JACKSON AUDIO AMP MODE boosterThe Amp Mode Boost is a Mosfet transistor boost and is the exact same circuit that is found in our best selling Prism preamp, as that mode is many musicians' favorite. Mosfet transistors are very popular types of transistors to use for boost circuits because they have many amp like" characteristics when they clip. Several very popular Mosfet boost circuits on the market have a very noticeable crackle when their boost knobs are rotated. Jackson Audio