The Bass Driver DI was designed as a "direct box," and works best direct. The idea was that you would plug into the Bass Driver and send the uneffected parallel output to your bass rig (just like a traditional DI) and use your bass amp as your onstage monitor. You would then send the amp emulated output of the Bass Driver to the mixing board and have the sound of a mic'd vintage amp without the hassles of mic'ing. We also gave you the ability to "blend" in your straight bass sound with the SansAmp emulation as this is a common techniques used in the studio.
The parallel output is hardwired to the input. On the older V1units the XLR output is a padded down output for microphone level and the 1/4" out can deliver up to line level depending on how the pedal is set.
If the unit is in bypass mode it can be used as a standard DI to convert a high Z signal to low impedance. You can also engage the unit and turn the blend counterclockwise to turn off the SansAmp portion of the circuit. Now only the level, treble and bass controls are active. With the treble and bass at their null points the unit is flat response but can be used as an active DI with tone controls.
There is a mod that can be done to the older Bass Drivers to disable the pad on the XLR output if desired. If you wish to do this please contact tech support. firstname.lastname@example.org