Been waiting a long time to post this one up. Yup. It is 1:1 with Rocktek DIR-01 Distortion. The schematic i found was missing a couple of values, so instead of guessing i got myself an original and checked them. My original just happens to be this beautiful japanese plastic thing. It doesn't quite reach the unity level, but there's one resistor determining the overall level. I marked that with an asterisk on the layout with a note, so you can swap it for something like 10K. This one is definitely nice platform for trying on some mods. Schematic is up at FSB.
While checking for additional info, i ran into this perfect demo video of later Rocktek unit. Priceless. Just Priceless.