Showing posts with label DIY. Show all posts
Showing posts with label DIY. Show all posts

Saturday, 23 March 2019

Wogglebug comparisons

The wogglebug is a great source of random voltage. Essential for all my patches.
It was inspired by the buchla 265
These 265s are very rare. I love the name ... the source of uncertainity.

Grant Richter of Wiard Synthesizers took inspiration from the "smooth" and "stepped" fluctuating random voltage sources that you can see on the 265 and came up with the wogglebug.
He expanded on this theme expanding it to such things as Woggle CVs (stepped voltages with decaying sinusoids edges).

There are many flavours of bug.

My first was the buchla version you can see on the right:

On the left is the Erica synths version in Eurorack format.
They are all slightly different.

The most common versions are from MakeNoise:


 No comparison would be complete without the orginals:


Links:
http://www.makenoisemusic.com/modules/wiard-wogglebug-legacy
http://www.makenoisemusic.com/modules/richter-wogglebug
https://modularaddict.com/erica-wogglebug-pcbpanel
http://www.wiard.com/modular/300series/wogglebug/index.htm


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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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

Wednesday, 27 February 2019

Mogue mixer & VCA - NLC build notes

My build notes for the Nonlinear circuits Mogue.


MOGUE is a VCA and Mixer inspired by early Moog designs... The mixer section was inspired by the Moog CP3
 

Andrew has made some changes to get the outputs into +/-5V range and for using easily available components.

The old Moog schematics:




The LM394N
Bipolar Transistors - BJT 
https://au.mouser.com/ProductDetail/Texas-Instruments/LM394N?qs=czFRc4EZNJgyK3N2awTVPQ%3D%3D

Another option are SSM2210s
The SSM221s & LM394Ns are matched NPN transistors. They are both obsolete.
One option is to replace these with Russian Clones: AS394 matched transistors.
Or you can try your luck with the Chinese ones on ebay.
I'm going to try using two BC547's first.
Transistor Matching
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Used this;
771-BCM857DS-T/R 
orientation ??? the dot marks pin 1 ???
I'm not sure of the correct orientation.
I think the dot marks pin 1

 Tayda



Links
+ NLC blog
+ official build notes & BOM
+ FB builders
 
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