How to boost a line-level signal (in a car) to acceptable levels?

December 11, 2006 11:58 AM

How to boost a line-level signal (in a car) to acceptable levels?

I installed a line-in to my factory stereo some time ago, and it works great with one of my mp3 players. The other (which is actually a GPS device that plays mp3s) comes out waaaaay too quiet. I have to jack the volume way up and even then it's not loud enough.

So I'm looking for a way to take my line level (1/8" jack or RCA, either one) signal and boost it significantly (6-10db) prior to feeding it into the line in.

I want it to be cheap and low noise. Battery powered is probably OK. DIY is just fine, I can solder and have all the equipt. I need to make such a thing. I see plenty of projects online that are *close* and could probably be converted to my needs but if anyone knows anything that is directly applicable that would be better. Small is good.

posted by RustyBrooks to grab bag (3 comments total)

I'm confused. Does the GPS have a line out or a headphone out? Why not a plain old headphone amp?
posted by Pastabagel at 12:12 PM on December 11, 2006

Any preamp should be fine. If it's 12v you can just patch it into the car's electrical system.
posted by rhizome at 12:45 PM on December 11, 2006

A cmoy headphone amp should do the trick. It's easier to drive a line stage than headphones, so the facts that it is a headphone amplifier doesn't matter. The default gain of 11x sounds about right, but it's easy enough to make it lower. Most cmoys are set up for a 9V battery but you can run it with 12V from the car.
posted by exogenous at 12:53 PM on December 11, 2006 [2 favorites]