Wednesday, 17 July 2019

FaderBank - 16n

Some of my build notes re the fader bank.
This is a eurorack compatible module, however it does use midi and i2c so I hope it is compatible with other synths.

The official website is here:

You can make your own PCBs and panels for it.

The module uses a teensy microcontroller

The official build notes are here:

cd 4067
This is a cmos 16 channel multiplexer

This is a quad op-amp

diodes: D1 to D4 are four SOD-123 diodes.

 R17 and R18 are 4.7k resistors.
+ If you plan on using I2C with an ER-301,
   Ansible or TXo, (ie I2C "MASTER" mode) you should populate the 4.7K resistors.
+ If you plan on using I2C with a monome Teletype,
   do not populate these resistors - it may well cause problems.

........................ I'll leave these off for the moment... see how it goes

16n’s I2C jack is a 3.5mm stereo jack wired as follows: tip SDA, ring SCL, and sleeve GND (ground).

 the stereo jack sockets for MIDI and I2C.

the 16 mono jacks. 

tHE Teensy 3.2

 Created by Paul Stoffregen and the team from PJRC, the Teensy 3.2 is a microcontroller development board running a 32-bit ARM Cortex M4 processor, clocking in at 72MHz (overclockable to 96MHz). It also packs 1MB of flash, 4K of EEPROM, and 34 I/O pins

The switch setects different types of MIDI connectors Arturia Vs Korg
 'Arturia/Novation' (tip is current source) and 'Korg/Makenoise' (ring is current source) standards; board is labelled such.

There are two ways to flash the microcontroller

The Build guide uses the Arduino IDE/Teensyduino software.
The first step is to plug your new Teensy in using the USB cable.

All brand new Teensy boards come with the LED blink program pre-loaded. You should see the Orange LED blink slowly, 1 second on, 1 second off.

Before you can flash your Teensy you will need two pieces of software:
1. The Arduino IDE
2. Teensyduino

First install the Arduino IDE. (I'm using version 1.8.9)

Next install Teensyduino

Within the Arduino IDE software application, you need to open the Tools men.

be sure to set the Board to Teensy 3.2, USB type to MIDI, CPU speed to 120mhz overclock.

Open the _16n_firmware.ino file in the Arduino IDE.

Flash the board (upload the file).

I ran into a few problems using this method ... compiling errors such as:

A friend suggested I try the simple Teensy Loader Application
This is the second method.
This, only uploads hex files.

And it worked perfectly.

+ Teensy First use
+ Using Teensy with Arduino IDE 
+ Teensyduino - software
+ Microcontrollers - general info


Based on original work by Brian Crabtree and Sean Hellfritsch.
Minijack MIDI, I2C circuitry and CV outputs by Tom Armitage.
Firmware by Brian Crabtree, Tom Armitage, and Brendon Cassidy.

Tuesday, 16 July 2019

Shat-Noir Phaser - Build notes

These are some un-official build notes for the Non-linear Circuits Shat-noir Phaser
It's an eurorack module.

This module uses light dependent resistors (LDRs).
You can find other phasers using a similar idea: notably the Carlin, Compact Phasing A,
Morely Phaser and ADA final Phase.

You will need to build a light-proof box to house the LDRs and the central LED.

+ NLC Blog
+ Wiki

First components

Click here to return to the NLC Build Index: 

waiting for some parts .....To be continued................



Monday, 15 July 2019

The Apollo guidance computer & the NOR gate

If you are familar with modular synthesizers, you will probably be aware of logic gates.
But did you know of their connection to the Apollo mission to the moon?
It's nearly 50 years since those heady days.
Apollo changed our lives in so many ways & the technology used then, permeates our society to this day.

Above is a pic of the AGC - The Apollo guidance computer.
 (The original uploader was Grabert at German Wikipedia. [Public domain])
This was the computer that took those 3 men to the moon and back. In addition, it was one of the first computers to use integrated circuits (ICs). The AGC was in fact the world's first "embedded system".

Today ICs are everywhere. But back in the late 1960's they were a revolution 
NASA's goal was to use components that were low weight, had low volume & operated on low power. Coupled with this, they had to be extremely reliable.
With these goals in mind they decided to use a single simple integrated circuit for all logic functions.

Since just one chip was used, NASA could really test it under whatever extreme conditions it liked.... to make sure that it could survive everything which space travel could throw at it.
AGC dual 3-input NOR gate

  This single chip contained a three input NOR Gate. It's incredible to think that it's possible to carry out all logic functions to take men to the moon with just a NOR gate. 
  This gate gives a positive output only when both inputs are negative.

The beauty of the NOR gate, is that it is what is known as a universal gate.
In other words, it can be combined with itself to make any other  kind of logic gate

For example a NOT gate can be made by joining the inputs of the NOR gate.
The OR gate can be made by inverting the output of a NOR gate.

 The AND gate is made by inverting the inputs of a NOR gate.

 We can go on and on, but I think you get the idea.
The AGC dual 3-input NOR gate schematic

The above schematic shows the makeup of the NOR gates using discrete transistors.
They are just really simple NPN/resistor designs.
You could possibly build this using any NPN type transistor (for example 2N3904, BC547, BC548, BC549 etc.)
 The use of transistors for the construction of logic gates uses their ability to act as fast switches.

 NASA used about 5,600 NOR ICs in total for the later AGC versions. 

Getting back to synths, the 4001 IC is  a useful chip to have in your bag.
It's a CMOS IC containing four NOR gates

So in theory, you can build any logic module with just CD4001s

Below is a Serge module... one of my favorite Synth logic modules.
At first glance, there doesn't seem to be a NOR gate.
 AND: Output goes "high" when all inputs are "high".
 OR: Output goes "high" when at least one input is "high".
 XOR: Output goes "high" when a odd number of inputs is "high" and the rest is "low".

The logic inverters can change the functions into NAND, NOR and NEXOR.
 Note: a logic inverter turns a "0" into a "1" or a 1 into a zero
 It inverts the logic state, not the voltage value (i.e. +10V will not turn into -10V).

+ Schematics of the AGC
+ Ljunggren Audio
+ The Boolean Serge
+ CGS 39 - Ken Stone's Quad logic gate
+ Talking electronics - about the CD 4001
+ About CMOS
+ Pittsburghmodular logic banks
+ Transistors - basic info
+ Making logic gates from transistors

Sunday, 14 July 2019

Mahamudra 14

New Sound Waves are hosting a night of Modular Electronic Music this coming Wednesday.

Location: The Hideaway Bar.
                 156 Enmore Road, Enmore (Sydney)
Starts at 7.00 pm

Facebook link:

7:15 Hunter 
7:45 Vitals 
8:20 ECHO.8OT
9:00 Virus Installer 
9:40 Allinaire 
10:15 Slit Sensilla 
10: 45 Post Global Disorder


Some build pics of the 204r.
These aren't official... just my working 'notes' to help trouble shoot.


IC headers, caps, resistors, etc

i found these on ebay

 The microcontroller atTINY 84a

The ATTINY84A-PU is a
Amtel 8-bit Microcontroller - MCU 20MHz Ind. Grade 
There are 14 pins

I have an Olimex avr programmer so might try that first 
The Olimex has a 6 pin & 10 pin ribbon cable

 The 10-pin cable fits only the ICSP10 connector.
(In Circuit Serial Programmer) 

I'll be flashing the chip via the ICSP 10 connector.  Pin 1 can be identified with an arrow and the red stripe

I'll program this chip using a breadboard.


+ Microcontrollers - general info