Voodoo Lab

Hi,
I plugged my passive Dunlop vol pedal (with a 250k pot) into the pedal #1 input of my orig Ground Control..and I put pedal #1 on and I went to set my limit.....it accepts the min just fine...but only sees about half of my vol pedals travel. After about half it says "no good" or some similar message. I have tried this numerous times, and now I am turning to you guys. Whats going on?
Its the right pedal (I checked with DigMusic corp) before buying...it is a good cable..iit is a mono guitar cable...t is hooked up to the OUT of the vol pedal...
I dont get it. Any help appreciatted.
GtrGeorge
myspace.com/georgebarrysolo

It appears that the Input jack on the Dunlop volume pedal is a switching/normaling jack that likely shunts the tip to ground when nothing is plugged in to it. The solution here is to put an open dummy plug into the Input jack to make the pedal function as an expression pedal with the original Ground Control.