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Roland JX-08

Synthesizer By Gordon Reid
Published July 2022

Roland JX-08

Roland add another classic polysynth to their Boutique range.

The JX‑08 is the second of Roland’s latest Boutique modules, and is based upon the sound engine of two of the most significant polysynths in my life. These are the Roland JX‑8P and the Super JX‑10, the latter of which is, essentially, two JX‑8Ps frolicking in an enhanced bi‑timbral architecture. How significant? Well, between 1984 and 1987, I discarded an impressive but unwieldy pre‑MIDI keyboard rig in favour of one of each, replacing an RMI Electrapiano, a Logan String Melody II, an Odyssey, a ProSoloist, an MS20 and other classics with just these two polysynths. Sure, the nature of the music that I was playing had changed, but this illustrates how flexible and pleasing I found — and still find — the JX architecture and sound to be. Consequently, I had high hopes for the JX‑08.


Like some previous Boutique modules, the JX‑08 panel gives the impression of being similar to its inspiration while being nothing like it. I placed it next to my Super JX‑10’s PG‑800 programmer and it took no time at all to spot numerous differences — fewer controls, knobs where before there were sliders, common controls for the VCF and VCA contours, a smooth fader for the high‑pass filter rather than four preset positions, no physical controls for dynamics, and more.

Internally they’re very different too; the original instruments were DCO‑based analogue polysynths while the JX‑08 has a heart of pure zeroes and ones. The earliest Boutique modules used a technology that Roland call ACB, and this can be used to build highly accurate models of the synths that it emulates. However, it’s processor‑hungry, and this limited the Boutique versions of the Juno‑60/106, Jupiter‑8 and JX‑3P to just four voices. In contrast, the technology used for the JX‑08 appears to be a newer system that Roland calls ABM. This offers greater polyphony for a given processing bandwidth so, while it may not capture every nuance, there’s a strong argument for using it when emulating synths that require more voices.

I set the JX‑08 up alongside my Super JX‑10 and began my tests by comparing their oscillators against one another. This went well and, despite one synth being nearly 40 years old and the other being barely 40 days old, the two exhibited much the same character across all waveforms. Things started to diverge when I turned to the cross‑modulation options that play such an important part in the sound of the JX‑8P and Super JX‑10. On the originals, this has three settings: sync, sync plus x‑mod, and x‑mod, but the JX‑08 has only two. This is the architecture used by the JX‑8P emulation on the Jupiter‑X and Xm as well as the Zenology JX‑8P Model Expansion, reinforcing my view that the JX‑08 is a Zen technology synth rather than a dedicated emulation of the original.

I moved on to the filters, and soon came to the same conclusion. I created a filter sweep on each synth and passed various waves through it at various levels of resonance. The differences were quite audible, so I went hunting for a reason. This was when I discovered the JX‑08’s ‘F.typ’ parameter, which allows you to select from three options for the low‑pass filter. The sparse documentation tells you that this (and I quote) “Sets the change characteristics, modeled after an classic analog synthesizer LPF (low‑pass filter)”. I remembered this architecture from when I reviewed the Jupiter‑X and Xm (which each offer three filters named R, M and S) and the same three options are again found on the Zenology version of the JX‑8P. So if — as seems likely — filter 1 on the JX‑08 is the same as filter R on the Jupiter‑X, I’m not surprised that its response is different from that of the original.

At this point, I gave up on a feature‑by‑feature comparison because it seemed clear that the JX‑08’s synth engine is a Zen technology approximation rather than a specific ACB emulation. I have no problem with this, but Roland’s marketing department does the company no favours when it writes that the JX‑08 is an “authentic recreation of the Roland JX‑8P synthesizer”, which clearly isn’t true.

Nonetheless, there’s much to like about the JX‑08. For example, it’s bi‑timbral. Unlike the JD‑08, where the provision of two Parts was a considerable shortcoming when compared with the original, the two Parts in the JX‑08 elevate it from approximating the JX‑8P to approximating the Super JX‑10 that was, in many ways, Roland’s greatest analogue polysynth. Sure, the Jupiter‑8 is in many people’s minds unassailable in that regard, but it had lesser polyphony, was neither velocity‑ nor aftertouch‑sensitive, and it lacked many of the sound‑design capabilities of the largest JX. Anyway... the two Parts in the JX‑08 can be split or layered across the keyboard and can be used to create some of the lushest pads you’ve ever heard as well as complex sounds that would be impossible to obtain using a single Part.

