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 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.
Expert Sleepers
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
config. I use it with Buchla & well as Korg.
The CVs are digitally controlled which makes for high precision.
Endorphin.es
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.
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)
Kenton
Pro-solo
Pro-2000
Korg synths & sequencers
MS 20
MS 20 mini
MS 50
VC 10 (vocoder)
X-911 (guitar synth)
MS-02
MS-03
SQ-10 sequencer
SQ-1 sequencer
SQ- 64
Tracks A,B and C are for melodic/chords tracks and all have GATE/CV and MOD control voltage outputs for modular gear
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.
Ladik
U-202 V/oct to Hz/V converter (4HP) eurorack
U-201 Hz/V to V/oct converter (4HP)
+ Polyend
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
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
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”.
XOR Electronics
Nerdseq - eurorack tracker sequencer
Yamaha Synths
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 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
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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 it).
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.