Car charger, audio cable, and noise interferenceSupport


  1. malklavious

    malklavious Well-Known Member

    On my first road trip with my new Droid I eagerly hooked up an 1/8" stereo cable between my Droid and car stereo with great results. Then I plugged in my car charger (brand new "RocketFish" from Best Buy) and there is a ton of audio interference. As I rev the engine of my car there is a high-pitched whine that is almost the same pitch as the RPM's of the engine.

    Has anyone else with a RocketFish car charger have the same problem?

    Has anyone else had this problem with an official Verizon car charger?

    Has anyone else had this problem at all?

    Thanks!

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  2. aaronbrannt

    aaronbrannt Member

    I'm having the same issue with my Droid and car audio system. I have a generic Motorola car charger from K-Mart, it was only $10. Other audio inputs such as my iPod work flawlessly, my Droid works flawlessly until I plug in the car charger. I'm experiencing the same engine revving frequency interference as you described. Also I hear interference when scrolling on my Droid through Apps. It's really strange.

    I'm thinking it may be a Droid issue because the Droid is allowing the interference from the car changer to be transmitted through to the Aux out. But I'm not sure.

    Any other information on this issue would be greatly appreciated. I'll update if I find anything.
  3. Polymira

    Polymira Well-Known Member

    Sorry to bump an old post, but you never did get your answer.

    This issue would be what's called a ground loop problem. It would happen with a droid, iphone, ipod, etc... doesn't matter (i've been dealing with it for years, but it's just a tiny bit louder on the droid then my old apple gear).

    I'm planning on fixing it tomorrow by opening up my dash and finding a better ground for the cigarette lighter. BUT, you can also fix it by purchasing a ground loop isolator (google/amazon search it).

    Another charger however, won't fix the issue at all.
  4. sho95

    sho95 Well-Known Member

    Or just a [FONT=Times New Roman, Times, serif]alternator noise. Speacially if it a rebuilt unit or an old unit starting to go bad.[/FONT]
  5. malklavious

    malklavious Well-Known Member

    Thank you for the information, Polymira and sho95!
  6. jandrewt82

    jandrewt82 New Member

    I also have the same noise coming from my droid when I use the Rocketfish adaptor. I have a hard time believing that it is my car because it is a 2008. I was hoping I could get some more input on this issue.
  7. sho95

    sho95 Well-Known Member

    In this case it could be our adapter. Have you tried another adapter?
  8. jandrewt82

    jandrewt82 New Member

    I tried a new charger and phone today. I tried a Motorola charger instead of a Rocketfish and same thing. I also tired a new Droid and same thing. However, I tried my friends car with the Motorola charger and it worked fine. Now it looks like it is either my stereo ground, or the aux cable. I will let you know when I can try these.(Maybe a week) sho95 did you get a chance to ground yours yet?
  9. bthoward

    bthoward Well-Known Member

    You've got a ground loop. What you need is an audio cable that is transformer coupled. I'm not sure where you can buy one but try searching for a ground isolated audio cable or transformer isolated audio cable.... Something like that... Worst case you can just find and buy an audio transformer and make your own (thats what I'd do...) but explaining it here is probably beyond the scope of what you're looking for.
    xmancool2 likes this.

  10. it's called cycle 60 hum. the same as fluorescent lights. anyway, if you've ever bought a pc monitor, it probably came with the exact audio cable you're talking about. you can find them at just about any best buy, office depot ... blah blah, you get it. it will help out, but you can never truly get it all out if you charge while using a cable to plug into your audio system. if you use bluetooth, the problem won't be there.
  11. Bobarazzi

    Bobarazzi Well-Known Member

    Mine sounds great, even with my 8 dollar, generic charger.
  12. JustROLLIN

    JustROLLIN Well-Known Member

    xmancool2 likes this.
  13. kdogg

    kdogg New Member

    Definitely a ground loop. If you rev your engine with the phone plugged in you should hear the pitch of the whine go up with the rpm's. It would be no different if you plugged an ipod or your laptop into your stereo while they were charging in the car. The easiest/cheapest way to kill the noise is to unplug the charger while the phone is plugged into your stereo, but the adaptor from crutchfield should do the trick.
    I don't know why car companies haven't caught up on this yet. My wife and I have two different 2007 Toyota vehicles with standard aux inputs and both share this annoying problem.
  14. az_r2d1

    az_r2d1 Well-Known Member

    I have the same issue with the cheapie monoprice charger. It also does not really charge the phone. It reports a charge but still dies after a while. Can't keep the phone going let alone charge.
    xmancool2 likes this.
  15. malklavious

    malklavious Well-Known Member

    As a follow up, I got a "ground loop isolator" as recommended earlier in the thread. Problem solved! Thank you for everyone who suggested this route. I found the part online:

    RCA Noise Filter Ground Loop Isolator PAC SNI-1/3.5
    xmancool2 likes this.
  16. JustROLLIN

    JustROLLIN Well-Known Member

    Thats great. I just transfer mine from one car to the next whenever I get a new vehicle.
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