Check the listing for details. MXR MC401 CAE Boost/Line Driver Effect Pedal. Condition: Open box. Listed at 111.87 USD. The Boost pedal cleans up nicely when you roll back your guitar volume, making it extremely responsive to picking dynamics—without thinning out your tone! High quality components provide quiet operation and trouble-free interaction with other pedals on your board. The Boost function has an adjustment from 0+20dB of clean uncolored gain boost. MXR and Custom Audio Electronics founder Bob Bradshaw—two names that have shaped the tones of the world’s greatest guitarists—join forces to bring you a dynamic line of pedals. The Boost/Overdrive and Boost pedals are the first offerings in the series produced by MXR, featuring the unique sonic stamp of legendary designer Bob Bradshaw. Since 1980, CAE’s innovative pedal designs were made in limited quantities only for his select clientele. When it was.