Noise-less power access point?

groundshock

Original poster
Member
Dec 4, 2011
248
Have an antenna input in my truck to plug in my phone for music, and a charger.

Used the factory radio harness to tap into +12V for the adapter, and the charger is a cig lighter setup.

When the phone or anything is plugged in, there's an audible buzz and whine from the speakers, and when I connect the charger, Ho-lee crap, the noise is insane.

I'm going to try and re-wire the stuff to another power point but I'm wondering what others have done to get rid of these noise issues?
 

jonbo2002

Member
Sep 27, 2012
213
when I plug in one of my USB charger adaptors in the cig power point mmy radio stations barely come in, but its only the one USB adaptor everything else is fine.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Cheap chargers are like that. Try another brand. Or go to Radio Shack and get a noise filter capacitor (0.1uF or 1uF) and connect it right across the terminals at the back of the 12V receptacle.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
That's a good one. Ceramic caps are not polarized, so either way to connect it will do. They are also better at handling high frequencies than the polarized (have a positive and a negative marking) electrolytic caps.
 

groundshock

Original poster
Member
Dec 4, 2011
248
Thanks for the advice. One last question, would this create a drain on the battery when the truck is off, now that the + and - terminals are connected?

I've also been reading about ground loops and noise in audio systems so I may re-ground the head unit directly to the battery as well to provide a better ground.
 

mcc

Member
Apr 8, 2012
49
No- the capacitor will not pass the DC current from your battery. It creates a way for AC noise to bypass the receptacle.

It's essentially a selective way to keep the power from your battery from being shorted while shorting/buffering unwanted noise on the same line,
 

CaptainXL

Member
Dec 4, 2011
2,445
**INFORMATION

Bulletin No.:*06-08-44-015C
Date:*March 30, 2012

Subject:*Information on Eliminating Noise in Audio System When Using Portable Playback Device

Models:*2013 and Prior GM Passenger Cars and Trucks

Supercede:This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 06-08-44-015B (Section 08 - Body and Accessories).

Some portable audio equipment may be susceptible to certain types of electronic noise present in the vehicle's 12V power outlet.

Here are two ways to eliminate this type of interference:

-If the audio device is capable of being self-powered (battery), use it that way instead of plugging it into the vehicle's power outlet.

-Have the customer purchase a Ground Loop Isolator, such as *Radio Shack Catalog #270-054. This device plugs in between the radio and the customer's audio device. It is packed with one included Y-Adapter. If purchasing the *Radio Shack product, you will require an additional Y-Adapter (Catalog #274-369). This device should be installed between the audio player and the AUX input of the vehicle radio. These catalog numbers are stocked nationally at *Radio Shack Retail Stores in the U.S. and are currently available. Other similar products are available through other electronics or car stereo retailers defined as Ground Loop Isolators.Parts InformationParts are currently available nationally in the U.S. through *Radio Shack retail locations or through the mail at Radio Shack direct ordering 1-800-843-7422. In Canada, parts are available nationally through *The Source By Circuit City retail locations or at www.thesourcecc.com.
 

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