The Bass Bump Headphone Amp is an audio accessory you can build to improve all of your private music listening. It has enough power to give clear sound and punchy dynamics through most any pair of headphones, or even a set of small speakers. The custom bass enhancement circuit lets you boost the music’s critical low-frequency spectrum to your taste. It sounds better than the headphone driver circuits in most smartphones and MP3 players because it has a lower source impedance and much higher drive current. This means the sound from your headphones is unaffected by factors like long cables or impedance mismatches. All of the parts come from RadioShack, right down to the rechargeable battery and external charger. Build one and you’ll hear the difference right away.