ALM MCO MKII (2024–)

A 6HP Eurorack time machine to the digital soul of the ’90s and 2000s—packed with polyphony, presets, and enough synthesis flavors to replace half your rack.

Overview

Plug in the ALM MCO MKII and your modular system suddenly remembers how to sound like a synth. Not just another oscillator with a digital sheen, this is a full-fledged voice module that crams seven distinct synthesis engines into a mere 6HP—each one a love letter to a different era of digital synthesis. You’re not just getting waveforms; you’re getting entire sonic identities: the shimmering super-saws of a JP-8000, the gritty talkbox rasp of a vintage vocoder, the squelchy pulse of a SID chip, and the mathematically rich textures of additive synthesis that could pass for SND or Gabor Lazar patches. It’s rare for a module to feel both nostalgic and forward-thinking, but the MCO MKII does exactly that—bridging the gap between desktop workstation magic and Eurorack immediacy.

What makes it work isn’t just the density of features, but how ALM has refined its now-signature interface language. The high-resolution color display and single encoder/button combo—familiar from Pam’s PRO Workout and the MFX—make deep editing not just tolerable, but intuitive. You don’t need a cheat sheet to navigate layers of menus; the UI is visual, responsive, and forgiving. Long-press for settings, short-press to dive in, twist to scroll, click to select. It’s the kind of design that disappears when you’re in the flow, which matters when you’re tweaking additive harmonics or assigning CV to vocoder bands. And unlike many compact digital modules that sacrifice tactile feedback for space, the MCO MKII feels deliberate, almost luxurious in its usability—especially when you realize you’re editing a 12-operator additive engine with the same control scheme you use to set a clock divider.

This isn’t a one-trick module pretending to be seven. Each engine behaves like its own instrument. The DigiWave engine builds on the original MCO’s wavetable foundation but adds user-uploadable tables via USB-C—meaning you can port in custom or community-made wavetables, or even pull them from vintage synths if you’ve got the data. The ToneSum additive engine doesn’t just cycle through static spectra; it allows for per-harmonic detune, spread, and amplitude modulation, opening up evolving, inharmonic textures that move far beyond glassy pads. The BC8000 mode nails that Roland digital DNA: supersaws with chorus depth you can feel, unison stacks that thicken with a twist, and the kind of bright, cutting leads that defined trance and progressive house. And then there’s Sylon—the vocoder engine—which isn’t an afterthought. It’s a full 16-band vocoder with internal carrier, external carrier input, and modulator sidechain, capable of everything from robotic speech effects to lush formant sweeps that morph like living organisms.

Specifications

Key Features

A Synthesis Engine for Every Era

The MCO MKII doesn’t just dabble in different synthesis methods—it commits. The DigiWave engine resurrects the original MCO’s multidimensional wavetable approach but adds stereo output options and a newly introduced multi-mode filter, letting you sculpt the raw digital output with resonance and slope. ToneSum, the additive engine, is unexpectedly deep: with 12 operators (harmonics), each with independent amplitude and detune, it can generate anything from pure sine stacks to metallic bell tones and evolving drones. The BC8000 mode doesn’t merely imitate the JP-8000; it expands on it, offering multiple unison types, spread controls, and the ability to modulate the supersaw width at audio rate. And then there’s Oomph—the bass engine—which isn’t just another sub oscillator. It’s tuned for punchy kicks, sub-bass layers, and percussive thumps, with internal envelope shaping that can stand in for a dedicated drum module. The inclusion of the SID GUTs engine—a faithful port of ALM’s discontinued SID chip module—is a nostalgia bomb for C64 fans, delivering authentic 8-bit grit, ring modulation, and filter sweeps that scream “Commodore.”

Polyphony and Chords in a 6HP Slot

Four-voice polyphony in a 6HP module still feels like witchcraft. But the MCO MKII pulls it off by treating chords as first-class citizens. Each engine can trigger pre-defined chords—major, minor, diminished, 7ths, 9ths—with options for inversions and user-defined voicings. This isn’t just for noodling; it’s a compositional tool. Sequence a single CV into the pitch input, and the MCO MKII can output rich, evolving harmonies without any external logic. The chords respond to glide, envelopes, and LFOs just like monophonic lines, making it possible to create pads that breathe, arpeggios that swell, and basslines that shift tonality on the fly. For live performers, this means fewer modules to manage; for producers, it means faster sketching. And because the chords are stored per-preset, you can switch between a solo virtual analog lead and a four-note vocoder chord with a single preset change—no patching required.

