Analog synthesizer manufacturers typically adopt one of several standards:
Hz per volt - used by Yamaha and Korg
1V per octave - used by Moog, Roland, ARP and Doepfer
1.2V per octave - used by Buchla and EML
0.32V per octave - used by EMS
0.26V per octave - used on oscillator 3 of the EMS VCS3
I've been playing a lot recently with my old Korgs.
I keep coming back to them. They are real classics !!!
They use the hertz/volts CV standard, meaning they follow a linear characteristic
where each successive octave requires a doubling of the control voltage.
In practical terms this means that the number of instruments which you can
successfully integrate with your vintage Korg synths is limited.
Here is a list ..
I'll update as I go along.
If I have missed any, please let me know so I can add it to the list.
Arturia
Beatstep Pro
Key step
Keystep Pro
Microfreak - one of the few modern synths whose sequencer can be configured to output Hz/v
Arturia Minibrute 2s
The MiniBrute 2S works. I suspect the rest of the "brutes" also work with old Korgs.
The standard used on most Eurorack modules and on Arturia's Brute series
of synthesizers is V/Oct (1Volt per octave),
however, it can be changed to Hz/V (Hertz per Volt) using Arturia's MIDI control center.
CVs in the range 0V-1V, 0V-2V, 0V-5V, and 0V-8V.
Five clock standards are supported, including analog clock, 24ppqn and 48ppqn.
Of special note, the Brutes, beatsteps, etc can convert analog clock to MIDI Clock and then
transmit this over MIDI and USB.
Thus you can synchronise MIDI equipment to those analogue clocks.
Keystep
The default is 1V/Oct , though this can be changed to Herz/Oct.
(1.2V /Oct is not supported).
Keystep pro
By default, the transmitted pitch voltage is compatible with the 1.0 V per octave standard,
To use a 1.2 V per octave or a Hertz per Volt (Hz/V) standard you can change the corresponding setting in the MIDI Control Center.
Microfreak
By default, the transmitted Pitch voltage is compatible with the 1v per octave standard.
To use the 1.2 V per octave standard, you have to change the corresponding setting in Utility>CV/Gate>Pitch Format or in the MIDI Control Center.
Gate signals can also have different output ranges (S-Trig, V-Trig 5V, V-Trig 10V). These too can be changed in Utility>CV/Gate>Gate Format or in the MIDI Control Center.
Doepfer
This is a MIDI to CV/SYNC Interface in Eurorack
You can set the CV to Hz/V and the trigger to -ve polarity
Expert Sleepers
Disting Mk1/2 (Eurorack)
Disting Mk 3
Disting Mk4
Silent way - software
It runs as a plug-in for your DAW
Elby Electronics
This is a eurorack module
Elektron
A4 - Analog 4
The synth's sequencer has a very flexible CV/gate
config. I use it with Buchla & well as Korg.
The CVs are digitally controlled which makes for high precision.
Endorphin.es
Shuttle control
PITCH 1V/OCT, PITCH 1.2V/OCT AND HZ/V are
the control voltages available
SHUTTLE CONTROL outputs +5V at C4 note
(the highest voltage SHUTTLE CONTROL can transmit).
Then 1 octave lower C3 will return +2.5V, C2: 1.25V, C1: 0.625V, C0: 0,313V, C-1: 0.156V and the last one C-2: 0.078125V (with pretty bad resolution however).
As you may see, the accuracy in the lower octaves is bad and on the edge of SHUTTLE CONTROL's CV resolution possibilities.
That is why the useful range for controlling such type of synthesizers is roundabout 3 to 4 octaves.
Future Retro
Mobius sequencer
G-storm
This is a eurorack module
Electro KVP Pitch CV + Gate Voltage Processor for MS-20
Harvestman aka Industrial Music Electronics
English Tear (eurorack)
Hexinverter
Mutant brain - polyphonic CV/gate
CV output resolution: 12bits (V/oct or V/Hz)
Keith McMillen
QuNexus - keyboard/sequencer
Use the editor to set this to 1 Volt per Octave, 1.2 Volts per Octave (Buchla) , or Hertz per Volt
Kenton
Pro-solo
Pro-2000
Modular Solo
Korg synths & sequencers
One thing to always remember is that although the MS-20 uses Hz/V, the
original Korg designers showed some forethought & added a TOTAL IN
socket on the patch panel.
This can be used as a V/Oct CV Input (with some careful adjustment of the
frequency modulation MG/T.Ext knob)
It's not a proper V/Oct CV in (I think its better suited to filter, than pitch)
but certainly better than nothing.
MS 20
MS 20 mini
MS 50
VC 10 (vocoder)
X-911 (guitar synth)
MS-01 - foot controller pedal
MS-02 - CV/trigger interface
MS-03 - signal processor
(Pitch to Voltage circuit)
MS-04 - pedal (CV modulation)
SQ-10 sequencer
SQ-1 sequencer
SQ- 64
CV out can be: Hz/V, 0.26V/oct, 0.32V/oct, 1V/oct, 1.2V/oct -
with voltage bias adjustment and 0V reference note adjustment (per track)
Gate out: 10V, 5V, V-Trig, S-Trig
Mod out: 0V-10V, voltage bias adjustment
Track D - the drum track has 16 possible tracks, via MIDI with 8 drum trigger
outputs for working with modular gear.
