Tube overdrive / VCA with built-in filtered feedback path.

• Miniature vacuum tube
• IN/OVERDRIVE : drive the tube (white pot)
• FEEDBACK : reinjection level
• FB COLOR : low pass filter for feedback path
• GAIN CV : tube gain control
• FEEDBACK : second signal input. Output of the filter (color) is normalled to this input. This allow to bypass the filter in the feedback loop.

https://www.atonal.be/tube-overdrive/