The JX‑08 also benefits from increased polyphony. Although Roland were initially reluctant to say what this is, it turns out to be 20 voices, which means that you can play up to 20 keys when using a single Part or the two Parts in split mode, and up to 10 keys in dual mode. I regularly ran out of notes on my JX‑10, and note stealing could become obvious when sounds used anything longer than minimal release times, so the JX‑08 is much nicer in this regard. And as before, the JX‑08 also offers a monosynth (solo) mode and unison in both mono and poly modes on a per‑Part basis. Unfortunately, this is one area in which it falls short of its predecessor; there’s no unison detune so, instead of creating massive, lush carpets of sound, by and large things just get a bit thicker and louder.

Its effects section is also enhanced. Original JXs merely offered two chorus settings and, useful as these were, this meant that you had to turn to external boxes for any additional effects. In contrast, the JX‑08 offers an MFX per Part, allowing you to choose one from 17 effects including three choruses (called Juno‑106, CE‑1 and SDD‑320), four delays, overdrive, fuzz, a fattener, a bit crusher, a compressor, a multi‑stage phaser, an MXR phaser emulation and two pitch‑shifters. Roland have many more MFXs in their Zen arsenal but, given the apparent processing constraints, this subset is well chosen. Just be careful with the choruses... as on so many other Roland synths, they’re the shortcut from the mundane to the gorgeous, and this can tempt you to overuse them. Happily, the wide range available stops everything from sounding like it’s poured from the same sonic tin. Whichever MFX you choose is then followed by a reverb section with emulations of two rooms, two halls and a plate. As you would imagine, this effects structure adds hugely to the flexibility and polish of the sounds that you can obtain.

Some other improvements are less obvious. One of these is tucked away in a Part parameter called EHP, which, in theory, extends the range of the LFO rate as well as the VCF cutoff frequency, the amount of filter resonance and the envelope times. I found some of these to have little effect, but the enhanced resonance allows the filter to oscillate at high values, which is very welcome. Another subtle enhancement is the provision of multiple portamento curves to emulate the responses of a wider range of synths, while yet another is the availability of three velocity response curves. And, since you can play the JX‑08 from the controller of your choice, its response to aftertouch can be much nicer and more musical than that of the JX‑8P, the keyboard of which was always horrible in this regard.

In addition, the JX‑08 features an arpeggiator that offers the usual up, down, up/down, random and ‘as played’ modes, with programmable rate, range, transposition, gate length and velocity, plus hold. This felt so familiar that I checked the online help and, as I suspected, it’s identical with the JD‑08’s arpeggiator. It also boasts a polyphonic sequencer. The controls for this are different from those on the JD‑08 because the buttons are laid out differently, but it otherwise appears to be the same. This means that it offers two tracks, 64 steps in four pages of 16, real‑time and step input, plus programmable velocities, gate lengths, ties and shuffle. It also shares the same CC (motion) recording and replay, as well as the same six replay modes and random performance generator. Again, there are 128 sequence memories alongside the 256 patch memories, and you can select the patterns that you want to play using Program Change messages on the System MIDI channel so that you can chain them together to create longer songs. And, as before, there’s an analogue clock input on the top panel that allows you to synchronise the sequencer to non‑MIDI equipment.

The JX‑08 has fewer controls than a Super JX‑10 PG‑800 programmer, but about as many as you could reasonably fit on the 300 x 128mm panel.The JX‑08 has fewer controls than a Super JX‑10 PG‑800 programmer, but about as many as you could reasonably fit on the 300 x 128mm panel.

