Booster

How can I boost an amplifier for a better sound?

Before you boost the loudness check the amp with someone else... I boosted my car amp years back.. It wasn't a fault amp, but my ears getting bad. Now I have this guy in my inner ear rattling a crisp packet for the rest of my life... I used the old amp as a pre-amp and bought a bigger amp as a final stage..
I wish I hadn't...