Review: Koma Electronik Field Kit FX

The Field Kit FX consists of three effects groups and three additional CV tools - all for under 250 Euro. Anatol Locker was blown away by this powerful, portable system.  

Effects Lab Kit for the Adventurous Eurorack Enthusiast

After the success of their experimental lab "Field Kit“, Koma Elektronik started a second crowdfunding campaign for a "Field Kit FX“ in October 2017. The Berlin-based company was looking to reach a €20,000 goal to build a companion to its highly successful predecessor. They crushed the goal within 24 hours and ended up with €182.634 and nearly 660 backers. They then managed to serve their backers in time; and the Field Kit FX is now shipping from stock. 

For €249, the Field Kit FX offers plenty of CV controllable effects: digital delay, spring reverb, frequency shifter, looper, bitcrusher, sample rate reduction, 4-channel mixer plus a 4-step sequencer, which also can be used as an ADSR. For 36 HP, that’s a lot of functionality.

Look And Feel

The Field Kit and the Field Kit FX look very similar and come in identical wooden cases. If you want to rackmount the Field Kit FX, you need a Eurorack faceplate that you can order for additional €29 Euro from Koma Electronics. Koma also provides an additional "Field Kit FX Expansion Pack“. It costs $69, and adds a spring reverb tank, cables, two contact microphones, a split stereo cable and an attenuverter cable.

The new effects module is a great companion to the Field kit, as its signal was "a little dry“. As Koma Electronics want to get Eurorackers to use their tools outside, they even premiered an as-yet unnamed power supply device at Superbooth 2018. It’s a small splitter that divides the juice of an external power bank to two devices.

The Field Kit FX offers 7 separate functional blocks, made for mangling and altering incoming audio and / or CV signals. We first cover the effects section and then go for the CV control options (which are manifold in this module).

Field Kit FX: The Effects sections

1. Frequency Shifter 

If you want to change timbre, harmonic content and the texture of a sound, frequency shifters are great. Once you add an audio signal, you get metallic phasing effects that alter the harmonic content. You can set a positive and negative shifting amount and also alter the sideband content.
This effect is better heard than explained, so please listen to the demo of the Frequency Shifter here.

2. Looper

Flick a switch to get to the looper of the Field Kit FX. With it, you can loop any incoming signal to 3.5 seconds. You also can record on top of each recorded layer (“overdubbing”). The audio signal is recorded in 12bit, which is reminiscent of the early samplers like the SP-1200. You start overdubbing by pressing and holding the button. Unfortunately, you can’t start recording via CV. Also, the buffer is lost if you turn off the Field FX Kit. Even if 3.5 seconds don’t sound like much, you can add a nice additional FX layer to your sound or lay a base for a track. Recording is easy and we found the looper to be extremely fun. A big "meh“ is that you can either have the Frequency Shifter or the looper, not both.

3. Sample Rate Reducer / Bitcrusher

Once you have the loop in your system, you can alter it (or any incoming audio) with a sample rate reducer and a bitcrusher.
The bitcrusher significantly adds punch to the signal, so be prepared for a wall of noise and harshness. The higher the crusher’s amount, the fewer bits are assigned. The bit crushing effect can heavily distort the output audio, bringing its sonic characteristics into harsh, noisy territories. The Sample Rate Reducer adds more aliasing artifacts and thus change the timbre of the output audio.

4. Digital Delay

The delay offers a range from 30 milliseconds to to 5.5 seconds. Longer delay times will degrade the audio quality and introduce artifacts (Hint: try building your own William-Basinsky-style loops by feeding the degraded audio signal back into the delay). You can boost weak signals with +6 db. Echo time and feedback can be controlled manually or with the built-in CV interface (see below). The looper uses the same chipset (PT2399) as the Korg monotone delay, but thanks to some programming tricks, it shows more character. The feedback options range from a single echo to self-oscillation, which sounds similar to turning up the resonance in a filter. Feedback can be controlled by CV, thankfully.

5. Spring Reverb

To use the spring reverb, you need a reverb tank. Unfortunately, the Field Kit FX doesn’t come with one, so you need to buy one. The Expansion Kit, sold separately, will give you a spring reverb tank (8BB3C1B, for the experts) with tree longer springs. The tank is open, the springs can be touched for more extreme sound manipulations. In our system, we had to crank up the gain significantly to get a decent signal back, especially working with amplified signals from sample based material. Also, the tank picks up any electromagnetic waves nearby - so don‘t expect a sound you would get from a Valhalla DSP plugin.
To shape the sound, you have a lowpass and a bandpass filter. The higher you turn up the feedback, the more likely you get a resonance boost.

