Thursday, 14 March 2019

NLC GENiE - build notes

These are my build notes for the Genie Eurorack module.
Its from nonlinear circuits in Western Australia.
The video shows an earlier version of the Genie
I guess you can describe it as an audio distortion / manglier / effects processor, 
Though it also works with CV.
You can input both CV and Audio at the same time.

It's pretty wild and uncontrolled.

Notes:
+ NLC Blog
+ NLC Wiki
+ BOM & build guide
+
The name is from the computerdescribed in the 1964 Keith Laumer novelThe Great Time Machine Hoax, although this module differs in ability (can’t time travel or get married ..... afaik), the name is quite suitable
 
Andrew has been experimenting with these circuits for many years.
I have some early versions of this in 4U format. They mesh really well with my serge.
The difference rectifier is the second last "module" on the right.
 
 
There are 4 neuron's in the panel below




IT's BASICALLY 3 neuron circuits and a difference rectifier.
You only need 1 signal input. but there are actually 10 input jacks.
It seems that the five top inputs are duplicated.
In1, In 1/2, In2, In2/3, In3
4  of the inputs are shared ... in1/2 and in2/3

This allows you to feed the same signals to neurons 1&2 and neurons 2&3.

The Difference Rectifier compares the outputs of neurons 1&3 to the output of neuron 2.
It can be used to process audio, CV, anything really.

There are 5 outputs
OUT 1
OUT -
OUT 2
OUT +
OUT 3
The +/- outs are your difference rectifier outputs

...

How to use this?
I basically feed lots of inputs (Audio & CV) into any of the top 10 jacks and then see what comes
out from the bottom 5 outputs.

On with the build:
 

 
I'll use 10K RL resistors (x3)

All pots are B100k (x9)





So what is a  difFerence rectifier ??
It is described by Andrew thus:
"This circuit is a hybrid of two basic op amp ‘building blocks’ .....a difference circuit and a rectifier.
 It takes the outputs from the neurons and supplies a signal that is the difference between them"
 http://www.sdiy.org/pinky/data/dif.html


The NLC module uses two standard 1n4148 signal diodes for this rectifier circuit.

"Basically the circuit compares the voltage on the ‘-‘ inputs with the voltages on the ‘+’ inputs. (on the 072 op-amp). The difference between these voltages is fed to the outputs. If the difference is positive  it appears on the ‘+’ output, if the difference is negative it appears on the ‘-‘ output. Again, a great way to mix boring CVs to get something interesting, audio frequency wave - shaping. "
 
 
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http://djjondent.blogspot.com.au/2015/03/non-linear-circuits-ncl-index.html 

Friday, 8 March 2019

mENG Qi - Dual Passive Low Pass Gate

I've been looking for some Buchla inspired LPG modules lately for my performance case and came across one by Meng Qi.


There were no build notes with this but its pretty simple so was easy to figure out.
Parts:
Resistors: 390R x 2
Diodes: 1N4141 x 1
Capacitor:  1500pF or 1.5nF (152)
Misc: Vactrol, jacks, panel, pcb, LED

These are not official build notes... just my record keeping in case of future trouble shooting.
 Make sure you get the LED orientation right.

So what exactly is a low pass gate?
The term was first used by Don Buchla and was used in the 200 series 292 module.
It can behave as a VCA, a low pass filter, or a combination of both.
The Buchla design used a vactrol to process the control voltage input. The choice of a vactrol was a stroke of genius as it introduced non-linearities which made the lowpass gate a good module for making percussion sounds like hand drums, bongos,congas & steel drums.

I'm not sure what vactrols are used in the version as the labeling appears to be blocked out.
So this shall remain a mystery. Don used VTL5s . You could also make your own using a LDR and a LED.
The NLC Dual LPG is a good example of how to do this.

The module is only 2HP width.
The gates are I think 6dB slope ... that is single pole/


What surprises me about this module is just how good it sounds ........and all without any power .
A single trigger pulse is all you need 


Orientation of vactrol ... match the dots.


a REALLY simple build ... great as a starter SMD project.







Useful Links:
1. CGS/Elby - Ken Stone's LPG
2. Buchla Tech - Verbos's excellent blog - 292c Secrets with schematics
3. Synth.NL.Blog - 292 5U build notes
4. Modular Synthesis - Build notes for Thomas White's LPG clone.
5. Doepfer A-101-2 LPG filter
6. Natural Rhythm Music - Thomas White
7. NLC Dual LPG

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For more Euro DIY builds click here:
http://djjondent.blogspot.com.au/2017/12/diy-index.html
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Monday, 4 March 2019

NLC Spasm

The SPASM is a LDR controlled jerk chaos module in Eurorack format.
This is a DIY build.

This module takes the classic Sprott jerk circuit and replaces all the resistors with LDRs.....a 7 way vactrol. 

 
This means the brightness of the LED in the giant vactrol controls the frequency of the circuit.

What exactly is a JERK circuit..??

"Jerk equations were developed by JC Sprott, .... (they) are very simple equations that are easily implemented as circuits, the diode is the nonlinear element, which is cheap and easy to get. Many chaos circuits use multipliers like the AD633 ($15 each), so I like to avoid those". (Andrew F).
The intro of this paper is a good explanation - http://sprott.physics.wisc.edu/pubs/paper229.pdf

Op amps first.


RL LED resistor ... using a 0805 resistor for panel LED... I'm using a 10K.
RLBox .. using a 2.2k 

I'm using GL5549 LDRs...I have a bag of 100's of these suckers.
These LDRs can go up to 10M+ (In fact they range anywhere from 10MΩ to 20MΩ), so they will be a lot slower but should give a much wider frequency range and some very unpredictable outputs.

I'm going to use 1uF caps with this so as not to go too slow. The great thing about SMD caps is that they are so easy to change. Andrew F says that 10uF will make this extremely slow, and 100nF very fast

 Building the vactrol box

 Line everything up & then solder
Only using double headers as i didn't have any singles on hand.

Feedback pot. "If building a very slow version, a 1M pot is better but not essential". (AF)
I'm using a A500k pot
There is a single LED in the Vactrol surrounded by 7 LDRs


Get the LED orientation right.

The LED section of the vactrol schemo.
 The anode goes to ground









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More links to NLC (nonlinearcircuits) projects.
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Links:
+NLC Blog 
wiki

bom


+ Sprott's Gateway 
+Wolfram - Demos

Keith Flint

Just heard the news that the Prodigy's Keith Flint is dead at 49.




A post shared by jono (@dj_jondent) on
One of the pioneers of electronic music.

The Prodigy only just toured Australia and by all accounts, the tour was a huge success.
The band's fusion of techno, punk, break-beat and acid was one of my earliest electronic music influences.

Lam Howlett  founded the band back in the early 1990s and he picked Flint to be the bands frontman. Flint scared my parents with his menacing live performances and goulish makeup....and that was part of the attraction. Hopefully this isn't the end of The Prodigy. Howlett's music is synonymous with late 1990's British Electronic music. Along with Fatboy Slim, Orbital and the Chemical Brothers they were the soundtrack of the late 1990's dance culture.

49 years old is way too young.

Moscow pics 2

Some old pics of a trip to Moscow .. back in 1998.

sT Basils






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kREMLIN tOWER

Wedding outside the Kremlin







KGB HQ

The Red Gate









 Peter the Great Statue







 vIEW from my homestay overlooking the Moscow river & Gorky Park.
The Russian Spaceshuttle can be seen through the trees




For more travel postcards click here: