T-Rex Octavius

The T-Rex Octavius, sold as the Octavius Tri-Tone Generator, is a polyphonic octave divider pedal from T-Rex. It produces an octave above and an octave below your guitar's signal while maintaining the original, giving you three voices at once: your dry note, one octave up and one octave down¹. T-Rex pitches it as a way to "triple your impact," and the maker describes its tone as warm and vintage sounding².

Because both generated octaves and the direct signal each get their own level control, the pedal works as anything from a subtle thickener to a full three-voice stack. Premier Guitar's reviewer found that mixing the three sounds creates "a wide assortment of big, fat doubling effects, and thicker-than-thou guitar lines"¹.

What the Octavius does

An octave divider, or octave and pitch pedal, generates new notes at fixed intervals from what you play rather than shifting pitch over time like a vibrato. The Octavius generates one octave up and one octave down from your input, and keeps your original signal in the mix¹. T-Rex calls the result a tri-tone generator: three tones from one note².

The feature T-Rex emphasizes most is tracking speed. The maker states the pedal "reacts on the spot" with no latency, on chords as well as single notes². That claim matters because many octave pedals, especially analog octave-down circuits, track only single notes cleanly and glitch when you play chords. Premier Guitar's 2010 review backed the maker up:

The reviewer found that chords and single notes alike sounded transparent, clean and bigger with the pedal engaged¹.

The controls: Lo Oct, High Oct, Master Mix and Boost

Four knobs and two footswitches run the whole pedal⁴. Each generated octave has its own volume control, and a master control sets how both sit against your dry signal.

The On/Off footswitch bypasses the effect; the second footswitch kicks in the Boost function⁴. Because Master Mix balances both generated octaves against the dry signal, you can run the octaves well underneath your original tone for thickening, or push them up front for a more obvious doubled sound².

Power and connections

The Octavius runs on external DC power only. Its connectors are an input jack, an output jack and a 9 to 12V DC power jack². T-Rex's specifications list a current draw of 150 mA at 9V DC². The pedal ships with a 12V DC, 1250 mA external supply that runs on 100/115/230V AC at 50 to 60 Hz depending on the country². Premier Guitar's review noted the same 12V supply and reported a 155 mA draw at 9V DC, slightly higher than the maker's current figure¹.

Other specifications from T-Rex: input impedance higher than 1M Ohm at 1 kHz, output impedance lower than 1K Ohm at 1 kHz, and a maximum input signal of 2,5V p-p². The 2010 press release listed a slightly higher maximum input of 2,7 Vp/p, so the two published figures differ⁴.

Where it came from

T-Rex Effects has been building pedals since 1996¹. The Octavius appeared in 2010: Premier Guitar covered it in a June 2010 press release alongside the Mudhoney II distortion, and the pedal was shown as new at the 2010 Summer NAMM show that August¹³. At launch it carried a US street price of $279¹.

T-Rex frames the pedal as its take on an unusual and powerful effect, one with a lineage the maker traces back to Jimi Hendrix and his innovative use of distortion, wah-wah, vibe and phase shifter pedals².

What reviewers said

Published coverage of the Octavius has been positive on its core function. Premier Guitar's 2010 review, part of a "Tone Games" roundup of ten stompboxes, found the tracking seamless and praised that chords stay usable with the effect on¹. The same review highlighted the mixing flexibility as the pedal's strength, from doubling effects to thick lead lines¹.

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