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)



--------------------------------------------------------------------


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


Monday, 21 January 2019

Custom Buchla modules - Synovatron

I'm finally getting around to building some half size Buchla modules.
This first one is a Euro to Buchla trigger converter.


I commissioned  these from Tony at Synovatron back in 2014.
Tony supplied the kits and two fully built modules.
The built modules are awesome. I use them all the time.

I'm putting together a second Buchla performance case and thus my need to get these kits built.



Almost there..

To be continued........

Links:
Tone's synth Projects
Tones synth - more buchla to euro translators

A tale of two computers - CSIRAC and Tec-1

This is a story of two Australian inventions that I think are worth remembering
as they both have a part to play in the evolution of electronic music.
One so big it will fill your house (if you possessed it). The other a fraction of its size that you can build yourself.

The first is CSIRAC.

https://commons.wikimedia.org/wiki/File:CSIRAC-Pano,-Melb.-Museum,-12.8.2008.jpg
jjron [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], from Wikimedia Commons

CSIRAC  stands for Council for Scientific and Industrial Research Automatic Computer).
This was originally known as CSIR Mk 1. It was Australia's first electronic programmable digital computer, and the fifth stored program computer in the world.  She ran her first program in 1949 which makes her 70 years old this year.

I first saw this machine at the Melbourne Museum in 2016. (sadly no pics) . You can today pay her a visit at the Scienceworks centre, also in Melbourne.  (Maybe take her a birthday cake)

 CSIRAC is the oldest surviving first-generation electronic computer (The Zuse Z4 at the Deutsches Museum  in Germany is older, but was electro-mechanical, not electronic). CSIRAC was constructed by a team of scientists led by Trevor Pearcey Geoff Hill and Maston Beard. Though it had but a fraction of the brain power of your average smart phone it was a revolution in its day.

In addition to being used for things like weather forecasting and banking,  CSIRAC was the first computer in the world to play digital music. This took place during Australia’s first computer conference in June 1951. The tune was Colonel Bogey, . Sadly there are no recordings.


The second Computer we are looking back at is the TEC-1

https://commons.wikimedia.org/wiki/File:Tec-1_Z80_Computer.jpg
Otherunicorn [CC0], from Wikimedia Commons


 It is a single-board kit computer first produced by the Australian hobbyist electronics magazine Talking Electronics in the early 1980s. The design by John Hardy and Ken Stone was based on the Zilog Z80 CPU.

If you are a regular reader of this blog you will probably know who Ken Stone is. The founder of Cat Girl Synths (CGS).

Th TEC-1 used a  Zilog Z80 CPU, had 2K of RAM and 2K of ROM in a default configuration.

Those twenty round keys on the right are the main input. They are made up of 16 hexadecimal keys for numeric inputs and address, a GO key to execute a program, + and - keys,

This is the original prototype.
https://commons.wikimedia.org/wiki/File:Original_TEC1_Prototype.jpg
Binarysequence [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons

The TEC-1 was first featured in 1983, in Volume 1, Issue 10 of the Talking Electronics magazine, pages 57 to 75. I plan to build one of these and will document it in a future blog and hopefully use it to play a tune or two ... maybe Colonel Bogey.

It the 1984 issue of Talking Electronics magazine,  (Volume 1, Issue 11, pages 11 to 36, and pages 50 to 55) are two peripherals designed by Ken Stone for the TEC-1 -an 8x8 matrix display, and a relay driver board. These allow the TEC-1 to be interfaced to other equipment.

Notes:
+ Colossus (1943) was the first electronic digital programmable computing device, and was used to break German ciphers during World War II. In December 1943, Colossus was shipped to Bletchley Park, where it was delivered on 18 January 1944 and attacked its first message on 5 February. Colossus included the first ever use of shift registers and systolic arrays, enabling five simultaneous tests, each involving up to 100 Boolean calculations, on each of the five channels on the punched tape.
A reconstructed working copy of one of the Colossus machines is now on display at Bletchley Park.

