I just bought a Kent Armstrong MM/OLP pickup to put into my bass replacing the rubbish stock single soapbar that I had in it originally. I also saw some decent reviews for the KSBT so I was able to pick it up cheap of my friend who was no longer using it.
Downside is I'm having trouble installing the preamp without an actual wiring diagram. I'm not using the switch either because I want it in active mode always. Anybody that can help woould be great
Installing a Kent Armstrong KSBT w/ Kent Armstrong MM/OLP p'up 
