You are here

Teenage Engineering Pocket Operator Modular

Modular Synthesizers & Sequencer By Robin Vincent
Published January 2021

Pocket Operator Modular 400 synthesizer.Pocket Operator Modular 400 synthesizer.

True to form, Teenage Engineering’s approach to modular synthesis is about as idiosyncratic as it gets.

The Pocket Operator Modular range was first introduced to the world around the time of NAMM 2019. They were bold, striking, unexpected and slightly odd. With everyone around them going mad for Eurorack, Teenage Engineering seemed to offer a more unique approach with these stunning objects of sound and colour. It’s an approach that seems to divide opinion and generates strong discussions about the relative merits of design, aesthetics and functionality. However, there were some issues highlighted by early reviewers in the first run of the POM 400 (the big yellow one), and the POM 170 (the red one) ran into some production problems causing very long delays. Eighteen months after their initial release the dust has settled, they’ve had a few course corrections in the latest production run and they are now available through regular distribution channels. So, I thought it would be the right time to dig under the surface of these design statements of music, metal and plastic, and see how engaging they could be.

Meet The Family

There are three products within the Pocket Operator Modular or ‘POM’ range. We have the 16 sequencer, the red 170 single oscillator modular synth and the three‑oscillator expanded 400 modular synth. Just to be clear the 170 and 400 are modular synths in the sense that they are made up of individual synthesizer modules that have to be physically patched together. However, as the front panels are fixed the actual modules are not interchangeable so you can’t really call it fully modular because you can’t change the architecture of the synth. So could they be described as fixed synthesizers with modular articulation? Possibly, but there does tend to be a bit of confusion around the way Teenage Engineering labels and defines things.

Pocket Operator Modular 170 synthesizer.Pocket Operator Modular 170 synthesizer.

The best way to describe the 170 is as a modular TB‑303 with a massively overspec’ed sequencer. In its rather gorgeous red console‑like form the top half has a single square‑wave oscillator, a filter, ADSR envelope, VCA and an LFO. The bottom half integrates the sequencer and touch keyboard from the 16 which is capable of sequencing and gating three more channels of CV than the 170 possesses.

The 400 appears to be designed much more like the ARP 2600, which is the sort of comparison that I’m sure many people would object to, but this realisation made a lot of sense to me in trying to articulate what this synth is all about. It has three oscillators, a mixer, two envelops and VCAs, a filter, a noise generator, a sample and hold, an LFO and a much simpler sequencer. It stands up with a near‑vertical rake and will probably be the most eye‑catching thing in your room. Some people have worried about the stability when patching, which I haven’t found to be a problem, but I’ve also seen that a few people have mounted it upside down and laid it flat to give it more of a console feel.

Both synths have a small speaker built in and can run on batteries for perfect portability. Or you can add an optional DC power supply for a more permanent installation.

The physical presence of these two objects is quite remarkable. None of the photos prepared me for how fantastic they are in the flesh. They are beautiful works of electronic art that would look outstanding on your sideboard or coffee table. The bouncy, rubberised patch cables contribute to that and they don’t even have to make any noise; you just want to touch them.


The synthesizers come flat‑packed and part of the deal is that you have to put them together yourself. This plays into the idea that these are a bit toy‑like, which is a very common comment I hear when talking about them online and is usually meant dismissively. They do have a flavour of Meccano and Lego about them and I believe that’s deliberate simply because it’s fun and playful. The knobs are, in fact, compatible with Lego Technic pieces, which is very handy for reasons I’ll come on to. It comes with a brilliantly illustrated Lego‑style manual to guide you through the building process. I built them with my kids, aged 8, 10 and 13, who had no problem following the instructions for the most part.

Here it comes a little unstuck because the manual can be confusing in places. The manual contains the instructions for all three products and appears to be in three separate sections. We built the 170 first and found that a lot of details were missing and had to search around online to find some answers. We ended up having to take the thing apart multiple times and struggled endlessly with getting the ribbon cable from the touch‑keyboard in place. When we came to build the 400 we discovered to our annoyance that all the missing 170 detail was right there in the 400 section.

One of the criticisms I’ve read of the build was that the standoffs were not threaded, and so to screw the modules in you had to exert an impressive amount of force onto the tiny screw going into a tiny object with a tiny screwdriver. This is one of the improvements they’ve made with the production run and I am happy to report that they all now have screw‑threads. All except one. We had one module that had the old‑style standoffs and I can see how it could make people angry.

