The MXR Blue Box Octave Fuzz has been a unique and peculiar effect from its inception. The clean signal is taken and a two octave dropped square wave output is spewed out. You can control the blend with your guitar signal and volume of the effect with the two knobs – and that’s it. This effect is at its best with a strong line level signal or neck pickup, past the twelfth fret, for some really lo-fi bass lead sounds. The pedal is chaotic and wild and not one to be reigned in. It does not track chords or the high string very well and is known for its volume drop, even with the OUTPUT at 5 o’clock. So I tried to address these issues and make it even wilder.
This pedal is an original 1977 Script logo that came in for some upgrades. First, the pedal was true bypassed, indicating LED added, and a DC jack added. Then, I aimed to give the pedal a bit more of a volume boost. If you read about Blue Box mods, a common one is the ‘C11′ mod. This involves cutting the C11 capacitor off the board to give more of a boost at output. However each board is labelled differently so if you haven’t modded one before beware that the C11 does not apply to all Blue Boxes. This pedal didn’t even have markings for any capacitor but I was able to find a similar capacitor to bypass for the boost.
But finally, the owner of this Blue Box wanted it to be extreme so I went about finding some mods and circuit bends for a unique effect. This included a switch to select between one octave or two octaves down. The other small toggle on the face is a gated fuzz sound – an almost square wave tremolo that chops up the -2 octave drop. The top toggle is a big volume fuzz boost that bypasses the octave divider and provides a really nice fuzz sound that pushes the amp’s preamp for a great overdrive/fuzz sound.
If the pedal was wild before, I think it can now be called extreme…
Below is a demo from Dunlop showing the sounds of a stock Blue Box if you haven’t heard one before: