Showing posts with label Eurorack. Show all posts
Showing posts with label Eurorack. Show all posts

Wednesday, 23 January 2019

The Integrator Circuit - analog computers, Buchla, Serge & eurorack modules

The Op-amp integrator is a very important electronic circuit which I come across again and again.
The West Coast style of synthesis uses it a lot in modules like function generators, and slope generators.
In the synth world, what is possibly the most popular of all modules, the Make Noise Maths I think uses this circuit. (let me know if I'm mistaken).



The Fritz chaos circuits are also made of integrators.

The op-amp integrator is, as the name implies, based on the operational amplifier (op-amp). It performs the mathematical operation of integration (with respect to time). The magnitude of the output voltage is proportional to amplitude as well as the length of time a voltage is present at its input.

This probably sounds like lots of gobbledy gook to most people. Sorry.
To simplify all this nerd stuff.....
Usually operational amplifiers are used as part of a feedback loop circuit involving a resistor.
 Something like this:


 But what if we swap the resistor with a capacitor?
We now have a RC network This new circuit is commonly called a Op-Amp Integrator


Electronic integrator circuits can be found  in old analogue computers:

The COMDYNA GP-6

Integrators, mutipliers, dividers, counters, function generators, operational amplifiers, differential amplifiers, voltmeters... etc etc... These old analog computers had many of the modules you will commonly find in a modular synthesizer. They are arguably the inspiration for many of today's synths.


 Digital systems Lab

Anyway, probably my favorite module, the Buchla 281 QUAD FUNCTION GENERATOR uses it, as does the Buchla 257..... this is a voltage processor. Don experimented with integrators well before the 257. He created the Buchla 155 Dual Integrator module for  the system 100. These are extremely rare and I have never even seen a vintage one.
---------------------------------
"Model 155 Dual Integrator
Produces continuous control voltage functions when used in
conjunction with sources of discrete control voltages (e.g. keyboards, sequencers).
Positive and negative  slopes  may  be  individually  and  continuously varied from
15 volts in .0025 seconds to 15volts in 10 seconds; either or both slopes may be
voltage controlled. Particularly useful for generating complex voltage controlled envelopes,
frequency glides, and repetitive control functions." 


(from a catelog for the 1992 Ars Electronica exhibit Eigenwelt der Apparatewelt.
Pioneers of Electronic Art, edited by David Dunn)



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Buchla Dual voltage processor . Buchla 257.

It's looks a bit confusing. M is a control voltage. "It provides the capability of transferring control from one applied voltage (Vb) to another (Vc). The algebraic manipulations include addition,  subtraction, scaling, inversion, multiplication". You can crossfade & use this module as a VCA.


There is also a intergrator section in the lower right corner of the Buchla 266

 In the Serge world the DUSG (Dual Universal Slope Generator)... often referred to as the "Swiss army knife" is all about the integrator. The Slope generator is an amazing module. 


These Positive & Negative Slews preceded the DUSG


Depending on how one patches it, the DUSG can be a VCLFO,  a envelope generator; a oscillator; a  slew generator; a voltage and audio mixer; an attenuator and inverter; an envelope follower; a comparator; a VC pulse delay, a audio processor,.... whew !!! ........... it's pure genius !!!!

Bananalogue put out the  VCS almost a decade ago I think. This is based on a Serge slope generator

MATHS = DUSG/Buchla 281 and Buchla 257.???

The Befaco Rampage is another variation of the DUSG.


Just released during NAMM 2019 is the Verbos Control Voltage Processor:
It's a bit of DUSG and Buchla 257. Can't wait to get one.

So to sum up....in most op amp circuits, the feedback that is used is usually a resistor. However for the integrator this is not the case - the component providing the feedback between the output and input of the op amp is a capacitor.
It works a bit like this:
When a voltage is initially applied to Vin, the capacitor has almost zero resistance.... it acts like there is a short circuit.... so no current will flow through the op-amp. A virtual earth exists at the op-amp’s inverting input.

