Pot Value/Taper for Passive Volume Pedal?

CyrusF

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I've been looking around at volume pedals, and thinking about DIYing a compact one for my board before I commit all that space to a full-sized unit, but I'm not sure where to begin for pot values. I want it to be low-z, to go after my drive pedals, before my time based stuff. Has anybody messed with something like this before? Any help is appreciated!
 

Ziggy587

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I haven't done this for a volume pedal specifically, but I've experimented with adding pots for mods on other effect pedals. You definitely want audio taper. Unless you're planning to true bypass it with a switch, you may consider using a no-load pot. As for the value, my guess would be to start with 500 k. I would grab a few different values and see which one I like better, then go with that one.
 

CyrusF

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I haven't done this for a volume pedal specifically, but I've experimented with adding pots for mods on other effect pedals. You definitely want audio taper. Unless you're planning to true bypass it with a switch, you may consider using a no-load pot. As for the value, my guess would be to start with 500 k. I would grab a few different values and see which one I like better, then go with that one.
That makes sense! Hopefully I'll have a chance to pick up some parts, or else scavenge what I have lying around to try something soon. Thanks for the info!
 

mictester

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If you're going the lower impedance route - after your dirt pedals - you probably want to go down to 50kΩ or even as low as 10 kΩ. I've found that most pedal mechanisms don't achieve full rotation of the pot, so you're going to get some amount of loss. Logarithmic is almost right with most mechanisms, but I found that an exponential taper gave better results. This can be achieved with a linear pot and a couple of tapering resistors - see "The Secret Life Of Pots" to find out how to get the curve you want.

There will almost certainly be some amount of loss through your volume pedal, so you will probably want to put a small amount of amplification after the control, to compensate - a simple, clean op-amp stage will give you the little bit of level that you need to recover, and won't alter the tone in any way. That way you'll be able to fully bypass the pedal without any jump in level!
 




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