DISTORTION PEDAL New version of the AT that has a pedal-controllable Boost control that basically works as a second channel. The volume control controls the output of the effect, the EQ setting is like a filter to achieve a darker or brighter tone, the Air setting behaves in a similar way but focuses more on the extreme highs to suit most environments. amplifiers, and the Drive adjusts the amount of distortion or gain you need. 3-position Headroom switch that reproduces different powers of a tube amp: The 100W position is clean, with a lot of volume and power. The 50W position offers a crunch with a lot of frequency response, like a British gain stage from the JCM800. The 25W position generates distortion with rich harmonics, lots of mids and a very cutting presence.