Personal Circuits Midi-CV-8 User manual

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Midi-CV-8 v1.3 – User Guide
This is the setup and user guide. The unit is designed for a monophonic Analog synthesizer and a PC
and/or a MIDI keyboard with a DIN cable and/or a MIDI-USB music keyboard.
The module is designed and sized for Eurorack systems. You will need a 16-pin Eurorack power
ribbon connector with –12/0/+12 and +5V which is connected to a synth power supply.
The following MIDI-USB Keyboards are supported:
Arturia MiniLab MKII
Arturia MiniBrute
MidiPlus AKM 320
M-Audio Keystation 49
M-Audio Keystation 61
Others may work also.

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Programming the MIDI-CV-8
1. If the PIC24 chip is preprogrammed, there is nothing else to do.
2. If you intend to program the chip yourself with our .HEX file, use your favorite method to
program the chip. If using the ICSP port on the GATES board and MPLAB-X IDE, you can follow
this tutorial to set up a pre-built project with our HEX file:
http://microchip.wikidot.com/mplabx:projects-prebuilt
Connections
1. You can connect a DIN keyboard using the TRS jack. You will need a MIDI/TRS Type A cable or a
MIDI/TRS Type B cable depending on how you have configured the jumpers in the MIDI-CV8.
2. You can connect a USB keyboard. The device will operate as a USB host and power the keyboard
on its USB bus while receiving MIDI data from the keyboard.
3. You can connect the Midi-CV-8 as a USB device using a computer or other host connected to the
Midi-CV-8's USB-B type socket. This connection will be used for connecting your DAW, such as
Ableton Live, to the MIDI-CV-8.
Playing modes
a. Mode 0: Omni On/POLYPHONIC. Standard mode. It receives channel messages sent on
any channel and plays notes polyphonically. The device will play 8 polyphonic voices.
The device responds on ALL midi channels.

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b. Mode 1: Omni On/MONOPHONIC. It receives channel messages sent on any channel
and plays notes monophonically. The device will play monophonically with the same
note playing on all 8 outputs. The device responds on ALL midi channels.
c. Mode 2: SPLIT-LOW-POLY MODE. The device will play 7 polyphonic voices on outputs 2-
8 for keys on and below the split and monophonically on output 1 for keys above the
split. The device responds on ALL midi channels.
d. Mode 3: SPLIT-HIGH-POLY MODE. The device will play 7 polyphonic voices on outputs 2-
8 for keys on and above the split and monophonically on output 1 for keys below the
split. The device responds on ALL midi channels.
e. Mode 4: SPLIT-POLY-POLY MODE. The device will play 4 polyphonic voices on outputs 1-
4 for keys on and below the split and 4 polyphonic voices on outputs 5-8 for keys above
the split. The device responds on ALL midi channels.
f. Mode 5: Omni Off/POLYPHONIC. It receives channel messages sent on ONE specified
channel and plays notes polyphonically. Now the device will play 8 polyphonic voices
but the device responds only to the selected midi channel.
g. Mode 6: Omni Off/MONOPHONIC. It receives channel messages sent on a set of
specified channels and plays notes monophonically. Now the device will play
monophonically, with each input midi channel mapped to one output channel. The
initial midi channel sets the midi channel that will output from the device on channel 1.
The remaining 7 outputs will be assigned consecutively starting with initial midi channel
+1 etc.
h. Mode 7: Omni Off/Mapped. This mode will receive messages on three specified
channels and each channel will be mapped to a small set of polyphonic voices for each
channel. This mode effectively breaks the MIDI-CV-8 into three smaller MIDI-CV
converters, each responding to a different midi channel. The Midi Channel (channel x)
that the FIRST device should respond to defines the mapping. The device will output as
follows:
i. Play 3 polyphonic voices from channel x on outputs 1-3.
ii. Play 3 polyphonic voices from channel x + 1 on outputs 4-6
iii. Play 2 polyphonic voices from channel x+ 2 on outputs 7-8.
As an example, you can patch three outputs playing an electronic piano patch
responding to MIDI channel 1, three voices to a brass patch responding to channel 2
and the two remaining voices could be patched to percussion responding to channel
3. Your modular now acts like three small synthesizers, each with a different patch
responding to messages on their own MIDI channel.

