An optimal solution to convert MIDI signals to Control Voltage is to use a MIDI/CV interface. Almost every modular synth manufacturer has its own interface, more or less complex, to let their machines interact with a digital system. In the modular world, however, MIDI/CV converters are individual modules to be integrated into an already existing system that includes a case, a power supply and a distribution bus.
In contrast, several semi-modular synth manufacturers, such as Arturia with MicroBrute or Korg with SQ-1, are creating stand-alone machines with integrated MIDI/CV and several panel CV inputs and outputs, to patch them with the modular analog world.
Resuming the setup of the previous post, we are able to use the MicroBrute sequencer to play Volca Modular and in addition use the MicroBrute MIDI IN input to control its sequencer with Akai MPC1000.
If we don’t want to use the Microbrute sequencer but only its MIDI/CV converter, we can program the Volca Modular notes directly on the MPC1000.
It’s interesting to mention that Arturia MicroBrute can also work as a USB/CV converter, thus allowing a software sequencer like Ableton Live or Logic Studio to control modular synths, without having to use extra equipment.
However, as explained in part 2 of this series of articles, “Arturia Microbrute doesn’t recognise velocity commands if they are sent via MIDI but only if they are sent by computer via USB.
In this case it will be useless to program the Microbrute track paying attention to the velocity, since they will not be recognised anyway from the synth.”
We can immediately realise the limitations imposed by a MIDI/CV interface that doesn’t convert anything other than Gate and Pitch, as the executive expressiveness given by the velocity control and the synchronization given by the Clock would be lost.
Clearly it also depends on the synth that receives the signals.
In the case of Volca Modular, in addition to Pitch and Gate, we have a Clock input available, to modulate the internal parameters while maintaining the same Bpm as the Master.
To do this we use Doepfer’s MIDI/CV A190-1 interface, which allows us to take advantage of Volca Modular’s full potential.
Without going into the technical specifications of A190-1, which we’ll see in the next post, we immediately notice Clock, Gate and CV1 (Pitch) outputs that we’ll use to control Volca Modular.
Connect the left channel/tip of a Y-cable to the A190-1 Gate output and its right/ring channel to the Pitch output. The stereo end of the Y-cable is then inserted into the CV-In input of Volca, from which we take the CV/Gate voltages properly scaled. We use a normal patch cable to connect the Clock output of A190-1 to the Sync input of Volca Modular.
As previously seen, on the MPC1000 we select the MIDI channel related to A190-1, while the Clock is received automatically. In order to use the Volca sequencer we have to activate it by pressing PLAY, so it can sync to the MPC1000.
In the next article we’ll see how to use the A190-1 MIDI/CV interface to control a Doepfer A100 system via MPC1000, see you soon!
