Doepfer

Hi,

I want to build my own filter just for fun and have already red a lot about different filter topologies and poles and stuff. But I can't find any schematics about how to control the filter frequ just with one mono pot -- since you actually have to change the cut-off freq of each pole in a filter simultaneously, so you would need a stereo pot for e.g. a 2-pole and so on...

Guys, what is trick?
An example schematics would be great.

Olli