If you love tinkering with bass electronics (or just want to make some modifications to your bass yourself), check out the website of Markus Hoppe (alias „Cadfael“). He created a free thirty-something page PDF file with all kinds of different bass circuits. The diagrams also can be understood by people that – like me – were not born with a soldering iron. You only need to know some German… Thanks, Markus!

Free download of Cadfael's bass circuit diagram collection (PDF)