4ms Tremulus Lune ()
It’s not just a tremolo—it’s a living, breathing pulse you can ride like a wave.
Overview
The 4ms Tremulus Lune isn’t the kind of module that shouts at you from across the rack. It doesn’t need to. Plug it in, twist a knob, and suddenly your patch has a heartbeat—deep, organic, and just a little unpredictable. Built for Eurorack modular synthesizers, this compact 4HP unit delivers voltage-controlled tremolo with a character that feels more like an instrument than an effect. And while it may look modest on paper, owners report it brings a dimension to sound that few other modules can match. Reviewers have called it “the best tremolo on the planet,” and one gave it a perfect 10 without hesitation. That kind of praise isn’t tossed around lightly in the modular world, where subtlety and utility often matter more than flash.
What sets the Tremulus apart isn’t just its optical tremolo circuit—though that’s part of the magic. It’s how deeply you can shape the effect. With manual and CV control over both rate and depth, plus a waveform selector that cycles through triangle, square, and random (sample & hold), this module doesn’t just modulate volume—it transforms the rhythm of your sound. Whether you want a smooth, undulating swell or a staccato square-wave chop that cuts like a machine gun, the Tremulus can do it, and do it musically. It’s not just a utility; it’s a voice.
And if your rack’s tight on space or you’re looking to simplify signal paths, here’s a bonus: the Tremulus includes a built-in VCA. That means you can use it as a standalone voltage-controlled amplifier when the tremolo’s not needed. No extra module, no patching gymnastics—just clean, direct control over amplitude. For a 4HP slot, that’s a lot of function packed into a tiny footprint. It draws only 20mA from the +12V rail and 5mA from -12V, so it’s easy on your power supply, too.
Specifications
| Manufacturer | 4ms Company |
| Width | 4HP |
| Depth | 30mm |
| Power | +12V: 20mA, -12V: 5mA |
| Input impedance | 100k |
| Output impedance | 1k |
| Controls/Parameters | Rate (with CV input), Depth (with CV input), Waveform selection (triangle, square, random) |
| Features | Built-in VCA, voltage-controlled tremolo, CV inputs for Rate and Depth |
Key Features
Optical tremolo with soul
The Tremulus uses optical components to shape its tremolo effect, giving it a smooth, natural swell that digital LFOs often struggle to replicate. Unlike hard-edged amplitude modulation, optical circuits respond gradually, creating a more organic rise and fall in volume. This isn’t just about vintage warmth—it’s about feel. When you dial in a triangle or sine-like wave, the swell feels alive, almost like breathing. Even the square wave doesn’t snap on and off with clinical precision; it rounds at the edges, adding a subtle softness that keeps it from feeling mechanical. That’s the optical character in action.
Three waveforms, endless motion
Triangle, square, and random—on paper, that’s a standard tremolo waveform set. But in practice, the way these waveforms behave in the Tremulus gives them surprising range. The triangle wave delivers that classic, smooth undulation perfect for surfy guitar lines or ambient pads. Switch to square, and you get that choppy, rhythmic cut that can turn a drone into a pulsing sequence. And then there’s random: a sample-and-hold driven waveform that introduces unpredictability, making your sound shiver and stutter in ways that feel almost improvisational. Paired with CV control, this turns the Tremulus into a generative rhythm engine, not just a volume modulator.
Full voltage control—no compromises
Rate and depth aren’t just knobs here—they’re full CV-controllable parameters. That means you can modulate the speed of the tremolo with an LFO, an envelope, or even a sequencer. Want the pulsing to sync with your track’s tempo? Patch in a clock divider. Want the depth to swell in response to a note’s velocity? Route a CV from your keyboard. This level of integration is what makes the Tremulus feel at home in a modular setup. It doesn’t sit on the edge of your patch—it becomes part of the conversation.
Built-in VCA: one module, two roles
It’s rare for a dedicated effect module to double as a utility, but the Tremulus pulls it off. Its built-in VCA means you can use it to control amplitude without engaging the tremolo at all. Just set the depth to zero, feed in your audio, and use the CV input to shape volume changes. This is especially handy in smaller racks where every HP counts. Instead of dedicating a separate VCA module, you’ve got one baked right in. It’s a small feature on paper, but in practice, it adds real flexibility.
Compact but capable
At just 4HP wide and 30mm deep, the Tremulus fits into even the most crowded cases without issue. It’s not trying to dominate your rack—it’s designed to disappear until you need it. But don’t let the size fool you. With input impedance at 100k and output at 1k, it plays well with other modular gear, avoiding loading issues that can plague mismatched modules. And with such low current draw, it’s a power supply-friendly addition, especially in systems where every milliamp matters.
Collectibility & Value
The 4ms Tremulus Lune is currently priced at $199.00 USD, according to Big City Music. While there’s no confirmed original MSRP or production timeline, its presence in the Eurorack ecosystem has earned it strong praise. Reviewers have called it “one of the best tremolos around,” with one giving it a perfect 10. That kind of reception usually translates to steady demand, but so far, it seems many players haven’t fully discovered it—some forum users note “many folks have not heard of it,” which might keep prices from inflating too quickly.
There’s no data on common failures or maintenance issues specific to the Eurorack version, but one builder-reported issue from the DIY pedal variant mentioned paint damage during assembly. While that likely doesn’t apply to the factory-assembled module, it hints at a hands-on origin that some might find charming. For now, there’s no secondary market data for the Eurorack module, so current value is effectively the retail price. If you’re hunting for one, keep an eye out—it might be underrated, but it’s not underperforming.
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