Traced by AlexS and Fuzzhead, this is a quite tweakable and heavily modified HM2 variant with more gain on tap, more volume, two on/off/on diode switches and a very flexible four band eq.
It is a quite noisy beast when Gain and all eq controls is maxed out though but a buffer up front helps a lot. Or you can increase 1K resistor connecting to Gain 3 to calms things down. Stock HM2 value is 47k so there is a pretty wide margin to experiment within.
Layout is verified.
