Rainger FX Dr. Freakenstein Chop Fuzzz

The Rainger FX Dr. Freakenstein Chop Fuzzz (with three zs) belongs to a family of appropriately monstrous fuzz devices built by London-based mad pedal scientist David Rainger.

One of those was the Chop Fuzz with just two zs,  the predecessor of the Chop Fuzzz, which is a rather deep, still fully analog redesign of the original gated fuzz with modulation design, featuring a new two-speed system with separate LFO speed knobs, and an extra footswitch to toggle between the two. It also features a “tunable drone facility” – capable of ring modulator tones – and a noise gate.

The two aforementioned speeds are applied to the Overtone effect, which controls the range of an extreme phaser that, combined with the fuzz, produces a very cool pulsating sound. Extra modulation can be applied via the Chop knob, which controls the speed of a square tremolo. Both effects can be turned off via a dedicated push button.

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Rainger FX Dr. Freakenstein Chop Fuzzz, Builder’s Notes

The Chop Fuzzz is an uncompromising all analog, full-on gated fuzz pedal – with a whole bunch of interesting ways of manipulating the signal.

It’s the latest instalment in the Dr Freakenstein dynasty!!!

As well as fuzz, it has two types of modulation, a pressure-operated expression pedal (to do wah wah-like effects), a tunable drone facility – capable of ring modulator tones – and a noise gate; it’s actually a very specific kind of multi-effects pedal.


The fuzz circuit is the same massive distortion one used in the original Dr Freakenstein Fuzz (plus the three versions that followed, and the first Dr Freakenstein Chop Fuzz, and the six minipedal versions). It’s incredibly loud, with a ton of low-end, and searing highs available.

Yet it’s weirdly quiet when you’re not playing.

The ‘OVERTONE’ control

This is like a wah wah with the tone of an extreme phaser. Set it using the knob, or manipulate it in real time by foot with our Igor pressure pad controller (supplied).

The ‘LFO’ section

This modulates the signal in a slightly more ‘3D’ way than the ‘overtone’ sound. Moving in a triangle waveshape, the speed can be set using two knobs. ‘Slow’ has a low speed range – for long, slowly-twisting cycles right up to fast wobbles, while the second one – ‘fast’ – is in the audio range; tune it in to a specific pitch (across several octaves) underneath the notes or chords that you’re playing.

Toggle between these two on-the-fly with the footswitch.


The Chop Fuzzz has a hard squarewave tremolo built-in. When locked-on, in combination with the ‘LFO’ section it can create all kinds of slowly sweeping helicopter effects, or fast, bubbling synthy-sounds.

Or flash it on and off at specific points for a chop accent using the Igor controller.

What else?

  • It has a ‘Hi/Lo’ intensity switch.
  • It can be controlled using 5v CV by sequencer or modular synth.
  • There’s a spooky ‘eye meter’, showing the input signal level, but also – using backlight illumination – the LFO and ‘Chop’ operation and Hi/Lo setting.
  • The LFO and Chop switches light up – for extra clarity and LED thrillpower!
  • Both the desk-style enclosure and the knobs are custom Rainger FX designs.
  • The pedal is true bypass.
  • The Chop Fuzzz is easily the most advanced Dr Freakenstein pedal we’ve produced.
  • An extreme pedal for extreme sounds.