Trig/Gate

[Kenneth]

I got a small analog toy synth, a GAKKEN SX-150. For the prize ( $38 ) it sonds really great. The worst problem with it is that it has not got a keyboard, just a carbon board that act as an potentiometer = control is not easy, well, you can simulate a theremin kinda easy but I like precision.

So the first mod I'm thinking of is a keyboard, for that I can use any toy keyboard and put a switch under each key and after that put a pot that controls the pitch for the key, no problem, that I can fix.

Next thing will be a small sequencer and there is where the problems starts, I'm a noob at things like that but I understand it is not that complicated if you don't care about nice but not needed functions.

My first question around this is; what's the difference between trig and gate? (trig is like on/off I know but how about gate?)

I think the GAKKEN can be operated using a simple trig but I like to know anyway

Edit: here is a small demo of the GAKKEN I just uploaded to the tube:

http://www.youtube.com/watch?v=kchVtyOywLI

[Sam_Zen]

Like the words say, a trigger triggers an action, while a gate is open or closed.
So the trigger is just a (small) pulse to start something, and a gate turns things on as long as the pulse is 'high'.

[Kenneth]

OK, thanks. But it left me with a new qestion; What is "high" and what is not?

I'm talking about signals, levels, is it like 0 volts = closed and x volts = open? x depending on what's used in the particular system, I know there are diffrent levels used in diffrent synths, like +5V or +10V.

Let's say it's +5V, will it go open on a threshold level that is somewhere between 0 and 5V?

[Sam_Zen]

Good question.
In most digital systems 'high' means a voltage level of around at least 4.7 volt.
To be precise : 'high' do not always is the same as the 'active' function. Sometimes a 'low' level does that.

And indeed, analoge systems often have different power systems, like 9v, so different thresholds.

Binary systems have two different type of inputs to activate something :
An input, normally at zero, like an AC signal input. So a higher voltage will cause something.

Or an input, being forced to a 'high' level via some (internal) resistor from plus, becoming active if the level is dragged down to zero.
Via a hardware switch, a diode, or otherwise.

[Kenneth]

Wery nice, thank's again