4ms DLD Firmware v5 (2016)

The update that turned a powerful delay into a rhythmic brain with split personalities

Overview

Overview

The moment you update your 4ms Dual Looping Delay to firmware v5, the module doesn’t just gain features—it starts thinking. That’s the sensation: like the DLD wakes up, stretches its legs, and suddenly sees rhythmic possibilities it didn’t before. Released in August 2016, v5 wasn’t a minor patch; it redefined how the module interacts with time, synchronization, and user input. For owners still running v3 or earlier, the jump felt like upgrading from a tape echo with a single repeat knob to a full-blown phrase looper with polyrhythmic intelligence. The most immediate change? The Delay Feedback knob now defaults to a linear taper, making subtle adjustments far more intuitive—no more sudden runaway oscillations from a slight twist past noon. But that’s just the warm-up act.

Where v5 truly flexes is in its handling of external clock sources. Before this update, erratic clock signals from analog sequencers or jittery DIY modules could cause timing glitches or audio artifacts. Firmware v5 introduced selectable de-jitter modes, smoothing out those irregular pulses so the DLD locks cleanly to all but the most chaotic sources. This made it vastly more reliable in mixed digital-analog systems, especially when syncing to vintage gear or modular setups with fluctuating clock voltages. But the real game-changer was “Quantised Change Mode,” a feature that forces actions like time adjustments, reverse toggles, and infinite hold engagement to wait for the next clock pulse before taking effect. Without it, tweaking parameters mid-loop can result in audible clicks or abrupt shifts. With it, transitions are seamless—critical when performing live or building evolving textures where timing precision matters. It’s not without trade-offs: on long delay times, the delay between pressing a button and hearing the change can feel sluggish, almost like the module is taking a breath before responding. But that’s the price of stability, and most users find it a fair one.

Another subtle but significant upgrade was the introduction of variable splice cross fade time (CFT). When changing delay time, reversing playback, or entering infinite hold, digital delays often produce clicks or pops due to abrupt buffer shifts. v5 softens these transitions with a crossfade window that can be adjusted, effectively masking discontinuities in the audio stream. It’s not a lush, reverberant fade—it’s surgical, designed to preserve the integrity of the loop while eliminating digital artifacts. For a module that thrives on long, evolving soundscapes, this small refinement keeps the illusion intact.

And then there’s Ping Lock—a feature so clever it feels like cheating. By locking one channel’s timing reference to a fixed ping value while letting the other track the live clock, you can run one side in tight sync with your sequencer while the other drifts into ambient, free-time territory. Or vice versa: use the locked channel for glitchy, rhythmically precise stutters while the unlocked side explores longer, shifting phrases. It’s not full dual-clock independence, but it’s a brilliant workaround that expands the DLD’s rhythmic vocabulary without complicating the interface.

It’s worth noting that v5 also laid the groundwork for alternative firmware variants, most notably the “Send-Return-Pre-Loop” mod. This unofficial version, based on the open-source v5 code, repositions the send/return jacks to sit *before* the delay memory buffer, allowing external processing to shape the signal *before* it enters the loop. That might not sound revolutionary, but in practice, it transforms how effects like filters or distortion interact with looping content—now you can filter the entire loop history, not just new input. However, this mod isn’t compatible with all PCB revisions (specifically, it excludes v1.2-F446), and installing it means giving up some of the official v5 behaviors. Many users treat it as a secondary option—something to flash temporarily for specific patches, then revert when they want the standard workflow.

The update process itself is quirky: delivered as an audio .wav file, it’s loaded by playing the file into the DLD’s input while holding a button to enter bootloader mode. Some older power supplies don’t provide enough current to initiate this mode, so users with vintage modular cases may need to borrow a beefier PSU to complete the flash. Once installed, the firmware version can be confirmed via a binary light code—Reverse A and Infinite Hold B LEDs lit means v5 is active. It’s a low-tech verification system, but in the world of Eurorack, where firmware updates are still rare, it’s part of the charm.

