TheGigRig UnderLiner has been designed to sit in your amps effects loop and give you 2 extra master volume controls enabling you to set 2 different attenuated rhythm levels and then use the bypass setting as your boost.
UnderLiner also features an active loop enabling you to integrate effects in your amps effects loop with no tone loss from long cable runs.
Switch between your settings with the included UnderLiner FS Footswitch which will also provide power to the UnderLiner sitting back at your amp.