Tuesday, 28 February 2017

Integrated circuits - classification - Families & packages

ICs are mainly classified according to their family & packaging.
Building synths these days means ordering parts from various suppliers.
Olders synths often use parts developed decades ago.
IC packaging has evolved from the simple through hole in the 1970's  to mini SMD & STM today

It's essential to know pin numbers.
Each pin has a special function.
Pin 1 is always located  below the notch, dot or band in a DIP package.

Pins are numbered counter clockwise, starting from pin 1.
Thus, the last pin, is always located above pin 1.

ICs are also classified into families:
The 3most common are:
1. TTL (Transistor - Transistor - Logic)
3. Linear - mainly amps, oscillators, regulators, etc

So many ......
The most common are:
1. Dual In-line Package (DIP)
2. Small Outline Package (SOP)
3. Quad Flat Package (QFP)
4. Ball Grid Array (BGA)

1. DIP = Dual inline package.
It's through hole.
It consists of two rows of pins . It connects to a circuit board with either a through-hole or a socket.
The pins are spaced by 0.1" (2.54mm). This is a standard spacing designed for fitting into breadboards and other prototyping boards.

The IC is designed to fit perfectly into the big gap in the centre of the breadboard.
There is a  0.3″ (7.62 mm) spacing between the two rows of pins.
This type of package is great for your synth DIY experiments.
You can have up to 64 pins on such a package.

2. SOP = Small Outline Packages
When it comes to Surface mount, you will often use SOP (Small-outline package) types for the ICs.
These usually have a rectangular shape with pins along two edges.
 ICs will also use the SOIC Small-outline integrated circuit package.

With SOIC packages, each pin is spaced by about 0.05" (1.27mm)

 Another common IC SMD package is the TSOP (Thin small-outline package).
TSOPs are common on ICs that power RAM and flash memory.
They are very low-profile (about 1mm) and have tight lead spacing (as low as 0.5mm).

SSOP (shrink small-outline package) is an even smaller version of SOIC packages.

 Notice that one edge has a bevel.
This bevel also lies on the side with the dot marking pin 1.
You can also see the notch .
Sometimes, the ICs are so small, that the dot isn't visible or present.
Thus, look for the bevel when trying to orientate the chip

TSSOP (thin-shrink small-outline package) is yet another variation.
It has a rectangular surface mount plastic package with gull-wing leads.
It is also smaller and thinner than a TSOP with the same lead count. 
The TSSOP comes in body sizes of 3.0mm, 4.4mm and 6.1mm. 
Lead counts range from 8 to 80. 

You may com across these adapters:
I get these from RS components
They are useful for converting various Small Outline packages
 (SOP/SSOP/TSOP/TSSOP/MSOP/QSOP) to dual in line package (DIP) format.

3. QFP = Quad Flat Packages.
Mostly, these are flat and square.
You will see the component with leads along each of the four edges.
QFPs can have pin numbers ranging from 32 pins to 304 pins.
It all depends on the pitch range.
The shape can vary too ... include low-profile and thin. 

These are really common in your microcontrollers
This is a Teensy 3.2
Micro-controllers are getting pretty common in Synth DIY, esp in Eurorack

4. Ball Grid Array (BGA)
You hopefully wont encounter any of these in synth DIY.

One side is covered with balls of solder. These are the connectors.
You will need special instruments ...either a reflow oven or hot air gun to work with these.
Specialised rework stations, vacuum devices to lift the IC, and  thermocouples to monitor the temperature are needed when repairing these.

Transistors  and diodes often use this type

The old metal cans. These are named : TO-3/5/8/18/39/46/52/72
These can have many more than just 3 pins.
In the 1960's early chips were housed mainly in either TO-5 or TO-18 packages
These were commonly used to package bipolar transistors.

The metal can was ok, but as more and more leads were added something more
durable was needed.... thus the DIP package was invented.

Tuesday, 21 February 2017

Deluge Synthstrom - Single Cycle Waveforms

The Deluge synth can use SCWF (Single Cycle Waveforms) to create unusual oscillators.
Audio files less than 20ms are perfect.(but it can use waveforms that are longer)
The preferred format is:44.1kHz 16/24bit.WAV or AIFF up to 32bit 96kHz.
You can make these using Audacity.

Steps to load a SCWF into the Oscillator section
There are 2 ways I've found to load these:

Method 1 (short way)
1. Be in Clip/track view
2. Shift + Browse (this loads the first osc to the browser.
3.  ‘bot-toP’ will scroll on the display to
       indicate the bottom-to-top note range.
4.  Press the select button
5. scroll to your SCWF folder
6. to change the SCWF , just press the Select knob again
7. use the audition pads to play.

