The WL-20L model is functionally identical to the Boss WL-20, with the exception that it eliminates cable tone simulation. This makes it the best choice for instruments where cable capacitance has little or no effect on the tone, such as an acoustic/electric guitar with an onboard preamp, a guitar or bass with active pickups, or a line-level device like a keytar or Roland’s Aerophone digital wind instrument. The WL-20L also works great with passive pickups if you don’t need the subtle treble roll-off provided by cable tone simulation.
