aux input volume and buzz (solved)

[dogfish]

I have a Mazda5 with the factory stereo which comes with an aux input. I have a new Android phone I'm using as an MP3 and Pandora music player, and realized I could plug it in, headphone jack to aux input, and listen to Pandora while driving. (Thank you unlimited bandwidth plan!)

There were two problems -- first, the volume was very low; cranking the phone up all the way still required turning the volume on the stereo up almost all the way. Second, when I also plugged the phone in to the cigarette lighter (using a converter) so I could keep it charged while listening to music I got a buzz in the speakers. (Maybe some sort of ground loop? noise from the charging circuit?)

I started looking for a battery powered headphone amp to increase the volume and I ran across this thing, a little box (2"x3" maybe) that has two audio-grade transformers and a couple of jacks. It raises the voltage level (4x maybe?) so I get good volume, and it also solves the buzz problem (breaking the ground loop, maybe). A guy in NJ named Pete, a hobbyist, puts them together and sells them on the web.

It's a little cheezy looking, but it comes with some velcro stickies so I can easily mount it out of sight. And it comes with a 3.5mm cord, no hunting around for a spare.

It's really nice to have a passive solution that doesn't eat batteries. And the guy is very friendly and helpful via email, good customer service, and has a 100% money-back guarantee if you don't want to keep it.

(Note: I am in no way affiliated with the guy who makes and sells these. I'm a satisfied customer.)