All hail the PAM8302A and PAM8403 mini audio amplifiers - the little amps that could. For those not familiar with class-D amplifiers, these little PCBs packs a lot of punch. They were traditionally was made for Arduino consoles, but really work well in any console - especially in handhelds. This mod helps boost the volume of your traditionally quiet hand-held console.
PAM8302A: 2W mono amplifier
PAM8403: 3W stereo amplifier
Game Boy Color PAM8302A tutorial here
Note: Commission may be earned from the links provided above