Yamaha DTXpress/DTXplorer/DTXtreme

Hi all,

Wanted to see if anybody has a suggestion for some sort of foot pedal 
volume control that would be placed between the output of the DTXpress 
brain, and the amp.  I think it would be helpful to be able to control 
the output of the brain going to the amp w/o having to do that by hand.

Will that work, and if so, is anybody doing something like that out 
there?  What are you using if so.

Thanks in advance!
Rolf in Colorado