1981 MXR Distortion +

Designed in the early '70s, the MXR Distortion + is an incredibly simple—yet highly effective—distortion pedal. Although the name might suggest otherwise, the Distortion + has a relatively mild sound. When used with high-output pickups and a cranked tube amp, it can dive deep into heavy metal territory, but the smooth, subtle tones it produces at lower gain settings attracted a wide variety of guitarists outside of the metal scene.  The Distortion + uses a single op-amp and two germanium diodes for clipping. Its an incredibly simple pedal that originally ran only off of a 9V battery, and until the 1981 iteration, it didn't even have an LED to let you know it was activated. Just two controls: volume and distortion. Famously, the treble content increases subtly as you increase the distortion knob.  The MXR Distortion + has been copied numerous times (most famously by DOD as the 250 Overdrive/Preamp), and the versatile clipped tones it produces are heard on a wide variety of recordings. I