This page is read from MIDI Instrument Definitions, a Python library used in the author's other projects, in which every number is traced to a document its maker published. Its source is on GitHub.

Roland αJUNO-2 MIDI implementation

The MIDI implementation of the Roland αJUNO-2: what it answers to, and the 5 controls it offers.

At a glance

Firmware: Not recorded.
MIDI channel: Any one of 1 to 16.
MIDI mode: 3: omni off, poly.
Voices: 6.
Note range: 0 to 127: C-1 to G9, counting middle C as C4.
Velocity: Sent and received. Release velocity is ignored.
Aftertouch: Channel pressure, one value for every key.
Pitch bend: How far it bends is not recorded, and the range can be changed.
Program change: Received and sent, with 128 presets.
MIDI clock: Neither sent nor received.
Start and stop: Neither sent nor received.
Control change: 5 controls, in the table below.
NRPN: None.
System exclusive: Supported.

Controls

In the order the definition gives them, by group. Under each control is the name a program calls it by, once pymidiinstrumentdefs.load("roland/alpha_juno_2") has loaded them.

Control	CC	Values
Modulation `modulation`	1	0-127
Portamento Time `portamento_time`	5	0-127 Received, never sent
Main volume `main_volume`	7	0-127
Hold `hold`	64	0-63 `off`, 64-127 `on`
Portamento `portamento`	65	0-63 `off`, 64-127 `on`

Where these facts come from

Source documents

αJUNO-2 Owner's Manual, its user manual, read on 9 October 2026 (the file read).
Roland - Support - Manual Archive, its download page, read on 9 October 2026 (the file read).

How they were read

A SCAN OF ROLAND'S OWN MANUAL, READ BY EYE. 54 pages, each one image and not a character of text, served by Roland from its US manual archive under the name JUNO-2 Owner’s Manual; the cover reads αJUNO-2 and the specifications open with "α JUNO-2 (JU-2): 6 voice polyphonic and programmable synthesizer" (manual p. 47). The MIDI Implementation is dated Jan. 27 1986 (manual p. 48) and its chart Jan.27 1986 (manual p. 49), both Version : 1.1. No quotation below can be checked by a machine, so a second reader checked every one against the rendered page.

FIVE CONTROLLERS, FROM THE IMPLEMENTATION. It sends Modulation on 1, Main volume on 7, Hold on 64 and Portamento on 65, and it receives all four and Portamento Time on 5 (manual p. 48). The volume it sends is the expression pedal's: "The value of the Main volume message is controlled only by EXP PEDAL IN." (manual p. 48). Hold and portamento are switches, sent as 0111 1111 and 0000 0000 and received as 01xx xxxx for on and 00xx xxxx for off, which is the band at 64 below. The hold it sends is presumably the hold pedal's, whose jack turns "the Hold effect" (manual p. 12) on or off, though no page says which jack sends the message; the pedal switch sends program change, system exclusive or portamento, or nothing, by its function (manual p. 34).

THE CHART'S CONTROLLER BLOCK DOES NOT LINE UP, SO THE IMPLEMENTATION'S NUMBERS ARE CARRIED. The block prints 1, 4, 5, 7, 64 and 65 beside five lines of cells, level with the first five numbers (manual p. 49). Read as printed, 4 is portamento time, 5 the expression pedal and volume, 7 the pedal switch and hold, 64 the portamento switch, and 65 nothing. Read with every line after the first one number further down, the remarks fall on Portamento Time at 5, Hold-1 at 64 and Portamento Switch at 65, the line at 7, which has no remark, reads * EXP PEDAL in and ** Volume, and the transmitted column crosses 5 and marks the other four as settable, which is the implementation's transmitted data exactly. The block disagrees with itself, a list with a number its own lines do not reach, and the implementation's channel tables agree with each other and with the block read that way; so the block reads as misprinted, and no 4 is carried. A stray 4 and a lost blank line cannot be told apart on the page, and both give the same five numbers.

EVERY CONTROLLER, BEND, AFTERTOUCH, PROGRAM CHANGE AND EXCLUSIVE MESSAGE IS BEHIND A SWITCH, AND ALL BUT ONE ARE ON FROM THE FACTORY. "Transmitted if the corresponding function switch is ON." (manual p. 48) and "Recognized if the corresponding function switch is ON." (manual p. 48), and the chart's own note: "Can be set to ○ or × manually, and memorized." (manual p. 49). The MIDI chapter's table gives eleven functions and their factory presets (manual p. 32): the channel 1, OMNI off and Exclusive off, and Local Control, Aftertouch, Bender, Hold, Modulation, Program Change, Volume and Portamento on. The notes themselves carry no such note.

