Kenton Pro-SOLO MkII - Manual (Page 15)

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MIDI-CV converters can have up to four different types of outputs used to control analogue
synths, usually labelled CV, GATE, S-TRIG and AUX. Below is a description of what they do:
Pitch - CV outputs (V/oct, Hz/V)
The CV (control voltage) is a voltage that tells the synth what note to play. Most synths use
the 1 Volt per Octave (V/oct) pitch scaling system to control the pitch. This means, that each
octave is 1V (V=volts) apart (or 0.0833V per semitone).
For example, bottom C (MIDI note #36) corresponds to 0 Volts. The next C will be 1V, 2V, 3V
etc.. Synths using this system include Roland SH101, Sequential Circuits Pro 1, ARP Odyssey,
Oberheim OB 1.
Some other synths, most notably Korg and Yamaha, use a different pitch scaling system. This is
an exponential method called Hertz per volt (Hz/V). This means that for the next octave up,
the voltage is doubled. So bottom C (note#36) will be 0.25V, the next C will be 0.5V, 1V,2V,
4V etc.
If you are not sure which C is MIDI note #36, use MIDI analyser mode to check.
If you use a Hz/V synth with a V/oct pitch output (or vice-versa), the synth will play out of tune
but will not cause any damage to the synth.
Note - The Korg Monopoly is an exception. Although other Korg synths use Hz/V scaling, this
synth actually uses V/oct scaling.
Gate - (Or S-TRIG)
The GATE (sometimes called V-trig [voltage trigger]) signal is a voltage that tells the synth
when to play the note. The GATE voltage will usually be a positive voltage when the note is
on, and 0V when off.
Some other synths, like Moog, Korg, and Yamaha, use S-TRIG (Short Trigger) instead of GATE.
This signal still tells the note when to play, but it is a different type of signal (electrically). To tell
the note to play, the converter will provide a short circuit at it’s S-TRIG output (0V), and to turn
off the note the output will be open circuit (literally like opening and closing a switch).
A point to watch for; unless you know the synth, it will not always be clear what type of CV
and GATE signals are required to play the synth.
For instance, the Korg MS20 requires an S-TRIG signal, but the input is labelled TRIG. Another
example is the Yamaha CS5. The pitch input is marked CV, but requires a Hz/V signal. The best
way to check is either ask someone who knows, or just try all types of output till the synth
works correctly. If you do plug your synth to the wrong outputs, it shouldn’t do any harm,
although always start out with minimum voltages.
Here’s a general guide to the most common synths and how to hook them up to your converter
SYNTH MODEL CV OR
HZ/V?
S-TRIG OR
GATE
AUXILIARY
CONNECTIONS
NOTES
MINIMOOG CV S-TRIG (5V) FILTER OR LOUDNESS CINCH-JONES CONNECTOR NEEDED
MOOG PRODIGY CV S-TRIG (5V) FILTER KIT AVAILABLE FOR FILTER IF NOT FITTED
MOOG ROGUE CV GATE (5V) KIT AVAILABLE FOR FILTER
MOOG SOURCE CV S-TRIG (5V) KIT AVAILABLE FOR FITLER
ROLAND SH-101 CV GATE (5V) CLOCK IN (SYNC) KIT AVAILABLE FOR FILTER/MODULATION
ROLAND MC-202 CV GATE (5V) KIT AVAILABLE FOR CV/GATE/FILTER/SLIDE
ROLAND TB-303 CV GATE (5V) FILTER (SEE RIGHT) KIT AVAILABLE FOR CV/GATE/FILTER/SLIDE/ACCENT
SEQUENTIAL PRO-1 CV GATE (15V) FILTER
KORG MS-10/20 HZ/V S-TRIG (5V) ANY OTHER THERE ARE MANY EXTRA INPUTS ON THE MS10/20
KORG 700S/770 HZ/V S-TRIG (5V) FILTER KIT AVAILABLE FOR CV/GATE AND FILTER
KORG MONOPOLY CV GATE (15V) VCF/PORTAMENTO ARPEGGIO CAN ALSO BE CONTROLLED
YAMAHA CS-10/20/30 HZ/V S-TRIG (5V) FILTER AVAILABLE FOR CS-5
ARP ODYSSEY (&AXXE) CV GATE (15V) KIT AVAILABLE FOR FILTER
ARP 2600 CV GATE (15V) FILTER
OCTAVE CAT/KITTEN CV GATE (15V) FILTER
A BRIEF GUIDE TO MIDI TO CV CONVERSION FOR THE BEGINNER