In Use

Stating the obvious, the JX‑08 has a physical control panel that makes it far easier to use than a naked JX‑8P or Super JX‑10 without a PG‑200 programmer. Furthermore, its knobs and faders — while small — are smooth and accurate in use. However, there’s one obvious anomaly that proves to your fingertips that this is a digital rather than an analogue synth; when you turn the tuning knob in either DCO, any held notes are retriggered at each step. But this is a small point. More significant is the fact that the JX‑08 is far less easy to edit when you want to adjust parameters that are not revealed on the panel. This is because, like the JD‑08, it has an inadequate four‑character screen that often displays hieroglyphics rather than anything meaningful. To be fair, the programmers haven’t had to work as hard as they did on the JD‑08 because there are fewer and less arcane menus to navigate, but can you honestly say that it’s obvious that the AF.F9 parameter is the one that determines the amount by which aftertouch affects the filter cutoff frequency? The problem is again compounded by the lack of a manual, whether in paper or downloadable and printable form. I hate to sound like a broken record, but it remains incomprehensible to me that Roland have refused to produce either of these, and offer just online hyperlinked help pages that present the information in a form that, if you have no Internet connection, goes from being awkward to totally inaccessible! And, as before, the manual needs a good proof‑read. This is the first time that I’ve come across a “VCO Cutoff Frequency”!

Like the JD‑08, the JX‑08 is not USB class compliant, so you need to download a driver whether you’re running it with a Mac or PC, and drivers are only available for Mac OS 10.14 onward and Windows 10 onward. While I understand the company’s reluctance to dig deeper into the past, many other manufacturers support earlier operating systems, and I wish that Roland did so too.

Unfortunately, the dreaded USB whine has reared its head again. To recap, this is caused when there’s a loop created by a combination of analogue audio and USB connections and, while Boutique modules are far from the only synths to suffer from this, I can’t fail to mention it for that reason alone. There are workarounds — separate power sources, battery operation and audio over USB (provided that you have a recent enough host system) — but it’s a shame that you’ll be forced to use them to obtain a quiet signal.

Neither the JX‑8P nor the JX‑10 output MIDI CCs when you edit them using a PG‑800, so you can’t use the original synth to program the JX‑08. Nor can you load patches from one to the other. However, the choice of CCs makes it possible to automate the JX‑08 in a way that was never possible when using the vintage synths. What’s more, its two Parts can be set to different MIDI channels and will respond separately to any received CCs, which is great. Happily, the JX‑08 doesn’t suffer from the problem of ‘hidden’ synths that bedevilled the JD‑08, although it still doesn’t allow you to switch the MIDI channels for Parts A or B to ‘off’, which is ridiculous. Finally, in respect of MIDI, the documentation states that the JX‑08 neither transmits nor recognises channel aftertouch but recognises poly aftertouch. This seems to be another typo because my tests showed that it responds to channel aftertouch as expected.

Unlike the JD‑08, which was less than the JD‑800 that inspired it, the JX‑08 is more than the JX‑8P on which it’s based.

The Sound

I was a huge fan of both the JX‑8P and the Super JX‑10, and I find them to be as useful today as they were in the 1980s. Sure, the JX‑08 isn’t exactly the same as either and there are some things that it can’t do, but it sounds great and, despite its shortcomings, it’s much more flexible in many other areas. And once you’ve accepted that the JX‑08 is an approximation, its three filter options offer a much wider range of underlying timbres than would otherwise be available. Whether you view this as a vile perversion or three times the fun is, of course, up to you.

So, having completed my forensic tests, I spent considerable time creating some new sounds on the JX‑08 and found that it offers the same character of strings and pads, leads, basses, orchestral emulations, mid‑’80s DX imitations, percussion and effects as before, but then takes things much further. Sure, the loss of one of the sync/x‑mod options makes it harder to create certain sounds (for example, I couldn’t obtain the same imitation of PWM that’s easy to program on the originals) and I sometimes found myself pining for the Super JX‑10’s patch memories and performance parameters, but I would have no hesitation in using the JX‑08 if the situation arose. Sure, it’s the same sound generator as the Zenology JX‑8P Model Expansion software, but it comes in a self‑contained little box that offers a degree of hands‑on control and has no licences or subscriptions to annoy you. Whether you use it as a notepad using its onboard sequencer, as a small performance system when combined with Roland’s own K‑25m or a miniature keyboard from elsewhere, or as a powerful expander controlled by a 76‑ or 88‑note workstation, it sounds really good.


