Super JX (JX-10) 12 Voice Polyphonic Synthesizer

Super JX (MKS-70) 12 Voice Polyphonic Synthesizer and JX-8P 6 Voice Polyphonic Synthesizer

The Roland Super JX (JX-10) appeared in 1986 (which is when I purchased the one above) and was manufactured until 1989. It is a 12 voice, analog/digital hybrid synthesizer with 24 DCO's and a 76 key velocity and pressure sensitive keyboard. Each voice consists of two DCO's, a VCF, VCA, and two ADSR envelope generators. There are 100 internal TONES (Roland's term for root sounds) 50 of which are ROM and the other 50 RAM, and 64 on-board perfomance patches. Memory can be expanded by the use of M-16C or M-64C cartridges for an additional 32 or 64 patches respectively (in early 1987 I purchased a "Symphony 128" Cartridge which provides four switchable banks of memory for a 256 patch capacity). There is an internal scratch sequncer and song data is stored in the memory cartridges (M-16 approx. 400 notes and the M-64 approx. 1600 notes). It has a single bender/modulation lever and a 32 character blue fluorescent display.

The MKS-70 module shares the same voice architecture and features as its keyboard counterpart, but has the advantage of SYSEX capabilities, whereas the JX-10 is hopelessly crippled. The JX-8P also has the same voice architecture but with six voices. It uses the M-16 cartridge only (although, the M-64 cartridge can be used at half capacity) and lacks some of the performance features such as Cross Fade, Touch Voice, Chase Play, and the internal scratch sequencer. While this synthesizer sports one TONE module, its DCO Detune and Cross Modulation riches will generate very rich pads much like its siblings.


The JX-10 is comprised of two completely separate 6 voice TONE modules (A-Upper and B-Lower) which allow it to function as a single 12 voice synthesizer or as two 6 voice synths capable of layering, splitting, or crossfading two different TONES. The JX-10 has six KEY ASSIGN modes:

  • DUAL - layers sounds from both TONE modules (which can be balanced)
  • SPLIT - allows for split keyboard play of the TONE modules (upper and lower sections can overlap)
  • WHOLE A - Upper TONE module controlling all 12 voices
  • WHOLE B - Lower TONE module controlling all 12 voices
  • TOUCH VOICE - adds velocity switching
  • CROSS FADE - similar to Touch Voice, aftertouch pressure controls one Tone to fade in while the other Tone fades out

CHASE PLAY alternates patches from the the Upper and Lower TONE modules at programmed intervals.

Programming parameters:

  • Oscillators - four octave range with sawtooth, square, non-variable pulse and noise / semitone tune (over plus or minus one octave) / fine tune for DCO2 / LFO depth / two types of envelope depth (one if your using just the envelope, the other if velocity is being used to alter the envelope depth--in which case you can alter the sensitivity to velocity / envelope mode (chooses one of the two available envelopes and determines whether response is normal or inverted). There are four oscillator sync modes:
    • SYNC1 - which is a hard sync
    • XMOD (cross modulation) - oscillator frequencies (DCO1 and DCO2) modulate each other
    • SYNC2 - which is sync1 and Xmod
    • OFF - each oscillator is independent of the other
  • Mixer - adjusts the level of DCO1, DCO2 / amount of envelope if envelope controls DCO2's level / dynamics range (when envelope controlling DCO2 is being altered by dynamics) / and envelope mode for DCO2's amplitude envelope (this choses one of the two envelopes and determines whether response is normal or inverted)
  • VCF - fixed high-pass filter frequency / VCF cutoff / VCF resonance / LFO depth / VCF envelope depth / VCF tracking (called KEY FOLLOW) / dynamics range (when the envelope controlling the VCF is being altered by dynamics) / envelope mode (choses one of the two envelopes and determines whether response is normal or inverted)
  • VCA/Chorus - VCA level / VCA mode (whether amplitude is affected by envelope 2 or a simple gate) / dynamics (response to velocity) / Chorus offers two chorus options and off
  • LFO - sine, square, or random / LFO delay (quantized to 99 levels) / LFO rate (quantized to 99 levels)
  • Envelopes - two envelopes with individual parameters for attack, decay, sustain, release and KEY FOLLOW (where higher pitches have shorter envelope times)

The rear panel provides two CONTROL ASSIGN jacks which, when selected via C1 and C2 on the top panel, allow control of the following performance control functions:

  • UPPER / LOWER BALANCE
  • PORTAMENTO TIME
  • TOTAL VOLUME
  • UPPER MIDI VOLUME
  • LOWER MIDI VOLUME
When PEDAL SWITCH is selected on the top panel and a footswitch plug inserted in the PEDAL SWITCH jack, the following functions can be assigned:
  • PATCH SHIFT
  • PORTAMENTO (on/off)
  • CHASE PLAY
  • UPPER / LOWER HOLD

The output section on the rear panel contains a TOTAL MIX with switchable levels (H,M,L) and four PARALLEL OUTPUTS, which can be connected in the following ways:

Also on the rear panel are HOLD PEDAL and PHONES jacks, a PG-800 connector, memory PROTECT switch, and MIDI (IN OUT THRU) connections.

The PG-800 programmer facilitates quick editing and access to all TONE parameters of a selected Module. It can be used with the JX-10, MKS-70 and JX8-P.

PG-800 Programmer

For other information on this line of synthesizers visit:

Text of this color denotes actual switches or programming parameters of the JX-10.

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