Specifications

Key Features

Quantised Change Mode: Taming the Chaos

One of the DLD’s strengths—its deep interactivity with CV and manual controls—is also its greatest source of frustration. Without synchronization, changing delay time or engaging reverse mid-loop can introduce jarring clicks or phase jumps. Quantised Change Mode solves this by queuing parameter changes to occur only on the next clock pulse. It’s like giving the module permission to pause for a split second before obeying. This is especially valuable when using fast CV modulation or erratic gate sources that might otherwise cause unpredictable behavior. While it adds a slight latency, the trade-off is worth it for clean, musical transitions. Some users disable it when they want immediate response for glitchy, aleatoric effects—but for structured compositions, it’s indispensable.

Ping Lock: Dual Rhythmic Personalities

The DLD has always been a dual-channel delay, but v5 unlocked a new dimension of independence. Ping Lock allows one channel to remain locked to a fixed tempo reference while the other follows a live clock. This means you can, for example, set Channel A to a slow, ambient 30-second loop while keeping Channel B tightly synced to a 120 BPM sequence. Or use the locked channel for rhythmic precision while modulating the unlocked one with an LFO for drifting, seasick delays. It’s not full dual-clock operation—both channels still share the same master clock source—but Ping Lock provides enough flexibility to simulate it in most practical scenarios. The feature is accessed via a hidden menu, requiring a button hold and knob turn, which keeps the front panel clean but means it’s not something you’ll tweak constantly during performance.

Variable Splice Cross Fade Time (CFT)

Digital delays often suffer from audible artifacts when changing parameters in real time. The DLD’s CFT feature smooths these transitions by crossfading between old and new buffer states, effectively eliminating clicks and pops when adjusting time, reversing playback, or entering infinite hold. The crossfade duration is adjustable, letting users balance seamlessness against rhythmic precision. A longer CFT creates a smoother transition but can blur the timing of rhythmic events; a shorter one preserves attack but risks artifacts. Most users settle on a middle ground—just enough fade to mask glitches without smearing transients. It’s a subtle feature, but one that significantly improves the module’s musicality, especially in live settings where parameter changes are part of the performance.

Historical Context

When the 4ms Dual Looping Delay first appeared, it occupied a niche: a high-fidelity, clock-syncable delay with unusually long memory for Eurorack. But early firmware versions treated both channels as rhythmically dependent, limiting their independence. By 2016, modular synthesis was shifting toward more performative, dynamic patching, and users demanded greater control over timing and synchronization. Firmware v5 arrived at exactly the right moment, transforming the DLD from a capable delay into a rhythmic powerhouse. Competitors like the Red Panda Particle or Hologram Electronics Microcosm offered granular or spectral manipulation, but the DLD carved its identity through pristine audio quality and deep temporal control. The decision to open-source the firmware was equally significant—it invited community contributions, leading to variants like the Send-Return-Pre-Loop mod, which pushed the module’s capabilities beyond what 4ms originally envisioned. This openness contrasted sharply with other manufacturers who locked down their code, and it cemented the DLD’s reputation as a hacker-friendly, evolving platform rather than a static product.

Collectibility & Value

Firmware v5 itself has no monetary value—it’s a free download—but its presence significantly affects the desirability of a used DLD. Modules confirmed to be running v5 (or later) are preferred, as earlier versions lack critical stability and performance features. Buyers should verify the firmware version before purchasing, either by checking the LED binary code (Reverse A and Inf Hold B lit for v5) or asking for proof of update. Units still on v3 or earlier may require a firmware upgrade, which is straightforward but requires a computer, audio interface, and potentially a more robust power supply. The most common failure point isn’t the firmware but the physical jacks and buttons, which can wear out after heavy use. The module draws 180mA at +12V, so underpowered cases may cause instability, especially during firmware updates. Used DLDs in good condition typically sell for $300–$380, depending on firmware version and cosmetic state. Fully updated modules with clean faceplates command the higher end. Because the hardware hasn’t changed significantly since v5, there’s little reason to seek out newer firmware unless specific features (like later Send/Return enhancements) are needed. The real collectibility lies in the module’s versatility—owners report using it for everything from tight rhythmic delays to ambient drones, making it one of the most enduring digital delay modules in Eurorack history.

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