The DOD FX35 Octoplus is a monophonic analog octave pedal, released in 1986, that DigiTech says delivered a thick, synth-like sub-octave below the original signal1. It sat in DOD's lineup through the late 1980s and early 1990s, and MusicRadar describes it as a pedal players have long coveted on the used market2.
What it does and how it is controlled
The Octoplus generates a sub-octave, a note one octave below what you play, and blends it with your dry signal. DigiTech describes the result as a thick, synth-like sub-octave below the original signal1. It is an analog design and monophonic, meaning it tracks single notes and simple lines rather than chords.
The front panel carries three knobs:
| Control | What it does |
|---|---|
| Octave Level | Sets the level of the sub-octave signal1 |
| Tone | Shapes the character of the octave voice1 |
| Direct Level | Sets the level of your dry signal1 |
DigiTech sums up the layout this way: "With only three knobs, Octave Level, Tone, and Direct Level, it was easy to dial in, yet its effect was anything but subtle"1.
Where it came from and where it lives on
The Octoplus is an '80s circuit. Guitar World calls it "DOD's revered '80's FX35 Octoplus sub-octave circuit"3. Although the pedal itself has not been made for some time, the circuit has had a second life: the octave section of the DOD and Morley Wah-ocTo-Fuzz pedal uses the DOD FX35 Octoplus circuit, producing what Bass Musician Magazine calls "a classic analog octave blend"4.
How it compares
MusicRadar's Jonathan Horsley wrote that the Octoplus circuit "wasn't a million miles away from something like the Boss OC-2"5, Boss's analog octave design that many modelers still base their octave effects on6. In other words, it belongs to the same family of analog sub-octave pedals rather than the modern polyphonic pitch shifters you will find among today's octave and pitch pedals.
Pairing it with other pedals
DigiTech notes that the Octoplus "worked especially well when paired with distortion or fuzz, creating a gnarly, growling sound"1. That makes it a natural companion to fuzz pedals and distortion pedals rather than a pedal that needs a clean path to work.
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Questions
Is the DOD FX35 Octoplus monophonic?
Yes. DigiTech describes the FX35 Octoplus, released in 1986, as a monophonic analog octave pedal. Like other analog octave designs of its era, it tracks single notes best, and DigiTech says it delivered a thick, synth-like sub-octave below the original signal.
What do the Octave Level, Tone and Direct Level knobs do?
The Octoplus has three knobs: Octave Level, Tone and Direct Level. Octave Level and Direct Level set the balance between the sub-octave signal and your clean signal, while Tone shapes the octave voice. DigiTech notes that with only three knobs it was easy to dial in, yet its effect was anything but subtle.
Is the Octoplus similar to the Boss OC-2?
MusicRadar's Jonathan Horsley wrote that the Octoplus circuit wasn't a million miles away from something like the Boss OC-2, Boss's classic analog octave pedal. Both are analog sub-octave designs rather than modern polyphonic pitch shifters.
Does the Octoplus work with fuzz or distortion?
Yes. DigiTech says the Octoplus worked especially well when paired with distortion or fuzz, creating a gnarly, growling sound. That makes it a natural partner for pedals like fuzz and distortion rather than something to keep clean.
Which other DOD pedal uses the Octoplus circuit?
The octave section of the DOD and Morley Wah-ocTo-Fuzz pedal uses the DOD FX35 Octoplus circuit, according to Premier Guitar and Bass Musician Magazine, producing what Bass Musician Magazine calls a classic analog octave blend.
Sources (6)
- Vintage Product Spotlight: DOD FX35 Octoplus, DigiTech, 2025-06-12
- DOD x Morley Wah-OcTo-Fuzz review, musicradar.com, 2026-07-24
- DOD and Morley unveil triple threat Wah-ocTo-Fuzz pedal, Guitar World, 2026-05-27
- Gear News: DOD and Morley Unite to Drop the New Wah-ocTo-Fuzz Pedal, Bass Musician Magazine, 2026-05-30
- Morley and DOD team up for 3-in-1 wah, fuzz and octave pedal, MusicRadar, 2026-05-28
- Octaves stompboxes, HeadRush (revalver.headrushfx.com), 2026
