I've noticed on a couple of basses I've had that pushing the active eq (bass, mid, and maybe a bit less treble) to near max and then adjusting the input gain down on the amp can result in a nice fat tone.
I watched a video of rich brown on YouTube and he said that he does this on his active basses with bass and mids and then knocks out all the treble.
Anyone else doing this to achieve their tone?