Erica Synths MIDI-CV User manual

GUIDE TO ASSEMBLY OF ERICA SYNTHS MIDI-CV MODULE
If you are reading this, most probably, you are about to build Erica
Synths DIY MIDI-CV module. This module is 35mm deep, skiff
friendly, has solid mechanical construction and doesn’t require
wiring. Erica Synths Black MIDI-CV is compact, highly accurate and
easy to use duophonic MIDI interface. It emulates classical
monophonic and duophonic synth behaviour, as well as can be
configured for use in two independent MIDI channels. Bonus
features –MIDI clock output and analogue glide circuit on both
channels.
The DIY MIDI-CV kit comes in three versions:
1) 2PCBs + pre-programmed controller chip + connectors + glide
potentiometer,
2) 2PCBs + pre-programmed controller chip + connectors + glide
potentiometer + panel,
3) Full kit.
FEATURES:
•Two CV and Gate outputs
•MIDI clock output (4ppq –sequencer friendly)
•Configurable MOD output –modulation wheel or velocity
•Analogue glide on both MIDI channels
•One or two MIDI channel configuration
•One or two voice switch
SPECIFICATIONS:
•CV range 0-8V
•Max CV deviation 0.001V; 1cent
•Gate and Clock level 5V
•Glide time 0 –2”
•Module width 6HP
•Module depth 35mm
•Power consumption +40mA, -9mA
1
3
4
2
5
6
1
2
3
4
5
6
Use this knob to set the glide time on the
output CV! It affects both channels
simultaneously.
This is Modulation CV output. You can
configure it for modulation wheel CV output or
key velocity. Refer to the table below!
These are CV outputs.
These are Gate outputs, LEDs indicate active
gates.
This is Voice switch. In one MIDI channel mode
you can select between one voice mode
(highest note priority) or two voice mode
(highest and lowest note priority).
This is 4ppq Clock output –ready to control
your sequencers. In two MIDI channel mode
make sure, only one MIDI device has MIDI
clock activated.
8
7
7
Push PROGRAMM button promptly to send
MIDI panic message. Push and hold the button
and you will enter configuration mode. Please,
refer to the table on configuration settings.
8This is MIDI input, obviously.
Setting MIDI
channel
Connect MIDI keyboard to the module! Push and hold
PROGRAMM button for 2”. MIDI LED will start to blink slowly.
While holding PROGRAMM button, select midi channel by
pushing a key on the keyboard. C of any octave corresponds to
MIDI channel 1, C# - channel 2, D –channel 3, etc. Channels 1-12
can be assigned to send midi messages to the module.
For two MIDI channel configuration push two keys
simultaneously. CV1/Gate1 will be assigned to the lowest midi
channel, CV2/Gate2 –to highest.
As you release PROGRAMM button, the module will advance to
MOD output configuration.
MOD output
configuration
In MOD output configuration mode MIDI LED starts to blink
faster.
If you wish to assign a modulation wheel to MOD output, simply
rotate it on the midi controller.
If you wish to assign key velocity to the MOD output, push any
key on the keyboard.
Push PROGRAMM button to confirm, and the module will exit
configuration mode.

Take precautions with regard to electrostatic discharge (ESD) safety. Handling components should be done in
electrostatically safe environment. Use personal and workplace grounding. Any discharge (even a minor one)
from body to a component may permanently damage it.
Our PCBs have silkscreened both component values and designators nevertheless we highly recommend you to
print out files with component placement before you start assembly of the module. And, please, at least take a
look on this manual!
Some components are marked as NU (not used) –leave those unpopulated! Some components are market as
OPTION (those are for optional modifications) –leave those unpopulated for now.
ASSEMBLY
1Solder resistors and diodes on both PCBs (Controls board and Main board) and ferrite beads on the controls PCB!
Pay attention on orientation of diodes! In order to save space and make the module more compact, resistors on
main board are installed vertically (you also may want to replace them with 0805 smt resistors). See the close-up
for correct installation! Pay attention on resistor placement – don’t accidentally install them in the testpoint hole!
2Solder IC sockets on the Main board, capacitors, jacks, potentiometer, switch and the pushbutton on the Control
board!
GUIDE TO ASSEMBLY OF ERICA SYNTHS DIY MIDI-CV INTERFACE
Controls board
Main board

3Turn the Controls board around and solder two
resistors, female connectors, PSU connector and
electrolytic capacitors! If you use 10mm high
capacitors (most common ones, and ones included
in the full kit), solder them horizontally!
5Use M3 screw to fix the 11mm spacer!
GUIDE TO ASSEMBLY OF ERICA SYNTHS DIY MIDI-CV INTERFACE
4Solder ceramic capacitors, electrolytic
capacitors, ferrite beads and 16MHz
crystal on the Main board!
Solder these
horizontally!
This is the negative lug of
the electrolytic capacitor!
6Turn the Main board around and solder male
connectors and an electrolytic capacitor!

7Use two black M3 screws and nuts to fix DIN5 midi
connector! Midi connectors typically are installed
upside down. Solder wires to lugs 4 and 5
9Insert ICs, connect both boards together
and fix with M3 screw!
GUIDE TO ASSEMBLY OF ERICA SYNTHS DIY MIDI-CV INTERFACE
8Place LEDs in the relevant places (mind the
polarity), but do not solder them yet! Install
the front panel, fix it with jack and
potentiometer nuts! Push the LEDs in relevant
holes on the front panel and solder them. Cut
off their pins! Also solder MIDI connector wires
in the relevant holes!
10 Congratulations! You have completed
assembly of Erica Synths DIY MIDI-CV
interface! Now it’s time to do some
calibration!

CALIBRATION
With Erica Synths MIDI-CV interface you can achieve extremely accurate VCO tracking, therefore some calibration
is required.
You will need a VCO with good 1V/oct tracking, midi keyboard and a chromatic tuner.
Connect midi keyboard to the module, set VOICE switch to 1 Voice mode and connect CV1 output to a calibrated
VCO 1V/oct input and a chromatic tuner to the output of the VCO.
Disconnect MIDI-CV module from the PSU. Then push and hold PROGRAMM button and connect the module to
PSU busboard! MIDI LED will start to blink, which means the module is in calibration mode.
Play C3 on the keyboard, and tune the VCO so that tuner reads C3!
Play C4 on the keyboard and check the reading on the tuner. If it reads something higher than C4, play B3 on the
keyboard repeatedly until the tuner reads C4. If it reads something lower than C4, play C# repeatedly until the
tuner reads C4.
Play C5 on the keyboard and check the tuner. If it reads something higher than C5, play repeatedly B4 until the
tuner reads C5, etc.
Continue until you have perfect tuning along all octaves.
Push the PROGRAMM button to quit calibration mode.
NOW IT’S TIME TO USE THE MODULE FOR YOUR MODULAR MASTERPIECES! ENJOY!
GUIDE TO ASSEMBLY OF ERICA SYNTHS DIY MIDI-CV INTERFACE