OC2

• The Boss OC2, know as the Octave, is the original octave pedal that allowed guitarists to play three notes simultaneously. The OC2 is capable of playing the original note, one octave below it or two octaves below the original note. There are individual controls for each note other than the original, so you can choose between the two options. The OC2 is made of metal and sturdy enough for use on the stage as well as in the studio. True bypass prevents the pedal itself from adding any noise to your signal when the effect is turned off.
  
  

OC3

• The Boss OC3 Super Octave pedal is a more advanced version of the OC2 Octave pedal. Not only does it have the individual controls for the two octaves, but it also adds the versatility of distorting the octave played as well as individual inputs for each type of instrument, guitar or bass guitar. The Polyphonic mode adds the ability to play chords and to have the octaves present as well as the option of distortion on the first octave. The updated OC3 has better tracking capabilities than the OC2 and is useful for guitar or bass guitar.
  
  

Differences

• The OC3 Super Octave adds a few key features that make it more versatile than the OC2 Octave pedal. There are separate inputs on the OC3 tailored for the frequency range of the instrument itself whereas the OC2 has one input that can handle either a guitar or a bass guitar. You can adjust the amount of distortion placed on the octave as well as the amount of signal sent through while in "Poly" mode for chords.
  
  

Similarites

• Both the OC2 and OC3 are brown, which is an easy way to identify the pedals as being octaves. They are made of the same type of material and offer true bypass so that the pedal causes no ill-effects when added to the signal chain. Each pedal has a five-year warranty as well, backed by Boss against malfunctions and defects. Both the OC2 and OC3 have one knob to set the level of the original note as well as both octaves, but the OC3 octave knob has multiple functions.