SYSTEM EXCLUSIVE IS OFF UNTIL SOMEBODY TURNS IT ON, BUT FOR THE BULK DUMP. Tone parameters travel only by system exclusive - "Transmitted if EXCL in the MIDI function is on." (manual p. 48), as all thirty-six parameters at once or one at a time - and "Bulk Dump has no relation with the EXCL in the MIDI function." (manual p. 51), which the data transfer chapter says the other way round: "This function is available even when the MIDI Exclusive in the MIDI Functions is turned off." (manual p. 38). No tone parameter has a controller number, so none is a control here. The exclusive formats differ from themselves twice: the individual parameter list gives five parameters, the three aftertouch depths and the two key follows, as 0 - 127 (manual p. 48), where the bulk dump's tone format stores each in four bits (manual p. 51); and the all-parameters message is sent with the tone's name and received, under the same operation code, without it (manual pp. 48, 51).

SIX VOICES, VELOCITY BOTH WAYS, AND CHANNEL AFTERTOUCH ANSWERED TO. The keyboard has "61 keys, 5 octaves, C scale with Dynamics and Aftertouch" (manual p. 47). The implementation sends velocity as vvvvvvv = 10 - 127 and receives it as vvvvvvv = 1 - 127, ignores it on a received note off, and receives Channel After Touch (manual p. 48); the chart circles velocity in both columns and crosses key aftertouch in both (manual p. 49). Whether channel aftertouch is also sent, the chart and the implementation disagree - see below.

128 PROGRAMS, BOTH WAYS. "0 - 63 : MEMORY GROUP or CARTRIDGE GROUP" (manual p. 48) and the preset group above them, and the MIDI chapter's table maps two groups of eight banks of eight to 1 to 128 (manual p. 35). With a memory cartridge in, the instrument has 192 tone colours, but the cartridge's 64 take the memory group's program numbers, so 128 are in reach by program change at once.

EVERY NOTE SOUNDS, TRANSPOSED IF IT HAS TO BE. It receives 0 - 127 and "Note numbers outside the range 12 - 108 are transposed to the nearest octave inside this range." (manual p. 48), so the range below is all 128, as roland/jx_8p records the same rule. It sends 12 - 108, which the MIDI chapter accounts for: the keyboard can "transmit data from 2 octaves lower to 1 octave higher than the actual keyboard." (manual p. 34).

THE CHART DIFFERS FROM THE REST IN THREE MORE PLACES, ABOUT NOTHING A FIELD HOLDS. It marks channel aftertouch as settable in its Transmitted column (manual p. 49), where the implementation's transmitted data has no aftertouch row at all (manual p. 48); the MIDI chapter's MIDI Aftertouch switch (manual p. 32) does not say which way it works. This definition's aftertouch is what the instrument answers to, which both agree is channel aftertouch. It marks received volume ** Volume (manual p. 49), with the note about the panel's knob and without the * that marks a switch, where the implementation puts volume behind its function switch (manual p. 48) and the MIDI chapter gives MIDI Volume a switch of its own (manual p. 32). And it labels the hold it sends Pedal sw. (manual p. 49), where the pedal switch's messages do not include hold (manual p. 34). Nothing is chosen.

nrpn: none IS A CHECKED ABSENCE. Neither document names 6, 38 or 98 to 101: not the chart's controller block, misprinted or not, and not the implementation's channel tables. Clock, transport, song position and song select are crossed in both of the chart's columns (manual p. 49) and are not in the implementation.

NOT RECORDED: the pitch bend range, which is a tone parameter for the memory tones, BENDER RANGE 0 - 12 (manual p. 48), and one setting for all the preset tones together, from 0 to 12 (manual p. 15) - so it is settable, and the chart gives it as 0 - 12 semi (manual p. 49). Nor the chord memory, which a received MONO ON with one channel turns on (manual p. 48), and which this format has no field for.

AND ONE DOCUMENT THE MANUAL POINTS TO THAT ROLAND DOES NOT SERVE. Its second page asks the reader to read a separate volume called MIDI before the manual (manual p. 2), as the JX-8P's does, and the archive lists no such volume; nothing in the manual says whether it is about this instrument or about MIDI in general.