Feedback noise using dongle with power

CoryNat · #1 (**permalink**) 02-13-2009, 09:52 AM

Searched and did not see anything on this. I am curious if anyone else has tried their TP in the car with the supplied dongle. I have it plugged into the aux inputs on my DVD player in the car. Sounds great when it is just the sound plugged into the dongle. When I plug a USB cable from a 1 amp 12v power supply, I get a lot of hiss and feedback. Tried various USB cables and the level of noise does vary somewhat, but goes away completely without the power. I am going to try an invertor with the OEM HTC power supply next to try and determine if it is the 12v power that is dirty or not. Anyone else experiemtned with this and have any suggestions as to the best setup or power accessory to use. Maybe I went too cheap.

**guitardoc64** · #2 (**permalink**) 02-13-2009, 10:26 AM

It's dirty power from the charger, and a possible ground loop. Ground loops happen when two or more paths to ground exist and are at different potential. I run across this a lot in sound system installations, particularly in churches. Additionally, the 12V charger is probably picking up ignition "hash" and passing it on to the audio because of the ground loop. The inverter might solve the problem.