FK - 3 Korg Vol pedal (not really part of the MS range, but still works well with them)
FK - 5 korg pedal
Sigma - KP-30 analog monophonic synthesizer
Cool joysticks & 19 presets
It possesses Hz/V CV & gate
inputs/outputs
SE-500 Stage Echo
This is a Tape Echo machine.
Its has trigger inputs for feedback and turning the effect on/off.
There is also a CV input for controlling the speed
Torso Electronics
T-1 algorithmic sequencer
Ladik
U-202 V/oct to Hz/V converter (4HP) eurorack
U-201 Hz/V to V/oct converter (4HP)
Metasonix
S1000 Wretch Machine
RK4 Bandpass Filter/Osc (eurorack)
RK6 Dual-triode 12dB LPF
R-60 MIDI/CV interface
TM-3 SN80 Tube VCO
TM-2 filter
TM-1 Waveshaper/Ring Modulator
R54 Vacuum Tube Oscillator & Filter
R-55 Thyratron VCO
TS-23 DUAL THYRATRON VCO
+ Phillip Rees
Little MCV - Midi to CV converter
These are out of production, but I do see them come up
occasionally second hand on Reverb and Ebay
Can generate control voltages for the common one-volt-per-octave (logarithmic VCO, as used by Roland and Moog) system and the so-called volts-per-hertz (linear VCO, as used by Korg) system. CV type is selected by a slider.
+ Polyend
Polyend 2 - eurorack MIDI to CV converter
1-4 Gate (0-5V or 0-10V),
1-4 Pitch (0-10V, V/Oct, Hz/V, Buchla standard 1.2v/oct).
A really handy module that allows you to use the sequencer
of your choice
Pioneer
Toraiz Squid sequencer
2x CV OUT (V/Oct, Hz/V)
CV output range: 1V, 2V, 5V, 10V, ±5V (V/Oct) / 8V (Hz/V)
2 GATE OUT (V-Trigger, S-Trigger)
GATE output range: 5V, 10V (V-Trigger)
Sequentix
Cirklon sequencer
Its a MIDI sequencer but the
CVIO option adds 16 CV and 8 gate outputs.
The CV outputs support V/octave and Hz/V modes plus portamento/glide and micro-tuning options.
The gate outputs can be configured in 5V v-gate or S-trig modes.
Squarp
Pyramid sequencer
CV V/oct or CV Hz/V,
or exotic voltages like 1.2, 0.32 or 0.5 V/oct.
Synthstrom
Deluge - synth/sequencer
A number of settings are available in the settings menu.
Each CV output may be set, in 0.01V increments, to any value between 0.01V and 2.00V per octave, or to “Hz per volt”.
TouellSkouarn
Jedonian 1V/Oct-Hz/V bidirectional Converter (eurorack)
Moog
The original Taurus I
PAIA
4700/2700 modular
Fatman
XOR Electronics
Nerdseq - eurorack tracker sequencer
Yamaha Synths
CS-5
CS-10
CS-15
CS-20 / CS 20M
Cs-30 ... has a built in sequencer.
Cs-40 / CS40M
These old Yamahas are Hz/V but have a different range
than say the Korg MS-10 or 20.
The CS is scaled I believe at half the voltage of the MS
(Yamaha's probably 0.25 to 0.5 to 1v and so on instead of Korg's 1V to 2V to 4V)
It's still double each octave ....so they have the same scaling curve) but the range
is different.
In practical terms this means you can sequence it with something like a SQ-1
but you will probably find it won’t go down to the lower 0.25V?? octave of the CS.
(I don't think the SQ-1 goes below 1V in Hz/V mode).
It's interesting that Yamaha never made a independent CV/gate sequencer.
It's a shame, as this would have made things a whole
lot easier
So the question is why even bother to add these connections??
I think the answer was to aid with expansion.
ie joining more than one synth....
in order to make a multiple-system synthesizer
Zlob
Dual VCO
This is a DIY eurorack VCO
There is a control voltage input, and a switch for selecting exponential or linear cv in.
The exponential setting should be good for Korg & Yamaha keyboards & sequencers
The exponential setting should be good for Korg & Yamaha keyboards & sequencers
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Final thoughts & conclusions
As I compiled the list I found that there were actually quite a lot of sequencers
that use the Hz/V standard.
It's a testament to the MS20 in particular. It's legendary status ensured that lots and lots
of manufacturers chose to add a Hz/V option.
(Some even down right copied the synths).
I think it would be great if more manufacturers added a Hz/v option to new synths to add to this legacy.
I'd love to expand my MS system with a new 3 oscillator Korg MS 30
For the moment (as far as synths that can use this standard go),
I'll have to be satisfied with using old Korg, PAiA & Yamaha synths.