The final act of the build is to place the knobs. Once pushed in they are easily as sturdy as any of the smaller knobs you find in Eurorack. There are two different types for no real reason other than to look interesting and either can fit into the same pot. The larger knobs are great with something like a small paddle sticking out, which makes it easier to turn and usefully indicates the position. The smaller knobs, I confess, I’ve come to loathe over my time with them. To begin with, you put up with them and blame the modules for being inaccurate or your fingers for being too fat. They do have a tiny indent to show position but I can never see it. After working with these synths for a couple of months I can confidently say that they are the most fiddly and uncomfortable knobs I’ve ever had to play with. However, there’s a solution — Lego. They are like the axle parts of Lego Technic that go into the wheels, which is the first thing you try, but wheels are just too big. After experimenting with a few options I settled on what is called Lego Technic ‘Bushings’ (part #3713 / 6590). They come in a range of colours, cost 2p each and are about 7mm tall and wide and fit over the knobs perfectly. Use a permanent marker to indicate the position on them. This makes the knobs a great deal more comfortable and easier to see.

The Background

When it comes to the sound and architecture of the synthesizers they find themselves both beautiful and wayward, powerful and limited, simplistic and yet complex. They are not one thing or the other, which makes them troublesome to pigeonhole. The 170 makes for a great bassline synth but it’s also terrific at FM and Ring Modulation‑type sounds and that sequencer can run a whole army of synths. The 400, with its dual envelopes and VCAs, can pull off two synths with detuning, complex modulations and FM all over the place, driven by a weird little sequencer and a frantic heartbeat.

The synthesizer modules were designed by Jon Nensén, also known as The Human Comparator. If you check out his other work you’ll find things like the Two Thousand Six Hundred ARP 2600 clone, some interesting Buchla modules and the forthcoming two oscillator Recursive Machine synthesizer. My only point is that this is not a designer of entry‑level synths for beginners. He’s managed to squeeze a tremendous amount of tone and complex possibilities out of an inevitably compromised budget modular system. As with any modular system it takes time and patience to pull sounds from it, unlike the self‑playing semi‑modulars that they are often compared to. And so while the price makes it attractive to beginners the workflow can be quite challenging.

The price is very important to keep in mind. The 400 is only £500$599 for a 13‑module modular system in a battery‑powered case with its own speaker. Building something similar with basic Doepfer modules comes in at over a grand and you haven’t bought the case and power supply yet. A better comparison is with AE Modular where their Starter Rack 2 would have a similar range of modules for a similar price. AE Modular has the advantage of being fully modular but is not mechanically compatible with Eurorack, whereas the POM range can patch straight in. The £400$479 price on the 170 seems expensive when compared to the 400 but that’s because it has the £200$239 16 sequencer built in. I think this is the cause of some consumer confusion as the power of the sequencer is under‑appreciated but could also be seen as unnecessary in a single‑oscillator synth. If it was £200$250 with a much simpler sequencer, like in the 400, I think they’d be far fewer objections.

The Synths

When working with the synths you do find character defects that are perhaps implicit in the price but you also discover multiple personalities and surprises that push you into rethinking your approach.

The oscillators generate a single waveform, which is a limitation, but they all have three outputs which can make for an overload of rather delicious audio‑rate modulation. The tuning troubles of the first batch are gone and I can track seven to eight octaves without any difficulty. The tuning knobs are not great and require a fine touch to bring the three together. Adding bigger Lego pieces helps with this enormously. The Sine and Saw oscillators both have attenuatable FM inputs which are a load of fun for clangy, spacey and R

adiophonic‑type sounds. The Square oscillator, which appears on both the 170 and 400, has slightly odd Pulse‑width Modulation. The waveform modulates from square wave to pulse from the seven o’clock to 12 o’clock position and then vanishes beyond that. Teenage Engineering say this is by design so that you can throw in some alternative rhythmic gating by pushing a high voltage into that input. That does work quite nicely, actually.

The LFO offers triangle and square waveforms, two of each on a single rate knob. The range of the rate knob is again quite odd in that you only get a small turn before it’s up into audio rate. There’s no CV control on the rate/pitch of the LFO but you could easily add it in as a drone or use it for some extra bags of that chaotic audio‑rate modulation.

There’s also something odd about the filter. The cutoff knob doesn’t open the filter very far. The 170 and 400 have the same filter module, but I found that you could hardly hear anything of the 170’s oscillator through the filter whereas it appeared to open further on the 400. In either case you needed to add an envelope or other modulator, or CV source to the cutoff’s CV input to open the filter fully. Once an envelope was engaged then the filter worked perfectly normally. In fact there are two cutoff control inputs which let you create some interesting filter offsets and modulations. As with the oscillators, there are three outputs on the filter which gives you all sorts of audio processing possibilities if you were patching out to a larger system.

