so... I had a Tech 21 Sansamp... nice device- but more than I needed.... so I just picked up a Markbass Super Booster... nice! I play thru a Markbass rig- so I wondered if the 'filters' woul be somewhat redundant- but they are not. I really just wanted an occasional volume boost... now have that + a nice tone change option (seperate) button! happy now 
