Sunday 10 March 2024

NLC Stochaos - Build notes

These are my build notes for the nonlinear circuits "stochaos" module.
It's a 8hp eurorack.


STOCHAOS...... It's a random rhythm pattern generator or sequencer which produces gates and control voltages 














There are just two inputs ; IN & RST
Everything else is an output


Links


This is a decent sized build using 2 PCBs
Start with the ICs and transistors.

The module uses a lot of cmos
CD4070  x2....... XOR
CD4040 x2  .... clock divider 



CD4040 clock divider's outputs feed the four binary inputs of a CD4028 BCD to Decimal converting chip, creating pseudo-random sequences, depending on different CD4040 outputs feeding different CD4028 BCD inputs.


"The circuit can be easily modified by replacing the two 4070 XOR chips with two 4081 AND chips (or any other 4 channel two input logic chip – OR, NAND, XNOR, NOR). I might Build both versions ....the one-gate-at-a-time version tends to get a much faster clock signal" (Andrew F). 




CD 40175... Quad D-type Flip-Flop















CD 4028....... BCD-to-decimal Decoder






























Resistors

Pink noise level :
*** 1M-10M? x 1 ........................select for pink noise level .
................ im using a 10M

RL (LED resistor)  x 9 ..............select resistor to suit LED
brightness (prob 4k7 to 10k) ..... im using 4.7K



....
power rectifier BAT54GWX


Diodes
LL4148

5mm LED for chaos circuit on top PCB, any
crappy LED is fine but high V-on is
good so a blue one if you have it.

headers to unite the two PCBs





















switch

SPDT - 
on-off-on














Jacks

3mm LEDs x 8 ....Up to you, diffused lens are easier
on the eyes. Square hole = anode 


I always do these last.

You're there


First tests.
The LEDs light up. That's promising.



the input needs a SAW or SQUARE wave 
Sine & Tri waves don't trigger the module very well.

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You can find more NLC builds here.
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