A question on my basses sound

[Ronen Tat]

It seems to me you're pushing the pre-amp to its limit. I've never felt a need to do that in a playing situation, or at all.
There's a mini control inside the cavity (I think it's on the mid board, the small one) which is used to preset the preamp gain. Maybe turning it down a little will solve this for you. The pickups in series mode have more output.
If I recall right the instruments leave the shop set up with the passive mode equals in volume to active with everything flat, with pickups in parallel mode (standard Smith sound).

-- Edit --
On the current pre-amp the mini control is a tiny white box on the middle board, located right above the bass pot in the cavity. On the older 9V pre-amp it's on the Mid board.