Synthesizer Logic Modules - The 7 gates

Logic gates are great ways to create interesting rhythms or combine triggers from various sequencers.
Recently I've been using them to trigger drum modules.

Some logic gates also work at audio ranges.

There are 7 basic gates: OR, XOR, AND, NOT (inverter), NOR, XNOR, & NAND.

To make things even simplier, the 3 basic fundamental gates are OR, XOR, AND.

They use the inverter (NOT) to make NOR, XNOR, & NAND.

 

One final grouping of gates is what is known as Universal Gates

A universal gate is a gate which can implement any Boolean function without need

to use any other gate type.  

The NAND and NOR gates are universal gates.

These 2 gates are the basic gates used in all IC digital logic families. 

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

OR gates
Output a high signal whenever one or more of its inputs are high.
Useful if you wish to combine several gate signals into one.

You can use this instead of a mixer or multiple.

In1	In2	Out
0	0	0
1	0	1
0	1	1
1	1	1

XOR Gate (Exclusive OR gate)
Will only output a high signal when one input is high and the other is low.
It allows the signals to pass Except when they happen simultaneously.
It's like when 2 people try to squeeze through a narrow door at the same time.

(use this for your two snare drums - to prevent them triggering simultaneously)

In1	In2	Out
0	0	0
0	1	1
1	0	1
1	1	0

AND gate
Outs a high signal when all its inputs are high.

(If only one input is high it will output a low signal)

In1	In2	Out
0	0	0
1	0	0
0	1	0
1	1	1

NOT gate

The above 3 gates are available as inverted versions (N = not):

In	Out
1	0
0	1

OR -----> NOR

XOR -----> XNOR

AND-------> NAND

NOR Gate

This is a OR gate followed by and inverter.

This is quite a useful gate to have, as it's possible to build the other basic logic gates

using only NOR gates.

In1	In2	Out
0	0	1
0	1	0
1	0	0
1	1	0

Its output is "true" if both inputs are "false." Otherwise, the output is "false."

XNOR

This is a XOR gate followed by an inverter

In1	In2	Out
0	0	1
0	1	0
1	0	0
1	1	1

NAND Gate

This is a AND gate followed by an inverter

In1	In2	Out
0	0	1
0	1	1
1	0	1
1	1	0

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

For most Eurorack modules:
Low signal = 0V to 1V (usually)
High signal = greater than 1V to 5V (Usually)

Many logic modules respond to continuous CVs like LFOs .
They are reading the CV as a high gate when it exceeds 1V (usually) and a low gate when it is below.
So they can be used as comparators with a fixed threshold.

The logic synth modules you can buy or build will either use discrete diodes, transistors & resistors,

or use integrated circuit chips. TTL and CMOS are the most common types of ICs.

TTL IC’s may often be labeled as the 7400 series.

CMOS ICs are commonly marked as 4000 series.

Eurorack Logic Modules
+ Elby ED132 - Boolean Logic (Also a Serge Version)
+ Erica Synths - Pico Logic
+ Mystic Circuits ANA
+ Intellijel OR, Plog, Spock , uMod II
+ AniModule  LogicOgic, XX_OR
+ 2HP - Logic
+ Mutable Instruments - Kinks (OR & AND gate)

+ Doepfer A-166 (Dual Logic Module) .... AND, OR & NOR, plus two inverters.

+ NLC - Bools, Neuron, Chopper, 8 bit cypher,

+ RYO - Boolean Logic

+ Ken Stone's Quad Logic Module

+ CGS Funky Drummer

+ CGS Boolean Logic

+ EMW Logic 101, Logic 202

+Wiard /Malekko - JAG

+ Snazzy FX Ardcore

+ Synthrotek - Either-OR Eurorack OR Module

+ Pittsburgh Modular - Logic Banks

+ Analog Ordnance - Logiplex, OR gate,

+ Ladik B-010 Bool2, B-020 Bool3,

+ Circuit Abbey - ANDY, ORY, XORY, VERTY

+ Synth Cube Dual Logic

+ Temps Utile

+ LZX - Castle 100, Castle 101

+ AE modular - Logic

+ Pulp Logic (1U tiles) -Logical AND, OR, Diode-OR, XOR

,,,

Plog - Intelligel

This has AND, OR, NOR, XOR, NAND, and XNOR gates

RYO

NOT, XNOR, NOR, OR, NAND, AND

Links

+ Yusynth

Serge Index

Serge - CGS & Driscoll

* Power Supplies

* TKB - Touch Keyboard Sequencer - build notes

* SYNTHACON VCF - CGS 35 build notes

* CGS 86 - Build notes for the Serge Touch Keyboard

* Utility LFO - CGS 58 - Build notes

* CGS 81 - Voltage Processor build notes

* CGS 22 - Master pulse divider - Build notes

* Serge Resonant EQ/Filter - Euro format (CGS 202)