To complete, the overall oddness of the 400 16‑step Sequencer is also slightly strange. Before adding the Bushings and permanent pen it’s annoying and tricky, but once that’s sorted out it’s actually quite clever. Each knob sets an unquantised CV value that can be patched to all three oscillators simultaneously. The tempo runs from ‘fast’ to ‘really fast’ unless you patch something more sedate into the Clock In. There’s no gate output, but you can use the Clock output to trigger your envelopes for every step, or there’s a ‘PO’ Pocket Operator output which runs at a quarter speed and is intended to sync‑up one of their little drum machines. Turning a step’s knob all the way clockwise will reset the sequence back to the first step, which is an interesting way of setting the sequence length, although until you read about that in the manual it’s awfully mysterious. You can change direction with a gate input and there are also inputs for resetting the sequence, and four others which will send the sequence to step 2, 4, 8 or 12. There’s nothing in the 400 itself that can really utilise these sequence mangling inputs. However, once you’ve slowed it down from an external clock and brought some gates and triggers in from outside then it can get rather interesting.

The other modules act largely as expected. Features like dual outputs on the envelopes are well thought out and the ‘Saw’ output on the Noise generator makes for a decent source for the ‘Rand’ sample & hold module. Just don’t ask it to sample & hold a tune — it’s not terribly stable.

I’ve had these machines a couple of months now and I find them thoroughly entertaining.

The Sequencer

Finally, we need to look at the 16 Sequencer, which forms half of the 170 and is also available as a standalone, battery‑powered, pocket‑sized, desktop four‑channel CV and MIDI sequencer.

Pocket Operator Modular 16 sequencer.Pocket Operator Modular 16 sequencer.

Following the overall theme of the Pocket Operator Modular series the 16 is both brilliant and slightly awkward. The feature set is pretty fabulous. Four independent tracks of up to 64 steps of sequencing with rests, ties and individual pattern lengths. Step time or real‑time note entry quantised to one of four scales or completely custom pitches. Individual tempo divisions per track, four swing modes, 16 arpeggiator patterns, muting and soloing tracks. There are performance effects that mess about with gate lengths or drop in glide and legato notes. Track 4 even has three CV and Gate outputs to use with multiple oscillators or to route out as modulations. Save the lot into 1 of 16 slots for instant recall. Did I mention that it will do all of that over MIDI as well with each track on a separate MIDI channel?

The only glitch in this otherwise fruity matrix of sequencing heaven is the touch‑keyboard interface. You have to lean into it quite hard to get it to work to the point that after a while your fingers start to hurt. This is compounded by the fact that you often have to hold a button down while pressing other buttons and you find it’s not working because you’re not pressing down hard enough. However, once you’ve got the hang of it the fun and depth of this sequencer overrides the interface irritations. I’d love to be able to plug in a MIDI keyboard, though.

The row of 16 knobs seems mysterious at first. You assume that they set the pitch of your first 16 steps, when in fact these knobs tie in directly to the 16 notes on the keyboard. You could enter all 16 notes in a row and then the knobs do indeed control the pitch of each note in turn. Maybe that’s what they are intended for. The manual seems to suggest that they are CV generators to be used to set up modulation tracks rather than notes, but either case can work. You can reset the notes by selecting one of the inbuilt scales and then you’ll have to turn the knobs through the current value to capture control again. A bushing and a pen mark dramatically improve the use of the knobs.


I’ve had these machines a couple of months now and I find them thoroughly entertaining. Sure, they have some character defects and some personality flaws that occasionally let them down, but considering what’s on offer these quirks are easily forgiven. With the 400 you’re getting an entirely modular synthesizer experience for under £500$600. A modular system needs to be learnt and discovered and the 400 is no different. It’s playful and portable and begging to be used outside and in unusual places. I’m currently testing the battery life and have it running a sequence on the other side of the room and that little speaker isn’t half bad. It can find a whole other life when it gets its hooks into other bits of modular and runs through a decent sound system. The battery life of the 400, by the way, was around four hours on eight AA batteries.

The 170 does seem expensive for a single‑oscillator mini‑synth, but it has a very under‑appreciated sequencer which makes up half the price. I think a 170 ‘lite’ with maybe just a touchstrip and arpeggiator for under £200around $250 would fly off the shelves. However, that sequencer is a really interesting little box with four tracks of CV/MIDI and a ton of possibilities.There’s no denying the toy‑like qualities, and it does seem slightly ridiculous that they are improved with some Lego modifications, but a bit of colour and fun are worthwhile attributes these days. While the design and limitations won’t please everyone there’s a lot to like and enjoy in these quirky bits of electronic playfulness.


  • Beautiful electronic objects.
  • Genuinely modular music‑making.
  • CV and socket compatible with Eurorack.
  • The 400 is fantastic value.
  • 16 sequencer is immensely powerful.
  • Completely portable.
  • First run issues with build and tuning have been solved.


  • Can be odd.
  • CV range can be limited.
  • Those knobs.
  • Might be too quirky for some.
  • Challenging for a beginner.


The startlingly designed Pocket Operator Modular synthesizers from Teenage Engineering offer a quirky dose of colour and playfulness with a sometimes challenging modular workflow and imperfect architecture. That sequencer, though.


POM 16 £199, 170 £399, 400 £499. Prices include VAT.

POM 16 $239, 170 $479, 400 $599.