Sample and Hold - Not Holding

On a hardware MS-20, I would typically use the Sample & Hold to sustain voltages keyed by patterned triggers from the SQ-10 or the Keyboard. The Sample & Hold function on the MS20V seems to sample okay when triggered but does not hold the voltage (as I hoped and expected it would). For instance, put pink noise on the S&H input and the keyboard trigger out to the S&H clock input and route the output to TOTAL and turn up pitch mod. You’d expect to have a typical S&H random pitches with each keypress. However, when you release the key, the S&H circuit does not hold but rather passes through the pink noise. It’s worse if you use the Trig Out from the Sequencer and doesn’t seem to Sample or Hold. This seems more of a bug or oversight than a feature. Any thoughts?


I can confirm the behavior you describe, when using the connections you describe.
I also agree one normally would exspect the behavior you describe.

Are you sure it work like that on the hardware?

Have a look at this video KORG MS-20, complete in depth guide tutorial. Including patch bay - YouTube at 1:09:19 and forward. Especially at 1:13:30 about the BUTTON/ Momentary Switch.
Notice the noise, when the Button in that example is released. I think that’s what you talk about.

However - Reading in the manual about the S&H module, tell us that the original S&H module was a Track and Hold circuit.
This apparantly will let the noise determine the output, when you release the key.
I don’t know if the KBD trigger behavior is authentic or not. It trigger both on key down event and key up event. Can Arturia tell something about that?

You can use the External Signal Processors AMP input and output to get some results.

If you ie wan’t a single trigger of the S&H module, then you can do this:
Connect the BUTTON/ Momentary Switch trigger to the ESP input, and then connect the ESP AMP output to the S&H Clock input. Adjust the ESP SIGNAL LEVEL - start around 5 perhaps.
Now play a note and press and release the BUTTON. If you release the held key, then the last sample is held during the release phase without noise. For some reason the the BUTTON in this case work on Release. (I would like an explanation about that.)

You can ie also connect the Sequencer to the ESP like described for the button.

There might be other ways to get results.

BTW: The results is’nt allways the same when making connections in the patch panel in my exsperience. So i also find there are bugs in the patch panel. But i don’t know if this is authentic behavior or not.

Hi again LBH. Yes, that Bitwig demo shows exactly how I expect Sample and Hold to work. On each pulse/trigger/gate, it holds the voltage until the next pulse. In the MS20V the S&H Circuit seems to hold when the gate goes high, but does not continue holding when the gate goes low. I don’t have the hardware handy to compare but the video suggests it needs a narrow trigger to function properly. I also tried the S&H in Cherry Audio’s PS20 and that one actually holds as expected/desired but Korg’s MS20 plugins does not. So if you are S&Hing something with a long decay, it passes the source. Not a very desirable sound :slight_smile: Here’s what I’m mostly trying to do… create rhythmic patterns (some trigs on / some trigs off) in the sequencer to play long decaying sounds. Traditionally, you’d take the CV and trigger out of the sequencer and route them through a S&H circuit… so each triggered note sounds for as long as it needs (and the untriggered steps/voltages in between are ignored). I fear that unless Arturia fixes the S&H to work like the Bitwig demo or Cherry Audio PS20, it won’t be possible. Bummer.

Hi again John_young,

I don’t see the video confirm your exspectations.
Arturias version work excactly like the hardware Korg in the video with the same examples and settings. And there are noise in the video. (I don’t talk about Bitwig, but the Korg in the video.)
Where excactly do you see the Korg in the video work different from Arturias version?

The only problem is the video does’nt show an example using Key triggering and using long EG2 release time. I would like to see that.
I’m especially interested in what happens at Key up event. If it does’nt block the S&H output at Key up, then we will hear noise, when noise is used as the S&H input. It look like it does’nt block no matter it’s a manual Key trig or a Sequencer Key trig.
If it does’nt block in the hardware, then Arturias version is working Authentic in this case too.

I find there is a strange behavior and difference between Key down and Key up event, as the noise only is there when in Release phase and not in Sustain phase of the EG2. The original hardware do have some strange behaviors, but i don’t know if this is one of them. I hope Arturia will tell in this thread. Otherwise i suggest you ask Arturia support.

