Grids to trigger Korg MS-20 mini


#1

Hello everyone,

I didn’t find the topic about that - can anyone tell me if it’s possible to use Grids’ to trigger Korg MS-20 mini? Do I have to use Harvestman’s English Tear to convert trigger signal? I do have English Tear but I didn’t use it until now and I’m pretty unsure what are the capabilities of that converter. Also I have read about Eurorack’s triggers (5V) and that sometimes it is not enough to trigger some non-eurorack stuff. Maybe someone could explain me more about this?

thanks in advance! :slight_smile:

regards,
Ben


#2

yep, it’s v-trigger (eurorack) that you want to convert to s-trigger (korg, and a few others). V-trigger goes up from zero when trigger is active, S-trigger does exactly the opposite.
English Tear will exactly do that (as one of its functions) - I used it yesterday to drive an MS-20 mini from a Metropolis - works great, and I imagine Grids will work as well.


#3

Thank you! Now I understand that I have some problems with either my Grids or English Tear modules… as it is not triggering even though the lights on the Grids are blinking… :confused:


#4

You can get DSO-1 oscilloscopes (like this) for really little money, I really recomment getting one since it will make troubleshooting problems like this a lot easier. I can’t recomment a particular brand of them (they’re an open source project, so they are all over the place), because I don’t have mine here. I remember that there is some good and some bad ones, but maybe somebody else here on the forums can add more info to that.


#5

Well, i think I’ve cracked it - to my surprise, it was not working here either! You have to put Grids into Gate mode (as opposed to the default Trigger mode). Press TAP/RESET to enter config mode, turn the MAP Y knob until the leds turn on, then leave config mode with another long press on TAP/RESET.

@Papernoise - you’re right about the oscilloscope, I used a Tool+, and it immediately became clear where the problem was coming from.


#6

O! Thank you Eewee! As this is not mentioned in any Grids manual I couldn’t think of this - it works! Thank you :slight_smile:


#7

And actually in such a way it works without English Tear - I connect Grids directly to MS20mini and the trigger (gate) works!


#8

Actually it is described very well in the manual under ‘OPTIONS’.
There is even a settings reference card available.


#9

I’ve just opened it again… my bad, I’ve read it some time ago, but didn’t realise what this part means - “the output stays high for the whole duration of the clock’s positive cycle” - now I understand. Anyway, thank you it really did help :slight_smile:


#10

One more interesting thing, that I didn’t find in the manual - if I change Grids into Gate mode it works with Korg MS20mini WITHOUT English Tear. It is good, but now I am really confused does that mean that Trigger and Gate modes are working in different way?


#11

I don’t have an MS-20, but I think what is happening is that your MS-20 is being triggered by Grids on the falling edge of each gate.

As eewee mentioned, s-trig (which the MS-20 uses) is triggered when a signal moves from high to low (the opposite of Eurorack). Putting Grids into gate mode likely kept the signal ‘high’ for a long enough period (when the gate is ‘active’) for the MS-20 to register the removal of the gate as an s-trig signal.

If this is what is happening the only issue is that your MS-20 trigs will all be delayed by the length of the gate, since they are triggered by the falling, rather than rising, gate edge.


#12

Thank you, it’s getting clearer! But at the same time another question arises - if I have converter to s-trig (English Tear) and use Grids in Trigger mode - it doesn’t work even with English Tear. If I use Gate mode - than it does work without any converters. So therefore I now understand that I can trigger with Gate, but how to test wether English Tear is working properly? It’s maybe a bit wider question, but maybe anyone could tell me how to check (for example - with voltmeter) the module - if I measure the volatge of the holes for wires - what result should I get?


#13

No, it only appears to work - the timing is off.


#14

It’s possible that the trigger in general is too short to trigger the MS20? If you have a voltmeter, connect a patch cable to whatever you want to measure. Set the voltmeter to measure a DC voltage. Put the ground probe on the ‘sleeve’ of free end of the patch cable, and the test probe on the ‘tip’ of the patch cable. Grids should be about 0v when not triggered / gated and around 5v when triggered / gated. After going through the English Tear this should be inverted, 0v when triggered / gated, > 0v otherwise (it might be 5v or might be higher depending on the logic inverter circuit).


#15

Most meters have a reaction time of half a second or more (range adjustment, data conversion, averaging several measurements), so they won’t be able to provide any useful measurement of the signal generated by Grids, unless you use a slowww clock… and only in gate mode, as the 1ms trigger is way too short.