One Knob, Two Positions, One of the Greatest Chorus Sounds in Rock History

There is a chorus pedal that shaped the sound of a generation, and it is defiantly simple. The Electro-Harmonix Small Clone offers exactly one rotary control, a two-position depth toggle, and a single LED. No stereo outputs. No tap tempo. No expression jack. What it does have is a bucket-brigade circuit that produces an organic, swimming, slightly warm shimmer that became the definitive analog chorus sound the moment Kurt Cobain switched it on for the opening bars of “Come as You Are.”

That association has been both the Small Clone’s greatest commercial asset and a subtle limitation of how players think about it. The pedal is far older than Nirvana — designed in 1979 when Electro-Harmonix was still a New York City scrappy operation challenging the dominance of Boss and MXR — and its sonic fingerprints appear across genres that have nothing to do with grunge. But Cobain’s use of it on Nevermind burned the Small Clone into collective guitar memory in a way that few pieces of gear have ever managed, and it has remained in continuous production (with one dormancy period in the 1980s) ever since.

This is the complete guide to the EHX Small Clone: where it came from, how its circuit works, who actually used it and on what recordings, how to dial in its best sounds, and how to choose between the vintage original, the modern reissue, and the family of stripped-down alternatives EHX sells today.

From New York City Basements to the Bucket-Brigade Revolution

Electro-Harmonix launched the Small Clone in 1979, at the tail end of the first wave of BBD-based chorus pedals. Bucket-brigade device technology — cascaded capacitors and transistors that pass an audio signal in discrete increments, creating a delayed version of the input — had been commercially viable since the mid-1970s, and EHX had already built its reputation on the Big Muff Pi and the Memory Man delay. The Small Clone applied the same BBD principles to a strictly chorusing application.

The original circuit used one of two BBD chips depending on production date and availability: the Reticon SAD1024 (a 1024-stage device from a California semiconductor company) or the Panasonic MN3007 (a Japanese-made chip that became the more common of the two). From 1979 through approximately early 1981, units could contain either chip. The EHX forum moderator known as “The EH Man” has documented that there is genuinely no reliable rule about which chip appeared in which unit — even serial numbers close together sometimes differ. After early 1981, the MN3007 became standard.

Both chips produce lush chorus, but collectors and tone obsessives assign particular reverence to the SAD1024 units — primarily because those were the variants Kurt Cobain is documented to have used on Nevermind and the subsequent touring cycle. The sonic difference is subtle: the SAD1024 units are often described as slightly more “watery” with a small inherent signal boost, while the MN3007 allows higher signal levels with somewhat less noise. Neither is objectively better; the preference comes down to whether you want the specific shimmery quality of Cobain’s sound or simply great chorus.

The original production run ended in 1983 when Electro-Harmonix fell into bankruptcy. Mike Matthews relocated to Russia for a period, and EHX went dormant as a commercial operation. When Matthews relaunched the company in the early 1990s — aided partly by a distribution deal with Sovtek that had kept him connected to the music industry — the Small Clone was among the first pedals to be reissued, and it has stayed in the catalog ever since.

The reissue uses the MN3007 and introduced one important circuit change: true bypass via a 3PDT footswitch, replacing the FET switch of the vintage units. The vintage units were not true bypass — the signal passed through the circuit even when the effect was off — which meant the preamp stage contributed a subtle coloration to the dry tone at all times. Whether this is a feature or a bug depends on your signal chain philosophy.

How the Circuit Works

The Small Clone is a single-voice analog chorus built around a BBD delay line modulated by a low-frequency oscillator (LFO). The incoming signal is split: one path runs clean to the output, and the other path enters the BBD, which stores it briefly and releases it slightly delayed. The delay time is not fixed — it is continuously varied by the LFO at a rate controlled by the Rate knob. When the delayed signal is mixed back with the dry signal, the constant pitch-shift created by the changing delay time produces the characteristic chorus shimmer.

The Depth switch controls the modulation depth: in the “Mini-Chorus” or shallow position, the LFO swings the delay time across a narrower range, producing a subtler, more restrained chorus. In the “Full Chorus” position, the depth increases and the wobble becomes more pronounced and immersive. At very slow Rate settings with Full depth engaged, the pedal moves into vibrato territory — the pitch fluctuation becomes perceptible as a gentle wow rather than a pure shimmer.

The Rate knob spans from very slow (lush, almost imperceptible movement at one extreme) to quite fast (a distinctive tremolo-adjacent warble at the other). Cobain famously ran the Rate quite slow and the Depth on Full — the result is the watery, floating quality of “Come as You Are” rather than the faster, denser chorus associated with 1980s pop guitar.