If you ie set EG1 to Trig mode, and then set all 3 EH1 parameters to minimum, and then use it’s positive output as trigger for the S&H Clock, then you get no noise when Noise is in the S&H input even when EG2 have Release time. (This is the method that give the result that i think you exspect by connecting the KBD trig directly to the S&H Clock.)
If you have attack and/ or Release time set, then you get noise.
And if you set EG1 to Gate mode, then you get noise holding the key down, which you don’t in EG2 - EDIT: Except when using EG2 as S&H Clock input EDIT END.
It look like the S&H Clock input respond to Gate signals, and that’s because a reason why it’s called Track and Hold?
This perhaps can help to understand, what i talk about.

I think if the S&H on the MS-20V functioned like the video showed in Bitwig or how Cherry Audio implemented it in their PS-20, it would be much more useful and musical. I just want the S&H to actually Hold the voltage between triggers. When I used to do it in hardware, I may have used the MS50’s S&H for this very reason. Either that or I modded the circuit with a soldering iron. It was a while ago :slight_smile:

Hi @john_young,

After consulting the DSP engineer that work on the project aswell as trying on our own original MS-20 I can tell you that what your describing is the actual behaviour of a Sample & Hold, however even tho ‘Korg’ labelled it this way, it behave more like a ‘Track & Hold’ (in the original units at least).
This design was made to either follows the signal or holds a value.
A regular sample & hold never follows the input signal.

Hope it answer your question :slight_smile: :pray:



Arturias Korg MS-20 V work like the hardware Korg in the video, when recreating the shown examples.

I think i have got my head around the KBD trigger behavior.
I’m not sure if Korg MS20 use a S-trigger or a inverted trigger.
But Korg MS-20 KBD trig send out signals when key up. It change when key pressed, and thus only trigger at initial press and then stop triggering while key is down because the present signal (or lack of signal) does’nt trigger the S&H modules Clock.
As Korg MS-20 S&H module actually is a Track and Hold, then it will keep tracking the constant signals coming from the KBH trig when Key up, and then be triggered all the time. This will result in hearing the modulated signal in the Release time phase.

So as i see it, then Korg MS-20 V work like the original hardware. That’s good.

However i don’t mind having added options like ie not having the S&H module tracking. Or whatever can be good addons.

Thanks Adrien. I understand. I may have used some voodoo (with the ESP or MS50/SQ10) to get the hardware to actual Hold the voltage between key triggers/gates. Probably complicated by the upside down logic of s-trig. But even the example in the MS20V manual isn’t very musically useful for anything but very short release sounds. It would be awesome if the circuit actually held the voltage from trigger to trigger (as described in the MS20V manual) " That voltage is sent to the OUT, and stays at that level until the next clock pulse causes the input to be sampled again." Anyway, much appreciation for listening and checking it out.

It does’nt sound like you have tried this John.
Instead of connecting the KBD Trig to the S&H Clock, then connect the Positive EG1 output and use the settings i described. Then the EG2 Release time will play with the last sampled value at key up. No noise.

Thanks LBH. I was playing with the inverted EG1 (and other things) with no more success than with the KBD Trig. But your combo of positive EG1, set to trig with knobs zeroed seems the best so far. You can hear a little bit of (sampled input) funkiness sneaking through on the attack but this is plenty good enough. Even better. it works when sampling the sequencer voltage, which is what I really wanted to do. A very simple example patch attached. Much appreciation !

KORG MS-20_Preset_JY Sequence and Hold_20230615_18h26.msx (56.7 KB)

Glad you could use the solution option.

A part of the noise is modulating directly the target only when the MG waveform is not full right.
When full right, the sound is as expected from a S/H on the filter or on the FREQ.
It’s like that also on a real old MS20 that I own.

Hi @denmakesmusic.
Welcome to the community. Glad to get your contributions. Keep it coming.

You are correct in what you say about the MG.
However just to make sure this topics issue is’nt confused - the MG is not in use in this topics original cases.