JEN Jumbo Fuzz

The JEN Jumbo Fuzz is a rare Italian fuzz pedal from the 1970s, built by JEN Elettronica as its take on the Electro-Harmonix Big Muff Pi. It swapped the Big Muff's knobs for sliders and added a germanium noise gate, and it has since become one of the more sought-after Muff-style pedals of its era. Delicious Audio's buying guide calls it "a rare Muff clone from the 70s, the JEN Jumbo Fuzz"¹.

A Big Muff circuit with sliders and a germanium noise gate

The Jumbo Fuzz is, at its core, a Big Muff. Premier Guitar's reviewer put it plainly: "The original JEN Jumbo Fuzz was essentially a Big Muff circuit with a few modifications, most notably a germanium noise gate"³. Kit Rae's history of Big Muff clones records that by the early 1970s "the Big Muff was being cloned by both minor and major manufacturers, including Jen, Sola Sound/Colorsound, and Ibanez"⁴.

What sets the Jumbo Fuzz apart from the pedal it copies is the gate. Kit Rae notes that some versions carry a germanium gate section: "The gate includes two Germanium transistors and two Germanium diodes"⁴. A noise gate silences the signal when you stop playing, which tames the hiss and hum a high-gain fuzz generates; the Sovtek Deluxe Big Muff Pi later offered a similar GATE control knob, described as a "Noise gate to eliminate high gain hiss noise or hum"⁵. For a player, the Jumbo Fuzz's gate means the fuzz stops dead between phrases instead of washing on underneath everything.

The voicing is not a straight Big Muff copy either. SolidGoldFX, which studied the original closely when designing a modern tribute, describes it this way⁶:

In other words, compared with the scooped, bass-heavy character some Big Muff versions have, the Jumbo Fuzz keeps more midrange, closer to the Ram's Head era of the Big Muff⁶.

Where it came from

Kit Rae dates the pedal to the mid-1970s: "I estimate this pedal was made circa 1973-75", with the place of manufacture listed as Pescara, Italy⁴. The maker, JEN Elettronica, was a substantial Italian manufacturer in its own right. As Delicious Audio's Paolo De Gregorio notes, "JEN Elettronica was an Italian manufacturer who made pedals for Vox, Dallas Arbiter and Sound City (among others)"². Other JEN-built fuzzes of the period include the Jen Fuzz FZ III and the JEN Double Sound.

The Jumbo Fuzz design also traveled under other names. Kit Rae's history records that Jen introduced the Jumbo Fuzz in 1973, "also rebranded as the Dallas Arbiter Jumbo Fuzz and Sam Ash Jumbo Fuzz/Fuzzola II"⁴. A related Italian branch of the family is the Colorsound Tone Bender Jumbo, about which TONEHOME observes: "The sound - as well as the circuit - reveals: this is more a Big Muff than a Tone Bender"⁷.

Knobs or sliders?

Sliders. Guitar.com's Cillian Breathnach describes the original as a pedal "which used sliders and voiced for a little more midrange a la the Ram's Head Muff"⁸. The slider format carried over to the modern tribute as well: Premier Guitar's announcement of the SolidGoldFX Imperial MkII notes that the Jumbo Fuzz "swapped the knobs out for sliders"⁶.

For comparison, other pedals in the extended Jumbo family went back to knobs. The Way Huge Smalls Swollen Pickle Jumbo Fuzz, whose name borrows the "Jumbo Fuzz" label, uses three knobs: a LOUDNESS knob that "sets output level", a SUSTAIN knob that "sets fuzz intensity", and a FILTER knob that "adjusts tone from mellow to bright", per Jim Dunlop's manual⁹. Pedal of the Day's guest review of the Swollen Pickle confirms "it features three knobs for loudness, filter and sustain"¹⁰.

Why vintage units differ

If you play or shop for an original Jumbo Fuzz, expect variation between units. The germanium gate is the reason. SolidGoldFX states that "vintage units vary greatly from one unit to another, with some gating too much and others not at all"⁶. Guitar.com adds that "time and component drift have rendered them slightly unstable"⁸. Germanium components drift with age, so two Jumbo Fuzzes bought on the same day can gate and respond differently decades later.

The Jumbo Fuzz today

The original is long out of production, and originals are scarce. Its design resurfaced in 2021 when SolidGoldFX released the Imperial MkII Fuzz, a pedal inspired by the JEN Jumbo Fuzz, with sliders, a redesigned silicon noise gate and a new Contour slider². Pedal of the Day's review of that pedal covers its JEN Jumbo Fuzz-inspired design, JFET preamp, silicon noise gate and Contour slider, and refers to "the Jumbo Fuzz's germanium transistor design"¹¹. For players drawn to the gated, mid-forward Muff sound of the original, the Imperial MkII is the modern route to it; for more on the effect type itself, see Fuzz Pedals.

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