     Audio Equalizers

* Serge Bi-Directional Quad Switch (CGS 88)

* Warren Burt's Driscoll/Serge synth

 

Driscoll Synth

* Warren Burt's- Driscoll pics  (Panels 1, 2, 3)

* Driscoll Synth - panels 4 & 5 (pre Restoration) 

* Roland mixer - PSU replacement using Ken Stone/CGS ideas

Vintage / Paperface 
* The Morley Serge - Phaser & Reverb repairs (CGS/Ken Stone)
* The Morley Davidson Serge - Reverb Tank - Girls of Milton (KS)
* David Morley's Serge - The Sherman Chaos Bank (CGS/Ken S)
* Morley Serge - Chaos Bank pics (CGS)
* Morley Serge - Final restoration pics (Thanks to Ken Stone)

* Two panel vintage paperface - Pre restoration pics.

* Warren Burt's Driscoll/Serge synth

* Warren Burt - Serge panel 2/2

* Warren Burt - Serge Negative Slew - repairs

* Warren Burt - WAD and TKB restoration pics (NLC & CGS)

* Warren Burt - Driscoll pics  

* Serge Restoration Paperface 2.1

* Serge Positive Slew - Paperface - restoration

* Driscoll Synth - some old panels (4 & 5)  

* The Ship of Thesus

 

Liquid Foam

+ herbs and stone - liquid foam

 

Fenix

+ Fenix II & III

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

Voltage Processor - CVP - Build

Though not the sexiest module in your modular rack, the voltage processor is very useful and in fact essential to get the most out of your system.

I've got a quite a few in the Buchla format.
These are great pages concerning the Buchla CVPs
++http://buchlatech.blogspot.com/2008/10/musings-on-voltage-processors.html
++ Muffs = 257r build

Serge also have many voltage processors. These links should get you started
++http://www.serge-fans.com/m-class-cv-processor.cfm
++Random source
++http://djjondent.blogspot.com/2015/11/voltage-processor-cgs-81-build-notes.html
++Elby ES14
++ Serge.net -R1 The paperface dual voltage processor

Today I'm building a Euro CVP From Manhattan Analog
The build notes are here

Pretty easy build. the components are marked on the PCB.
The trimpot is 20k

The two ICs are basic Op-amps ... a TL074 & 072

There are two 50k and a 1M pots , The 50k are Linear.
I've seen builds of this with the 1M being either audio or linear (P3/Glide is the 1M.)
I'm building this with 1M linear.
I'll build another one with a audio pot and see how it behaves.

The anode of the LED goes into the square hole.

to be continued......

 

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

Audio Equalizers

Equalization is a fundamental processes in music production. 

Every music producer should have various types of EQ in their arsenal.

These may be studio based or can be used in live performance rigs.

 

Equalizers are basically filters. They influence the volume of audio at specified frequencies.

Note that the audible frequency spectrum range lies between 20Hz and 20KHz.

There are many types of EQ. The most common are:

parametric, dynamic, graphic, and shelving.

 

Parametric Equalizers

Parametric EQs are the most common and I think the most flexible.

They take many shapes and forms. They can be a digital software plugin, can be part of a mixing console, or be a hardware device.

Parametric EQs all have common controls.

Frequency, Resonance or bandwidth (Q) , Gain, Filter type, Filter Slope.

 

 

(the left pic is of Abelton's EQ8)

Dynamic

These combine an equalizer with a compressor.

They can cut or boost frequencies depending on the amplitude of the signal at its input.

A traditional EQ is static. Dynamic EQ combines equalization with selective compression/expansion and sidechain triggers. It kicks in only when the signal you’re EQing goes above certain threshold which you pick. 

 

Graphic Equalizers

These boost or attenuate a range of fixed frequencies using a bank of evenly spaced slider controls.

