4ms Phaseur Fleur ()
It hums when you’re not even playing—some call it a glitch, others call it alive.
Overview
The 4ms Phaseur Fleur isn’t your standard phaser pedal. It’s a boutique-grade, optical-based stompbox that walks the line between lush modulation and barely-contained chaos. Built by 4ms—yes, that 4ms, the same outfit famous for their dense, knob-covered noise and drone machines—the Phaseur Fleur stands out as a rare foray into the guitar effects space from a company otherwise rooted in modular synthesis. It's officially discontinued now, which means if you want one, you’re either hunting down a used unit or rolling your own from the DIY layouts once shared on the Commonsound/4ms website.
Despite its compact footprint—packed into a 4″ square box—it’s dense with character. Marketed primarily as a phaser, it’s also been labeled a "vibe pedal" and even a "ring modulator pedal" in some corners, suggesting its behavior flirts with multiple modulation territories. That ambiguity isn’t accidental. Owners report it delivers a "smallstone-ish flavor," evoking the thick, organic swirl of vintage phase shifters, but with a wider, more experimental range. It’s capable of "wavering phase shifting, fluttering vibrato," and sounds that sit somewhere between musical and uncanny. It’s been praised as "beautiful on guitars," "absolutely gorgeous with s..." (the quote cuts off, but the sentiment is clear), and versatile enough for guitar, synth, or bass.
But let’s be honest: this isn’t a plug-and-play effect. One builder put it perfectly—“It did take some major tweaking of the trimpots to get some nice phasing.” That’s not a flaw, necessarily, but a feature of its design philosophy: it’s “incredibly tweakable.” You’re not just selecting a sound; you’re coaxing it out, dialing in the sweet spot where it breathes without screaming.
Specifications
| Manufacturer | 4ms / Commonsound |
| Product Type | Phaser pedal |
| Number of Stages | 6 stage phaser |
| Phase Shift Capability | one thousand eighty degrees of phase shift |
| Power Requirement | standard 9V |
| Enclosure Size | 4″ square box |
| Number of Pots | 5 pots |
| Blend Control Pot Value | B10K pot |
| Other Pots Value | B100K (suggested) |
| Bypass Type | True-bypass circuit with LED indicator |
Key Features
Optical 6-Stage Phaser with Deep Control
At its core, the Phaseur Fleur is a 6-stage optical phaser—meaning it uses light-dependent resistors (LDRs) and LEDs to create its sweeping phase effect, rather than voltage-controlled amplifiers or transistors. This optical approach gives it a smoother, more organic response, with a natural lag and bloom that many describe as more “musical” than solid-state designs. The “one thousand eighty degrees of phase shift” isn’t just a marketing flourish; it translates to a wide, immersive sweep that can go from subtle shimmer to full-on jet-plane whoosh. With five front-panel pots, users have direct control over the primary parameters, though the exact labeling isn’t specified in the fact sheet—what’s clear is that the blend control requires a B10K pot, while the others are suggested to be B100K. This level of detail in the DIY documentation suggests the circuit is sensitive to component values, rewarding careful assembly.
True Bypass (With a Caveat)
According to Reverb listings and user observations, the commercial version of the Phaseur Fleur features a true-bypass circuit with an LED indicator—meaning when the effect is off, your signal passes through untouched. However, this conflicts with information from Guitar FX Layouts, which describes the DIY layout as buffered, not true bypass. Given that 4ms released both commercial units and DIY designs, it’s likely the bypass type varied between versions: true bypass in the retail pedal, buffered in some DIY implementations. If you’re buying used, this is worth checking—especially if you’re sensitive to tone-sucking in your signal chain.
Rate LED as Status Indicator
One small but telling detail: the layout includes a rate LED that doubles as a status indicator. It’s not just there to show the LFO speed; it also tells you at a glance whether the pedal is engaged. This kind of thoughtful integration—utility baked into function—is typical of 4ms’s design ethos. It’s the kind of thing you don’t miss until you’ve used pedals that make you guess.
Mod and Custom Variants Exist
The Phaseur Fleur’s open design philosophy has spawned modifications. One known custom version adds an extra control for output volume—a useful addition, given one builder’s observation that “the ring is insanely loud!” when the trimmer is turned up. This suggests the stock unit can hit high output levels, especially in extreme settings, making a dedicated output knob a logical upgrade for live use.
Sound and Application: From Guitars to Synths
While marketed to guitarists, the Phaseur Fleur’s range makes it a natural for synth and bass as well. Its “smallstone-ish flavor” gives it vintage credibility, but its tweakability pushes it into more experimental territory. It’s “great for guitar, synth, or bass,” and capable of everything from classic phase washes to fluttering vibrato and modulated textures that border on ring modulation. The fact it’s been categorized as both a vibe and ring mod pedal hints at its sonic ambiguity—sometimes a bug, often a feature.
Collectibility & Value
As a discontinued pedal with limited production, the Phaseur Fleur has quietly gained cult status. However, specific market prices aren’t documented in the available research, making it hard to pin down current value. What we do know is that units occasionally surface on the used market, often with notes about condition quirks—like one listing that mentions “the switch seems to be a little tired,” suggesting the mechanical components may wear over time. More concerning is a builder’s report of a “strange siren sound oscillating with or without any audio source,” a behavior that appears tied to potentiometer values and trimpot settings. This isn’t universal, but it’s a known issue some users have had to troubleshoot.
Maintenance is feasible for the DIY-inclined: schematics and build information were historically available on the Commonsound/4ms website, lowering the barrier to repair. But since the pedal is no longer in production, replacement parts or factory support are unlikely. Collectors should treat it as a niche, specialist item—valued more for its unique character and 4ms pedigree than as a mainstream collectible.
Builders who’ve assembled the pedal report mixed but generally positive experiences: “The phaseur works and sounds great,” one says, while another confirms “I get a good range of sounds.” The consensus seems to be that it’s worth the effort—but only if you’re ready to dive into the trimpots and find its voice yourself.
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