KHDK Electronics, the effects company founded by Metallica guitarist Kirk Hammett and industry vet David Karon, has released the No. 1 Overdrive, which uses an original circuit based on a blend of op-amp and mosfet technology. It has two cascading Gain controls to; the first begins with a clean boost while the second shares a knob with the Bass control and acts as an active high-pass filter for the second stage, allowing the user to set the amount of bottom-end response. The pedal is hand-built in Kentucky.