Nigel,
thank you for the information, but perhaps I'm not articulating myself well enough.
A lot of basses are fitted with active preamps; one might ask why, but it is a technological progression that bass players and musicians appreciate. However, passive basses are still popular, particularly those made by Fender. On these instruments, the tone is remarkable, only needing a small amount of EQ from a bass amplifier. Where other makes of bass guitar are based on the Fender design (but not only), obviously, they are not the same. For this reason, many bass players make modifications to their instruments in the hope of sigificantly enhancing its tonal quality. Hence, my inquiry. I want to modify my instrument, avoiding a the need to rout and drill into it. If, however, it is being suggested that I am wasting my time in this attempt, or that it is not possible to achieve such a modifcation, then I am deeply disappointed.