Here's the sad story of an innovative and interesting experiment in guitar building in the late 70s:
https://www.vintageguitar.com/3810/renaissance-t-200g/
Somehow, in nearly 30 years of collecting I've never seen or heard of them before. Anyway, the FSB related thing is that it's a defeatable active preamp (pickups into volume controls, with phase switch, into switch to output or to preamp). The preamp has active bass and treble controls with a center detent. Feels like it could be baxandall although I'm not sure. Anyway, pics...
I apologize that they're so big, if you open them in a new tab (right click) you can see them in their entirety...