by Jef | Approximate reading time: 2 Minutes
MXR Poly Blue Octave

MXR Poly Blue Octave  ·  Source: Jim Dunlop


The new MXR M306 Poly Blue Octave pedal takes their Blue Box pedal, and makes the circuit way more versatile. Now you can mix in fuzz and octave effects. It even has a polyphonic or mono switch, making it a significant update to the original circuit, often associated with Jimmy Page.


MXR Blue Box

The original MXR Blue Box, as used by Jimmy Page on Led Zeppelin track Fool in the Rain, is a very peculiar pedal. It achieves a fuzzed out monophonic octave effect. I really like the original and use mine for odd effects now and again. But it sure is an oddball effect. The recent Way Huge Atreides Weirding Module reminds me of the Blue Box on steroids, and made my Top 10 Effects of 2021.

MXR Poly Blue Octave

Now, MXR has taken the effect and added more control, and a polyphonic mode and dedicated fuzz switch. You now have access to four separate octave divisions, with their own level controls; Sub-1, Sub-2, Oct+1 and Oct+2 knobs. The M306 Poly Blue Octave also has dedicated mini push switches for both fuzz and mono, plus controls for Modulation and Dry.

MXR Poly Blue Octave

MXR Poly Blue Octave · Source: Jim Dunlop

Phase 90-esque tones

When used in monophonic mode, it provides swirls and swooshes that MXR says were inspired by the Phase 90, another added option that the original Blue Box circuit didn’t have. You can also use an expression pedal to control various parameters, and a dual-mode modulation effect that gets you in the realm of Leslie/Phase 90-style effects, depending on which pitch-shifting mode you have selected.


No Fool

It runs from an external power supply only, so no option to use a battery with this new edition of the effect. I think it is definitely one to check out this year, and looks like a lot of fun. Premier Guitar has already had one to demo. You can check it out below to hear this new little blue box in action.

RRP – USD 199

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MXR Poly Blue Octave Video

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MXR Poly Blue Octave

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2 responses to “MXR Poly Blue Octave: An updated Blue Box for the modern guitarist”

    Brian says:

    Pre ordered one super stoked on the features. Very dissapointed. Just digital noise and hash. No usable tones. I was excited for the feature set as I often use modulation fuzz and octave down from separate units. Thought this would replace the three…not even by along shot. Even just the supposed straight tone sounds like hash. Bummer….but mxr is dunlop and dunlop kinda sucks

    Rog says:

    And back to earth. A completely brilliant pedal and execution. Comparing to the Boss OC5 it only loses range control. Otherwise it destroys the OC5. With the expression pedal I have it like an OC5 in the up position then suddenly switch to adding the +2 and -2 Octaves for a huge symphonic sound. With my ES8 switcher I have it either in front of amp or after preamp. Both are fantastic. Shame you can’t set up more presets because there’s plenty of great sounds in there. Maybe a large box version will follow?

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