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  1.    #1  
    I didn't see this mentioned anywhere and figured it is worth bringing up.

    If you are experiencing ground loop/engine noise/alternator whine when using your Pre as a music source through your car stereo while the charger is plugged in, the Touchstone should eliminate it.

    The short version is that when the Pre (or any other portable source) is plugged into a charging cord and a stereo cable to your head unit, you essentially have the Pre grounded at two different places with two different ground potentials... bam... you now have an ideal situation for engine noise. The Touchstone isolates the ground from the charging cord to the Pre by way of its inductive charging... no hardwired ground to your Pre through the charging circuit that can be a potential source for that pesky engine noise.

    I had mild engine noise in my car (alternator whine, the high pitched kind of noise that gets louder when there's more draw on the charging circuit of the car) that was completely eliminated when I started charging through the Touchstone.

    Just something to think about if you're considering putting a Touchstone in your car.
  2. #2  
    Interesting. Now if I could only improve the Pre's bluetooth mode. :*( My car's bluetooth + my pre != friends.
  3.    #3  
    FWIW, you would get the same isolation effect by sending the audio over Bluetooth rather than a cable.
  4. vreihen's Avatar
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    #4  
    Quote Originally Posted by DrHeathenScum View Post
    FWIW, you would get the same isolation effect by sending the audio over Bluetooth rather than a cable.
    ...and you can get double isolation if you do like I do and send your audio over Bluetooth while charging on a touchstone.....
  5. #5  
    Quote Originally Posted by vreihen View Post
    ...and you can get double isolation if you do like I do and send your audio over Bluetooth while charging on a touchstone.....
    Which is exactly what I do. Only downside is the phone draws more power than is recharged by the touchstone when sending pandora over BT.
    -Joshua
    I've decided to become enigmatic.
  6.    #6  
    Quote Originally Posted by vreihen View Post
    ...and you can get double isolation if you do like I do and send your audio over Bluetooth while charging on a touchstone.....

    OMG, you're dividing by zero!!!
  7. #7  
    Not all ground loops are noisy. On my car (2004 Mini) the aux input just cuts out after ten minutes to an hour when there is a ground loop. So if this is happening to you, try the touchstone to see if it fixes your issue.

    It is possible to get a ground-loop isolator that you just plug in on the audio connection, but it's much better to isolate on the power side, as the Touchstone does.

    Man, I sure hope Palm makes a Touchstone car kit some day.
    Palm III-->Handspring Visor-->Sony Clie PEG-NR70-->no PDA -->Palm Treo 755p-->Palm Pre-->HP Veer
  8. #8  
    I want to add the touchstone charger to my '07 Acura MDX. There is a perfect flat service to mount it. The MDX has an A/C outlet in the center console. So would there be any difference when using the Touchstone between using the 9V socket or the A/C Outlet?? BTW - Touchstone's by themselves are on sale at RadioShack for $15.99 now as they are clearing the Pre inventory.
  9.    #9  
    9v socket?

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