Well, I just put an aguilar obp-1 preamp into my curbow 6 (with the bartolini pickup) and it sounds really smooth and deep. The previous preamp sounded harsh and unnatural (I think it was the mighty might preamp!?), but this one really complements the bass well. Anyone else replace their Curbow preamps? Any general opinions on the curbow 6's? For what I paid, this is one sweet bass.