+ ENIAC (1945) (Electronic Numerical Integrator and Computer) was the first electronic programmable computer built in the US. ENIAC was the first Turing-complete electronic device, and performed ballistics trajectory calculations for the United States Army.


Links:
Facebook - Tec-1 Z80 computer


Saturday, 19 January 2019

Lorre-Mill U Tone build notes

Some pics of my build of the U-tone diy synth.
Looks like a cool way to learn about CMOS ICs.

Lorre Mill make the wonderful Double Knot synth.


"The utone circuit uses CMOS logic, a resistor ladder, and a few other simple pieces to create audio forms. The scale inherent in this instrument is the undertone series, giving divisions of the main clock frequency."

Only the PCB is supplied



I'm not sure how I will eventually encase the synth.
I may end up incorporating this into a larger project.

tHE CMOS ICs used are a CD4046BE & two CD4015BEs

The CD4046BE is a PLL (Phase Locked Loop)
The CD4015 is a Counter Shift Registers, Dual 4-Stage








 Quite a easy build.


Lancaster's CMOS book is the bible


I'm not sure how i'll encase this.





Links:
Muffs
Official - Lorre Mill
CMOS & Lunetta Synths

Friday, 18 January 2019

NewSoundWaves - next meeting on the 10th Feb, 2019

Our next Synth meeting will be held on Sunday the 10th Feb 2019.
This is something to look forward to:
An evening with This Is Not Rocket Science
3pm - 7pm.
 

Location : 107 Projects
107 Redfern St Redfern.

Bring your synths, play and meet. Lots of fun !


TINRS (this is not rocket science) will be there (all the way from Holland) and you will get a chance to see some module demos & chat with their creators.



For more info check out the FB page
https://www.facebook.com/newsoundwaves/

An evening with This Is Not Rocket Science


Teenage engineering - They have gone modular

I was surprised and delighted to see this today.
I'm a big fan of this Swedish company.

The teenagers have got a new series of synths out.
Beautiful Scandinavian designs.
Their website describes this as the poor man's modular but I can see these being sold in art galleries.

The System 400 (as my friend Justin pointed out) harks back to the EMS Synthi E
And I think the similarities are more than just its colour

The Synthi E was designed for education, and I feel that these new TE synths will open up the world of modulars to a much wider audience.


The flat pack idea reminds me of  IKEA. Another Swedish company... who are known for selling good, minimalist designed products at affordable prices.

As far as I can tell from the manual, the patch cables are 3,5mm but the module size is their own format (not Eurorack).

The 400 has  3 OSCILLATORS, NOISE, RANDOM GENERATOR, 2 ENVELOPES, 2 VCA'S, LFO, FILTER, MIXER, SPEAKER BOX, POWER PACK AND A 1–16 STEP SEQUENCER.

THE COMPLETE KIT COMES WITH CHASSIS,16 MODULES, 15 PATCH CABLES.

It doesn't look like you can move these modules around within the system.
The kit comes with a flat metal face (reminds me of my old Meccano set) where you bend (the edges) to make the case...

The modules are then screwed onto the back of the face ??


The other two synths released are the 170 & the keyboard

The 170 is a analog monophonic synth with step sequencer. It costs $349USD and includes a chassis, nine modules and eight patch cables.
The modular membrane keyboard has tuneable keys and a step sequencer. It seems to be designed for use with the 400 & 170 model... and hopefully will conform to Eurorack CV/ gate standards

The module dimensions are here.

The TE system uses M2 screws., 5mm spacing mount holes. Module dimensions are 30x90 for a 6HP module. ie the height is 90mm which is approximately 2U

Euro specs are M3 screws, 5.08 mm spacing mount holes, and a 3U height.

But the PSU  is compatable ... both +/-12V

I hope this is the first of many future module additions. Maybe a case that allows for free placement of the modules..... I can see this system expanding 

Links:
Teenage Engineering