The Defects FX Dirty Filter is a very tweakable, limited edition resonant fuzz + filter (in that order) hailing from Prague, where it’s lovingly hand-built.

Each effect has its separate footswitch, but the filter gets the lion’s share of the controls, with knobs for Frequency, Filter Type (bypass, low-pass and hi-pass), Resonance, and Filter Output, plus a toggle switch giving you two resonance levels: Normal and High, for a more intensely synthy effect.

The fuzz has an output knob and an Intensity toggle switch that changes its character and dynamics.

This looks and sounds like a cool creative pedal, we added it to our article about the best filter pedals. Check out the demo below.

Defects FX Dirty Filter, Builder’s Notes

This is Dirty Filter. Fuzz and active fiter. Limited Edition of 10 pieces.

It`s a most variable pedal in my production. Inovated Fuzz circuit with intensity switch.

It allows you to set really unobvious fuzzes. Resurrection of naturaly decaying sound that you never heard before. In connection of very variable active filter. It makes this pedal most variable fuzz on market. You can get really insane sounds from this pedal. Both effects can be used indepedently. Fuzz circuit is before active filter circuit.


  • Fuzz footswitch : It activates fuzz section. It switches as true bypass.
  • Intesity toggle switch : It switch intensity and character of fuzz.
  • Filter footswitch : It changes frequency range of pedal.
  • Fuzz output : It`s a classic master volume on fuzz section.
  • Dirty Filter footswitch : It activates filter section. It switches as true bypass.
  • Filter selector : It changes between low pass, band pass, high pass filter.
  • Filter freq : It sets cutoff frequency of the filter.
  • Filter resonance : It sets a resonance of the filter.
  • Filter resonance toggle switch: It changes a resonance of filter resonance knob
  • Filter output : It`s a classic master volume on filer section.
  • EXP / CV input : You can plug CV control (0-3.0v) or expression pedal for external
  • control of Filter freq knob


  • Dimensions : 12.0 x 14.5 x 5.6 cm
  • Weight : 554 g
  • Power : 9V DC center negative adaptor
  • Current Draw : 25 mA
  • Pedal is handwired and handrilled from the standard boutique quality parts.
  • Alpha pots and true bypass switch
  • Professionally printed faceplate
  • Professionally made pcb board
  • Powering by standard center negative 9V DC adaptor only