There three different ways a bass can be active: passive pickups with an active preamp, active pickups with no preamp, or active pickups with an active preamp.
I made a thread a little while ago to compare a Fender Marcus Miller jazz bass with the preamp on or off. This bass has passive pickups into an active preamp. You can listen to those clips to hear some of the difference.
Here's a link!
In the end, though, recordings can only clue you in so much, especially with all of the variables involved in the recording process.