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Roland JX10

Super JX Analogue Polysynth (Retro) By Derek Johnson
Published May 1994

The JX10 was Roland's 'final analogue statement' before the advent of their ground‑breaking D50. Derek Johnson reveals the good, the bad and the ugly aspects of this supersynth, now available on the secondhand market for less than a third of its original asking price.

Launched in 1986, the JX10 Super JX synth (alongside its rack‑mounting, modular counterpart, the MKS70) stand as Roland's last word on analogue synthesis. Soon afterwards, the company started down the now well‑worn path of 'sample + synthesis' instruments with the release of the D50. Historically, how does the JX10 fare? Is it the final statement it should have been, given Roland's long and successful history of accessible, interesting and popular synths?

That's a tricky question, and the only way to answer it is with a hedged "Yes and no..." On the plus side, we're talking pure synth power: two oscillators per voice, 12‑voice polyphony, powerful split and layer modes, great 76‑note keyboard. There is a down side, and established users will know what I'm talking about: the JX10's MIDI implementation is frustratingly incomplete — see box for more details.

Synthesis Power

The JX10 has at its heart two synth boards, each roughly equivalent to a Roland JX8P — itself something of an analogue classic. This internal layout leads to a two‑tier operating system that can be a little confusing. At one level, there is the Tone — equivalent to a fully fledged, 6‑note polyphonic patch on a JX8P. There are 50 preset and 50 user Tones. The other, higher level of operating system is the Patch (64 available), each consisting of two Tones (called Upper and Lower) with an attendant name and a range of parameters which allow the pair of Tones to be used singly, layered, split, detuned and so on; each Tone can also have its own MIDI channel, making the JX10 officially bi‑timbral (there are even two sets of stereo outputs, one for each Tone, with stereo chorus). The downside of this system is that any time you alter a Tone, you also alter any Patch that uses that Tone, which may lead to unexpected and unwanted results.

Access to the internal operation of the JX10 is by the now‑too‑familiar parameter access system: dial up a parameter on the large, friendly fluorescent display with the alpha wheel or keypad and alter its value. There are not hundreds of parameters, and all Tone parameters are screened onto the front panel, so this isn't too time‑consuming. The alpha dial, while large and tactile, can be a bit tetchy — you can find yourself twirling it for ages, especially on parameters that only have a few possible values. The alternative editing tool is the optional PG800 programmer, the same unit used with the JX8P. This plugs into a dedicated socket at the rear and allows you to edit Tones with switches and sliders just like a 'real' vintage synth.

The JX10 offers all the sound creating and shaping facilities you could reasonably want from an analogue synth. Features include:

  • Two digitally controlled oscillators, each with a range of 2, 4, 8 or 16 feet; sawtooth, pulse, square and noise waveforms with LFO and envelope modulation, plus tuning (fine tuning on DCO 2).
  • VCF (consisting of a low‑pass filter with cut‑off frequency, resonance, and LFO and envelope modulation), plus a high‑pass filter with three preset values of cutoff frequency .
  • VCA.
  • Two envelope generators (ADSR).
  • Chorus (two preset types).
  • Low‑frequency oscillator, with sine, square and random waveforms, rate and delay.

In addition, the oscillators can be sync'd or cross‑modulated for even wider (nay, wilder) tonal possibilities, envelopes can be inverted, and there are a variety of velocity sensitivity curves.


The mark of a good synth, for me anyway, is being able to create a sound from scratch and get a good result without adding effects. This is a tricky concept for modern workstation synths, where a lot of the drama and impressiveness of patches comes from (and dodgy sample loops are hidden by) built‑in dual multi‑effects processors — just bypass the effects and run through the presets on a typical machine to see what I mean. Not so with the JX10. It is possible to produce rich, fat, bright, gutsy, ethereal, sparkling and/or cutting sounds that work well with no effects — reverb, chorus or some other treatment becomes the icing on the cake. The one thing you can't do is stack all 24 oscillators into one gigantic, monophonic patch. Well, you can't have everything.

Sounds of digital clarity as well as analogue murk can be made to emanate from the JX10, and impressionistic or bloopy sound effects are also part of the JX10's daily bread — it has a mean filter. Despite Nick Magnus' comments in his 'Creating Analogue Sounds on Digital Synths' article last issue, the JX10 can produce bass sounds. The EGs may be a little more sluggish than an SH101, for example, but astounding bass sounds can be produced — besides, who ever heard a real‑world bass instrument (string bass, tuba, bass guitar) that had an electronically fast, crisp attack? It's been said before, but check out the opening chords to the classic Trevor Horn‑produced Grace Jones album Slave to the Rhythm for an example of pure JX10. I find myself turning to the JX10 again and again for rich, detuned or airy pads, and lead lines with presence and definition.

What about price? Luck aside, you could typically expect to pay around £600‑£700 or so for a JX10, about the same for an MKS70, and anywhere up to £300 for a PG800 programmer — it's in demand for three different instruments, although prices can be as low as £50 or £100 if you're lucky. The M64C memory cartridges the JX10 uses, in demand for even more of Roland's instruments (the TR909 and JX8P use them too), can set you back as much as £80. As usual, shop around: prices can be much lower as well as higher.

