rotary encoder or potentiometer

[theladuke]

Noob questions...

How can i tell an encoder from a pot?  I have a guitar effects board (korg ax3), and wanna custom mount the pots/encoders in a custom case I'm making.  But they are mounted on a board, one with no threads, and the other w/ very short threads.  The plexiglass I'm using is  3mm thick, so i need to order 2 with longer threads.  One controls the effect selection, and has 11 detents, and the other controls the strength of the effects w/ no detents.  Both have a stop point.  Are they pots or encoders?  Also, I can't seem to find an encoder w/ 11 detents...does it matter?  Can I use one with no detents, and will it still select through the 11 options, or if i use one with lets say 30 detents will it work?  Also, I'd like to add a on/off moment button interrupt, too. What's the best location?  Logically, I just thought in line with one of the wires going towards the output.  And if I wanted to change the speed of the effects, can I just add a pot somewhere, and which one/where?  I ask because hooking the board up directly to my Behringer mixer through its fx input lets the unit function itself as a wicked tone/noise generator (while looking hot seeing the internals through plexiglass, and not a lame ass cheap pedal fx unit).  There are select buttons on it too, just simple push buttons to select through the various effects, also mounted directly on the board with little moment buttons, and I'm assuming I can replace them with off/on moment buttons that will instead be mounted through my plexiglass. 

Thanks!!!