Synthi VCS3 Quad Midi-CV Interface
New Feature! Three 20-turn trimmers on rear to adjust 0.32v/oct scaling for cv1-cv3. This allows setting up of chromatic oscillator scaling irrespective of whether or not your synthi oscillators are tracking precisely at 0.32v/oct .
This is a Quad Midi-CV unit designed to be used with a Synthi VCS3 mk2. Its basically the same spec as the Synthi AKS Quad Midi-CV. It is based around Marc Bareille’s fantastic 4-channel microcontroller based Midi-CV converter called the ‘MCV876’ (which Marc has kindly allowed me to incorporate in the modules)
See details of Marc’s unit at his website:-
MCV876 Midi to CV
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.
Red and green panels LED’s light when midi Gate 1 and/or Gate2 are triggered.
Gates 5 and gate 6 outputs are via 3.5mm 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 AKS matrix (Input Ch1, Input ch2, and row 16 of the matrix).
There is also the option to invert CV3 source into row16 of the matrix via another toggle switch..again adding to the creative possibilities.
Finally Cv1-CV4 are also available via special cable that connects to the unit with 4 ems patch pins on one end and mini-din plug on the other. The CV is connected to the tip of the pins only and is designed to be able to inject CV1-Cv4 into any of the synthi control inputs (ie matrix columns). The pins are colour coded with green, blue and yellow corresponding to CV1-CV3 and black to CV4.
The point of this cable is that CV1-Cv4 can be used even when control of the synthi input channels is via the DK (via the toggle switches). So its possible eg to use the DK keyboard and still have cv1-cv4 available via the matrix pin cable to add dynamic envelopes etc created via midi for e.g. filter control, Reverb mix, ouput channel level envelopes etc..
PlayModes
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
It can be used e.g. with 3 of
the 4 channels being used to inject CV1-CV3 into the matrix (Input Ch1,
Input Ch2, row16) and the 4th channel used to offer noveltriggering
modes of the ES.
The unit derives its power from VCS3 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.