As well splitting a guitar input over three separate fuzz pots, the variable frequency control and resonance switch of Fairfield Circuitry’s new Four Eyes Crossover Fuzz pedal help make it one versatile fuzz box. It gives users more control over the tones produced, which range from the "extreme to relatively subtle; from super thin to ridiculously fat."

The product page of Fairfield Circuitry's website describes the Four Eyes Crossover Fuzz as having "three parallel JFET fuzz circuits driven by a voltage controlled state variable filter with resonance control, mu-amp input stage and quite possibly, a wedgie." Gizmag enlisted the help of its creator, Guillaume Fairfield, to explain exactly what that means.

"The way it works is quite simple when broken down into different parts," says Fairfield. The first stage is the input, where the mu-amp circuit is based on a "topology that was popularized by Jack Orman's work on the Minibooster." Although the circuit provides input enhancement in its own right, the Four Eyes sends it off to a state variable filter for some special treatment.

The signal is then split into three parts, each sent to its own filter - a band pass, low pass and high pass output. Each second order signal is centered around the same frequency which is "defined by the filter's resonant frequency which is, in this case, variable." The split signals are then fed through appropriately marked volume pots and sent to their respective single stage JFET fuzz circuits, biased to provide maximum asymmetry. Explaining the reasoning, Fairfield said: "What this allows for example is a very fuzzy sound in the low end while maintaining a sense of clarity in the highs, or vice versa."

Once through the fuzz circuits, the signal is recombined and sent for some final pitch or tonal frequency alterations at the hands of the user, the prominence of which in the overall sound is controlled by a resonance switch. The user also has the option of "external control over this center frequency by either expression pedal or any voltage source, such as a step sequencer or any other synth with voltage outs."

Much more than just a supercharged parametric EQ in front of a fuzz pedal, "the action of splitting and recombining coupled with the amount of distortion the signal endures creates phase relationships that are hard to predict." Fairfield sees the Four Eyes as being more than an effects pedal, "it reacts to what you do and you react in turn. It's not just an electronic effect being applied to this or that signal, it's an instrument."

Unlike most of the stomp boxes in my gig bag, the Four Eyes doesn't have a battery compartment. Fairfield told Gizmag: "it's a move many manufacturers are taking. All this effort into having our products lead-free, then throwing out all these toxic batteries in the course of the product's life kind of makes RoHS feel like a fool's errand."

The Four Eyes Crossover Fuzz effects pedal is currently at the pre-order stage with a July release date penciled in and carries a price tag of CA$225 (US$215), although early birds are being rewarded with a special introductory offer - see website for details.

The video demonstration below showcases the impressive range of user controlled tones offered by the Four Eyes: