Hz/volts - synths and sequencers

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 - cheap & flexible.

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

A-190-1 MCVS 

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

ED102 - Octave-Volts-Hertz

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.

MS10

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

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.

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

RK7 VCO (eurorack)

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

The Deluge has been designed to support the widest range of CV / gate standards possible. 

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 

-------------------------------------------------------------

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.

Endorphin.es - West coast patch notes

Some Basic West Coast Patch notes using mainly endorphin.es modules

Out of Furthr ---> in of LPG (Terminal or Takaab LPG)

The main sound source is the final output (triangle icon on a modern Furthrr) of the Carrier.

The Furthr is a complex oscillator made up of a mod osc and a carrier osc.

It's layout is close to a Buchla 259.

 

 

 

The terminal is made up of two LPGs and two modulation sources.

Reminds me a bit of the Buchla 208 LPGs and envelopes.

These envelopes/modulation sources are called Airplane A & Airplane B.

We are using these on the Furthrrrr generator.

 

The unedited video:

 

Airplane B modulates the waveshaper of  the Carrier Osc

Airplane B modulates the frequency (via the ‘mood index’) ... those 4 switches

which separate the mod osc & Carrier osc.

Just using the unipolar outputs of both airplanes.

 

 

Using CV output #9 of the shuttle control.

It's connected to a Faderbank 

see post:

• Endorphin.es Shuttle control & faderbank 16n

..

This is sending out a LFO/SH .. the timing is controlled by the 16n

CV output #10 is also good for this patch

Its sending out a fluctuating LFO

 Envelope A (Airplane A) modulates the decay of Airplane B

 

Finally using shuttle control outputs  1 and 2

They are plugged into the main CV in of both MOD and CARRIER oscillators

of the Futhurr 

 

 See post

Endorphin.es Shuttle control & faderbank 16n

Allows a bit of octave shifting

Endorphin.es Shuttle control & faderbank 16n

 The Faderbank -16n 

is a excellent controller for the Endorphin.es Shuttle control

 

It sends midi CC messages via the USB

The editor is at:

https://16n-faderbank.github.io/editor/

 

You should see a page like this

 

 

The 16 channels correspond to CC values from 32 to 47 (default)

You can of course customize this.

I decided to leave the CC values as they are for the moment

Set all the channels to Omni

 

The 16th jack is being used as my master clock.

It's a square LFO responding to CC 47

 

Happy 909 day

 The Queen of Pentacles just arrived in time for September 9.

Thank you endorphin.es & Happy 909 day

 

I don't know which drum I like the most.

I really like both and will probably keep both

They each have 7 voices.

The queen has 3 analog drum voices and 4 sample based voices. You can put your own samples in the SD card which is at the back on the module.

I dont mind this. Its a drum machine, not a sample player. The real estate is better utilised with more controls and effects than a SD card slot.

 

It's not a clone / copy of the Roland TR 909 which I'm happy about. We need new drums. 

Apparently, the 3 analog voices are based on 909 circuits ... but there is no intention to just copy.

This is so refreshing to see. Thank you Endorphin.es for creating something new, which still honours the past.

 

If you want a 909, get one.

 

The Blck Noir.

Here the circuits are loosely modeled on the Roland CR-78. 

Though it sounds nothing like my 78.

It's a little more noisy (in a good way) and the extra effects and controls open up the beast.

It reminds me of the DFAM. both very different, but industrial and metallic sounding.

It shares the same effects and filter as the Queen.

The voices are

• Kick
• Snare-drum
• Tambourine
• Closed hi-hat
• Open hi-hat
• Cymbals
• Metal beat

Missing the Guiro. It does have the "metallic beat" ..an accent that can be overlaid on the hi-hat voice

which I think sounds really neat.

The Master isolator-style LP/HP filter is great.

Playimg around with the DinSync 303 filter.

Sounds great.

The Endorphin.es Terminal is the old model .. just a buchla style LPG

 

 

 

The output of the Terminal is patched into the VCF 303 filter

I'm using the Terminal's LPG & left envelope Generator along with the Dinsync VCF 303 filter. 

 

The sound source is a endorphin.es furthrrrr generator. 

Sequencer : Winter Modular Eloquencer

Endorphin.es Terminal - function generators & LPGs

 I just received this in the mail. It's an Endorphin.es Terminal.

I think they were first produced in 2013 ???

 

 

This module is now discontinued and replaced with the Grand Terminal.

Though the original Terminal doesn't have the 8 filter types of the Grand Terminal I couldn't resist the old school dual voltage controlled AD/AR/looping envelope generators & analog vactrol LPGs.

 

Together with a Furthrrrr Generator module the Terminal creates one full West Coast voice. 

It's quite a complex and dense module, with lots of functionality.  Reminds me very much of a Maths.

The whole module uses the analogy of flying.

The 2 envelopes of the Terminal are called airplanes ... the takeoff and landing being analogous to attack / decay. There is a airport terminal, gates, exits, trip selectors, check-ins, cabin pressure & relative height.

As the module uses real vactrols I was hoping I could get similar sounds to my Buchla & Serge systems.

I'm not disappointed.

 

It's a fun module to own if you like DIY electronics.

The rear of the module has sockets for a quick and simple exchange of vactrols.

You can use the factory supplied opto-couplers, replace them with other ones or even roll your own.

 

You can use the Terminal to create envelopes, LFOs, and even Oscillators.

 

It's very reminisent of the Serge DUSG ... dual universal slope generators.

Just like in Buchla systems, the  gates are VCA/VCF combos.

The two red centre knobs open up the VCA and the two opto-coupler-controlled 

Sallen-Key 12 dB lo-pass filters.

The VCA/Filter section is in the centre of the module. 

These are called gates.

 

As mentioned earlier, they use vactrols which impart a "natural sound".

 

This occurs because altering the gates offsets changes both frequency cutoff and amplitude of the signal.

This gives a "natural musical" response, similar to acoustic instruments. 

 

Each gate has attenuverting CV input and gate A (left) has an attenuverting audio input.

 

 

 

 

 

 

 

 

When you open the gate, you will hear the sound getting louder and clearer. 

You can patch the gate to get other filter types apart from LP.

To get a high pass effect plug the same signal into both gates. 

Then invert the gate A using the bipolar attenuverting audio input.

The high pass effect is created by the mixing of the LP signal in gate B, with the inverted signal

of gate A.

 

The aux input and the attenuverters allow you to create hipass, bandpass gates, etc

There is no resonance control by patching the mono final output (marked with a loudspeaker) 

into the input of a gate. It's a feedback loop. It's probably better to send this into gate A since you will have additional control over the input phase and volume, given by the attenuverting knob.

 

The envelopes are on the left and right. 

In the Buchla world, they are called Function Generators.

In the Endorphin.es world, they are referred to as Airplanes.

The envelopes have 3 modes -- called the trip selectors.

1. cycling / looping

    (trip selector in far left position). Use this for LFOs or

    an oscillator depending on 

     the frequency of the cycle. Self triggering.

 

2. transient

    (trip selector in the middle position).

    This is a simple A/D envelope with no sustain.

    " the Airplane performs a take off after an incoming trigger 

     signal (may be short trigger or constant gate higher

      than 0.65 volts). Reaching the top of the ascent level, 

       the Airplane immediately performs a landing" (Endorphin manual).

 

3. cruise

    (trip selector to the far right)

    an Attack/sustain/ Decay envelope.

    " the Airplane takes off to thee highest level after 

      receiving a trigger/gate (higher than approximately 0.65 volts 

      constant signal) and stays in cruising mode as long as the

      gate signal remains high. At any moment the gate signal drops, 

      the Airplane performs  the landing. 

      During landing the Airplane will immediately gain altitude when a

                                                               trigger/gate arrives." (Endorphin manual).

You can either manually or with CV set the slope of these envelopes from linear to exponential or Log.

This is set via the 2 bottom black knobs/jacks on each airplane.

 

 

Each airplane also has unipolar(right) and bi-polar outputs(left) output jacks.

The bipolar one flashes red/green.

These are called Exits.

 

 

Trigger outputs are sent at the "End of (each) Stage", (end of Rise, end of Fall), of the envelope.

 

The gates can be pinged (opened) with a short trigger like the ones that come from the end of stage outputs.

 

This pinging of the gates sound is often referred to as the Buchla Bongo. To achieve this sound the trigger should be connected to the gate’s CV input and the attenuverting knob in full clockwise position.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cabin Pressure

This is a digital effect. It's a sort of echo/reverb/chorus.

It's intended for adding air to live performances.

 

Relative B height / Peak detector

This is useful for creating ADSR type envelopes.

The attenuating knob decreases the height of airplane B (relative to airplane A) .

Triggering both airplanes creates the combined envelope.

The peak detector tracks both airplanes and outputs the max of both. 

The CV output is the jack to the right of the Relative B height  attenuating knob.

The Attack and Decay stages are defined by the take off and Landing rates of Airplane A.

Sustain will be defined by the ‘relative Airplane B height’ knob and Release by the Landing rate of AirplaneB

 

 

 

 

Links

+ Official 

+ Manual

 

 

Julia Bondar: studio recording fragment from upcoming album

..

Very Cool.

It's so refreshing to hear danceable electronic music.

Hopefully more artists like Julia, come to Australia when the borders open.

Endorphin.es - Shuttle Control - choosing a USB controller

 Some of the midi controllers that work with the Shuttle Control

The old Korg Nano Control

 

 The Teenage engineering OP-1

The OP-z is particularly interesting as it has 16 midi tracks.

The online editor was a bit tricky at first to decipher, but these settings seem to 

work OK with the OP-Z

I decided to use jacks 5,6,7,8, & 13,14,15,16.

These correspond to midi channels 5, 6, 7, 8 which the OP-Z uses

for its Bass, Lead, ARP & Chords tracks.

I'm still experimenting with the rest of the jacks.

They could be sources of random voltages, LFOs, envelopes, Sync clocks, etc

-----------------------------------

To add a "analog clock" set one of the channels to

Omni       syncronization         PPQN+ 24 (1/4)

This is great for driving a sequencer

 

To divide the clock in half just use a PPQN +48 setting

 

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My Personal presets

Page 1 : OP-Z

Page 2: Abelton Live

Page 5 : 16n faderbank