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Empress Effects ZOIA

Modular Digital Synth & Effects Pedal By Simon Small
Published March 2022

Empress Effects ZOIA

Empress’ compact, powerful and versatile ZOIA is part multi‑effects unit, part modular synthesizer...

What do you get if you combine a guitar pedal with a modular synthesizer? Well, you get the ZOIA — a fully modular environment for creating instruments and effects, which comes in a stompbox format that’s equally at home on your desktop or a pedalboard. The ZOIA already includes over 80 ‘building block’ modules and more are planned; the collection includes control sources such as LFOs, oscillators and envelope followers, alongside MIDI, CV and audio I/O, switches, analysers, a mixer, and various effects and processors. The possibilities are almost endless: you can create custom effects, synthesizers, MIDI controllers and control voltage sources, as well as entire pedalboards. The ZOIA can also store up to 64 presets for easy recall during live performance, and patches can be shared in an online community.

But while the ZOIA is clearly intended for tone tweakers — those of us who are looking for the maximum degree of control over their effects — it doesn’t exclude players who prefer a few shortcuts. Not only can they can easily load one of the 20‑plus ready‑made effects modules (which cover delay, reverb, EQ, distortion, phasers, cab sims, a ring modulator and more) but, for such a complex pedal, Empress have managed to keep ZOIA’s front panel mercifully simple.

The ZOIA has actually been around for a while now but Empress introduced firmware v2.0 fairly recently, and as well as attending to bug fixes, this brought many new features to the pedal, many of which were requested by the community, including several new modules and the long‑awaited undo function. Coding optimisation has reportedly reduced CPU usage by a whopping 24 percent on average too. When I received my ZOIA, it was already loaded with a beta version of this firmware but, having read up on the previous version, I can see that it has transformed this pedal; it is wonderful to see the manufacturers continuing to develop the ZOIA, and if you have one and have yet to update, you should do it now.

Button It!

The stand‑out feature on the top panel is the 8x5 array of backlit buttons. These represent your main work space and provide access to each part of your chosen module, but they also have alternate functions. Press the Shift key (below the screen) and the top row, for example, becomes what the manual calls Action buttons, granting you instant access to the most useful controls for building your patches (move, copy, edit, delete, save, random and star). Other alternate functions for buttons include undo (new in firmware version 2.0) and help, which displays information on the highlighted function or modules — yes, there’s a built‑in manual!

At the bottom are three high‑quality footswitches, each with main and secondary functions. They’re usually set up as bypass, preset change (scroll or bank) and select, but holding the centre and right switches allows you to configure them as programmable triggers with latch or momentary functions.

The hi‑res 15 x 25mm OLED screen is used to display the ZOIA’s module and parameter information. Although its small dimensions were a source of concern when I was first researching the pedal, once I received and began using the pedal those anxieties quickly melted away. That said, anyone who is averse to menu‑diving when configuring their pedals should be aware that they’ll need to use this screen frequently. Thankfully, there’s never an overwhelming amount of information on the screen, which is clear and easy to read, and thought has clearly been put into what it’s most useful to see at a glance during a performance, with crucial data such as preset numbers and parameter values displayed in much larger text than the minutiae.

Accompanying the screen is an endless rotary encoder that doubles as a push switch. This is used to navigate the menu and make selections, and it feels right: very sturdy and of good quality. When held down it offers finer control, and the aforementioned Shift button makes it finer still.

The rear panel includes a microSD card slot, which can be used to transfer patches to a computer for backup and/or sharing in the online user community.The rear panel includes a microSD card slot, which can be used to transfer patches to a computer for backup and/or sharing in the online user community.

There’s plentiful connectivity on the back of the pedal, where you’ll find pairs of TS sockets to cater for stereo/mono inputs and outputs, 3.5mm MIDI input and output jacks (mini‑jack to DIN adaptors are included), and a dedicated control input for expression pedals, TRS MIDI, CV or external switches. These inputs and outputs can all be accessed by the modules. There’s a power socket here too, and the pedal requires a 9V 300mA supply. As usual it’s recommended to use dedicated isolated power supplies; I tested it with the Strymon ZUMA and Voodoo Labs Pedal Power 2 without incident. Conversion is 24‑bit/48kHz, though Empress tell us the internal processing is performed at 32‑bit.

A microSD card reader, also found on the back, is used for upgrading firmware (new modules and bug fixes have so far been added pretty frequently) and for loading/backing up patches. A smart‑looking Empress‑branded card is included. This card also makes it possible to move presets to a computer and share them online. There’s a thriving community on and I’ve found a huge amount of patch inspiration there, as well as on the ZOIA Discord server. Using the microSD doesn’t require any computer software and it’s simple to use, with clear documentation describing the protocol for saving files.

