The EXAR OC-04 Octavium is an incredibly versatile four-octave frequency multiplier and divider for guitar and bass.
It generates 3 signals; 1 octave above, and 1 and 2 octaves below the input signal using all analogue circuitry. It features independent volume/gain controls for each of the direct and synthesised signals, allowing any mix of the four octaves. Tone knobs for each of the 1 and 2 octaves below allow further fine tuning.
Being analogue, it tracks single notes best, and the range of the controls allow everything from a classic octave sound through to psychedelic 70's synth bass and octave fuzz sounds.
Controls
OCT+1: Adjusts the volume/gain of the signal one octave above the original
OCT-1: Adjusts the volume/gain of the signal one octave below the original
OCT-2: Adjusts the volume/gain of the signal two octaves below the original
DIRECT: Adjusts of the volume of the original signal
EXAR Effects 
