Here's an unreleased version of the Evil Filter. It's similar but not quite the same as the original. The schematic was pulled from a video interviewing DBA's Oliver Ackermann and was redrawn here. Some of the parts are a little pricey but the resulting sound is apparently amazing.
This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.