You can have up to 31 of these. The more sliders, the more accurate they are.

However, the frequencies are fixed and you have no control over the filter shape or bandwidth.

Shelving Equalizers.

These are very basic EQs which  boost or attenuate frequencies above or below a specified cutoff point.

Most shelving equalizers have high and low shelving filters like in the Shelves module below.

 

Filter types & Slope:

The most common types are Bell, Bandpass, notch, High Shelf & Low Shelf.

We can also add High Cut & Low Cut to this list.

Abelton's EQ 8 is a great equalizer and a great way to explore these filter types.

 

EQ 8 has 8 parametric filters. Each filter can be one of 8 types.

 

This is a low cut or high pass filter

It passes all high frequencies above the cutoff point.

It's x4 meaning it is 4 pole
 

 

 

 

 

 

 

 

 

This is another low cut / HP filter

It has a gentiler slope than the previous one.

 

Use a low cut filter to remove low frequencies or automate the frequency to create sweeping effects.
 

This is a high cut filter. Also known as a Low Pass.

it passes all low frequencies below the cutoff point.

It's fun to automate the frequency to create sweeping effects.

 

This is another LP filter (or high cut)

The 4X indicates a Steeper slope than the previous filter.

This is a Notch filter. Also sometimes referred to as a Band Stop.

It attenuates and removes a range of frequencies around a specified

center frequency point. It will pass all the other frequencies unaltered.

Modulating notch filters creates interesting shaping effects.

It's the opposite of a bandpass filter.

This is a bandpass filter.

This has been made using a LP & HP filter. 

Low and high frequencies outside the range are attenuated or cut..

Multiband equalizers often use multiple band pass filters to divide the audio spectrum into sections.

Here we have two bell filters. They are also known as peak filters. Use them to boost or reduce a range of frequencies with precision. 

The bandwidth/resonance (Q) sets the width of the bell curve.

 

 

 

These are two shelf filters 

On the left is a left shelf.

On the right we have a right shelf filter.

These are useful for boosting or reducing certain frequencies without totally cutting them out as you would have if you used a LP/HP filter combo.

 

 

You can make the filter slope less steep by dragging down the Q knob, or do the opposite by reducing gain.

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

Enough theory.

Here are some of my favorite Equalizers

 

The Cwejman VCEQ-3
 This is in Eurorack format.

The vceq-3 consists of 3 individual parametric equalizers.

 

 the frequency, bandwidth and amplitude can be controlled by dedicated knobs and/or by external signals, individually for each band.

 

Serge Resonant Equalizer CGS

Serge Resonant EQ/Filter - Euro format (CGS 202)

 

 It's a a comb filter based module. There is no CV control, but it has 10 bands of frequency to mix. The frequencies are fixed. It's closer to a Graphic Equalizer in design.

There is no control over the filter shape and bandwidth of each band. 

Below is a pic of a vintage Serge Res equaliser.

 
It's the 3rd module from the left. It's very compact in comparison to the Euro version and doesn't have
the extra outs from the 10 filter bands. And pot's are used instead for sliders.

 

 

 

Roland 100m 174 module

 

It's a really simple but beautiful module. 

The 4 channel EQ  has  independent level, bandwidth and frequency controls that span a wide frequency spectrum from 20 Hz all the way up to 20 kHz. 

 

Using the two outputs of this section, you can then patch signals to two different modules for some extra modulation and waveform sculpting possibilities and even switch between EQ’d and Bypass modes for a quick comparison.

 

 

 

 

 

 

 

 

 

 

 

 

 

Mutable Instruments Shelves

4 Channels.

It's a mix of  low-shelf, high-shelf, and parametric sections.

All share the same control ranges and scales

 

All channels have frequency & gain controls.

The middle two channels have resonance (q) controls.

These are the parametric sections. 

The first band is a low-pass shelving filter & the fourth band a high-pass shelving filter

 

 

The good old Doepfer 128 filter bank.

