Grounding clones. MXR Filter Question

[chicago_mike]

   Hey guys, the ggg and tonepad mxr clones dont have the pots grounded, should I ground them anyways?

Silly question I know...

[jefe]

I don't follow you... can you link to exactly which layouts you're referring to?

I just took a quick look at the Tonepad MXR Envelope Filter - is that the one? I just built one recently, and the pot wiring is just fine as shown, no need to ground them (?). Also not sure what what you mean by that...

[Mark Hammer]

Pots are a bit like wires hanging off the board.  In that sense, grounding the pot is like providing shielding.  Assuming that you built the circuit inside a metal chassis that the pots make viable contact with, and the chassis itself is connected to ground, there is no urgent need to make an additional connection between the pot (essentially the metal part that forms the back of the pot in most cases) and ground.

Is that the nature of your query?

[Boogdish]

I'm guessing that you are used to using pots as volume controls where there is an input lug, an output lug and one of the lugs is tied to ground.  That configuration is called a "voltage divider." 

The way the pots are configured in the MXR Filter is different, here they are being used as variable resistors, which only needs two of the lugs of the pot.  Don't connect the unused lug to ground, your circuit will not work, or at least won't work as intended.

[chicago_mike]

Gotcha!