One important circuit characteristic: the MN3007 chip’s natural high-frequency rolloff slightly darkens the repeats compared to digital chorus units, giving the Small Clone its warm, organic quality. There is no hardness or crystalline precision. The chorus blooms rather than clicks, and this is exactly what separates it from the cleaner Boss CE-2 (rank 654) or later digital chorus designs.

Specifications

Famous Players: Confirmed, Honest, and Caveated

Kurt Cobain — The Connection That Changed Everything

Kurt Cobain’s use of the Electro-Harmonix Small Clone is the most thoroughly documented and musically significant application of the pedal in its history. Cobain acquired a Small Clone around early 1990, just before Nirvana began recording what would become Nevermind. The specific unit he used on those sessions and throughout the subsequent tour is documented as an original-era model containing the Reticon SAD1024 chip — the rarer and now more sought-after of the two vintage variants.

The pedal is confirmed on multiple tracks from Nevermind. “Come as You Are” is the most obvious — the chorus effect runs throughout the entire song, creating the shimmering, aquatic quality of the riff that opens what became one of the best-selling albums of the decade. But the Small Clone also appears on “Smells Like Teen Spirit” (most prominently during the chorus and guitar solo), “In Bloom” (most noticeable on the bridge section before the chorus), “Drain You” (the intermission after the second chorus), and “Endless, Nameless” (throughout). Ground Guitar’s documentation includes a stage photograph confirming the Small Clone on Cobain’s pedalboard next to a Boss DS-2 Turbo Distortion during the Nevermind touring period.

The extent of the pedal’s contribution versus studio processing during mixing is, honestly, somewhat uncertain — recording engineers have noted that some of the Nevermind chorus effect was also shaped at the mixing desk — but the physical Small Clone was present, photographically documented, and used extensively throughout the touring cycle that followed. The MTV Unplugged performance in 1993 further confirmed the pedal’s role in Cobain’s sonic identity.

For players chasing the Kurt Cobain sound, the Small Clone is not optional equipment. It is the pedal.

J Mascis (Dinosaur Jr.) — A Claimed Connection Requiring Honest Caveats

J Mascis and Dinosaur Jr. are frequently cited as Small Clone users in roundup articles and gear guides, and it is certainly true that the band’s shoegaze-adjacent sonic vocabulary — dense with modulation, reverb, and sheer volume — suits the Small Clone beautifully. However, the 2012 Premier Guitar Rig Rundown for J Mascis, conducted on location in Madison, Wisconsin, is the most detailed primary-source documentation of his pedalboard, and it does not include a Small Clone. The effects documented in that rundown include a Ram’s Head Big Muff, a ToneBender Mk I clone, an MC-FX Univox Super-Fuzz clone, a CAE Twin Tremolo, a Z.Vex Double Rock, and an Electro-Harmonix POG2.

The Small Clone attribution may derive from earlier eras of Mascis’s rig, studio-only use, or secondary documentation that was not available for this article’s verification. EHX has mentioned Mascis’s name in connection with Small Clone use, and his sonic palette is entirely consistent with the pedal. But responsible reporting requires noting the gap between the claimed association and a verified primary source showing the Small Clone in his documented live rig. Mascis fans should seek current tour documentation before assuming the pedal is a fixed part of his setup.

John Frusciante — The CE-1, Not the Small Clone

John Frusciante is sometimes listed as a Small Clone user, but the more thoroughly documented reality is that his primary chorus pedal — the one that appears in verified gear documentation and that Guitar World has confirmed on his Red Hot Chili Peppers pedalboard — is the Boss CE-1 Chorus Ensemble. Frusciante’s chorus sound, particularly on recordings from the Californication and By the Way eras, has the specific character of the CE-1: a somewhat thicker, more complex chorusing with a slightly preamp-like quality. The Small Clone association appears in some gear forums and roundup articles, but does not have the same primary-source confirmation as the CE-1 connection.

The confirmed John Frusciante delay story is equally interesting: Guitar World documented his massive RHCP pedalboard featuring four separate delay units including the MXR Carbon Copy, Dunlop Echoplex, Boss DD-500, and DigiTech PDS1002. His approach to signal chain construction is famously maximalist, and Small Clone units may well have appeared in various studios or periods. But the CE-1 is the confirmed chorus anchor; the Small Clone should be treated as unverified for Frusciante unless a primary source surfaces.

Tone Recipes and Settings

Comparisons and Signal Chain Context

The most direct comparison is with the Boss CE-2 Chorus, which was the other dominant analog chorus pedal of the same era. The CE-2 uses the MN3007 chip as well, but its circuit architecture produces a somewhat cleaner, more defined modulation. The CE-2 has both Rate and Depth knobs independently adjustable, where the Small Clone uses a fixed depth toggle. Players who want more precise control over the modulation depth — and who prefer a slightly brighter, more articulate chorus — will find the CE-2 a better fit. Players who want the warmer, more organic swimming quality of the Small Clone’s specific circuit voice, or who are chasing the Cobain sound explicitly, will reach for the Small Clone.

