Having researched things for a couple of days now, I'm far from an expert on the topic, but let me contribute something new about 4 knob 3BOD variants:
There are 4 knob pedals that do not have Futura written on them, and these are not Futuras.
The pedal I pictured above is from Joe's Pedals (a shop in the UK, check it out, it's great!).
It is a 3BOD Blueberry, but it has an additional treble control. If you turn the treble knob fully CCW, it is cut from the circuit and the pedal behaves just like a normal Blueberry. Turning it up results in a mild treble boost after the clipping circuit.
It is designed to be mild enough that even cabs with tweeters don't sound harsh - so instead of a real boost, it is more a device to flatten the low pass nature of the Blueberry a bit.
(source: The Man himself)
There are 4 knob pedals that do not have Futura written on them, and these are not Futuras.
The pedal I pictured above is from Joe's Pedals (a shop in the UK, check it out, it's great!).
It is a 3BOD Blueberry, but it has an additional treble control. If you turn the treble knob fully CCW, it is cut from the circuit and the pedal behaves just like a normal Blueberry. Turning it up results in a mild treble boost after the clipping circuit.
It is designed to be mild enough that even cabs with tweeters don't sound harsh - so instead of a real boost, it is more a device to flatten the low pass nature of the Blueberry a bit.
(source: The Man himself)