Interesting bass with individual level controls per string!
Gibson had these as early as the mid-eighties with their Shadow Piezo basses (Explorer and Q-80). They make utter sense - on an acoustic bass guitar, different string loudness levels can drive you (or at least me!) nuts and it happens quickly if string to bone saddle pressure isn't even. That can cost you hours of trial and error padding of the piezo strip from underneath to equalize the different pressure levels, taking off the strings everytime.
Even on recordings I all too often hear acoustic basses where the piezo string levels are uneven. And it's not something you can hide with equalisation either.
I still play my trusted AB-20 frequently at home, I have better acoustic basses (Martin and Höfner) with better (more advanced) Piezo systems, but the AB-20 is probably the bass I do the most composing on.
