Problem with pots (current?).

I am having trouble interfacing certain pots with my arduino. I am trying to build a pedalboard for musical performance. I am planning on using hacked volume pedals as voltage dividers,a nd encoding the voltage to send control info to pure data. The problem is: when I attach the pedals, the board crashes. I know this has something to do with current consumption. I should mention that the board works fine with standard pots. How do I remedy the situation, and/or figure out how much current I need in terms of an external PS?

I know this has something to do with current consumption

No it looks like you are shorting something out. Just connecting a pot should not crash the machine. I think you are wiring it up wrong. Try checking it with a meter.