But, isn't a passive pre-amp supposed to be basic in nature?
Passive or active only refers to presence of electrically powered amplifiers in the signal path.
It does not refer to the presence of electrically powered accessories to make operation of the preamp easier. It's still passive if it has remote control, powered VC and source switching, LED level readout, etc.
As long as the signal never touches a tube, transistor, amplifier IC, then it's passive. Even if it uses magnetics to boost voltage or current.