I have never owned either model you tested/are purchasing. My first Dingwall was a passive AB-I. I never felt the need for a preamp when playing it. I usually play my Super J's in active mode with the bass/treble controls on the detent, no boost or cut. The exception is my five string with P/J pickups - I cut the bass a little. No personal experience, but every report I've read from others is that the B strings detune well. Looking forward to pics of your new Dingwall!
1,317th member of the Praise and Worship Bassist Club!