Yeah, I am using a passive L-Pad type control to drive my amps. It uses a 4 section linear 600 ohm pot. I also have a -20 db pad in front of the control so that I can have 2 ranges. (the left right balance is more than a db off on the botthom quarter of the pot) Here is a schematic on the web if you are interested:
http://www.gyraf.dk/schematics/bridge-attenuator.gif