Wow, missed this one last month! There's nothing at all stopping you from experimenting in this way, but you won't know if you'll like the sound until you try.
After checking with my dad, he thinks you'll probably want to put an attenuator on the output of the preamp that's in the effects return so you don't get a volume shift when you switch between settings.
(Message edited by mica on December 29, 2005)