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Use with a DAW
1. You can use the DAW to send midi sync and start/stop signals to the device and use these from
output jacks CLOCK and START. These jacks will send a 10V signal from these jacks.
2. Ensure that the DAW Sync output is switched on before starting the track otherwise no midi-
start messages will be sent on the clock track and the cock will begin randomly part way through
the track and will not be in sync with the track beats.
3. The Start/Stop signal is gated by default. When the midi-start signal is received, the output from
START remains high until the stop signal is received.
4. If using Ableton LIVE, set the sync to Pattern Mode for the start and stop signal. The device
doses not recognize the Song Position Pointer or "Continue" messages.
Commands
1. There are several commands that can be sent from the keyboard to modify the program of the
MID-CV-8. An understanding of the command mode is required to calibrate the DACs on the
module.
2. Playing modes are maintained after power off and the most recent settings will be available
when you power on the module again.
3. The various playing modes are maintained when the power is switched off.
4. To enter command mode
a. Send "All Notes Off" message to the Midi-CV-8. Or, on a keyboard, you can move the
Main Volume control to 0. If the control is already at 0, move it away from 0 and then
back to 0.
b. Next, you will need access to midi notes 0 to 20. Either by shifting octaves and
transpose controls until the lowest notes of the keyboard are accessible or using a
virtual "piano roll" interface on a DAW.
c. For MidiPlus AKM320:
i. Move the octave shift to its lowest setting by centering it and then pressing
octave down (-) 5 TIMES
ii. Move the transpose to its lowest setting by centering it and then pressing
transpose down (-) 5 TIMES

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d. For M-Audio Keystation 49:
i. Move the octave shift to its lowest setting by centering it and then pressing
octave down (-) 4 TIMES (The red LED over the (-) button will be bright red and
not flashing.
e. For M-Audio Keystation 61:
i. Press the "Advanced" button
ii. Press the key on the key on the keyboard marked "OCT"
iii. Press the "-" button multiple times until the "-" LED is red (two clicks)
iv. Press the "Advanced" button
v. Press the key on the keyboard marked "TRANS"
vi. Press the "-" button multiple times until the "-" LED is "brighter" green (12
clicks)
vii. You are now in COMMAND MODE
5. The commands are as follows:
a. ALL NOTES OFF. This is triggered as soon as the Main Volume is set to 0.
b. READY TO PLAY. Move the Main Volume from 0 to any value greater than 0.
c. Mode 0: Omni On/POLYPHONIC. Enter command mode. Play MIDI note 0 (usually the
first white key on the left). Now the device will play 8 polyphonic voices. The device
responds on ALL midi channels.
d. Mode 1: Omni On/MONOPHONIC. Enter command mode. Play MIDI note 1 (usually the
1st black key on the left). Now the device will play monophonically with the same note
playing on all 8 outputs. The device responds on ALL midi channels.
e. Mode 2: SPLIT-LOW-POLY MODE. Enter command mode. Play MIDI note 2 (usually the
2nd white key on the left). Now set the octave shift to the desired playing range and
play the note where the keyboard should be split. The device will play 7 polyphonic
voices on outputs 2-8 for keys on and below the split and monophonically on output 1
for keys above the split. The device responds on ALL midi channels.
f. Mode 3: SPLIT-HIGH-POLY MODE. Play MIDI note 3 (usually the 2nd black key on the
left). Now set the octave shift to the desired playing range and play the note where the
keyboard should be split. The device will play 7 polyphonic voices on outputs 2-8 for

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keys on and above the split and monophonically on output 1 for keys below the split.
The device responds on ALL midi channels.
g. Mode 4: SPLIT-POLY-POLY MODE. Play MIDI note 4 (usually the 3rd white key on the
left). Now set the octave shift to the desired playing range and play the note where the
keyboard should be split. The device will play 4 polyphonic voices on outputs 1-4 for
keys on and below the split and 4 polyphonic voices on outputs 5-8 for keys above the
split. The device responds on ALL midi channels.
h. Mode 5: Omni Off/POLYPHONIC. Play MIDI note 5. Now set the Midi Channel that the
device should respond to by pressing the corresponding key (Valid keys are 1 - 16). Now
the device will play 8 polyphonic voices but the device responds only to the selected
midi channel.
i. Mode 6: Omni Off/MONOPHONIC. Play MIDI note 6. Now set the Initial Midi Channel
that the device should respond to by pressing the corresponding key (Valid keys are 1 -
9). Now the device will play monophonically, with each input midi channel mapped to
one output channel. The initial midi channel sets the midi channel that will output from
the device on channel 1. The remaining 7 outputs will be assigned consecutively
starting with initial midi channel +1 etc.
j. Mode 7: Omni Off/Mapped. Play MIDI note 7. Now set the Midi Channel (channel x)
that the FIRST device should respond to by pressing the corresponding key (Valid keys
are 1 - 14). Now the device will output as follows:
i. Play 3 polyphonic voices from this channel on outputs 1-3.
ii. Play 3 polyphonic voices from channel x + 1 on outputs 4-6
iii. Play 2 polyphonic voices from channel x+ 2 on outputs 7-8.
k. TUNE. Enter command mode. Play MIDI note 10. Now set the octave shift to the
desired playing range and play the note to be tuned. The device will play this note
continuously from all outputs until the ALL NOTES OFF command is sent. See (a).
l. The device also responds directly to these built in commands if your keyboard sends
them:
1. ALL NOTES OFF
2. POLYPHONIC ON
3. MONOPHONIC ON
The device does not respond to the built in commands OMNI-ON or OMNI-OFF
since there is not enough information sent to fully program the MIDI-CV8. You

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will need to use the command mode settings described earlier to set these
modes.
Calibrating the MIDI-CV-8
If you bought PCBs or a kit, you should only need to calibrate the unit once. If you bought a pre-built
and tested unit, you can skip this section.
1. Power up the device and allow it to warm up for a few minutes
2. Send "All Notes Off" message to the Midi-CV-8. Or, on a keyboard, you can move the Main
Volume control to 0. If the control is already at 0, move it away from 0 and then back to 0.
3. Next, you will need a method to send midi notes 0 to 20. Either by shifting octaves and
transpose controls until the lowest notes of the keyboard are accessible or using a virtual "piano
roll" interface on a DAW.
4. Enter command mode (see above). Play MIDI note 1 (usually the 1st BLACK key on the left).
Now the device will play monophonically with the same note playing on all 8 outputs.
5. Connect the –VE probe of a multimeter set to the 20V range to your power ground.
6. Plug in a patch cord to CV socket 1
7. Connect the +VE probe of the multimeter to the patch cord.
8. Plug in the MIDI keyboard to the USB jack on the front panel.
9. Play and hold C3 (MIDI note 48) and read the voltage. This is a C note octave 3
10. Adjust the trimmer for channel 1 (corner of the board) until exactly 4.00V is displayed on the
multimeter
11. Play C1 (MIDI note 24) and make minor adjustments to the trimmer for channel 1 until exactly
2.00V is displayed on the multimeter. Try the following also:
a. C2 (MIDI note 36) = 3V
b. C3 (MIDI note 48) = 4V
c. C4 (MIDI note 60) = 5V
d. C5 (MIDI note 72) = 6V

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e. C6 (MIDI note 84) = 7V
12. Repeat the adjustments until you have the tracking as close as possible to 1V per octave.
13. Now do steps 4-9 for each of the remaining channels 2-8 by moving the patch cord into the
relevant jack socket and testing the voltages.
Tuning your Synthesizer
1. Power up the device and the synth and allow them to warm up for a few minutes
2. Produce a tone from your synthesizer using a selected VCO and chosen ADSR, VCA, filters etc.
Set the VCA so that it has 0 initial gain and is waiting for a gated envelope shaper to run the VCA.
3. Connect the CV and gate jacks of Channel 1 to your synth VCO CV input and envelope shaper
GATE input respectively.
4. Enter command mode (see above). Play MIDI note 4 (usually the 3rd WHITE key on the left).
Now set the octave shift to the desired playing range and play the note to be tuned. The device
will play this note continuously from all outputs until the ALL NOTES OFF command is sent. See
"Commands" above.
5. Play C3 and you should hear the tone on your synthesizer. This is a C note octave 3
6. Use the synth VCO frequency controls to obtain the note C3. (Approx 131Hz)
7. Tune C1 to C7 to hear all the C notes from Octave 1 to 7 using step and 5 again.
8. Repeat steps 3-7 for each VCO to be tuned. You can use any of the channels on the MIDI-CV-8
for tuning.
9. You can tune the synth to other frequencies if you know what you are doing!