modding the taper of an Ernie Ball Jr. volume pedal

[mordechai]

I just saw a nice little video from Analogman where he fixed the taper of an Ernie Ball Jr. volume pedal to have a more usable sweep and to have an added buffer to keep the highs there.  I can figure out how to apply the buffer mod, but I'm curious about the taper mod.  He switched it via what looked like a SPDT toggle to show the "with" and "without" of the mod, so I'm guessing he just tacked on a resistor to the pot in the pedal.  Here's the vid:

https://www.youtube.com/watch?v=8myBogxiwmU

Anybody have an idea what value resistor might be involved in this?  I am assuming that the resistor would go between Lugs 1 and 2 of the pot...

[strungout]

I don't but if you have a pair of alligator clips and a few resistors of different values you could open it up and experiment!

[stallik]

Yup, experiment but I'd start with 1/4 to 1/2 the value of the pot and I think you'll hear a difference between placing it between lugs 1&2 or 2&3 so you might like to try both options.
Someone will chime in with a proper calculation but that's my tuppence worth

[YouAre]

To add to this, instead of clipping in a resistor, why not clip in a pot to make the tweaking process easier? Once you find a value you like, replace the pot with that value resistor.

To add to the fun....check this out.
http://www.guitar-mod.com/rg_diag_treble_bleed.html

If you're REALLY gonna dig into this, I'd graph the volume pedal output in excel. Easy enough to model the equation.

[Dimitree]

Reading here:
http://www.mk-guitar.com/2010/09/07/ernie-ball-volume-pedal-modification-to-make-the-taper-sweep-like-with-the-old-allen-bradley-poti/

I guess you need to change the taper from Log to Rev Log

[Dimitree]

Also, check this picture
https://reverb.com/item/562654-ernie-ball-vp-junior-25k-6181-volume-pedal-with-analog-man-pot-taper-mod/similar