Minerva is a MIDI retrofit for the Roland Juno 60 synthesizer. It is installed internally but with a minimum harm to the original system hence can be called non-destructive.
The Minerva main board which sits in an add-socket actually replaces one of the factory Roland microprocessor without the needing of removing the processor itself. By unplugging the add-on board the original processor is back to work.
The MIDI sockets are prepared on a plate which is installed as a replacement of the DCB socket plate.
The Minerva pitch bend board is to be plugged at the pitch bend board of the Juno. This little board mixes the manual and MIDI pitch bend signals.
While Minerva adds superior MIDI functions to Juno it also provides fine extras for sound manipulation, too. An extra very flexible LFO and an extra mono envelope generator for the filter extends modulation capabilities. Both the extra LFO and the arpeggiator can be synced to MIDI. The voice generation and the tonal character of the synthesizer are not affected by adding Minerva.
The memory capacity is enlarged to 80 patches from the original 56 and the extra parameters are stored in the patch memory as well.
The firmware can be upgraded via MIDI and the patches can up- and downloadable as SysEx data.
2. Operation of the Minerva upgraded Juno 60
All the original functions of the factory programming are kept. The following functions are added:
- All programmable sliders and switches send and receive MIDI control change messages.
- Patch memory is expanded to 80 patches.
- Dumping of parameters via MIDI
- MIDI Program Change messages are sent and received.
- A so-called Second Page that enables control of the extra parameters.
2.1 Accessing parameters using MIDI messages
All the programmable sliders and switches send and recieve MIDI control change messages on the active MIDI channel.
List of MIDI messages detailed in the MIDI implementation chart.
2.2 Acessing patch memory
The original patch programmer let the user store 56 patches. Minerva has expanded memory space and stores 80 patches.
These 80 patches are organized into 10 banks. Bank 8 and 9 can be called by pressing bank buttons 5 and 3/4 together, bank 10 by the combination of 1 and 2.
Every time a patch is changed the MIDI message "Program Change" is sent.
Receiving "Program Change" on the active MIDI channel is recognized and processed.
2.3 Changing the MIDI channel
Minerva sends and receives MIDI messages on the active channel. The active channel can be changed on the Second Page using patch and bank buttons.
Actual MIDI channel is displayed when Second Page is active. Patch buttons 1-8 sets MIDI channel while bank buttons 1 and 2 select range for 1-8 and 9-16.
2.4 Patch exchange
The easiest way to dump a patch is using the snapshot function.
Pressing SAVE dumps the actual patch as a batch of controller data.
This data stream can be recorded and further edited in a DAW.
The second type of patch dump is using SysEx.
Pressing MANUAL + SAVE dumps all patches as a SysEx stream.
Pressing WRITE + SAVE dumps only the actual patch.
Recognizing and processing incoming patch SysEx is automatic.
2.5 Accessing additional parameters
The Second Page is toggled by the VERIFY button.
When Second Page is active the following sliders and switches act different as they set extra parameters.
LFO Rate - Speed of extra LFO.
DCO LFO - Modulation depth of extra LFO.
DCO Square - Changes waveform of the extra LFO (triangle, saw, reverse saw, square, random).
DCO Saw - Changes destination for the extra LFO (pitch bend, DCO LFO, PWM, sub level, noise level, VCF freq, resonance, VCA).
DCO Sub - Toggles LFO sync to MIDI clock.
LFO Trigger - Extra LFO trigger mode (Manual: one shot, Auto: repeat).
VCF Mod - Modulation depth of Filter envelope.
VCF Env - Positive or negative envelope for the extra filter envelope.
Attack - Attack time for the extra filter envelope.
Decay - Decay and release time for the filter envelope.
Sustain - Sustain level for the filter envelope.
Release - Decay and release time for the filter envelope.
Note: there is no seperate decay and release time for the filter envelope, the decay and release times are equal.
Save - Toggles soft midi thru. When on, incoming MIDI data are repeated on MIDI Out.
Load - Toggles solo mode for triggering the extra filter envelope.
Manual - Changes arpeggio divider when synced to MIDI clock
2.6 Synchronizing Arpeggio to MDI Clock
When there is no MIDI Clock messages received the Arpeggio Rate is under manual control.
When the clock signal is present the Arpeggio Rate is determined as a proportion of the tempo.
The proportion can be set by the Manual button on the Second Page or a Control Change (CC 15) message with the following parameters:
1 - Half note
2 - Fourth note
3 - Triplet
4 - 8th note
5 - 8th Triplet note
6 - 16th note
7 - 32nd note
2.7 Firmware update
New firmware can be downloadad via MIDI SysEx file.
Load the custom .syx file to your favourite SysEx manager program and start sending it to Juno. The numeric display shows progression of the update.
The version number is displayed at power on for a second.
3. MIDI Implementation
x: Active MIDI channel
Note On: 9x nn vv | nn (note number) = 24-87, vv (velocity) = 0: off, 1-127: as velocity assigned
Note Off: 8x nn vv | nn (note number) = 24-87
Program Change: Cx pp | pp (patch) = 0-79
Pitch Bend: Ex pl ph = resolution is 8 bit
Control Change: Bx cc vv | cc (control number), vv (value)
CC 16 - VCF Envelope
CC 17 - VCF LFO
CC 18 - VCF Keyboard
CC 19 - VCA Level
CC 20 - Attack
CC 21 - Release
CC 22 - Decay
CC 23 - Sustain
CC 24 - VCF Frequency
CC 25 - Noise Level
CC 26 - Sub Level
CC 27 - Resonance
CC 28 - PWM
CC 29 - LFO Rate
CC 30 - DCO LFO
CC 31 - LFO Delay
CC 32 - Chorus (0: off, 1: mode I, 2: mode II, 3: mode I + II)
CC 33 - DCO Waveform (0-7)
CC 34 - LFO Trigger (0: Manual, 1: Auto)
CC 35 - Transpose (0-3)
CC 36 - VCF Envelope Polarity (0-1)
CC 37 - PWM Mode (0-3)
CC 38 - HPF (0-3)
CC 39 - VCA Envelope mode (0-1)
CC 40 - Filter Envelope Attack
CC 41 - Filter Envelope Decay
CC 42 - Filter Envelope Sustain
CC 43 - Filter Envelope Depth
CC 44 - Filter Envelope Polarity (0-1)
CC 45 - extra LFO Speed
CC 46 - extra LFO Depth
CC 47 - extra LFO Waveform
CC 48 - extra LFO Sync
CC 49 - extra LFO Assign (0: pitch bend, 1: DCO LFO, 2: PWM, 3: sub level, 4: noise level, 5: VCF freq, 6: resonance, 7:VCA)
CC 50 - Arpeggio MIDI Sync
1: Half note
2: Fourth note
4: 8th note
5: 8th Triplet note
6: 16th note
7: 32nd note
CC 51 - velocity assign
0: No assign
CC 52 - filter trigger mode