Saturday, 3 July 2021

NLC VCAs - build notes - part 1

 Some build notes for the Nonlinear Circuits VCAs module.

Looks like a pretty straight forward build. 
This is quite a compact module, packing 3 VCAs into 8 HP.
Should match nicely with Andrew's Triad - triple envelope generator module.
If you combine this with a triple VCO & triple filter module we could do chords.

It might also work well with the NLC Choral Generator.
(I'll build this soon).


Some pics of the unpopulated PCBs
 

Some NLC words of wisdom

Excellent advice


Indeed !

I usually place the ICs first. They are the most fiddly part of the build.


These rectifiers protect your module if you accidently plug it in backwards.

 According to R.G. Keen; Ge gives fuzz (Tayda: A-1716), Si gives buzz (Tayda: A-157) and LEDs give crunch. If you use Ge or Si, you can leave the 10k* resistor at 10k. If you use LEDs, the gain will be too hot so change the 10k* to something in the range of 33k-51k.

Andrew reckons that Ge diodes sound best .
these are 1N34A 1N34 GERMANIUM DIODE DO-7

I don't have any Ge diodes in store and Tayda is out of stock.
But i have plenty of Si diodes .
1N4148 switching signal diodes should be OK.
So I'll use a 10K resistor in the 10K* slot.

Apparently this gives the VCA buzz sound
 

we want BC857s - these are PNP trannies

 
Get the rest of the resistors on


Time for the Caps
 

Waiting on some parts.

To be continued......
Part 2 is here:



Links

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