Author Topic: Trig/Gate for dummies  (Read 654 times)

Timko

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Trig/Gate for dummies
« on: July 05, 2017, 10:17:35 AM »
I'm at the beginning of the somewhat intimidated Nameless project, based on the Lovetone Flanger with No Name.  Part of the intimidation is the shear number of jacks on this thing (7 if you use all of them).  There are some amazing features, like an FX loop, expression pedal control, and stereo output.  However, there's also a Trig/Gate jack, which leaves me with the same image on the pedal: ??.  I've done some talking with Alan, and I've done some research on exactly what this does.  It appears to be a precursor to MIDI, used to control multiple effects with a single controller signal.  I'm trying to determine practically how to use it.  Do I have a controller pedal that controls multiple pedals with a single signal?  Do I use a tap tempo switch (like a momentary thing)?  Do I use an expression pedal here too?

midwayfair

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Re: Trig/Gate for dummies
« Reply #1 on: July 06, 2017, 09:52:51 AM »
I'm not very familiar with the project but I can give some general insight.

The trigger would presumably be a voltage switch, e.g. flip between 0V and 9V (or whatever the supply rails are). You can think of it exactly like a switch, but instead of an open circuit when off, it's 0V.

An expression pedal moving across those voltages would presumably duplicate the expression pedal function. I would also expect the trigger to be inserted in place of the expression pedal. Meaning the LFO is disconnected when either is in use. But the fact that there's a separate jack means I might be wrong on that point, or maybe the voltage switch is controlling something different from the expression.

If you want to use something like that as intended, you need to build a square wave LFO voltage generator to hook up to the jack. Your generator would be a pulse between the two relevant voltages.

It's described as a "precursor to midi" because you could chain a bunch of devices that could use the pulse, assuming that you could keep the signal strong enough to drive them all and they all required the same voltage trigger points. (Presumably Lovetone designed all their pedals to accept the same trigger voltages.)

A gate could do any number of other things. Note that you could also use it as an LFO input, that is, you could contorl multiple devices with the same LFO -- doesn't have to be a square wave pulse.
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alanp

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Re: Trig/Gate for dummies
« Reply #2 on: July 06, 2017, 11:23:17 AM »
Trigger and Gate are both very, very modular synthy terms.

Trigger is a short -duration, momentary High signal (usually the upper supply rail, as Jon says, a lot of the time it's 5V or 10V in Euro-land.) The ?Flange has a capacitor on the Trigger input to make sure it's momentary.

Gate is a continuous High signal for a length of time. The ?Flange's Gate input is DC coupled.
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Timko

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Re: Trig/Gate for dummies
« Reply #3 on: July 06, 2017, 11:54:47 AM »
Thank you for the replies.  Jon, I had a similar understanding as you did, so I'm glad I figured out that much on my own.

Alan, since you're the one who put this PCB together, you may have done some research into the original Lovetone pedals.  How did the original owners actually use this Jack.  I also noticed it on Moog's Moogerfoogers as well.

alanp

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Timko

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Re: Trig/Gate for dummies
« Reply #5 on: July 06, 2017, 02:39:07 PM »
Now THAT really helps.  Thanks!  I think I'll add it.