Grounding to negative wire - Toyota Nation Forum : Toyota Car and Truck Forums

gyz1893 · 08-08-2009, 08:51 PM

When I listen to my radio/cd, I hear a light hum/buzz through my speakers whenever I step on the accelerator. Through my research, it seems like I have a ground loop. I have read that connecting the ground wire on my cd player to the negative terminal of my battery will fix the issue. Do I have to run a wire directly from the battery to the CD player? Or can I just join the ground wire to the negative wire thats already there?

lenjack · 08-08-2009, 09:05 PM

I don't think t's a ground loop. Wait for others to chime in.

gyz1893 · 08-08-2009, 09:11 PM

It fits the description of an alternator noise. To me, alternator noise is the same as a ground loop. Please correct me if I am wrong.

lenjack · 08-09-2009, 12:31 PM

I agree that it is alternator noise, but I don't think that's the same as a ground loop.

Manny1337 · 08-09-2009, 03:41 PM

i had the same issue. you need a group loop isolator on the rca =P. if youre not running an amp then use the ground wire from the stereo right to steel. make sure there is no paint on the connection and its bare metal.

whip_cracker · 08-09-2009, 07:05 PM

Agree with Manny as well..

If not, would suspect alternator bearing... not sure how the Toyota ones work but had same problem with friend's Datto with the same noise.

gyz1893 · 08-10-2009, 11:07 AM

thanks for your suggestions guys. i will try grounding to the cage brackets. Also, (sorry to be a pain in the a$$

) I have listened to radio and a CD while the car was in "ACC" mode. I still heard some static coming out of the speakers. Could something else be wrong?

SexieWASD · 08-10-2009, 05:06 PM

What type of head unit do you have? is it a Pioneer by chance?

gyz1893 · 08-11-2009, 08:45 AM

Nope, I have a Nextar brand. Here it is: http://www.newegg.com/Product/Produc...82E16882558021 Picked it up cheap for $20.

Manny1337 · 08-11-2009, 11:43 AM

well that your issue then lol. buy something better quality

gyz1893 · 08-11-2009, 11:49 AM

lol i should. but i am on a tight budget (school, gas, etc...) Is grounding to the cage of the head unit a good idea?

Manny1337 · 08-11-2009, 04:53 PM

yeah as long as its baremetal anywhere will do

CROYCE992 · 12-14-2009, 11:31 PM

pardon the ignorance, what is a group loop isolator? I cant seem to find much information on google or where to buy one for product descriptions.

95PimpingCamry · 12-15-2009, 01:14 AM

^ it's a ground (not group) loop isolator. A ground loop is when the ground at one point in the car (i.e. stereo up front) is at a different voltage potential than at the ground at another point in the car (i.e. amp in the back). This potential difference will cause a slight DC current through the ground of the signal (RCA) wires. This DC current will produce unwanted noise when amplified.

Ground loops can usually be caused by poor grounds in a car in conjunction with large current pulls from appliances such as an amplifier. Since a poor ground can be seen as an electrical resistance, R, and the current drawn by an amp in the rear, I, passes through this resistance, the potential difference between the two ground points will be IR.

A ground loop isolator is basically a transformer with a 1:1 turns ratio. Since a transformer is magnetically coupled from side to side, not electrically coupled, this DC current cannot pass through it. The audio signal is an AC signal, so that can pass through the transformer. This transformer then passes through the audio signal and effectively filters out the ground loop.

CROYCE992 · 12-15-2009, 11:55 AM

sounds like something i could use. on rare occasions i seem to be getting a little noise like the subs are trying to reproduce vocals which might have more to do with my crossover tuning. anyways, this seems like a smart investment. where can i get these and are they hard to install?

Quote:

Originally Posted by 95PimpingCamry

^ it's a ground (not group) loop isolator. A ground loop is when the ground at one point in the car (i.e. stereo up front) is at a different voltage potential than at the ground at another point in the car (i.e. amp in the back). This potential difference will cause a slight DC current through the ground of the signal (RCA) wires. This DC current will produce unwanted noise when amplified.

Ground loops can usually be caused by poor grounds in a car in conjunction with large current pulls from appliances such as an amplifier. Since a poor ground can be seen as an electrical resistance, R, and the current drawn by an amp in the rear, I, passes through this resistance, the potential difference between the two ground points will be IR.

A ground loop isolator is basically a transformer with a 1:1 turns ratio. Since a transformer is magnetically coupled from side to side, not electrically coupled, this DC current cannot pass through it. The audio signal is an AC signal, so that can pass through the transformer. This transformer then passes through the audio signal and effectively filters out the ground loop.