Sunn Buzz SB-1G

This neat proto-distortion box was available by 1967, perhaps even as early as 1966.

A cursory glance and it appears to be FZ-1A inspired (single 1.5V AA cell, 3 transistors, two controls) but with silicon transistors. The first stage is a buffer, as in the FZ-1A, followed by two voltage amplifiers that surely distort rather extremely, again like the FZ-1A. What's interesting is that this circuit has to bring all of the stages into conduction with resistors, unlike the FZ-1A which relies upon germanium collector leak to bias the devices.

Q2, for instance, has a 27k and 15k divider to provide the base voltage. With Q2 open circuited, this would only provide a mere 525mV or so with a 1.5V battery. Adding Q2 into the equation, it can only lower that figure further due to the non-negligible input impedance of the common emitter with no emitter resistor. It's likely this is by design, i.e. the transistor is meant to just be "barely on" and emulate the germanium "no bias" fuzz design with silicon devices.