For a long time, modular users were mostly forced to look towards other formats such as the API 500 format if they were interested in adding high-end outboard-style processors to their setup.

This has recently changed with the arrival of Aircraft Designs, a young brand that specializes in bringing high-end audio processors to the Eurorack format. Their first module was the Ember stereo saturator released in 2024, which they are now following up with the recent Cascade compressor and Horizon EQ modules.

Intrigued by Aircraft Designs' approach to filling out this underserved niche in the Eurorack space — which has received a very warm resonance from many modular users so far — we reached out to them with a few questions about the philosophy behind their brand, their design process, taking inspirations from studio classics, as well as the age-old 12v headroom question. 

Stromkult: Your concept of building high-quality processing modules for the Eurorack format is very intriguing. Of course, there's many options in the API 500 series format, but that's a whole different rabbit hole to get into, and having these processors right in your modular rack is a lot more immediate. Were you thinking along similar lines when starting the brand?

Aircraft Designs: Above everything else, we’re a group of modular synth users, live performers, and long-time contributors to the Eurorack scene, people who’ve been deep in the community for years. We’ve spent a lot of time building systems, patching, playing live, and always looking for ways to make our setups better, and Eurorack is a brilliant format — you can have everything in one ecosystem and it’s small enough to take on stage.

But the deeper we got into building full live systems, the more we felt one big thing was missing, which is really high-quality processing tools. When you want your set or track to sound finished — like everything is balanced, tight, and glued together — you also need tools for finalization right inside the rack.

So we didn’t want to just make “another oscillator or mixer”, even though we love those too, and we started from something we personally needed: processing modules that sound amazing and have their own character and serve as creative tools that actually inspire you when you patch them in. That’s where our whole concept began. And we had solid engineering experience already, but designing our first module Ember took us more than two years of intense work. It was a deep and focused process, but more on that later.

Over the years, I have seen quite a few people make the claim that the Eurorack format is not able to supply the amount of headroom needed for serious pro-audio applications. I assume you have spent a lot of time thinking about the technical side of all of this before starting your line of modules, so could you address what is myth and what is fact when it comes to the topic of voltage, levels and headroom?

One hand, it is true that ±12V rails actually do limit the maximum clean output voltage compared to the ±16V used in typical studio gear. Most Eurorack designs operate with about +18 dB of headroom above nominal line level, which is a bit less than what you’d typically find in the 500-series world.

But it doesn’t mean it’s any less “pro” or “serious", since what really matters is how you choose to design for that space. In our modules, we use high-quality components like low-noise discrete op-amps in Horizon and Cascade, and ultra-low-noise integrated ones in Ember. These choices really let us squeeze the absolute maximum clean headroom out of ±12V rails.

We also spend a lot of time on proper internal gain staging, and if the gain structure is dialed in right, you can comfortably stay within that headroom even for complex bus processing. For most modern genres, +18 dB of clean headroom is more than enough, as long as you’re mindful of levels and gain staging. That said, we do treat every decibel of dynamic range as something worth protecting

How did you come up with the design for your first module, the Ember saturator? There's obviously a million possible ways to approach the concept of saturation, so what features and attributes were you looking for in a saturator?

There are indeed countless approaches to saturation, and we know the classic paths well: transistors, diodes, tubes, or transformers, each of which has its own nonlinearities that create the distortions musicians and engineers love.

But we didn't want to repeat what's already been done, so with Ember we deliberately moved away from traditional schemes and developed our own architecture, one that lets us shape harmonics in a new way. It can generate different flavors of saturation — from almost "clean" and transparent to more aggressive and expressive — while keeping control over stereo image, spectrum, and noise levels.

When designing Ember, we always thought not only about the sound, but also about the user experience, e.g. how intuitive and musical the response feels and how inspiring the module is when you patch it in. Many of our ideas were ambitious and challenging to realize, but they defined the character of this module. The ability to mix and shape harmonics individually really opens up countless interesting combinations — you can get close to the character of various iconic devices, or create entirely new sonic territories that weren't possible before.

How do you go about building versions of studio classics like the Pultec and G-Compressor for the Eurorack format? Are you striving for that "sounds exactly like the original" authenticity, or is it more about delivering your own take on these classics?

We have a lot of respect for the classics, both for the way they were built and the way they became an integral part of studio culture. But we don't do straight clones — for us, classic gear is just a source of inspiration, a starting point for developing a new vision.

So when we took on the Pultec with Horizon for example, it was clear that simply copying the original circuit made no sense, and we even built our own discrete op-amps to get closer to the character of the original tube gain stage without needing tubes.