As the capacitor starts to charge, negative feedback forces the op-amp to produce an output voltage to maintain that virtual earth at the op-amp’s inverting input. The rate at which the output voltage increases (the rate of change) is determined by the value of the resistor and the capacitor, “RC time constant“.

Once the capacitor fully charges, it acts like a open circuit.
The flow of current then stops.

If we apply a rapidly changing signal to the input then the capacitor will charge and discharge quickly. At higher frequencies, the capacitor has less time to fully charge. This type of circuit is also known as a Ramp Generator. 
A ramp generator is a way of converting a square wave to a sawtooth.... but that's another story.

 

Tuesday, 22 January 2019

NLC Motherload for 2019

These should keep me busy and out of mischief for some of 2019.
They are part of Andrews creations of 2018.


I'm trying to build at least one version of every Nonlinearcircuit module.

Signum Hyperchaos
GENiE - GEneralized Nonlinear Extrapolator
SPASM - LDR controlled jerk chaos
(bad) Digital Filter Simulator
Balter - Dual VC Gate Delay
The Big Room (Reverb)
Dual LPG
Noiro-ze VCF & VCA
Shat-noir Phaser
Mogue mixer & VCA
It's 555 .... resonator (Eurorack version)
Kareishuu VCO
STATUES
Ian Fritz's Hypster


Saturday, 12 January 2019

Caterina Barbieri - Masters Of Modern Sound

I really enjoyed this performance last night at the Art Gallery of NSW, Sydney, Australia.
This was part of an exhibition of art from the Hermitage, St Petersburg, Russia.


The exhibition attempted to fuse the paintings with modern music.

Thank you Caterina.


I was blown away with the breath of sounds Caterina was able to provide with such a small rig.
A lesson that less really is more.

For the geeks out there who are wondering about the system format. As far as I could tell from a distance:
Case: Make noise 7U shared system with a central CV bus.
Top row: Orthangonal Devices ER 101 sequencer, Make Noise Echophon, Erb Verb,
                LxD filter VCA,   Maths, Optomix (Voltage controlled filter/amplifer/LPG),
                Doepfer 190 USB midi to CV
Bottom row: Verbos Harmonic Osc, Make Noise woggle bug & DPO, ALM Pamelas workout,
                    Doepfer 135-1 VCA/mixer, doepfer A-105 VCF SSM 24dB Low Pass & Doepfer ADSR??

Possibly, Caterina was using a laptop to process the audio. Not 100% certain about this. I read somewhere she uses Abelton and is a fan of the ping pong delay. That's a Novation midi controller at the bottom with a MOTU audio interface.


Links:
https://caterinabarbieri.com/
FACT MAG
Discogs
Resident Advisor
Soundcloud
Loop//Abelton

Wednesday, 26 December 2018

Bastl Grandpa sampler module - adding samples

The Grandpa uses a microSD card which can be formatted using a standard windows computer.
I'm using windows 10
The format is Fat 32

From the manual:
 
"The files on the SD card need to be in the root directory and have specific names e.g.: P0.wav -P9.wav, PA.wav -PZ.wav etc. The first letter of the name has to be a capital P and second letter 0-9 or A-Z (also capital). "
 
I used Audacity to make my samples compatable with the Grandpa. It's a free piece of software  



 Samples have to be 22050hz, 16bit, mono wav files. (they can also be 44.1khz, but the sample rate will not allow pitch up then). 
 
 "You can remove the card from the device without powering it off. When you put the card back in hold the UP and DOWN buttons together for 2 seconds to reboot." ... from the manual

Tuesday, 11 December 2018

Castle Patching 001

This is a patch I read about on the LZX community site.
https://community.lzxindustries.net/t/castle-patching-001-digitizing-luma-video-sources/746

The aim is to digitize a video source and create a posterize effect.


It's really simple.
I'm using the visual cortex to input the video. It is a luma source.
It's also supplying a sync signal to to the Cadet I.
If you don't have a Visual Cortex, use a Cadet III for the video input. 

