This is part 2 of my Tracky dacks build notes.
Its an envelope generator.
Part 1 is here:
Some links:
The official NLC Build guide is here
The wiki page is here:
Here is the build so far.
The module uses just one PCB
Most of the SMD components are on.
Installing the Schottky, power
rectifier.
This protects the module if it is plugged into the power supply backwards.
You can also use a 10R resistor.
This module is a voltage controlled envelope generator.
Its a simple circuit based on the Triad module.
The circuit uses 2 vactrols. you can use manufactured ones but I like DIY.
Very easy to do. Just a LDR and an LED.
For more info about rolling your own vactrols, click here:
Andrew has suggested using GL5516 LDRs.
These give a resistance of about 5 to 10 Kohms at full brightness.
Dark resistance is 0.5M.
I'll stick with this but vary it if you like to experiment.
The choice of LED and its resistor will also have a bearing on how this all works.
I'm using a 10M LED resistor, though the official build notes use 2.2M.
Suggested LED colours are red/green/orange/yellow.
I read somewhere, that yellow LEDs make the most efficient circuit.
The best match is I think between green and green/yellow. A blue LED is probably the worst possible choice.
Also remember that LED colours are normally not standard or very precise from one manufacturer to another.
Im using a Yellow LED & GL5516 LDR
So if you take this DIY path each build will be different & unique which I think is kind of cool.
So do experiment if you have the time.
The 4 100K pots are linear.
(b-type)
Solder pots, jacks and the switch
on-off-on SPDT
This is the range switch.
The Range switch
allows normal (centre), slow (up) and very slow (down) operation.
The cycle rates can be controlled by
CVs on Up and Down, which makes it a very unusual LFO.
The 2 LEDs : Doing (envelope) & done (trigger) are quite important.
Im using some orange LEDs.
The 1k and 4k7 resistors on the outputs act as voltage
dividers to give 5-6V outputs and serve as current limiters for the
LEDs.
The LED on the DOING (envelope) output also serves to ensure
the output returns to 0V. So you want to choose LEDs that have a nice
brightness with 5k7Ω (1k + 4k7 = 5k7).
Usually most diffused lens
LEDs will be fine.
The trigger LED (DONE) only ever flashes very
briefly so a very bright LED is ok here. If you need to change the
resistors to suit your LEDs, try to keep the approx. 1:5 ratio
(1k:4k7).
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You can find more NLC builds here.
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