Sound Experience?

Conceptually the ZOIA makes a lot of sense, but can a pedal packed with this much content really deliver the goods sonically? The answer is a resounding yes! It sounds great. The reverb and delay modules are, as you’d expect if you’ve used other Empress pedals, of very high quality, and whether you’re looking for new tape, old tape, clean, BBD or ping‑pong delays, you can access them all here. The modulation options cover a lot of ground too, with the flanger being a stand‑out effect for me.

The quality of the fuzz and overdrive modules shocked me — and pleasantly so! I’m not often impressed by these sorts of effects in digital pedals, but I’ve frequently found myself reaching for the fuzz in my ZOIA patches. On guitars it absolutely rips (shout out to the ‘burly’ setting!) and when I tried it on synths it almost blew my head off! My only criticism is that it didn’t seem to ‘gel’ with the Cab Sim module quite as nicely as I hoped; I just couldn’t get it to sound quite right to my ears.

I should stress that the ZOIA is by no means limited to use with guitars. The selection of modules really does make the ZOIA a handy tool for the studio, where it’s suitable for mixing, recording and production generally. For instance, I had success using the ZOIA for processing stereo mixes. Being able to put together patches to build new effects for tracks I was working on was a fun experience too. More specifically, I liked creating vocal chains, such as a selection of delays, reverb and panning with the clock sync’ed via MIDI, to use on an effects bus.

Most controls have both primary and secondary functions, the latter accessed by pressing the Shift key beneath the screen.Most controls have both primary and secondary functions, the latter accessed by pressing the Shift key beneath the screen.

Building patches with these Modules was a breeze for me, although less experienced users should probably make sure they’ve read up on signal paths and some synthesizer terms (LFO, envelopes) before they start.

That said, with the ZOIA’s extensive manual, built‑in help system and the helpful community/video content, it’s easy enough to pick up what you need, and you can always start simple and build from there. For example, a delay patch can be created with only three modules: Input, Output and Delay. Connecting the modules together is as simple as pressing the two squares you wish to connect to create a ‘cable’. As you progress, you can edit the patch, for example to assign a foot switch as tap tempo or program an LFO to control the feedback parameter. Then you might decide to add an audio mixer with a chorus, to apply modulation to the delay tails, and hook up an expression pedal to the chorus for control.

The more confident I became with the ZOIA workflow and its module list, the more in‑depth and interesting my patches became, as I started to utilise analysis modules and envelope followers to create patches for looping and granular processing. In short, you can build it your way, and the flexibility means the result is only really limited by your imagination.

The synthesis capabilities of the ZOIA often get overlooked, and I think that’s a shame, since it makes for a very capable modular synthesizer. You can easily build traditional subtractive‑synth patches, of course, or you can explore the strange world of modular synthesis in more depth. With its built-in sequencer, clock divider, sample & hold, ADSR, filters, quantiser, CV mixer and much more, you have all the tools you need in a nice compact box.

What’s more, as there’s CV and MIDI I/O on board, you can interface it with your existing modular rack or MIDI‑based system. I tested this by sending CV from the sequencer to my Eurorack case, which worked perfectly, and I also used a MIDI keyboard to play some of my ZOIA synth patches. It’s a great addition to my hardware synth collection, and it could also work very well as a ‘travel synth’ due to its compact form — although as there is no headphone out you’d need to run it into an audio interface or stand‑alone headphone amp.

Incidentally, if you’re predominantly a Eurorack user, you might be interested in the dedicated modular version of this pedal, the ZOIA Euroburo.

With a little effort and a lot of creativity, you’ll find much to discover and even more to master.


The ZOIA probably won’t be for everyone, largely because the fully modular environment comes at the cost of some menu‑diving — but I love it and many others will too.

It is a deep device that still makes it fairly easy to get started, with some good factory presets. But the greatest joy I found in the ZOIA came from creating unique sounds, and with a little effort and a lot of creativity you’ll soon find much more to discover and master. Be warned, though: this is an extremely addictive pedal that makes it very easy to get distracted from your day; I’ve often found myself contemplating my next patch or reading about other users’ experiences when I should have been doing something else!


  • Huge library of modules for building effects and instruments.
  • Regular updates and new features.
  • MIDI and control voltage compatible.
  • Large community of other users and patch-sharing network.


  • Small screen means menu‑diving is required.
  • An optional autosave feature would be nice.


This versatile modular environment packs all of Empress’s excellent algorithms into a compact pedal, allowing you to combine various modules to create your own effects, virtual pedalboards or synthesizers.


£479 including VAT.

Empress Effects +1 613 627 0797


Empress Effects +1 888‑676‑1853