The negative aspects of the JX10 are covered in the MIDI box; there's really nothing else to say on this point, except to note that the most desirable classic synths — Minimoog and ARP 2600 and so on — have no MIDI or patch memories at all. JX10 owners have to create sounds as they need them, and resort to a combination of patch charts and/or RAM cartridges for backup. The JX's digitally controlled stability means that as long as you've written down parameter values accurately, it'll be possible to replicate a Patch easily at a later date.

The attraction of the JX10, and the reason why demand outstrips supply, is the classic combination of an extremely playable 76‑note keyboard with a highly individual sound. This synth is a monster; it's got pride of place at the heart of my studio, and that's where it's staying.

Slipping Through The MIDI Net

The main disappointment of the JX10 is its MIDI implementation: it's hard to see what Roland were thinking when they released the machine. Apart from transmitting and receiving MIDI notes, program changes, pitch bend, mod wheel and aftertouch (the simple stuff), MIDI simply doesn't exist on the JX10. Even on the stuff that works there are problems: the mod wheel only transmits a maximum value of around 120 or so; if you look at a patch change with a MIDI analyser, there is a lot of surplus data transmitted at the same time; and engaging a sequencer cartridge seems to cause the JX to output non‑stop MIDI clocks

Serious problems start with external sound storage and SysEx, however. In spite of some very small print in the MIDI implementation claiming otherwise, it's impossible to dump the JX10's memory contents via SysEx. And as for accessing parameters in real time via MIDI controllers, forget it; a quick look through the MIDI spec appears to reveal that anything this sophisticated has been left off. And remember, the JX10 was Roland's flagship for a few brief months before the debut of the D50. Another bug has all stored MIDI settings resetting to default values when the JX is turned off — I have to set up Local Off every time I turn on my studio.

I've consulted with several established users and spent £20 on the most up‑to‑date EPROM (there are three EPROMs to keep track of), and there are apparently no answers to these MIDI problems. It's possible to get the JX10 to think it's starting a dump over SysEx (the display says so), but no data flows out, and the receiving software usually bombs out. I've tried Atari ST programmes such as Genpatch, Chameleon, Sound Quest and so on, and none of them provide a solution. The only alternative for external patch storage is an M64C cartridge. I'm lucky enough to have a PG800 programmer, and I keep track of Tones and Patches on paper. Inconvenient, perhaps, but also cheap.

It's frustrating to know that real‑time MIDI control is possible on the older JX8P and that most of the JX10's SysEx problems were ironed out on the MKS70 module. Roland were soon to instigate a whole new era of synthesis with the D50, but it seems sad that an otherwise excellent instrument like the JX10 was robbed of its full usefulness by an incomplete MIDI spec.

Controllable Urges

As a controller, the JX10 performs well, though not to the standards of today's sophisticated MIDI master keyboards. It can transmit on two MIDI channels simultaneously and has an impressive keyboard, one of the best I've come across on a synth. There is front‑panel control over the amount of aftertouch transmitted and the pitchbend range, and a pair of assignable control pedal inputs (duplicated with sliders on the front panel) can be used to control upper and lower tone balance, portamento time, overall volume or the upper or lower MIDI volume (for externally controlled sounds).

Facilities of limited usefulness include the sequencer, which has no metronome or means of being sync'd externally; it uses RAM cartridges for memory, since the JX10 has no internal sequencer RAM. Novelties worthy of note include the Chase Play function; this creates a pseudo‑delay effect and can be used to create fake sequenced‑type effects; used sparingly, it can be both fun and musically valid.

Man Bites Synth

A few years ago I was on the way to my local music shop, a Roland JX10 Super JX in tow, hoping that they hadn't sold my JX8P during the week I had struggled with its so‑called superior stablemate. Essentially, the JX10 should be two JX8Ps in one keyboard (I can attest to the two JX8P circuit boards that were inside my machine). However, something went sadly wrong in the period between the design of the MIDI spec for the JX8P and the JX10...

On the JX8P, individual sound parameters can be adjusted by SysEx transmissions, something I rely on for 'on‑the‑fly' tweaking under sequencer control (like filter sweeps, for instance). The JX10 ignored all attempts to do the same. I later got hold of a MIDI implementation document and found that the facility had not been implemented!

I did manage to get the JX10 to transfer whole bank dumps. However, as I plugged in an M64C memory cartridge and began to explore the internal sequencer, the JX10 proceeded to spout MIDI clock signals — continuously — even during SysEx dumps, which now obviously failed! I managed to cure this by writing to the cartridge and unplugging it halfway through the operation in order to force a re‑format — I would not recommend this course of action to anyone else!

I began editing. There were sounds already present that I wanted to keep, and some that I was keen to add from my old faithful JX8P. I was aware that a JX10 patch consisted of a pair of Tones, called from a shared pool. Once edited, a Tone is altered in every patch that uses that Tone. After 20 minutes with a pen and paper my tolerance threshold was reached! I was horrified to see this tone‑sharing system re‑emerge on the Roland D70, and as for the Korg Wavestation...

My JX8P had been sold, but within a month I had it back. I was £150 poorer, but a little wiser. I've revisited the JX10 since these experiences, but have not changed my opinion. The cartridge/clock problems might well have been confined to my particular synth, but I still find the flawed MIDI implementation and the concept of shared tones (which should be punishable by law, in my opinion) to be very frustrating problems. How could Roland get it so wrong after the beautiful simplicity of the JX8P? Paul Ward