Bernard d'Uur's little lab; the docter is in!

Sometimes I get these pedals in that are clearly made by someone in a DIY fashion. No markings, no owner, just someone that liked to tinker with resistors and capacitors. Now this one came in:      The circuit and the sound Unknown, no markings, only a small PCB made on stripboard. I determined one knob to be the input volume ('Gain') and the other knob to be the master volume ('Level'). Hooked up to an amp the pedal sounds really gate-y with the gain set low but full-on blast fuzz when the gain set higher. The tone is rather piercing and cutting. Combining other pedals don't work as both pedals start to behave weird. I quickly traced the pedal: As you can spot this pedal has some issues. Foremost the ' Voltage Reference ' (Vref) is connected to uncommon places in the circuit where I'd expect a ground connection. I also miss a cap on the input to block any DC (especially from this Vref).  So what is this pedal? From the design I expect it to be some sche...