Another secret to John Mayer’s sound can be found in his Keely Katana boost. The boost pedals helps keep the volume up during solos. With John Mayer mostly playing his own rhythm and solos, this pedal comes in handy, which is why it’s one of the pedals that shows up the most consistently on his pedalboard. This particular boost pedal is a Keely modification, known for getting the best out every pedal.
Keeley Katana Boost
See John Mayer’s pedalboard profile