"The Gain control on the ADC goes from non-inverted on the left through zero to inverted on the right. Set the gain to around 9 o’clock. Adjust the Bias control on the ADC " (PBalj)


Patch 001a




The Luma input is plugged into the Castle ADC.
The ADC's 3 outputs are plugged into the 3 inputs of the DAC.
And the single Lumin output of the DAC goes into the Cadet II (RGB encoder)
The Cadet II is an output module.
It has 3 inputs ... red , green & blue. Plugging the lumin input into each colour will give the corresponding colour out.


If you plug the lumin into a mult and put each out into the R,G & B input you will get a B/W image.




LZX - Castle
Introduction
00_000 ADC - Analog to digital converter
01_001 DAC - Digital to Analog converter
02_010 Clock VCO
03_011 Shift Register
04_100 Multi Gate
05_101 Quad Gate
06_110 Counter
07_111 Flip flops


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Video Index page


Sunday, 9 December 2018

LZX Patches - Castle Shift register - module 011

Some additional patch notes for using the LZX 011 shift register module.
This is a DIY module in Eurorack format.
The patch is a basic experiment using this module. Please let me know if you have any other patches worthy to document.


The lumen out of the Visual cortex  is going into the input of the ADC module.
The ADC has 3 outputs. Take one of these (experiment with each as each has a different feel)
and plug into the shift register input. Clock the shift register with the VCO clock module .
The three outs of the shift register are plugged back into the VC (channel B)..... thats it!

patch video








LZX - Castle
Introduction
00_000 ADC - Analog to digital converter
01_001 DAC - Digital to Analog converter
02_010 Clock VCO
03_011 Shift Register
04_100 Multi Gate
05_101 Quad Gate
06_110 Counter
07_111 Flip flops

Links
+ LZX Shift register patch 1
+ LZX industries
+ Vimeo - video
+ CMOS 
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Video Index page

Friday, 30 November 2018

lzx Video Synth - 110 Counter module

These are some build pics of my DIY LZX 110 counter module.
It's part of the Castle series of digital modules designed by Philip Baljeu of Toronto.

I am in no way affiliated with LZX. These are pics to help me (and others) to trouble shoot.
Other modules in the Castle series are:

LZX - Castle
Introduction
00_000 ADC - Analog to digital converter
01_001 DAC - Digital to Analog converter
02_010 Clock VCO
03_011 Shift Register
04_100 Multi Gate
05_101 Quad Gate
06_110 Counter
07_111 Flip flops

One of the great things about building these modules is that the schematics are included.



It's described thus:
"The Counter is a 4-Bit clock counter/divider. Each successive output from Q0 to Q3 is half the frequency of the previous."

It also generates a sequence of numbers in binary counting order from 0000 to 1111 (0-15) in response to the level changes of a single clock input. After the counter reaches 1111 the next clock pulse will return it to 0000. At the end of the count (when it reaches 1111), there is a output pulse at RCO.

The Counter will take an oscillator signal from the vidiot and give you four divided outputs. /2, /4, /8, /16. And a fifth output that puts out a pulse when the counter has reached the last number in its count.(Philip)

Finally when used in conjunction with the Clock VCO and the DAC , waveforms can be synthesized.

The Counter module uses a inexpensive SN74HC191N -- it's a TTL Counter/Multiplier/divider logic IC.
It has 4-bit synchronous, reversible, up/down binary counters.





Links
+ ADC overview - LZX
+ LZX industries
+ CMOS
+ TTL chips
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Video Index page

Wednesday, 28 November 2018

LZX Castle - shift register patches

Just experimenting with the LZX Castle shift register... module 110
Some quick patch notes ...............

..



The module has three inputs. Clock, data & reset.

This is my first patch ... really basic.

Lumen from V cortex ------> input of ADC
Data out from the ADC ----> data in of the Shift Register
Clock is from the VCO clock
Reset - use a second oscillator... eg prismatic ray or a sequencer

There are 4 outs.
I plugged three into the V Cortex (no particular order).
----
Thanks to Chris for the following patch:
"put a ramp shape or camera input in to the DATA input. clock vco to CLK. take d0 out to your monitor. note the position on the screen. take d1 and it should be one clock cycle to the right from d0. etc with d2 and d3."

