Induced noise/Ground loop trouble shooting guide. - Page 3

RedGTiVR6 · 07-14-2006, 03:50 PM

so the USB sound card has absolutely no power coming to it other than from the USB?

do you have a link to the card (or a model number) that you are using?

j0hn · 07-14-2006, 03:55 PM

That's right, the sound card is only powered by USB.

Here is the link http://www.turtlebeach.com/site/prod...dioadv/roadie/

Will Albers · 07-14-2006, 08:58 PM

Quote: Originally Posted by Red GTi VR6

Will -

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

Nope, and I own a couple. Worthless PoS

Will Albers · 07-14-2006, 09:03 PM

Im not sure where to begin here. Could be induced noise, could be ground loop.

Have you tried grounding the chassis of the USB sound card? Might be able to ground the power wire (-) of the USB sound card. I cut out my USB sound card because of weird issues like this. Do you hear the static if you plug in a pair of headphones?

What does the internal sound card sound like?

j0hn · 07-15-2006, 01:46 PM

I was worried that the problem might be too goofy to fix. The internal sound card isn't working now, but I haven't messed with it much. I do hear static if I plug in headphones. Identical to the static I hear on the speakers. I will try grounding the USB ground wire to the chassis later today...couldn't hurt.

Will Albers · 07-16-2006, 12:33 AM

Well thats your first clue. This is before and has nothing to do with your amp. Lets work on the pc/sound card. Try the grouning of the sounc card chassis.

j0hn · 07-17-2006, 08:39 AM

So I grounded the USB to the chassis and it got rid of the constant static. Now I get more of a popping sound when the bass hits or when the music gets louder. Almost sounds like speaker problems. Will get my headphones from the office and try those out today to see if I get the same thing.

Thanks for your help.

RedGTiVR6 · 07-17-2006, 09:08 AM

have you tuned your system yet?

that could be the sound of your system not being properly tuned thus causing distortion.

http://www.350z-tech.com/zwiki/Tutor...plifier_Tuning

Follow that guide and let us know.

p&gcustoms · 07-17-2006, 10:02 PM

cheap pac ground loop isolator connects to output rca jacks for h/u or pc and connects go the inputs from the amp and the the other 2 wires to ground that solves what i like to call the little bird inside the car noise

j0hn · 07-18-2006, 08:35 AM

I did get a chance to try out the headphones and I get the same thing so it is still between the sound card and the amp. I will get a ground loop isolator and try it out. Anywhere local to get one of those or just order online?

Will Albers · 07-18-2006, 12:49 PM

If it happens on head phones it is NOT, i repeat NOT, a ground loop between your sound card and amp. The ground loop isolater is not the solution.

You are getting a ground loop between your PC/Sound card and inverter. Ignore all other components. Use headphones as much as possible.

This is what I would try: Ground the cassis of the inverter to the same point you ground the PC. Ground the Chassis of the sound card and chassis of PC to the same point. Ground the USB cable (if possible) to the same point. If you still get popping through the HEADPHONES, i would bet its an issue of inverter quality. Look into a DC to DC power supply to solve your headaches.

There may not be an easy solution to the problem. Again, these components are never designed for automotive use. Its not that the devices are bad, just not designed for what you are trying to do.

j0hn · 07-18-2006, 02:01 PM

Thanks for pointing that out. I suppose I didn't think that through.

Now, since I am using a laptop in a docking station plugged into an inverter, I should just have to ground the inverter to the chassis, correct?

Components not designed for automotive use...what were they thinking?

Will Albers · 07-18-2006, 02:34 PM

Quote: Originally Posted by j0hn

Thanks for pointing that out. I suppose I didn't think that through.

Now, since I am using a laptop in a docking station plugged into an inverter, I should just have to ground the inverter to the chassis, correct?

Components not designed for automotive use...what were they thinking?

Carnetix make a 1900 DC-DC power supply. I would bet you can get it to work on your setup really well. It may eliminate a lot of your problems.

Now as far as your question goes, im not sure what you are asking. What i was implying is you want to ground the chassis of all of your components (The metal box surrounding the guts) to the same place where you ground the actual power flow. Its way overkill, but its a simple enough thing to do and can help out in these strange situations. If it works, start removing them and find out where it suddenly kicks back in. That was your problem source.

Anyways, check your power supply of the laptop. If its 19volts output or lower, you can usually modifiy the carnetix 1900 to power the unit perfectly, plus you get to eliminate the inverters. It will even give you shut down controller and 5v source! Look on the classified section to find em less than $100

Good luck

p&gcustoms · 07-18-2006, 08:43 PM

Quote: Originally Posted by j0hn

I did get a chance to try out the headphones and I get the same thing so it is still between the sound card and the amp. I will get a ground loop isolator and try it out. Anywhere local to get one of those or just order online?

yes me im on lawndale between wayside and telephone i could help u out with that prob

soerenkroeger · 07-19-2006, 04:11 PM

Hi Will

just wanted to thank you for that thread - it really helped me to eliminate the data-noise i had on my system - which was caused by bad ground cable and/or the stock grounding point was on a piece of metal, which was tacked to the rest of the car

The only noise i have left now is a little whinening where the frequency depends on the engine revs. But that might be my dc-dc inverter which isn't inverting any more (yeah i did a shortcut on the output *doh*) ...

Thanks - this was really the best explaination i have found on the internet so far :-)

Best regards,
Søren