OKKO Diablo+

The Diablo is a modified BSIAB circuit and the Diablo+ version has an added boost at the output that's independent from the main overdrive circuit. I've laid it out for a 125B with top mounted jacks for a nice small footprint. Originals have a switch to run at 9 or 18 volts which I've left off-board so builders can choose their preferred voltage doubling method. Trim pots are extra controls, not for biasing, FYI.

OKKO Dominator

Here's a big one, and just so happens to be the 700th layout on the blog 😎—the OKKO Dominator distortion. It's a couple of JFETs pushing an opamp with active EQ, with a charge pump. Originals use a switch to select the range of the mids control, but it's easy to swap out for a pot. Schematic can be found here on FSB for reference. Easy fit in a 1590BB.