There are many reasons that people offer for not liking the virtual‑analogue products in the Boutique range, but many of these are specious. If you want a genuine analogue synth, feel free to look elsewhere. If you object because there’s a software implementation within the Zenology environment, feel free to look elsewhere. If you want quarter‑inch sockets or XLRs for live performance, feel free to look elsewhere. But if you judge the JX‑08 for what it is, what it does and how well it does it, it scores highly. Sure, it’s not identical with a JX‑8P or Super JX‑10 but, now that I’ve had a chance to reflect upon it, I think that Roland made the right decision to use an ABM emulation rather than a dedicated ACB model. A four‑voice JX‑08 would be hugely impaired compared with what we have here and, outside of a side‑by‑side comparison, I’m not sure that the sonic differences matter. Unlike the JD‑08, which was less than the JD‑800 that inspired it, the JX‑08 is more than the JX‑8P on which it’s based. Original JXs — whether of the JX‑8P or Super JX‑10 variety — are not as expensive as many vintage analogue synths but, given their increasing rarity, I can see the JX‑08 being a real success.  

Rear Panel & Power

Roland JX-08 rear panel connections.Roland JX-08 rear panel connections.

The JX‑08’s rear panel is identical to the JD‑08’s. This means that it shares the same 5‑pin DIN sockets for MIDI in and out, the same 3.5mm sockets providing a stereo output, a headphone output and an audio input, and the same USB‑C socket, power on/off switch and socket for a security lock. I would much prefer quarter‑inch audio connections but this isn’t the Boutique way and, given the size of the enclosure, I can’t be too critical of the choices Roland made. Similarly, the choice of USB‑C will become sensible in the future despite frustrating all of us who are still wedded to USB‑A and -B for everything. Note that, like the JD‑08, the JX‑08 doesn’t switch over to battery power if there’s a USB power failure. If you want to power it from batteries, you will have to switch it on with no USB supply connected.

Where’s The Editor?

The four‑character screen on the JX‑08 is — and here I’m being polite — inadequate. This means that there are many unreadable parameter names that hinder programming. Since Roland appear unwilling to add a small OLED to Boutique modules, a software editor/librarian is (in my view) a necessity to speed up sound design and housekeeping. Since Roland already has the basis of this in the GUI for the Zenology JX‑8P Model Expansion, I very much hope that it will consider the needs of customers who would like to delve more deeply into the JX‑08.

Which JX‑8P Emulation?

Strangely, the most immediate competition for the JX‑08 probably comes in the form of Roland’s own Jupiter‑Xm which, for about three times the price, offers five slots for the company’s legacy emulations including... the JX‑8P. Of course, there are huge physical and operational differences between the Jupiter and Boutique product families but, were you tempted to invest in a JX‑08 and some other Boutique modules, you might have to ask yourself whether an Xm, or even a full‑size Jupiter‑X, would offer a better price/performance ratio. They each have their pros and cons so there’s no right or wrong answer here; just choose whichever works best for you.


  • It sounds great.
  • Despite some shortcomings, it’s much more flexible than its inspiration.
  • It offers greater polyphony.
  • It adds an arpeggiator and a sequencer.
  • It sends and receives MIDI CCs.
  • It feels solid and robust.
  • It’s cheaper than a secondhand JX‑8P or Super JX‑10.


  • Its sound is not identical with the original synths’.
  • There’s no x‑mod+sync mode, nor is there unison detune.
  • It outputs an annoying whine if you create a USB/analogue audio loop.
  • The screen is inadequate.
  • It’s not USB class compliant.
  • There’s no software editor/librarian.
  • The documentation is woeful.


The JX‑08 is more flexible than its inspirations and it sounds great. It’s not a perfect emulation but, if you like the character of the JX‑8P and Super JX‑10 and you fancy a small hardware synth that can come very close, you should consider it very seriously.


£349 including VAT.