The Controls

All GWB basses come equipped with the Bartolini NTBT EQ. This active tone control preamp features independent Bass and Treble controls in stacked knobs ( top: Treble, bottom: Bass ) and each control boosts and cuts up to 15db. Also, there is a gain trim pot at inside the control cavity, so you can adjust the output level to match your amplification system. For your convenience, EQ bypass can be achieved by simply pulling up the volume control knob.

The Trim Setting

Inside the contol cavity on the back of the bass is the trim potentiometer that controls the maximum output for the bass.

Important:The first batch of basses were probably shipped with the trim control set to match the output of the passive setting (volume knob pulled up). Although this features the tonal similarities between passive and active, it also gives the false impression that the bass doesn't have much output. Go ahead and adjust the trim clockwise almost 180º
That'll be not quite full volume but significantly more than where it was originally. Feel free to readjust from there to meet your amp system needs.