4ms DLD Firmware v5 (2016)

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

Overview

Overview

Update your 4ms Dual Looping Delay to firmware v5 and the module gets a lot smarter about time. Released in August 2016, v5 wasn't a minor patch. It changed how the module handles time, synchronization, and user input. For owners still running v3 or earlier, the jump felt like going from a tape echo with a single repeat knob to a full phrase looper with polyrhythmic intelligence. The most immediate change is that the Delay Feedback knob now defaults to a linear taper. Small adjustments are easier, and a slight twist past noon no longer sends it into runaway oscillation.

The other big change is how v5 handles 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, which smooth out irregular pulses so the DLD locks cleanly to all but the most chaotic sources. That made it much more reliable in mixed digital-analog systems, especially when syncing to vintage gear or modular setups with fluctuating clock voltages. Then there is "Quantised Change Mode." It 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 clean, which matters when performing live or building evolving textures. There is a trade-off. On long delay times, the wait between pressing a button and hearing the change can feel sluggish. Most users find that a fair price for stability.

v5 also added variable splice cross fade time (CFT). When changing delay time, reversing playback, or entering infinite hold, digital delays often produce clicks or pops from abrupt buffer shifts. v5 softens these transitions with an adjustable crossfade window that masks the discontinuities in the audio stream. It isn't a lush, reverberant fade. It's a short, surgical one that keeps the loop intact while removing digital artifacts.

Then there's Ping Lock. It locks one channel's timing reference to a fixed ping value while the other channel tracks the live clock. You can run one side in tight sync with your sequencer while the other drifts in free time. Or you can use the locked channel for glitchy, rhythmically precise stutters while the unlocked side explores longer, shifting phrases. It isn't full dual-clock independence, but it widens the DLD's rhythmic range without complicating the interface.

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, moves the send/return jacks to sit *before* the delay memory buffer. External processing then shapes the signal *before* it enters the loop. In practice that changes how effects like filters or distortion interact with looping content, because you can now filter the entire loop history, not just new input. The mod isn't compatible with all PCB revisions (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 and then revert when they want the standard workflow.

The update process is quirky. The firmware is delivered as an audio .wav file, 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 start this mode, so users with vintage modular cases may need to borrow a beefier PSU to finish the flash. Once installed, the firmware version can be confirmed with a binary light code. Reverse A and Infinite Hold B LEDs lit means v5 is active. It's a low-tech check, but firmware updates are still rare in Eurorack.

Specifications

Key Features

Quantised Change Mode: Taming the Chaos

One of the DLD's strengths is its deep interactivity with CV and manual controls. It's also a source of frustration. Without synchronization, changing delay time or engaging reverse mid-loop can introduce jarring clicks or phase jumps. Quantised Change Mode fixes this by queuing parameter changes to occur only on the next clock pulse. This helps most with fast CV modulation or erratic gate sources that might otherwise cause unpredictable behavior. It adds a slight latency, but the trade-off gives clean, musical transitions. Some users disable it when they want immediate response for glitchy, aleatoric effects. For structured compositions, it's indispensable.

Ping Lock: Dual Rhythmic Personalities

The DLD has always been a dual-channel delay, but v5 gave the channels more independence. Ping Lock allows one channel to stay locked to a fixed tempo reference while the other follows a live clock. For example, you can set Channel A to a slow, ambient 30-second loop while keeping Channel B tightly synced to a 120 BPM sequence. Or you can 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, since 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. That keeps the front panel clean, but it means you won't be tweaking it 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. That effectively eliminates clicks and pops when adjusting time, reversing playback, or entering infinite hold. The crossfade duration is adjustable, so users can balance smoothness 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, with just enough fade to mask glitches without smearing transients.

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, which limited their independence. By 2016, modular synthesis was shifting toward more performative, dynamic patching, and users wanted more control over timing and synchronization. Firmware v5 arrived at the right moment and turned 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 built its identity on pristine audio quality and deep temporal control. The firmware was also open-sourced, which invited community contributions and led to variants like the Send-Return-Pre-Loop mod. That pushed the module's capabilities beyond what 4ms originally envisioned. Other manufacturers locked down their code.

Collectibility & Value

Firmware v5 itself has no monetary value, since it's a free download, but it 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 by asking for proof of update. Units still on v3 or earlier may need a firmware upgrade. It's straightforward, but it requires a computer, an audio interface, and possibly a stronger 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. Owners report using it for everything from tight rhythmic delays to ambient drones.

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