Early version EP3 with volume control question

[Meomy]

I'm using the layout below and am about to throw this in a box to test it out, but wanted to know if lug 3 of the volume pot be connected to any thing? If not i'd love to learn why. My first inclination as a newbie would be to connect it to ground.

[AC_FX]

I don't think it will make any difference the way this pot is being used.

[induction]

That's correct. This pot is used as a variable resistor, leaving Lug 3 is uncommitted. Connecting the uncommitted lug of a variable resistor to the wiper (lug 2) is standard practice. In this case, the wiper is tied to ground, so connecting lug 3 to ground is good practice.

Note that ground is not special here, it's just what lug 2 happens to be connected to. Don't assume that you can connect unused pot lugs to ground in general. Connect them to the wiper, not to ground.

[alex.s]

Indeed, while in this case it does eventually go to ground anyway, you don't want to be grounding any unused lugs when having pots as variable resistors as you might be grounding parts of the circuit that shouldn't be going to ground.

Also as a rule of thumb you want to stick with the indicated value when using pots as variable resistors more so than when they are voltage dividers, as the maximum resistance obtainable is likely to be a desired one.

An non pot-related question about the EP3 while I'm at it: does it offer some volume boost when cranked or not much? Would it be offering the 11dB claimed by Dunlop for their EP3 pedal or is it a different circuit/design altogether?

[Meomy]

Thanks for your help.
I boxed this one up last night (my first 1590A) and it sounds pretty good. I believe there is a little bit of boost, but couldn't say exactly how much. The first 2N5457 i put in it had me slightly below unity, then i switched it with another one i had and now its got a little bit of volume boost to it.

[alex.s]

It might be worth trying a J201 in place of the 2N5457 if you want more volume out it as I've read they can give out more output (but possibly more grit, too)... Unless I'm mixing things up and it's the other way round (2N5457 louder than J201), that it...!