USB-C and Expandability: The Modern Modular Touch

In a world where firmware updates are often a nightmare, the MCO MKII’s USB-C port is a quiet revolution. Drag and drop firmware updates. Upload custom wavetables. Back up your entire configuration—including user presets and CV assignments—with a single click. This isn’t just convenience; it’s longevity. As ALM continues to update the firmware (Version 106 added a multi-mode filter to DigiWave, Version 105 introduced the AEIOU formant engine), the module evolves. And with Axon expander support—adding up to four more CV inputs via AXON-1 or AXON-2—the MCO MKII scales with your needs. Want to modulate vocoder band levels from a second sequencer? Done. Need to assign additional LFOs to additive harmonics? Plug in an AXON-2 and go. It’s a rare module that feels both self-contained and expansible.

Historical Context

The MCO MKII arrives at a moment when Eurorack is both saturated and hungry. Saturated with oscillators—endless variations on VCOs, LFOs, and waveshapers—but hungry for modules that offer complete sonic experiences without bloating the rack. ALM, known for utility modules with deep functionality (Pam’s PRO Workout, the MFX), has taken that philosophy and applied it to sound generation. The result is a module that feels like a response to the minimalism of early digital oscillators and the complexity of desktop synths alike. It’s no accident that the MCO MKII draws so heavily from the 1990s and 2000s—those were the years when digital synthesis went mainstream, when Roland, Korg, and Yamaha packed entire sound engines into single chips, and when presets became part of the creative process. The MCO MKII doesn’t just emulate those sounds; it recontextualizes them for modular, where patching and modulation are king. It’s a bridge between the preset-driven workflow of the JD-800 and the open-ended exploration of Eurorack.

Competitors like Mutable Instruments’ Plaits (now discontinued) or the newer STG Soundlabs DUSG offered digital versatility, but none matched the MCO MKII’s blend of polyphony, presets, and engine diversity in such a small footprint. While Plaits focused on morphing between synthesis types in real time, the MCO MKII lets you stay in one mode and go deep. It’s less a Swiss Army knife, more a curated toolkit. And by embracing presets—something many modular purists still eye with suspicion—ALM acknowledges that inspiration often starts with a sound, not a blank patch. The MCO MKII gives you both: instant gratification and infinite tweakability.

Collectibility & Value

As a 2024 release, the MCO MKII isn’t “vintage” in the traditional sense—but it’s already positioned as a modern classic. Priced at £230 (around $290 USD), it’s not cheap for 6HP, but the density of functionality justifies the cost. New units sell quickly through authorized dealers like SchneidersLaden and Perfect Circuit, and resale prices remain close to MSRP, indicating strong demand and low churn. There are no known hardware failures at this stage, but service technicians note that the USB-C port and display are the most sensitive components—avoid forcing cables or exposing the module to excessive moisture. The firmware is actively maintained, with updates adding features like the AEIOU engine and smoother modulation curves, which bodes well for long-term support.

For buyers, the main consideration isn’t reliability—it’s workflow fit. The MCO MKII excels in small or travel racks, live setups, or systems where space is at a premium. It’s less ideal for modularists who prefer hands-on control over every parameter via dedicated knobs; this is a module for those who don’t mind menu diving for greater reward. Used units in good condition typically sell for 15–20% below MSRP, but mint units with original packaging and firmware up to date can fetch full price. Collectors are already holding onto them as “future classics,” especially given ALM’s reputation for long-term support and firmware evolution. If you’re considering one, check for firmware version (106 or later recommended), test all CV inputs with an expander if possible, and verify that the display has no dead pixels or ghosting. It’s also worth noting that the VCV Rack version exists and mirrors the hardware exactly—making it a legitimate way to audition the module before purchase.

eBay Listings

ALM BUSY CIRCUITS MCO MKII : NEW : [DETROIT MODULAR]

$300

ALM Busy Circuits MCO MKII Digital Oscillator EURORACK - NEW

$300

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