FYI, those are coring diodes. IIRC, they function as a crude noise gate.

They do function as a noise gate, but they also introduce crossover distortion, which is the part I don't care for.

I have the HM-2 and Boneshaker. There are some similarities to the HM-2, but they sound very different to my ears. If you block it out, The Boneshaker is SHO -> Opamp gain stage with Depth -> Si diodes to ground -> gyrator eq (or just SHO -> DOD 250 -> eq) The HM-2 is two transistor gain stages -> T...

In the HI eq, 37.2NF seems too high. Could it be 37.2PF (0.037NF) instead? That would maintain the ratio of around 50x between the two caps.