I like bass, but built in software equalizers suck. FiiO e3 and E5 amps are cheap and have good bass boost, but adds an extra lump on the cable and you have to worry about battery. I fixed that.

The concept here is two-fold: Add an analog volume knob, and make it USB powered. The volume control part is easy, just wire a stereo potentiometer to the line-in and you have an instant volume control that is much more accessible than the built in digital volume control of any computer. For the second part, you need more parts. USB plug, two 10uF capacitors and a 1.5V voltage regulator. Caps go on both in and out pins (between in and ground, between out and ground) and the USB plug carries the 5V to the input of the voltage regulator where it will magically turn into the 1.5V that the E3 natively runs off of (1x AAA battery).

Lastly I glued both the 3.5mm input jack and the USB plug to the Fiio in a way that makes it plug straight into the side of my EEE 1101HA, no lose cables, and act as a natural extension to my netbook. That way it’s not flimsy or clumsy in any way and I plug my headphones into the E3. The volume control works great and the bass boost is awesome. Best of all, it’s a very cheap project.