4ms Dual Looping Granular Sampler (2023–)

A stereo sampler that turns your microSD card into a universe of sound — and then lets you tear it apart with voltage

Overview

It starts with a click. Not the polite tap of a keyboard, but the sharp, satisfying mechanical snap of the Sampler’s Play button — the kind that tells you something real just happened. Then comes the sound: a voice from Poland scolding someone about beetroot, a glitchy granular smear of a synth stab, a perfectly looped 808 kick with just enough grit to feel alive. This isn’t some sterile digital playback module. The 4ms Dual Looping Granular Sampler — though it’s just called the Sampler on the front panel — is a hands-on, no-compromise portal into sample manipulation that feels more like sculpting sound than triggering clips. It arrived in mid-2023 as a streamlined, more accessible sibling to the beloved Stereo Triggered Sampler (STS), but don’t mistake it for a budget version. It’s a focused evolution, packing nearly all the STS’s power into a tighter 12HP frame and a lower price, with firmware that quietly expanded its capabilities from day one.

What sets it apart isn’t just what it does, but how it does it. You’re not buried in menus or touchscreens. Everything is right there: a knob for sample selection, another for start position, a third for playback length. Each has a CV input, so you can sweep through a sample like a turntablist using an LFO, or jump between samples with a sequencer. The real magic happens when you shorten the length — dial it down past 50%, and the module shifts from traditional sampling into granular territory. At its shortest, you’re playing back fragments as brief as 8ms, creating stuttering textures, pitch-shifted clouds, or rhythmic glitches that feel alive. It’s not a full granular synth like the Morphagene, but it’s granular-adjacent in the best way: intuitive, immediate, and capable of happy accidents that spark entire tracks.

And yes, it records — straight into 48kHz/24-bit WAV files on the included 16GB microSD card. Plug in a mic, a synth, or your DAW’s output, hold Play and Reverse, and you’re capturing. The recordings are clean, quiet, and split into manageable 4GB chunks so you don’t hit filesystem limits. You can resample your own manipulations by patching one channel’s output into the other’s input, building layered loops in real time. That feedback loop — literally — is where the module stops being a playback device and starts feeling like an instrument. But it’s not perfect. Unlike the DLD or Morphagene, you can’t layer multiple recordings on top of each other in real time like overdubbing. What you record is what you get — no sound-on-sound. And while the firmware allows cue points (if you enable them in the settings.txt file), it’s not as deep as a dedicated granular engine. But that’s not the point. The Sampler’s strength is its balance: deep enough for serious sound design, simple enough that you’re never more than three knobs away from a new idea.

Specifications

Key Features

Two Channels, Infinite Possibilities

The “Dual” in the name isn’t marketing fluff — this is a true two-channel stereo sampler. Each channel has independent controls for sample selection, start position, length, pitch, and reverse, plus dedicated CV inputs for every parameter. That means you can play two completely different samples at once, pan them across the stereo field, and modulate them separately. But the real fun starts when you patch them together. Route Channel A’s output to Channel B’s input, trigger a resample, and you’re capturing your own effects chain in real time. Add a filter, a delay, or a resonator in between, and suddenly you’re building evolving soundscapes that mutate with every pass. It’s a self-contained feedback ecosystem, and it’s dangerously addictive.

Granular Scrubbing Without the Complexity

You won’t find a “grain size” knob here, but you don’t need one. The Length knob is your gateway. Turn it down, and the module automatically shifts into granular playback mode, slicing the sample into tiny fragments. At full rotation, you get the entire file. Between 50% and 100%, you’re playing back 200ms to 5 seconds of audio. Below 50%, the behavior changes — the sample starts to stutter, smear, and pitch-shift in ways that feel more like granular synthesis than traditional looping. Owners report that this transition point around 12 o’clock on the knob can feel abrupt, almost like an envelope is kicking in, even with envelopes disabled. It’s not a flaw — it’s a feature disguised as a quirk. That sudden shift from smooth playback to glitchy fragmentation is exactly what makes it so expressive. Pair it with CV control over start position, and you can sweep through a vocal sample like a laser, pulling out syllables, breaths, and artifacts that were never meant to be heard in isolation.

Firmware That Grows With You

The Sampler ships with firmware that already feels complete, but 4ms didn’t stop there. Firmware updates are delivered as audio files — play one into the Record input, and the module rewrites its own brain. That’s not just a novelty; it means you can update it without removing the card or connecting to a computer. One early firmware addition was the ability to save your last-selected sample and bank, so the module powers up exactly where you left off — a small but crucial quality-of-life fix that owners had been begging for. Another hidden gem is cue point support: if you embed markers in your WAV files (Reaper is recommended), the Start Position and Length knobs will snap to them, making it easy to jump between verses, choruses, or specific transients. It’s not enabled by default — you have to edit the settings.txt file on the card — but once it’s on, it transforms the module from a freeform sampler into a precision performance tool.

Historical Context

The Sampler didn’t appear out of nowhere. It’s the latest evolution in 4ms’s long-running obsession with looping, delay, and sample manipulation in Eurorack. The company built its reputation on the Dual Looping Delay (DLD), a module that could stretch audio into ambient drones or rhythmic echoes with surgical precision. The Stereo Triggered Sampler (STS) followed, offering higher fidelity, more storage, and a cleaner interface. But at 24HP and nearly $600, it was a commitment. The Sampler arrived in June 2023 as a response to demand for something more accessible — both in price and panel space. It coincided with NAMM 2023 and Superbooth, where 4ms also introduced the Looping Delay, a more affordable take on the DLD. The Sampler was positioned as the entry point into 4ms’s world of sample-based synthesis: not as deep as the STS, not as experimental as the Morphagene, but perfectly balanced for players who want high-quality playback without the complexity. It landed in a crowded market — competing with the Bastl Instruments Soft Bite, the Critter & Guitari Organelle, and the ever-present Elektron boxes — but carved out its niche with Eurorack-native integration, hands-on control, and that unmistakable 4ms build quality.

Collectibility & Value

As of 2026, the Sampler is still too new to be “vintage” in the traditional sense, but it’s already a sought-after module in the Eurorack community. The built version sells for around $300 new, while the DIY kit is $199 — a significant savings if you’re comfortable with soldering. On the used market, expect to pay $220–$260 for a clean unit, depending on condition and whether it includes the original SD card and accessories. Units made before 2025 are 16HP and slightly deeper, but functionally identical — just harder to fit in smaller cases. Failures are rare, but the microSD card slot can wear out with frequent swapping, and the mechanical buttons may eventually need replacement after years of heavy use. The biggest risk isn’t hardware — it’s firmware. Always check that the module has been updated to at least v1.0.1, as earlier versions lack critical fixes and features like bank recall. When buying used, ask if the seller has enabled cue point support and whether the card is included. A unit without the card or with an outdated firmware file is essentially a paperweight until you can load new samples. Maintenance is minimal: keep the card clean, avoid hot-swapping during playback (wait for the Busy light to go off), and store it with the card ejected if not in use for long periods. It’s not a high-maintenance module, but it rewards care.

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