ye olde synthesisers of yore used a DC analogue voltage as a control mechanism, this is a simple document for my own considerations.
there are 3 basic variations of "sequence" voltage sent
- CONTROL VOLTAGE, sends variable voltages, used for wide ranging parameters such as pitch (or really anything with a patch point).
In regards to pitch there are different systems, however 2 major protocols have emerged [Volts per octave, Volts per hertz].
The voltages used varies per manufacturer/device. (with voltage range being related to the octave range of the device)
CV range examples (to demonstrate possible voltage range)
Volt/oct. the voltage range demonstrates the octave range, eg 0V to 7V (7 octave range) and +/- 2V for pitch bend (2 octaves)
Hz/Volt. 0.0625V to approx 13V, (7.5 octaves)
- GATE, basically sends 2 opposing states, off/on (eg 0V - 5V).
These generally either open the VCA to allow signal through, or trigger an Envelope tied to the VCA
CV/ Gate are sufficient to send simple melodic info.
The Clock Trigger is a regular pattern of voltage pulses (generally 5V) signifiying timing steps. eg 24 pulses per quarter note (PPQN).
Roland DIN sync (SYNC24) is a regular pulse at 24ppqn, Korg uses 48ppqn.
Clock systems with a simple pulse use Tip Sleeve cables, others use Tip Ring Sleeve allowing a 0V=stop and 5V=start signal.
for note triggers;
S-trig shorts the signal path and is not common.
Useful Device Information
Akai MAX49
CV - 0V to 5V (1V/octave)
GATE - ??
Arturia Beatstep Pro
CV. either
1 V/Oct (0V-10V corresponds to Midi note 0-127)
Behringer Neutron
CV - 1v/octave
Behringer TD-3
Sync in - More than 2.5v
CV out - 1V to 5V
Gate out - 0V to 12V
Korg Monotribe
is switchable between either Oct/V or Hz/v, also between active high/low for Gate.
CV must be limited to 5V and gate to 20V
KORG Volca Beat
SYNC IN - max 20V
SYNC OUT jack sends a 5V pulse of 15 ms at the beginning of each step.