The Small Clone pairs naturally with the EHX Big Muff Pi — both are EHX designs, both have a warmth and density that complements the other, and Cobain’s rig used both simultaneously across different parts of the Nevermind signal chain. Running Big Muff into Small Clone into a medium-gain amp produces the thick, chorused distortion tone of “Smells Like Teen Spirit” as closely as any straightforward pedalboard combination will get you.

The EHX Deluxe Memory Man also contains a chorus/vibrato function built into its BBD delay circuit, but the character is quite different: the DMM’s modulated delay produces a more complex, tape-echo-influenced shimmer rather than the Small Clone’s pure chorus. Using both together — chorus then delay — creates spatial depth that the two separate pedals complement rather than duplicate.

For players interested in the Cobain pedalboard specifically, the Ibanez TS9 Tube Screamer was not Cobain’s primary overdrive (he favored the Boss DS-1 and DS-2 for distortion), but it represents the mild-gain alternative that pairs interestingly with the Small Clone’s chorus for cleaner rhythm playing.

Vintage vs. Modern Reissue: What Actually Matters

The vintage Small Clone debate is real but often miscalibrated. Here is what the evidence actually supports:

The SAD1024 chip units (1979–approximately early 1981) do produce a slightly different sound from the MN3007 units — more watery, with a subtle signal boost. This is audible on careful A/B comparison. Whether it is audibly significant in a band context, through an amplifier, at stage volume, is a separate question from whether it sounds different in a studio controlled listening test. For most players, the honest answer is that the sonic difference will matter far less than other variables in the signal chain.

The reissue units (MN3007, true bypass, larger LED) sound excellent. The EHX forum’s own technical moderator has confirmed that the reissue is “pretty much the same as the vintage unit” in circuit terms. The major practical differences are: (1) the reissue is true bypass where the vintage has FET switching, and (2) the reissue accepts a standard 9V adapter where the vintage is battery-only without the power jack.

For players explicitly chasing the Kurt Cobain SAD1024 sound, vintage units in the $200–350 range (for confirmed SAD1024 examples) are available but require knowledge to identify correctly — the LED color (clear vs. red) and label style (no dash between FULL and CHORUS on vintage) are the primary external identifiers, though these can be modified. For everyone else, the modern reissue at under $100 new is an exceptional value proposition for what it delivers.

Buying Guide

The modern EHX Small Clone reissue retails for approximately $89–99 new and represents the most straightforward entry point. It sounds great, runs off a standard 9V supply, and is readily available from any dealer. There is no reason not to buy this version unless you have a specific vintage chip preference or collector motivation.

Used modern reissues sell for $50–75 in good condition. There is no vintage-year variation that matters among reissue units — the circuit has been consistent since the 1990s relaunch — so buying used is low risk provided the unit powers on and the footswitch engages cleanly.

Vintage units require more caution. The most sought-after examples are the original-era (1979–1983) units with the SAD1024 chip. These sell for $200–350+ in verified original condition. Identifying the chip requires opening the unit, and the external markers (small clear LED, no dash in the label, absence of the square footswitch cutout in the PCB) are necessary but not entirely sufficient — a chip swap is possible and not detectable externally. Trust verified sellers with return policies for vintage purchases.

The Nano Clone is EHX’s stripped-down compact version: even smaller, 9V, single Rate knob, no Depth switch. It sacrifices the depth toggle for a smaller footprint and costs around $50–60 new. The circuit is closely related but not identical. For players who want the Small Clone character in a smaller form factor and do not need the Depth position switch, the Nano Clone is a viable alternative.

Ownership Notes

The Small Clone’s 12mA current draw is standard and presents no power supply challenges. Any modern isolated power supply or one-spot will handle it without issue.

Buffering and signal chain position are worth considering. The reissue is true bypass, which means a long cable run before the Small Clone will accumulate high-frequency loss before the signal reaches the pedal. If your rig runs long cable from guitar to board, consider a clean buffer at the front of the chain. The vintage FET-switched units are not true bypass and provide a degree of buffering inherently — another reason some players prefer them for longer rigs.

Placement in the chain matters. Chorus pedals are conventionally placed after overdrive and distortion but before delay and reverb. Running the Small Clone after a Big Muff produces the thick, distorted chorus of the Cobain sound. Running it before distortion produces a denser, slightly more saturated effect where the chorus’s pitch variation gets processed into the distortion — an interesting sound but less controllable. Experiment with both positions; there is no absolute rule.

The Rate knob’s useful range is concentrated in the lower half of its travel. The fastest settings produce an effect that is more chaotic than musical for most applications, but at the extremes it can serve as a texture tool rather than a chorus effect. Most players find their working range somewhere between 7 o’clock and 1 o’clock.

FAQ