Saturday 2 March 2024

CMOSC - Drone Oscillator - Build notes - Nonlinear Circuits

These are my build notes for the Nonlinear Circuits CMOSC module
Its a eurorack format module.

CMOSC is an updated version of the 
4U CMOSC (CMOS drone Oscillator). 

Each module has 6 oscillators; the frequency of each
oscillator can be set with the pots. Feeding a signal to 
input will decide which oscillator signal will appear at the output. If the signal is low, oscillator A is heard, if the 
signal is high oscillator B is heard. 
This module gets very interesting when the outputs of each oscillator pair are fed into other pairs, which are themselves controlled by others and so on…..complex, evolving drones. Put
patchcords into every jack so every pair is controlled by another pair, listen to one of the outputs, twiddle the knobs until you feel satisfied.
The sync input actually disables the oscillators, the unmarked output is a sync output…or if you like; it goes high when the oscillators are disabled. It is most interesting to put an audio signal into the sync input, preferably from the other CMOSC module




The Eurorack CMOSC also  consists of 6 oscillators. 

each can be switched between two frequencies set by a single pot. When the pot is in the mid-point the two frequencies are about the same. Turn the pot to min or max to switch between higher and lower frequencies, or lower and higher. 














It's a gated oscillator.
Meaning  Each oscillator controls the switching of its subsequent neighbour
 (1-2, 2-3, 3-4, 4-5, 5-6, 6-1) via the switching pins of the input jacks. 
Patching in a signal will break this cacophony and allow you to have some control over proceedings.

Links
+ BOM







No hard to find parts



A single atom deprived of vibration could wreck the universe.
William Walker Atkinson

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"there's only so much you can do with a op amp "... Paul S

CD40106 1 soic Mouser: 595-CD40106BM96 or 771-HEF40106BTD-T



CD4053 2 soic Mouser Part No: 595-CD4053BM96 or 771-HEF4053BTD-T



TL074 or TL084 2 Soic Tayda: A-1140 or A-1137


LL4148 x 7 sod-80 Tayda: A-1213
BC847 x6 SOT23-3 Tayda: A-1339 
Resistors: 1k, 10k, 100k, 220K



The two 5V1 Zeners (SOD80) are optional...
The function of these 2 zeners is to keep the output of the summed stage to 
exact Eurorack …ahem…‘standards’.
The individual outputs generally swing between +/-5V (so 10Vp-p) anyway, which is pretty much
within the "standard range so I don't think I'll need them.
(The pads for the 5V1 zeners are there if I change my mind).
The summed out is very noisy and raw.



I'm using a VISHAY TZM5232B-GS08 from Tayda (X-4504) instead of the 5.1V
Zener Single Diode, 5.6 V, 500 mW, SOD-80 (MiniMELF), 2 Pins, 175 °C, Surface Mount
I'm hoping this will be enough.





I'm using a 10R instead of the Schottky (for the rectifier).
Just don't plug the power supply in backwards. 

caps
C1-C6 set the frequency range for each oscillator. 470nF gets down
to approx. 15Hz, so is probably the highest value you want to use
(assuming you want to keep things in the audio range). 
Andrew says its OK to mix values or keep them all the same.
I've decided to use all 470nF. Ill see how this sounds, then might experiment later.

*** I started to experiment with these caps. Changed C1 , C2, C3, C4 to 220nf.
      the drone was more audible*****


The other caps are 10uf and 100nF


Soldering the headers that join the two PCBs.

Pots & jacks.


You're done 




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You can find more NLC builds here.
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