I tried a version of this:
i took the lumen out (from the VC ) into the data input of the shift register.
....
patch 2


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Video Index page

Monday, 26 November 2018

LZX visual cortex - inputting external video - composite vs component

Just some quick notes to remind me (and hopefully help others) about inputting external video into the LZX Visual Cortex. When I first bought this module I didn't understand the difference between composite and component video.

The camera is a pretty old Sony HDR-XR260VE

The yellow input is a standard composite. going into the top "y" input.
This will only give you a black/white luma output.
 To get a full colour input you need to use all 3 component inputs: Y, Pb, Pr.

In Composite video all the video information is combined into a single line level signal that is used in analog television. The video cables do not carry audio but are often paired with audio cables.
In the photo above, the composite is the yellow, and the red & white are the left & right audio (and thus remain unplugged).



In Component video , the video signal is split into two or more component channels. 
Like composite, component-video cables do not carry audio but are often paired with audio cables.
Component video usually refers to analog YPBPR component video with sync on luma (Y).  


In the pic above, the green "Y" input is termed Luma for luminance or brightness. 
It also importantly carries the sync signal.
Pb carries the difference between blue and luma (B − Y).
PR carries the difference between red and luma (R − Y).

YPbPr is the analog version of the YCbCr color space; the two are numerically equivalent but YPbPr is designed for use in analog systems while YCbCr is intended for digital video.  
I have tried plugging a DVD player with YCbCr outputs into my Visual Cortex --- it just doesn't work !

The advantage of using the YPbPr inputs is that the quality of the extracted image is nearly identical to the signal before encoding. S-Video and composite video mix the signals together by means of electronic multiplexing (though S-Video does far better as it gives the whole video bandwith to luma and transmits chroma separately). So if you can use S-Video throughout the whole signal chain do it.


The rear of the Visual Cortex.


In the pic above I've plugged into the Y input a simple CCTV camera. Thus there is only a Luma output.
This is mult'ed into the Castle 000 ADC (analog to digital converter) and its output is passed back into channel B of the Visual Cortex. The Castle Clock VCO is triggering the Visual Cortex.



Links
+ LZX industries

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Video Index page

Sunday, 25 November 2018

Castle 111 Flip Flops - LZX video Synth

Some pics from my build of the Castle Flip Flops module.
It's a Eurorack format video module.


The module has three D type Flip Flops that share a common Clock and Reset.

So what's a flip flop? It's a bistable multivitrator. The outputs of Flip Flops have two stable states and can be used to store data. The Flip-Flop is also known as a latch. It's a fundamental building block in computers, counters, registers, memories, decoders & sequential logic.

Flip Flops are basically memory circuits. They can remember the logic state in which they were set. When a flip flop is set in one of its two possible states, it will remain in that condition until it is changed (or power is removed).

A D-type is also known as a Delay Flip flop, Data Latch or D-type Transparent Latch. They are used in Sequential Circuits.

The flip flop ic being used in this module is a SN74HC174N. 
It's a a hex positive-edge-triggered D-type Flip-flop  
It's a TTL series 74xx.

So Flip flops are like binary sample and holds. There are 3 so you can do a sample and hold type operation on the adc output for example. It has the effect of pixelizing. (Philip)

Anything can be used as an input, it doesn't need to be binary logic signals  



The SN74HC174 contains 6 flipflops, but it appears only 3 are used in the module.
The basic D Flip Flop has a D (data) input and a clock input and outputs Q.
It also includes a CLR (Clear) control input.
Information  at  the  data  (D)  inputs  is  transferred  to  the outputs  (Q) on  the  positive-going  edge  of  a clock (CLK)   pulse. This flip-flop is a positive edge-triggered flip flop. This means that the flip flop changes output value only when the clock is at a positive edge (or rising clock edge).






iT'S done !

LZX - Castle
Introduction
00_000 ADC - Analog to digital converter
01_001 DAC - Digital to Analog converter
02_010 Clock VCO
03_011 Shift Register
04_100 Multi Gate
05_101 Quad Gate
06_110 Counter
07_111 Flip flops

Links
+ LZX industries
+ CMOS
+ TTL (transistor-transistor logic)

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Video Index page