Synthi VCS3 Poly Midi-CV Interface
Same spec as for the Synthi AKS poly Midi-CV unit but built into
Afrormosia hardwood case and designed with a VCS3 mk2 + DK keyboard
controller in mind.
It is based around Marc Bareille’s fantastic multi-channel PiC microcontroller based Midi-CV converter called the ‘MCV876’.
See details of Marc’s unit at his website:-
MCV876 Midi
to CV
The MVC876 comes in 3 or 4 channel hardware versions and a clever intelligent ‘midi–learn’ feature (see Marc’s website) .
The Synthi VCS3 Poly Midi-CV uses the 3 channel unit.
The units come with the latest firmware programmed into the onboard microcontroller (pic182320). Thie units supports both mono and polyphonic play modes. Marc has created a simple windows software interface that allows the Midi-CV (either 3 or 4 channel versions) to be configured in different ways to offer different functionalities, all via midi sysex.
Control voltages CV1-CV3 is relevant for the Poly Mid-CV, CV1-CV4 is available for the 4 channel Quad Midi-CV (see elsewhere)
Mono* CV1-Gate1 assigned to NoteOn/Off messages
* CV2, CV3,CV4 are assignable to controllers, velocity or PitchBend..
* Gates 2,3,4 are assignable to controllers.
* One channel recognition
Multi2
* CV1/Gate1 and CV2/Gate2 are on channel N - CV1 assignable to MIDI notes
* CV3/Gate3 and CV/Gate4 are on channel N+1 - CV4 assignable to MIDI notes
Multi4
* CV1 to CV4 and Gate1 to 4 are respecxtively on channels N to N+4
* CVs or gates can be assigned to MIDI notes or controllers independantly.
Poly2
* CV1 +Gate1 and CV2+Gate2 are assigned to NoteOn/Off messages
* CV3 and CV4 are assignable to controllers, velocity or PitchBend..
PIC18F2320 only
Poly4
* CV1 to CV4 and Gate1 to 4 are assigned to NoteOn/Off message
PIC18F2320 only
The unit has Envelope Shaper (ES) trigger assignable to either DK
trigger or any of the 4 gates (gate1-gate4) via a front panel rotary
switch. How many of the 4 gates are available depends on the mode
used. Eg in Poly2 mode, only 2 gates are available (gate1 and
gate2). In poly4 mode or Controller mode all 4 gates are available
to trigger the ES. Gates 5 and gate 6 outputs are via 6.35mm jack
sockets and offer Midi start/Stop and Midi clock signals for
interfacing/synchronizing with other external midi devices.
There are 3 front panel level pots for CV1-CV3. Also there are 3
toggle switches that can flip the scaling between 0.32V/Oct
(standard synthi Oscillator scaling) or 1V/Oct when pots are set to
max level (10). The 1V/Oct option is useful if a CV channel is being
used as a modulation source rather than give pitch control of a
synthi Oscillator.
Toggle switches allow independent switching of DK control or Midi-CV control of each of the 3 independent CV input channels of the VCS3 mk2 matrix (Input Ch1, Input ch2, and row 16 of the matrix). So its possible eg to run DK controlled pitch via matrix row 16 and midi generated pitch sequences via CV1 and CV2 controlling Osc1/Osc2 in Poly2 mode and gate controlled via KS or gates 1-4. There is also the option to invert CV3 source into row16 of the matrix via another toggle switch..again adding to the creative possibilities.
The unit derives its power from VCS3 mk2 and is about 100ma mainly from the +12v side of the power rail. Tests on my VCS3 (mk2)+DK2 power rails show there is more than enough power in the main PSU (which is same as the Synthi AKS Main psu) to cover this additional drain even with the DK2 powered up.
The unit will work with a VCS3 mk1 but you wont have use of CV3 as
mk1's dont have the additional feature of allowing matrix row 16
to be used as an external input.