I was sniffing around on e(vil)bay and saw this. Obviously a distortion plus, but whats with the dual gang? Adjust volume and gain at the same time? Theres some jumper pads on the board, difficult to know what they do without seeing a project file...yeah was just curious about the function of that dual gang pot (and apparent lack of volume control)...
http://www.ebay.com.au/itm/Guitar-Distortion-Effect-Module-Board-1N270-Germanium-Soft-clipped-Distortion-/130896613869?pt=Guitar_Accessories&hash=item1e7a0bd1ed
Edit: Just saw this in the listing: NOTE: the module no Volume pot. and Distortion Enable/Disable switch.
Judging by the schematic, it's only using half of the pot. Looks like a Dist +/OD250. The different pad sizes on the drawing makes me think it's using the second gang pins for stability.
Bizarre... lol