Output level/volume control for pedals

[MoruyaGuitarist]

Hi All,
Just a silly question which I'm sure has been asked before - What's the best config for an output level / volume control for a pedal ?
You want the output to be low impedance. When I look up a lot of schematics quite often after Potentiometer to control volume it is followed by some sort of buffer. But some pedals do have a pot on the output. Just to diverge a little, can anyone tell me why with EMG pickups they insist on using 25k volume and tone pots ?
Understand the difference between passive and active but still seen plenty of pedal schematics with 100k pots or more on the output....

[duck_arse]

Moruya - are you test posting, or would you like this moved to the general area?

[MoruyaGuitarist]

Ah sorry, was probably trying to post is under "Misc", I don't know what topic it fits under.........

[MoruyaGuitarist]

Hi All,
Just a silly question which I'm sure has been asked before - What's the best config for an output level / volume control for a pedal ?
You want the output to be low impedance. When I look up a lot of schematics quite often after the Potentiometer to control volume it is followed by some sort of buffer. But some pedals do have a pot on the output, for example the OCD uses a 500k pot on the output.

Just to diverge a little, can anyone tell me why with EMG pickups they insist on using 25k volume and tone pots ?
Understand the difference between passive and active pickups but still seen plenty of pedal schematics with 100k pots or more on the output. (OCD with 500k)

cheers

[FiveseveN]

for example the OCD uses a 500k pot on the output.

Yeah, that's terrible and people often complain about the issues it causes.
A buffer after the pot (or an active volume control) is indeed the best choice.

Active EMGs can drive lower impedance pots, and you'd want the lowest value practical, to preserve the advantages of a low Z source when actually using the volume pot (not just when it's full or muted). But you have to balance that with what load the op amp is happy with (see the datasheet), and the 10K that's already there: https://www.electrosmash.com/emg81

[bluebunny]

You cross-posted.  I merged.  Let's keep this in one place to avoid brain-melt. 

[merlinb]

A buffer is ideal, but failing that you use the lowest-value pot you can get away with. A 20k-or-less pot is not terrible. 500k is awful.