Using old volume pedal as expression pedal Univibe AND volume control

[Michael2]

Hi all,

With succes I have build a forum vibe univibe. Now that it is completed I was thinking of putting this inside an old volume pedal enclosure to control the speed with my foot. And then I was thinking of combining this with a volume functionality when I'm not using the univibe setting. I do not need a true bypass on/off setting, cancel is just fine (I like the sound of the unive coming up when the cancel switch is off). I have a 3pdt that I use to cancel the univibe. Another set of lugs is being used to switch a led. That leaves 1 set of lugs available for a bypass routing to a buffer and a variable resistor to control volume (at least that is what I wish). The speed pot is a c100k stereo pot and with some effort I know I will manage to fit it in. But then there will be no space left for a 3d potentiometer (for volume). I played with the idea to make an optical volume control but the layout of the pedal does not makes it very suitable. To make a long story short:

Is it possible to use one of the c100k pots also to function as a volume control if the speed function of the univibe is not in use? I think it will be fine regarding wiper and one of the resistive tracks since the connection will shortcut when not in use? But for volume I think I need to ground lug 3 on the pot but for the speed control I guess that lug should not be grounded?

Can I:
- try it out without damaging the univibe?
- if the ground connection needs to be shorted would a 4pdt be the way to go?
- if this hole idea will not work, is there a better way, a workaround or other idea (beside an optical volume setup)?

Thanks and sorry for the long story, I don't know how to explain my question in a more simple way, English is not my native speech and I'm still learning.