4ms Micro Modular Recorder (2019–)

At 6HP, it tucks into a crowded rack like a secret — but one that captures every volt of your patch with studio-grade clarity.

Overview

The 4ms Micro Modular Recorder isn’t flashy, and it doesn’t try to be a sampler, looper, or effects unit. It’s a dedicated stereo WAV recorder built for Eurorack, and it does that one job with a kind of obsessive purity. At $269 when it launched in 2019, it wasn’t cheap for its size, but what it offered was rare: lossless 24-bit/96kHz recording in a format that felt more like an analog tape deck than a digital widget. Owners report that the audio quality is indistinguishable from direct computer recordings — a standout in a modular world where digital modules often cut corners on ADCs or suffer from noisy power rails. The design philosophy is clear: keep the signal path clean, the operation immediate, and the footprint minimal.

Despite its digital core, the interface leans into tactility. There’s no screen, no labels, no menu diving in the traditional sense — just a push-button, a gain knob, and LED indicators that communicate status through patterns. This hands-on approach gives it a retro charm, mimicking the immediacy of 1980s cassette decks, but it comes with a learning curve. According to available documentation, users must interpret blinking sequences and knob-turning rituals to navigate functions like file selection or sample rate changes. In a live set, this can feel more like decoding than performing. Still, for those who value sonic transparency and streamlined recording, the trade-off is worth it. The module normalizes its 3.5mm inputs, so a mono signal plugged into the left input automatically routes to both channels — a small but meaningful convenience in the middle of a patch.

Specifications

Key Features

24-bit/96kHz WAV Recording with Transparent Signal Path

The Modular Recorder captures audio in lossless WAV format at up to 24-bit/96kHz, a spec typically reserved for studio interfaces — not Eurorack modules. Unlike many digital modules that compromise on analog-to-digital conversion or share power rails with noise-generating digital circuits, this unit isolates its signal path to deliver clean, transparent recording. The result is a level of fidelity that owners report as indistinguishable from computer-based recordings, a rare achievement in modular synthesis where digital stages often introduce artifacts or coloration.

Tactile, Screenless Interface with LED Feedback

There’s no display, no rotary encoder with push-to-select, no OLED menu tree. Instead, operation relies on a push-button, a gain knob, and dual 6-segment LED bar graphs that serve as input meters. Status and mode changes are communicated through LED blink patterns — a system that works but demands memorization. According to user reports, this interface feels immediate once learned, evoking the tactile simplicity of vintage tape decks. However, tasks like changing sample rates or selecting files require precise knob turns and button presses, which can feel cryptic during live performance.

Normalized 3.5mm I/O with Adjustable Gain

The module features 3.5mm TS inputs and outputs for stereo or mono operation. The left and right inputs are normalized, meaning a mono signal plugged into the left jack automatically routes to both channels — a thoughtful touch for users patching in single-output sources. Input sensitivity is adjustable via a front-panel knob, offering up to +20dB of gain, allowing quiet signals to be brought up to optimal recording levels. Outputs are fixed and mirror the recorded signal, making it easy to route playback back into the modular system or to external gear.

microSD Storage with Hot-Swapping and Firmware Updates

Audio is stored on microSD cards up to 128GB in capacity, requiring Class 10 or higher for reliable performance. Cards can be swapped while the module is powered, provided the busy light is off — a practical feature for live sets or studio sessions where continuous recording is needed. Firmware updates are supported via microSD card.

Historical Context

The Modular Recorder arrived in 2019, during a period when Eurorack systems were increasingly incorporating digital elements — not just for sound generation, but for recording, sampling, and effects. While modules like the TipTop Audio One, Erica Pico Drums, and MTM Radio Music offered basic playback or sample triggering, few focused on high-fidelity, flexible recording with clean I/O. The Modular Recorder filled that gap, targeting users who wanted to capture their patches with studio-grade quality without leaving the modular environment. It represented a shift toward hybrid workflows, where the spontaneity of analog patching could be preserved digitally with minimal compromise.

eBay Listings

As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.

Related Models

• 4ms Ping
• ADC 27
• 2hp LPG V2
• ALM AXON-2
• AMS DMX 2000
• Marantz SD-930
• Accuphase A-60
• Accuphase AC-1
• Accuphase DP-100
• Accuphase DP-65V