Automotive 12-volt convert to dual 1.5 volt output
Here's the deal. I have two auxiliary inputs on my car radio. The signal is very weak, so I bought two cheap headphone amplifiers (Fiio E3) to boost the input signal (XM radio receiver and cell phone/tablet/mp3 player). The headphone amps work great, and make the input sound great and full; already tested with no issues.
Problem is, the amps are powered by a AAA battery, so 1.5 volts each. They only turn on when the output of the amp is connected, and last about 20 hours on a charge when constantly on. So instead of replacing the battery every day (I plan to have these buried inside the dash of the car, so the output will always be connected), I want to make some kind of voltage divider/regulator to power both headphone amps when the car ignition is on. So in theory I would have to drop 14.5-ish (engine running volts) down to two 1.5 volt outputs to drive each headphone amp.
Any ideas on how to accomplish this? Thanks in advance!