However, when I tried to use it to DI a double bass pickup, I got no signal whatsoever. Before jumping to conclusions, I did try one of my active DI boxes, and I also got no signal, so I am assuming that the problem was with the bass player's pickup. It was also no big loss since I never use DI with acoustic bass or guitar (or bouzouki).
I guess that his bass pickup requires a preamp before the DI.
After all of that... the question is: What is the practical difference between active and passive DI? I know that active DI requires power (from a battery, phantom power or other AC/DC adapter). I am hoping to learn is which applications favour one over the other.