USB power

**anti_commander** · 08-22-2007, 07:05 PM

i dont have a carputer just yeat, but i did mold the zune dock into my dash but in order for it to work it must have usb power, so i bought a usb power plug the plugs into the cigarette lighter, but when i charge the zune and play music i get a horrible static sound, and when i rev the engine a high pitced screech goes up and down arcordingly. so my question is, what can i buy or make that will power the dock, but wont have any feedback?

**91silvy** · 09-01-2007, 08:57 AM

I think it's a problem with the zune, not with your setup. My zune does the same thing. Mine does exactly the same thing, it's a pain to have to bring your zune into the house just to charge it (I always wind up forgetting to put it in my pocket before I leave).

**anti_commander** · 09-01-2007, 03:22 PM

i dont think its our zunes, i just went out and bought a power filter for my cigarrette (sp?) outlet and it filtered out the whining noise but not the static. but when i plugged the usb into my laptop (which now i have a working carputer setup) it goes away but if i pause the music and turn my stereo all the way up ill start to get feedback, but i never have it that loud.

**2k1Toaster** · 09-01-2007, 04:06 PM

It's a ground loop.

**anti_commander** · 09-01-2007, 05:45 PM

what do you mean by ground loop, where would it be, oh wait its in the zune. i remeber i had a radar detector that was on a switch with the ground wire being the switched wire, and everytime i had the zune pluged into the power outlet and and the switch to the radar off, then pluged in the headphone cable to the headunit, the radar would turn on. i guess the zune would complete the circuit.

**Incognitum** · 09-17-2007, 03:36 PM

I've had this exact problem with both a Creative zen V and my HP pocket PC. Interestingly, I can have the devices plugged into the USB charger while listening on headphones, or have it plugged into the Aux input in my stereo while operating on batteries with no ill effects. It is only when I have the devices plugged into both the USB and the car stereo that I get the hum, or the change in pitch while revving the engine.

So if it's a ground loop or whatever, what piece of equipment can I throw in the system to fix it, and how much does it cost?

**Incognitum** · 09-17-2007, 03:43 PM

Originally Posted by Incognitum

So if it's a ground loop or whatever, what piece of equipment can I throw in the system to fix it, and how much does it cost?

Or I could answer my own question....

Ground Loop Isolator

From Radioshack.com, $16.99

**schnottus** · 09-18-2007, 09:11 PM

If you look up inline noise filters they would probably do the trick, i know thats what you use on cb radios to get rid of whine, probably would do the same for a zune.