 

(Fixed Filter Bank) is a filter bank, made up of 15 parallel band pass filters, all with fixed middle frequencies and bandwidth (50 Hz / 75Hz / 110Hz / 150Hz / 220Hz / 350Hz / 500Hz / 750Hz / 1.1kHz / 1.6kHz / 2.2kHz / 3.6kHz / 5.2kHz / 7.5kHz / 11 kHz).
Each band pass filter has its own amplitude control knob

 

If you want to add a single audio output for each filter we have instructions for this modification available

 

Doepfer 128 - Fixed filter bank modifications

 

 

 

L1 Quad VC Resonant EQ

4 channels of Parametric EQ 

Also first band is switchable to LP mode and fourth band to HP to make low and high shelves. Also each band is switchable to boost or cut modes. Every parameter has voltage control, also master CV ins for all bands

 

 

 

Doepfer A 104

Trautonium Formant Filter

 

This was used in the Mixtur Trautonium by Oskar Sala. It is made of four parallel resonance filters, each filter can be switched to low pass or band pass or off.  

There is no VC.

Frequency, Q & Vol are all manually controlled.

Its a graphic EQ

Music Thing Modular

A compact, clean seven band Eurorack graphic equaliser inspired 

by the classic Boss GE-7 pedal.

 

Serge Bi-directional Quad switch - build notes

I've been searching for the perfect synthesizer router for my Serge.
The Serge Bi-directional router is fine but I would love to have more ins/outs.
Recently I built a NLC 32:1and NLC Router for Eurorack.
All excellent and I might one day adapt one for the Serge.
One I haven't tried is the serge Quad switch which seems to be an adaptation of the earlier
Serge Triple Bi-directional R.

The module I'll build is the Cat Girl Synth CGS 88.
Ken's Build notes are here:
https://cgs.synth.net/modules/cgs88_bds.html

The Quad switch uses a CD 4013B.
Its a CMOS Dual D-type flip flop that works as a two bit binary counter.

Looks like the switch used in the vintage 1970's module was a Motorola MC14007UB.
It was mounted on a separate board off the original R4 PCB.
You can still find these.

D = Drain, S = Source.

to be continued..... waiting for parts.

Euro build notes for a Serge Resonant EQ Mk. II

These are my build notes for a Euro format Serge Resonant EQ Mk. II.
Mk. II daughter board and Mk. II panel by Clarke

 First the virgin PCBs.

This Euro version still uses Ken Stones CGS 202 pcb.
http://www.cgs.synth.net/modules/cgs202_reseq.html

Above is a pic of a vintage Serge Res equaliser.
It's the 3rd module from the top. It's very compact in comparison to the Euro version and doesn't have
the extra outs from the 10 filter bands. And pot's are used instead for sliders.

 Official BOM for the daughter board:

SMT Components [3] TL074 (SOIC-14) [10] 330R Resistor (0805) [25] 47k Resistor (0805) [2] 0.1uF Ceramic capacitor (0805) Through-hole Components [18] Kobiconn 16PJ138 jacks [10] Bourns or Alpha 45mm LED sliders [2] Alpha 9mm pots or similar, value 50k Audio. [10] LED Current-limiting Resistors - value varies by slider brand and LED color.         I'm using 1.2K. [2] 22uF Electrolytic capacitors [2] 1N4001 Diode [1] 2x5-pin Eurorack power header

These are the 330R resistors.... outboard resistors.

Next the 47K SMDs.

[2] 0.1uF Ceramic capacitor (0805)
[2] 22uF Electrolytic capacitors
[2] 1N4001 Diode
[1] 2x5-pin Eurorack power header

SLIDER Pots, jacks, etc.

Now for the main PCB.

Resistors & headers 1st.

What capacitors should I use ???

Ken Stone's site says this:
"Traditionally, polystyrene capacitors are used for all of the smaller value capacitors in this module. I have not tried using other types and cannot say whether using the polystyrene capacitors makes any audible difference. From 10n, up greencaps were used. In modern terms these would be MKT or MKS. Note that there are also 10 x 10n decoupling capacitors. These decoupling capacitors can be MKT, MKS, monolythic ceramic, or anything else that will physically fit."

For this build I'm using ceramics for the 680pf & 220pf. The jury is out on whether axial polystyrene sound better. The price difference is considerable.
I'll use Axial poly's in my next build if I can detect a difference between this build and my vintage
Resonant Filter. .

It's now time to wire up the two PCBs.

Headers can also be used like this:

 This makes for easier trouble shooting.

This is not part of the original CGS build. Took a bit of schematic study and trial & error to work out where
to where to make the connections. they were basically the outs pins of the ten TL072s.. pins 1 & 7

Links:
1. Muff wigglers
2. Ken Stone - CGS
3  Video 1
4  Video 2