if you want the real deal check out roger-mayer pedals. he was hendrix's amp and pedal guy.
here is a bunch of info on the evolution of the original from the man who invented it.
The OCTAVIA is probably our most famous and distinctive creation. This guitar effect was designed in early 1967 and featured on "Purple Haze" and "Fire" by Jimi. It's unique tones can also be heard on such tracks as "One Rainy Wish", "Little Miss Lover", "Little Wing", "Machine Gun" etc.
The OCTAVIA produces a sound that is an octave higher than the note you are presently playing. This doubling effect is accomplished through electronic mirror imaging techniques that are program sensitive and also respond to the feedforward inputs of the player. The electronic circuitry is analogue in design and will react faithfully to all the subtleties and harmonic overtones from the guitar. The effect produced is very unique but human in quality. The unit that is manufactured today is representative of the latest evolution of Octavia that Jimi used and contains the feedforward and gating effect that my earlier evolutions lacked. The modern clones today often copy the Tycobrahe unit that in fact was a rip off of my earlier 24 volt versions. These units were not designed to work optimally with 9 volts and in fact you would be buying a clone of a copy so it makes sense to buy a unit from the man who invented it.
Electronically the OCTAVIA is an analogue circuit with the properties of a frequency doubler, envelope generator and amplitude modulator with addition frequency shaping filter circuits. The effect produced is subtle to wild depending on the settings used and will respond to the attack of the player. A clean tone from the guitar with say the tone rolled control rolled off will produce "ring modulated" overtones that characterise the solo to "Who knows". The sound is tangibly different if a fuzz unit is in front of the Octavia: an upper octave double is created, clearly demonstrated in the solo to "Purple Haze". The bright harmonics are more controllable if the neck pickup is selected and the tone control set to roll off the treble. The effect really comes into it's own on the top E and B strings from the 7th fret up. A clean and precise picking style is essential with particular attention to accurate fretting techniques.
Jimi placed the Octavia after a fuzz and wah unit in most cases so it would react to the combined effects of both the wah and one or more fuzz boxes. It is important to experiment with how much signal you are driving the Octavia with as this has a great influence on the sound produced.
more on next post