Blackbox Ultraviolet


  • Low Freq
  • Mid Freq
  • Hi Freq
  • Volume
  • Mix
  • Fuzz


Blackbox Music Electronics (2001)

The Ultraviolet is a dual channel fuzz with an active filter section. From warm, tube-like distortion to in-your-face wall of sound fuzz, the Ultraviolet features an enormous amount of window rattling low end and unreal sustain. Think of it as two parallel fuzz units plus a wide band active filter. The Ultraviolet boosts your guitar signal, routes it through two separate fuzz channels (each voiced differently to affect different portions of the frequency spectrum); then mixes them together in varying ratios before sending them through a low pass active filter. The assorted control knobs allow for a highly tweakable sound allowing you to get a wide range of tones from warm distortion to creating a very thick synth-like sound to "my amp is about to explode" sounds. The Ultraviolet also creates some really cool evolving harmonic structures at high gain settings.


  • Gain - Controls the amount of gain/boost before the signal is split and sent into the dual fuzz channels. The Gain control has a big impact on the density of the sound. If you have a guitar w/ really hot or active pickups, you may want to roll off some of the gain. Alternately, if you have really weak single coil pickups, you may need to increase the gain.
  • Volume - Controls the effect output volume
  • Fuzz Channel 1 Volume (Fuzz 1) - Controls the volume/mix of the first fuzz channel (voiced for lower frequencies)
  • Fuzz Channel 2 Volume (Fuzz 2) - Controls the volume/mix of the second fuzz channel (voiced for higher frequencies)
  • Filter - Controls the frequency cutoff of the active low pass filter section
  • Boost Switch - Engages/disengages the gain boost. Boosts your signal by approximately 30db! Turn your amp down to set the desired level before engaging the boost as it can blow out your speakers! Roll back the gain knob or volume if needed.
  • Bypass - True bypass switch. Engages/disengages the effect.

The following suggestions will vary depending on what kind of pickups your instrument has. These should be fairly accurate for the major guitar brands:

  • For milder warm fuzz/distortion: Turn the gain knob down to about 1/4-1/3 of the way up (about 10:00), boost disengaged.
  • For lots of low end: Turn the gain knob all the way up, fuzz channel 1 all the way up, fuzz channel 2 about 1:00, filter at about 2:00 and boost disengaged.
  • For lots of high end: Turn the gain knob all the way up, fuzz channel 1 at about 1:00, fuzz channel 2 all the way up, filter all the way up and boost disengaged.
  • To wake up the entire neighborhood: Turn everything all the way up and kick on the boost!

At high gain settings, it may be desireable to roll off some of the high end using the filter knob (tweak to taste). For some cool analog synth like sounds, turn both fuzz channels up, roll off a little bit of high end using the filter knob and add in a little chorus and/or reverb to fatten up the sound even more! The combination of both fuzz channel volume controls, gain and filter controls all affect the frequency response of this pedal.

Experimentation with your Ultraviolet is key! It may take you a while to figure out what sounds good with your particular rig but the results are well worth it!

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