JX family: the GR-700 #41

New issue

Closed

opened 2026-10-12 21:15:57 +00:00 by bcox · 2 comments

bcox commented

2026-10-12 21:15:57 +00:00

Owner

Ben asked on 2026-10-12 which instruments of the families already here were missed, and for an issue a family. Everything below is from recollection, with no manual read; issue #20's list was wrong in several places for the same reason, so read the manuals first and correct this. Each is to be an extension of the existing instrument, as the Jupiters and the JX family are, never a "model" switch.

GR-700 (1984): the guitar synthesizer recalled as built on the JX-3P's voice. Only its voice is of interest: whatever it has that the JX-3P's has not.

Ben asked on 2026-10-12 which instruments of the families already here were missed, and for an issue a family. **Everything below is from recollection, with no manual read**; issue #20's list was wrong in several places for the same reason, so read the manuals first and correct this. Each is to be an extension of the existing instrument, as the Jupiters and the JX family are, never a "model" switch. - **GR-700** (1984): the guitar synthesizer recalled as built on the JX-3P's voice. Only its voice is of interest: whatever it has that the JX-3P's has not.

bcox commented

2026-10-12 23:13:15 +00:00

Author

Owner

Gone through on 2026-10-12, by Claude with Ben away; commit bbf5039 on the branch family-extensions, not pushed. Not closed.

What was read. Roland's owner's manual for the GR-700, and its service notes (first edition, October 1984) for the circuit descriptions of the interface board and of the DCOs; not the schematics, the parts list or the adjustments.

Against the recollection. It holds, and more nearly than recalled: the synthesizer is not built on the JX-3P's voice so much as it is that voice. Six voices of two DCOs, a filter, an amplifier, one envelope and one LFO, edited by 32 numbered parameters or from the PG-200, the JX-3P's own programmer, which the owner's manual maps to them one for one, with the JX-3P's notes on sync, metal and the pulse. The service notes describe the JX-3P's DCO again (8253 counters, the sawtooth from a discharged capacitor, a switch named SYNMET). Neither document names the JX-3P.

What it has beside a JX-3P's voice, each of which mini-JX already has under another name:

Dynamics, one switch for DCO, VCF and VCA: how hard a string is picked sets the envelope's depth on the pitch and the filter, and the level, and never more than is set. That is dco.velocity, filter.velocity and amp.velocity. This is the only account in Roland's words of what dynamics does on this voice; the MKS-30's manual gave none.
A hold pedal (zone.hold, controller 64); a pedal for the pitch, up to seven semitones, up or down (bend.range), or for the cutoff; and vibrato from two touch plates (the lever, controller 1).

What was done. Nothing was built: a GR-700 tone is settings of minijxd, written out in CLAUDE.md, and it is named in README.md, instruments/README.md and docs/references.md.

Not done, and waiting on #17. The guitar's side: a pitch and a loudness from each string, a voice a string, a pitch that follows a bent string (or steps in semitones with CHROMATIC on), and hold and bend for some strings and not others. It has a MIDI output and no MIDI input.

For Ben (under "Open decisions" in CLAUDE.md): that nothing was added; dynamics taken as 1 on all three for the switch on, the manual giving no amount; whether the MKS-30's Dynamics button is this same switch, which is likely and unsourced; and that its filter chip is not named in the pages read.

Gone through on 2026-10-12, by Claude with Ben away; commit `bbf5039` on the branch `family-extensions`, not pushed. Not closed. **What was read.** Roland's owner's manual for the GR-700, and its service notes (first edition, October 1984) for the circuit descriptions of the interface board and of the DCOs; not the schematics, the parts list or the adjustments. **Against the recollection.** It holds, and more nearly than recalled: the synthesizer is not built on the JX-3P's voice so much as it is that voice. Six voices of two DCOs, a filter, an amplifier, one envelope and one LFO, edited by 32 numbered parameters or from the PG-200, the JX-3P's own programmer, which the owner's manual maps to them one for one, with the JX-3P's notes on sync, metal and the pulse. The service notes describe the JX-3P's DCO again (8253 counters, the sawtooth from a discharged capacitor, a switch named SYNMET). Neither document names the JX-3P. **What it has beside a JX-3P's voice**, each of which mini-JX already has under another name: - **Dynamics**, one switch for DCO, VCF and VCA: how hard a string is picked sets the envelope's depth on the pitch and the filter, and the level, and never more than is set. That is `dco.velocity`, `filter.velocity` and `amp.velocity`. This is the only account in Roland's words of what dynamics does on this voice; the MKS-30's manual gave none. - A **hold pedal** (`zone.hold`, controller 64); a **pedal for the pitch**, up to seven semitones, up or down (`bend.range`), or for the cutoff; and **vibrato** from two touch plates (the lever, controller 1). **What was done.** Nothing was built: a GR-700 tone is settings of `minijxd`, written out in CLAUDE.md, and it is named in README.md, instruments/README.md and docs/references.md. **Not done, and waiting on #17.** The guitar's side: a pitch and a loudness from each string, a voice a string, a pitch that follows a bent string (or steps in semitones with CHROMATIC on), and hold and bend for some strings and not others. It has a MIDI output and **no MIDI input**. **For Ben** (under "Open decisions" in CLAUDE.md): that nothing was added; dynamics taken as 1 on all three for the switch on, the manual giving no amount; whether the MKS-30's Dynamics button is this same switch, which is likely and unsourced; and that its filter chip is not named in the pages read.

bcox commented

2026-10-13 01:27:32 +00:00

Author

Owner

Closed by Ben's word on 2026-10-12. The work is on the branch family-extensions, not yet merged.

Closed by Ben's word on 2026-10-12. The work is on the branch `family-extensions`, not yet merged.