Field Kit FX: Modulation Sources

1. CV Interface

Control voltage is where the real magic happens. This CV interface consists of four CV inputs, which can be routed to most aspects of the effects and even the mixer. Assigning CV is easy: Let’s assume you want to alter the delay time with a slow LFO for some extra craziness. Just plug an external LFO in any free CV input of the Field Kit FX and press the corresponding button on the Delay time parameter. The four CV lines are color-coded. So just plug in a cable, press the corresponding button and you are ready to go. Theoretically, you could also map this LFO all 11 available parameters. Musically, it makes sense to map several parameters with several different modulation sources to really bring sounds to live. And with some clever patching, you can even cross-modulate the CVs themselves.

2. CV Generator "Roll-O-Decks“

"Roll-O-Decks“ is a four-stage CV generator. It can be switched to either behave as a 4-step-sequencer or a 4-stage envelope. With the "Threshold“ Dial, you can speed up the sequencer or trigger the ADSR curve with an external clock. This is one of the most versatile effects in the whole system. You can patch this to the CV interface, modulate, face in and out… there are tons of applications for this handy little CV tool.

Listen to an example of the "Roll-O-Decks“ automation doing its magic on the sound of a popular iPad ambient app. The Roll-O-Decks is plugged into the CV interface and then distributed to various parameters of the Field FX Kit.

3. 4 Channel VCA Mixer

This is pretty straightforward. Channels 1, 2 and 3 are standard channels with an input, EQ control that tilts around 600 Hz, plus a volume control. You can automate the volume by assigning CV from the CV interface - i.e. for fading in tracks or sending short spikes for drums. Channel 4 is a bit different, as it offers a gain control (+6 dB). This is great for adding external audio that needs a little boost to get up to the Eurorack levels. It is works exponentially, offering better control over small amounts of gain.

Here’s an experimental jam session using three channels of audio input:

The Verdict

Overall, the Field Kit FX consists of three effects groups and three additional CV tools. In Eurorack-land, €249 for such a modular multi-effects processor is considered to be an amazing deal. If you are looking for a multi-effects module in the same price range, there's also Dieter Doepfer’s A-187-1 Voltage Controlled DSP Effects which offers a lovely arrangement of delays, reverb and distortion. Also, in most cases, specialist modules can do much more. For example, if you are looking for a delay tool, you’re better off with something like like the 4ms Dual Looping Delay or a Makenoise Echophon. But that’s costly - and only can do its "one thing“.

Also, this comparison wouldn’t be fair. The Field Kit FX feels almost like a musical instrument of its own. It's a great tool for experimentation: send some spikes to the delay and modify the time; use this in combination with the reverb and the pitch shifter to get an outer space drumkit; spice up your leads with short delays or add some gnarl and grit with the bitcrusher - for sure, this Field Kit FX is versatile.

Don’t expect polished high-fidelity audio effects. You can degrade, roughen, mangle, crunch and tear up your sounds considerably, and that‘s where the fun really starts. We especially came to like the frequency shifter, which - in small doses - can really spice up a mix. Also, the looper is great fun to work with, especially as you can use layers to color your loops. Also, the idea of the "CV interface“ is brillant - just plug in an external or internal CV source and start modulating any effects parameter with just the click of a button.

The layout of the Field Kit FX is nice and clean. You can grasp the concept in an instant. If you use all of the inputs, the cable "spaghetti layer“ becomes a bit crowded, and getting to the 22 knobs in time can become a challenge. In a bigger modular system, the Field Kit FX gives you an extra ADSR, a 4-channel-mixer with integrated EQs, plus the audio-effects section that also can be used to alter CV modulation signals.

We had some problems with the delivered reverb tank humming and picking up electrical noise, but overall, it’s a great addition to the mix. Overall, the Field Kit FX is a little microcosmos that offers hours of fun. If you already own a Field Kit, you’ll love it, as it really starts bringing the sounds to life. If you want an effects section for your modular synth and you want to get down to the gritty sound of modular, this is a great module.

Also the looper turned out to be way more fun than we expected. Sampling bits and pieces during a performance, overdubbing, and mangling loops really was fun. As Koma has open sourced the firmware, you can hope to see alternative firmware uses for this module.

What really would complete Koma’s "Field Kit“ series would be a module that specializes in randomness, proper sequencing and CV mangling. Let’s see what Koma Electronics come up with next.

Field Kit FX – Modular Multi-Effects Processor

Field Kit FX Eurorack Panel

Field Kit FX Expansion Pack 

Pros: Most parameters are controllable via CV. Good sound quality. Easy to understand and fun to use. Excellent manual. Open source firmware.

Cons: No spring tank included. Can be a bit too gritty for some musical tastes


Learn more about modular synthesis:

Munich-based journalist Anatol Locker loves music and technology. If he’s not writing for German or US websites and magazines, he can be found playing improvised electronica gigs with Ambiosonics and Spheric Lounge; tweaking knobs at the Indietronic band MOC; or contributing to the Disquiet Junto project. His latest project is Lucid ... Read More


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