Did a pretty hefty A/B between Xotic Bass BB Preamp & Xotic AC Booster. Both are GREAT pedals for slightly overdriven to somewhere-in the-middle overdriven. AC Booster is not as good full on overdriven, but then again, it's voiced for guitar, not bass. Has a bit of a mid-hump (as intended) but nothing obnoxious. Actually, it sounds really good. A bit more 'bite' than the BB Preamp. And of course, this pedal is awesome on guitar. BB Preamp is better overall, as it's voiced for bass, but I tell you . . . in certain situations, it was close. Both pedals work GREAT with a Sansamp BDDI, IMO. The AC Booster replaces the mids that the BDDI scoops out and leaves the good qualities in there. That means less fiddling around for me. This is a nice setup for Yes or Rush or John Wetton type overdrive, I think. Just have to dial the treble back a bit, as it can get pretty zingy. With Sansamp and BB preamp, I don't know . . . the BDDI seems to add more 'meat' when the Gain is cranked on the BB. I use this combo when more overdive is called for. Have to experiment more. I like this setup for when I'm switching back and forth from active to passive basses. I can set up one pedal for passive, one for active. Xotic makes great, GREAT pedals.