Why do these have a volume in/out in addition to just the TRS Exp jack ? Will they work at a traditional volume pedal as well ?
Is this a ground up design or what it from a commercially produced housing, maybe with a custom spec pot and Fractal branding ?
They also work as a traditional volume pedal. There are two ganged pots inside, one is a high-impedance log-taper volume pot and the other is a low-impedance linear-taper expression pot. The design is our own.