I've seen a few queries on altering active basses to passive but I've still got some concerns. I've got a BTB405 which has an active pre-amp inside. I don't use the settings the pre-amp, much prefer working with the amp-cab itself. So, I'm thinking of making altering it from active to a passive bass. What I'd like to get is pickup selection (back, front, both), tone and volume. Thats all I really need. I'd leave additional pots on the bass rather than leaving holes in the body. Will this cause a deterioration in the sound out of the cab? With amp-head adjustments compensate for any loss in the signal - if there is any loss at all? Has anyone got any experience of this sort of conversion, any advice etc?