Sharing a controller pedal between 2 devices?

[David Trenkel <improv@peak.org>]

Not quite on topic, but since this list has the highest concentration 
of smart gear geeks I know, I figured I'd ask before trying (and maybe 
frying).

I have a Roland EV-5 continuous controller pedal that I'd like to use 
to control 2 devices, a Moogerfooger filter pedal and a Line 6 DL4. It 
works with either individually. Can I share it between both with a 
headphone splitter Y cable? The only problem I can think of is that one 
of the wires is carrying a voltage from the device to the pedal, if the 
output voltage is the same from both devices, I can clip one wire so 
only one device is sending to the pedal. I almost never use both 
devices together, and really only want to control one patch on the DL4. 
Am I being completely stupid here?