The Roland Super JX-10 is a synthesizer released by Roland in 1986. It is a 12-voice polyphonic analog synthesizer able to produce a warm, rich, and analog sound that continues to be valued by synth enthusiasts across the world.

The Super JX has two DCOs (digitally controlled oscillators) per voice, two DCAs (digitally controlled amplifiers) per voice, and a combination of resonant 24dB/octave lowpass and non-resonant highpass filters.

The synthesizer offers several notable features, including a chorus effect with slow and fast settings, and an innovative chase-play delay function that allows programmable delayed voice repeats by alternating patches between upper and lower modules.

Two programmable sliders provide real-time control, with the ability to record these adjustments alongside effects and keyboard modes into one of 64 program patches. The instrument's memory includes 50 preset and 50 user tones, complemented by a basic 1-track real-time sequencer. Data storage is handled through memory cards: the M16C card can store 400 notes, while the M64C card offers expanded storage of 1,440 notes and can also save patch and tone data.

The instrument's design traded traditional hands-on editing for a more streamlined aesthetic, replacing knobs and sliders with low-profile buttons and an VFD display. This design choice, certainly inspired by the now-iconic DX7 1st gen, so it made parameter editing more challenging, though users could mitigate this by either using the Alpha dial to assign and tweak parameters or purchasing the optional PG-800 Programmer, which provides dedicated sliders for more intuitive editing, but costs sometimes the same money as the synth itself.

One of the technical singularities of this analogue machine is that it includes two voice boards, 6 voices each, with an architecture closely similar to the JX-8P. There are some talks about the difference in the sound between the JX-10 and the JX-8P, but let's simply agree here that both sounds great and slighly different. You would not make a mistake soundwise choosing the Super JX over the JX-8P and vice versa.

For those seeking a rack-mount version, Roland also produced the MKS-70, which shared the JX-10's core characteristics and introduces a more advanced MIDI inplementation, allowing editing tones with SysEx.

The Roland JX-10 is one of the rare analogue synths to possess bigger than usual 6.5 octave keyboard with the same action and keys as the Alpha Juno 2 and the S-50. Surprise here, the JX-8P has a different keyboard which is mecanically and electronically not compatible, but keys themselves are almost the same and could be reused. That was a significant milestone as it was the first Roland synth equipped with a high-quality 76-note keyboard featuring velocity sensitivity and aftertouch - all analogue machines of previous generations were content with either 5 or 4 octaves' keybeds, often without the aftertouch or even velocity ability.

As many of top-range synths of its era, the Super JX precious internals are enclosed in a robust case consisting of a plyed wood underneath, metal front panel and plastic sides, becoming fragile after 30 years.

Technically, it's a quite solid electronic musical instrument, but there are some pesky problems that potentially could demand your attention. First of all, you need to replace the old PSU for a new equivalent which delivers more power because the original showed itself as underpowered. If you wouldn't do it and your JX is still alive, there is a high risk it dies.

Another task to fulfill is to replace the internal battery (3V common standard), and capacitors, especially for the PSU rails on the voice and assigner boards, also audio output-related ones.

Last 2 easy tasks could be to clean slider potentiometers, or to replace them, and to clean rubber contacts for the keys. If the aftertouch on your Super JX has lost its sentitivity, you could try to clean the aftertouch strip, but chances are low. The new non-original replacement costs prohibitely high money.