Ringmods, where can I find information?

[WyldeSnake]

I'm tryin to figure out how to make (and customize) a ringmod, but I'm having a REALLY hard time finding info.  Does anyone have any links to either schematics or theory on how a ringmod operates?

[Zero the hero]

I suppose Colin in his forum had a topic about ring modulators: it was well explained. http://experimentalistsanonymous.com/board/
On GGG there's a complete project for maestro ring mod.
TOmboy posted a schematic of a AD633 based ring mod.