.

Ya know, its been so long since i used one of those cassette adapters... I had thought it was purely magnetic, but i guess the heads do make contact and that can cause the connection for the ground loop.

alansanmateo · 07-14-2006, 12:58 PM

thanks, Will

I figured from reading the various posts that that was what I was dealing with, but I wanted to be sure. I didn't think this issue was different for PCs than for an ipod.

I will check (at lunch, when I leave my desk) to see if the problem is related to charging from the lighter.

I am really torn about trying to fix the problem versus buying a new head unit that will have a direct line in for an iPod.

cheers!!

Will Albers · 07-14-2006, 04:04 PM

Quote: Originally Posted by alansanmateo

thanks, Will

I figured from reading the various posts that that was what I was dealing with, but I wanted to be sure. I didn't think this issue was different for PCs than for an ipod.

I will check (at lunch, when I leave my desk) to see if the problem is related to charging from the lighter.

I am really torn about trying to fix the problem versus buying a new head unit that will have a direct line in for an iPod.

cheers!!

That direct line in head unit will not fix the problem unless it has specifically isolated inputs. You will need to eliminate the ground loop

RedGTiVR6 · 07-14-2006, 04:09 PM

Will -

I've yet to hear of anyone implementing an iPOD in their car and it sound worth a damn, have you?

j0hn · 07-14-2006, 04:37 PM

Somewhat of a newbie.

I've been reading these forums for a couple of months now and got my carputer installed last weekend. I have, from what I can tell, an odd problem. Here is my audio setup:

Toshiba Portege M205 Tablet
Toshiba Port Replicator (plugged into an inverter wired to a cigerette lighter)
Turtle Beach Audio Advantage Roadie USB sound card
Kenwood 4 channel amp

I am getting static when I plug in the USB sound card. I can plug in my iPod directly into the amp and it sounds great so I believe the amp wiring is good. I get the static even when I just touch the usb connector to the usb port on the docking station (not actually plug it in, just touch it to it). I went ahead and grounded the inverter to the same location as the amp (it was on the ground from the cigerette lighter), but that didn't help. I had an extra USB cable laying around so I plugged it in and cut the power wires and it stopped...but so did my sound card. I tried the USB sound card on my desktop and it worked great. All I can guess is that there is some issue with too much power coming to the sound card from the docking station, even though I would think that the sound card should handle that. If anyone has any ideas for me, I would appreciate it. Everything else is perfect with my setup and I would like to be done with it.

RedGTiVR6 · 07-14-2006, 04:42 PM

sounds like it's either a cheap USB sound card or it's not properly powerd/grounded.

j0hn · 07-14-2006, 04:48 PM

The sound card is pretty nice. It's the best Turtle Beach USB (for what that's worth). Where exactly would my improper power/ground be? The USB power is from the docking station that is plugged into the inverter. I get no change if I ground the inverter to the cigerette lighter or the chasis with the amp.

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