S-trig to1/4 cable issue!

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S-trig to1/4 cable issue!

Post by Wrigh2t » Tue Mar 31, 2020 2:29 am

i purchased a micro recently and with it i got this cable, but i really dont know its use. Please help me with it!

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Re: S-trig to1/4 cable issue!

Post by till » Tue Mar 31, 2020 8:32 am

There are several information about these. One here:
They sell cables to transform voltage trigger to switch trigger.
Or heat up the soldering iron for this schematic origin from the vintage Moog company:


But getting voltage trigger from a switch trigger output is a bit complicated, as you need some voltage source. I have seen schematics for this type too, but can't find them now.
keep on turning these Moog knobs

Prodigy * minimoog '79 * Voyager * MF102 * MF103 * MF104z * MP201 * Taurus 3 * Minitaur * Sub Phatty * MF105 * Minimoog 2017+ MUSE * One 16

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Re: S-trig to1/4 cable issue!

Post by dingebre » Tue Jul 21, 2020 6:36 pm

Here's a little primer on triggers I posted to another thread. I hope it helps.

First, some information on triggers/gates. A trigger is a fixed width, very short duration pulse meant to initiate an action but not be continuous. A gate is a variable duration pulse meant to initiate an action, but also prolong some aspect of the action. For example, a trigger may be generated on a key down event and tell a sample and hold to sample a voltage and hold it. A gate may be generated from a key down event, too, but will stay active for as long as you hold down the key. A gate is typically used to control an envelope generator and will cause the EG to ramp up, then decay to a sustain point, held as long as the key is down, then decay when the key is released (Note the ARP 2600 has to have both a trigger and a gate to drive the EGs).

There are two traditional types of triggers/gates. First is the "S-Trigger/Gate", the second is a voltage trigger/gate. The Model 15 uses S-Triggers/Gates as opposed to voltage triggers/gates like the Mother-32. The "S" stands for "Switch" or as explained on page 188 of the Moog Modular Operations Manual, "Short-to-Ground". For historical perspective, even Moog mixed and matched S-Triggers/Gates and voltage triggers/gates. Moog's 960 sequencer needed voltage triggers/gates to run it and generated voltage triggers/gates along with control voltages. It required an additional module, the 961, which converted S-Triggers/Gates to voltage triggers/gates as well as a section to combine the voltage triggers/gates generated by the sequencer and convert these combined triggers/gates to a single S-Trigger/Gate output. There's more to the 960/961 combination than this, but I think this description is sufficient for here.

The S-Trigger/Gate is typically an open collector transistor with a grounded emitter so that when the transistor "switch" is on, the collector is at ground potential. When the transistor "switch" is off, the collector is floating. Some circuits have a pull up resistor on the collector so that when the transistor "switch" is off, the collector is at the positive voltage supply potential. Since the collector is the output, this means when the S-Trigger/Gate is active, it is shorted to ground. This design has the advantage that if you want, you can combine triggers/gates from multiple sources simply by plugging them into a multiple with no fear of damage or bizarre behavior. This "ANDs" the triggers/gates. In contrast, to combine voltage triggers/gates, you need a mixer which can mix DC voltages, that is, DC coupled. See the Moog 961 module discussion above.

Voltage Triggers/Gates:
These are simply a positive going pulse when active and ground when inactive. Effectively, they are the opposite of an S-Trigger/Gate.

To your problem, you must convert the trigger/gate from the Mother-32 to an S-Trigger/Gate first. This isn't difficult, but must be done. Roger at Synthesizers.com sells a pre-made cable to do this:


The only difficulty is you will need an adapter to convert the 1/4 inch jack to a 3.5mm jack to plug into your Mother-32.

If you want to do it yourself, on this page:


Roger has an excellent discussion on gates and triggers and near the bottom, he has a link to the schematic. Look for the words "Here's the circuit".

The Cinch-Jones connectors are still available, but expensive. You can find them on ebay, or I buy them from Tedss.com;

https://www.tedss.com/catalog/details/2025004554 - Female
https://www.tedss.com/catalog/details/2025004574 - Male

I hope this helps. PM me if you want to discuss further or have other questions.


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