magic box that boost the alternator?

If he is using an accuvolt, it will demand more from the alternator, not boost it.  If you up the voltage into a given ohm load, current goes up as well.  That's basic ohm's law.  If the alternator cannot support this abuse, it will die an early death.My ex once told me I have a perfect face for radio.

Yes. But. Back in the good old days of non regulated power supplies and big dumb non Class D, X, H, or whatever have you (IE, everything was Class A or AB), you could really make that PG M44 (for example) really make some power by keeping the power supply seeing a 14-15V input voltage, car running or not. I remember when Accuvolts were all the rage when they came out..... of course, that was when you were also happily hanging out in the IASCA 1-150w power class for your entire system, and hitting 140db to annoy the neighbors wasn't a priority. Gus Wherever I go, that is where I end up......