The biggest challenge with the Horizon was definitely the inductors. In the classics, inductors often give that "magic" sound, but also come with various problems: noise, hum, difficulty matching stereo pairs, weight, and supplier dependence.So we developed our own floating-point synthetic inductor. It's not a ready-made emulation chip, but a unique topology built from scratch, and it took dozens of iterations before we found the right balance of harmonics, noise and dynamics. The result is a module that sounds new, but still nods to the character of the original.

A similar story happened with Cascade, our take on the famous "glue compressor." When we compared various clones and the original, we noticed they all sounded different. The reason is really the VCA block, which is the heart of this compressor and determines the harmonic profile, distortion level, and how tightly it glues the mix. And even with similar circuits, different VCAs produce different sounds. Our approach was really to tune it for minimal unwanted distortion, but leave in the harmonics that make the sound lively and musical. It was a process of balancing distortion, noise, and dynamic range.

So with both the Horizon EQ and Cascade compressor, the goal was never to "recreate the original," but to give it new life through our own vision. This philosophy guides all our work — respecting the legacy while pushing the boundaries of what's possible in the Eurorack format.

What has been the feedback you have received from early users of your modules so far?

Honestly, we haven't released that many modules yet, so the feedback we get now is extremely valuable for us. We pay attention to every video and comment, because for a young company without an established reputation, it is crucial to carefully listen to users. Overall, the feedback has been very positive and constructive: people use the devices exactly as we envisioned them, in real scenarios, and their experience matches our concept.

Of course, we also get suggestions for additional features. And we understand the desire to always get more for less, but our focus is to create functionality that feels organic, fits our concept, and reinforces our brand identity. So right now we carefully track feedback, analyze it, and then decide what suggestions really align with our vision.

Do you also have plans to take inspiration from weirder and lesser-known studio gear?

Yes, we're definitely open to drawing inspiration from weirder and lesser-known studio gear, though that's more of a future perspective for us. Right now we want to focus on establishing our core lineup, and also transitioning what you currently see in Eurorack into standalone versions, perhaps with some changes in functionality.

But we already have some interesting ideas brewing. For example, we'd love to tackle a midrange Pultec-style EQ like the MEQ-5 in our format. We already have the platform for emulating inductors and building new EQs around that core, so exploring some of the more obscure classics is definitely on our radar.

Our broader plan is really to build an ecosystem of processing tools inside Eurorack, giving users the ability to finalize their tracks "in one box". As we expand that ecosystem, diving into lesser-known gems becomes much more appealing, and there's so much character in those forgotten pieces of gear that deserves to be rediscovered!

Could you go into your decision to not include CV control over the parameters of your modules despite them being in the Eurorack format?

We often get asked about CV control. And on a certain level it makes total sense, since Eurorack is all about modulation, experiments, and flexible setups. But our concept is a bit different. The modules we build are designed mainly for processing and finalization, usually on the mix bus or master bus. And in that role, you don't really need CV most of the time — maybe for something like a dynamic filter or an EQ sweep, sure, but for saturation, compression or mix bus processing, in most cases CV really doesn't add much practical value to the workflow.

Then there's also the technical side. To do CV control at truly high quality, you need extra VCAs, analog switches, or digital potentiometers, all of which increase circuit complexity and cost. So we'd rather keep the signal path clean and put all our resources into optimizing the core sound.

And finally, we really believe in the upside of a "hands-on" experience. Direct knob control of parameters lets you make subtle adjustments by feel and hear the changes immediately while focusing on the music, especially when you're making those final mix decisions.

Are there any plans for upcoming designs not yet announced you can go into and is there anything else you would like to say?

We can't reveal everything just yet, but we can say that some exciting new designs will be shown at SuperBooth 2026! One of the most anticipated upcoming releases is definitely our Mixing Tools module. It includes multi-band monitoring, a crossfeed function, and a dedicated headphone output. People have been asking us non-stop about this one, so it feels great to finally bring it to life.

We're also working on a dedicated clipper module, which will make the finalization system feel complete. Together with saturation, EQ, compression, and the Mixing Tools, the clipper will provide the final stage of control and polish that many modular users are currently missing.

More generally, we are very aware that the direction we've chosen in Eurorack — e.g. high-end processing and sound-shaping tools — is still quite niche, and sometimes it requires a bit of explanation to help people understand why we focus on mix bus processing rather than wild CV modulation. The modular world has incredible creative energy, but it can often lack the final sonic polish that separates bedroom experiments from professional releases. That's really the gap we're trying to fill and every design choice is about helping artists cross that bridge from idea to finished art, and we do fully believe in this vision. 

You can find out more about Aircraft Designs over at their website and shop their modules over at SchneidersLaden.