Method 2 (long way)
1. Press the Clip/track button
2. Press the Synth button
3. Shift + Type (grid button) ...
4. Press select twice... you will see OSC 1 displayed
5. press select again ...you will see type displayed
6 Press select
7. Turn select to find "SAMP". (Sample)
6. Select a sample. Navigate to ‘FiLE’
7. Press select.
8.  ‘bot-toP’ will scroll on the display to
       indicate the bottom-to-top note range.
9. press select. navigate to your SCWF folder

To enter the Waveform view
1. Shift + Start
   You should see the waveform with start and end points.
2. You can play it by pressing the Audition Keys.
3. Start = Green
    END = Red
4. Pressing each will cause it to start flashing. You can move the start and end points.
5. You can zoom in using the left/right knob (hold down & turn) to increase the resolution.

Setting the start and end loop points.
1. Hold the start line with one finger and touch the new loop point with another finger
2. Do the same for the end point
3. Start = blue
     end = purple
4. You can zoom in using the left/right knob (hold down & turn) to increase the resolution.

Thursday, 16 February 2017

Power Supply - NLC - Build notes

Building a Nonlinearcircuits PSU.
This just supplies +/- 12V for Eurorack modulars.

Andrew's build notes are here:

The virgin PCBs

 Ok, lets twerk
Keeping Miley happy.

The PCB receives 12VAC from a plugpack/ wallwart
. The 1N4004 diodes split this into positive and negative waveforms.
The 4700uF capacitors then smooth out these waves
. The 7812 and 7912 regulators then convert the rectified & smoothed
signals to +12V DC and -12V DC and these are fed to the connectors to be distributed to your lovely modules.
I'm using 250v TDK film caps for the four small 100nf caps
Probably a bit overkill, but it's what i had in stock at the time.

Some pics of the 7812 & L7912 voltage regulators attached to various heatsinks.

 In the NLC build notes, Andrew stresses the importance of isolating the regulators from the heat sinks.

The smaller heatsinks came with grommets and mica insulators, so I think I'll use those.
He also recommended using heatsink paste.

Andrew F recommended I use these - http://www.taydaelectronics.com/capacitors/electrolytic-capacitors/4700uf-50v-105c-radial-electrolytic-capacitor-19x40mm.html

25V caps are okay but better to get 35V or 50V rating. just to keep the action well clear of the edge.

Always bigger is better with heatsinks, smaller ones cant soak off so much heat so will limit the current output of the regs. With a small one you will only get 3-400mA, a big one will get you double that (roughly...very)

The other thing to watch is the proximity of the heatsinks to the caps.
They do appear to be pretty close in the pics.
My sinks don't appear to get hot but they could cause problems if the temp exceeds the cap ratings.
These caps have a rating of 105 degrees celsius.

This PSU also has space for a 78L05 regulator.
Most of these are rated at 100mA

However, a standard LM7805 can be as high as 1A
A LM7805 might be a good substitution
If you are substituting remember:

1. the pinout is different so the 7805 goes in backwards

2. the 7805 can suck a lot more current than the 78L05 (10x more) and can take as much as the 7812, so keep it in mind and dont try to overwork it.

No need to change caps.

I'm using 1K resistors for the LEDs

Sunday, 12 February 2017

Double Knot - Synth

Thanks Cobramatic for showing me your new synth.
The Double Knot


It's very west coast. Uses Bananas for the internal patching.

Lots of great percussion.

Golden Rock - Burma

Golden Rock Buddhist pilgrimage site in Mon State, Burma.
 This precariously balanced granite boulder was according to tradition lifted by the Lord Buddah
and placed in this spot over 2000 years ago. It has remained in this position balanced by some strands of Buddah's hair.

New Years Eve.
So many people but very few foreigners.

The Rock is covered with 24K gold leaf.

The faithful
A new day

............... and a New Year.
Happy 2017

Our transport back down the mountain.

For more travel links click here:

Wednesday, 1 February 2017

Fairlight IIx - The 8 Inch Floppy Drives

Some pics of the 1980's 8 inch floppy drive.
A computer tech friend of mine said he remembered buying these for around $800 AUD back then.
This was a time when the average price of a new car was $9,000.

Taken from the rear of the computer. Ribbon & power cables removed.
The top of the drive

The underside of the drive.
In excellent condition considering its age.

 That rubber belt looks good for another 30 years.

The DS settings select the drive number.
Things really haven't changed much in this time

This was the secondary fairlight drive - used for holding the Sound Disk.
It's setting was DS2

The primary drive for holding the OS was set as DS1