Boomerang Hiss!

["Jonathan" <jonathan@kelloggcreek.com>]

    Hey everybody,
    I'm doing looping, primarily with a bass guitar, sometimes an electric 
guitar, using a Boomerang pedal.  When I do little gigs through a PA, the 
hiss usually isn't that bad; it's there, but I can work around it.  
However, 
when I run through the Boomerang into my bass rig, there is a LOT of hiss.
    I've tried everything I can think of, but I can't find a setting where 
the hiss isn't a big problem.  I don't have a "smiley face" EQ or a lot of 
trebble, and there's very little compression on my amp.
    I'd really like to incorperate looping into my shows with duo's and 
trio's, but that noise is just too much coming from a rig with that much 
power.  Any suggestions?
    Thanks!
    -Jonathan
    http://www.badspatula.com