A/B Volume (Mix) Selector

[Goga]

Hello people,

I have been thinking about a gadget that I have seen on Scot Henderson's pedalboard.
It was a Volume control knob that he turned clockwise and anticlockwise selecting and
controlling the Volume of the two lines that he had, connected into two amps.
In the first Marshall amp he had a dry signal without the effects in the chain.
In the second Fender amp he had chained some effects reverb, octaves etc.  
When the pott was in the middle position he had the same amount of signal passing
to both amps, clock wise or anticlockwise more of the one or the other (you get the picture)
His pedal (controller) was made by Sure.

Can you please tell me how to build one or suggest a product that is similar for this purpose.

Thanks
Gogo  

[Travis]

I haven't tried this myself so I don't have a specific schematic to recommend, but if you google "stereo panner schematic" there are lots of options

[Pavlos]

If I remember correctly, one of the Pearl Jam guitarists used (And possibly still does) to do something similar to this with a modified volume pedal to sweep between a driven and clean amp.