This effect has a unique name, you may not believe me, hahaha ... the name is Big John Obama Wah, this effect gives nice distortion and wah-filter additional control, 2 Separate certainly interesting effects in one box (Filter & Fixed Wah-Distortion)
The Big John Obama Wah is for any guitarist and bassist, who will take you on a fixed distortion and wah filter, Perfect for bass, guitar, or synth, the Big John Obama Wah has a filter that can be used on its own or in conjunction with the distortion. The distortion Gain control actually changes the voltage in the gain circuit to produce different levels of gain, but also different textures. The Big John Obama Wah is a truly unique effect built point-to-point by hand in Belgium.
and below is a video demo for the Big John Obama Wah