If you’ve ever tried to couple a cheap mp3 player with good headphones, you know much of a pain it can be. This is a walk-through of how to build your own.

“Chu Moy designed a very popular headphone amplifier that’s easy to build, and it can be built small enough to fit in a pocket, power supply and all. It’s powerful enough to drive very inefficient headphones to thunderous volumes from even weak sources, and it sounds excellent considering that you can build a bare-bones CMoy amp for just US$20, and a pretty nice amp for under $50. Considering that the cheapest of the worthy commercial amps is $100 and most of them are in the $200+ range, this is a very worthwhile cost difference.”