Monday 30 May 2016

Basic Chords & Arpeggios for synths

 Some basic chords you can learn which are useful for lots of tunes:

C, F, G and A minor.

It's important to be able to play these chords in many different shapes and inversions.
Synths offer hundreds , if not thousands of different ways of playing these simple chords.

All these chords come from the C major scale.
 
The only difference between an arpeggio and a chord, is that in a chord, you play
the notes simultaneously, while in an arpeggio you play the notes one after the other. 
Arpeggios are sometimes referred to as broken chords. 

C chord
The C chord contains three notes – C, E and G




F chord
 F Major : F A C





The G chord
 G Major: G B D





The A minor Chord
A min uses A C E



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Chord progressions
A very basic chord progression is C, G, A minor, F
Another good progression is  F, G, Am, C, F G Am, Em

You can play these keys in any inversion.
The left hand may play just one or two of these keys to form the bass notes.

The right hand plays all 3 keys of higher notes

The lowest note played with the left hand has a big effect on the whole sound of the chord.
It's often the one its named after  (the root note).
This is a kind of a default but you don't have to always follow this rule.

Practice , practice, practice.....

Many thanks to Bill and Jordan for their great tutorials around which
these notes are based:
 
Of course once you have got these under your belt you can think about
layering arpeggios of these chord notes over their root chords

1, 3, 5 ... remember these numbers 
They belong to the Fibonacci Sequence.
 --- welcome to the world of the arppegio.
 
The 1, 3, 5 pattern is known as a triad.
It makes the most simple chords. 
The C major, the F chord, the G chord and the A minor chord are all in the
basic 1,3,5 sequence.

Links
 

Sunday 22 May 2016

Korg PS 3100 - Temperament Adjust

The Temperament Adjustment allows you to tune the synth to different scales.


In the manual, it's described as a 12 note Temperament Adjust
Eg: Mean tone system, the Hepatonal Scale & the Just intonation scale.

In the Western world, we are used to the "Well Tempered Scale"

Saturday 21 May 2016

Korg PS 3100 - Signal Generator - Oscillators

The signal generator (SG) is Korg speak for the oscillators.
The different waveforms are TRI, SAW etc.

PWM, Frequency adjust... fine & coarse.

Immediately below the SG section we have the modulation section.

For this to be active push the right orange switch to "on".
Notice the reverse switch on the left.
This section allows you to route MG1 (LFO) , the GEG (General Envelope Generator) or some external modulation source to the SGs.
So you can frequency modulate. :-)




Friday 20 May 2016

Korg PS 3100 - Dynamic Low Pass Filter

The Low Pass Filter.
You have your standard controls ... Cut off frequency (Fc) & peak resonance (Q).
Remember that the PS 3100 has a independent filter for every key.
The Peak resonance (Q) knob adjusts the degree of emphasis at the cut off point, determined by the Fc knob


Below this is the KBD Filter balance & expand.
They allow you to adjust how the filter behaves along the span of the keyboard.

The KBD Filter Balance adjusts the Fc of each of the key's independent filters over a rising or falling slope corresponding to the scale of the keyboard.

The EXPAND knob adjusts the degree to which the Fc is varied by the envelope signal formed by the EM section (to the right).


Below the filter section is a modulation section.
You need to push the orange switch to "on" for this section to be active.
There are controls for the MG1, GEG & external CV modulation signals.
The MG 1  & GEG knobs adjust the depth of modulation.

 It's very similar to the mod section of the Signal Generators.


Korg PS 3200 - 11. GEG - General Envelope Generator

The GEG is a 3 stage envelope generator: Delay-Attack - Release.
 There is also a Auto switch -- when on, the envelope will automatically loop.
The 5 bottom jacks consist of 3 outputs & two trigger inputs.

There is also an input for control of VCA 1 .... which is part of the TSM

There are 2 types of triggers you can use:
a. Keyboard Trigger (KBD TRIG)
b. Momentary switch  (M.SW)..... a foot switch..... triggers the beginning of an operation.

Notice the 3 different envelopes.
a. -5V to 0V
b. +5V to 0V
c. 0V to +5V





Thursday 19 May 2016

Roman 208 build pics - Version 2

Some pics taken during the build of this wonderful module.

It's not a Buchla Module, but should be compatible with most Buchla modules.

It follows the same size, format & the circuits used are I understand based on Don's schematics.


I'd say it took about 40 hours to put this together. It's more difficult than the TTSH (ARP 2600 clone).
I just finished it last night and couldn't believe that it worked first time.
So excited !!! I just had to post some pics.

 These are pics of the motherboard.

There are 12 daughter boards which plug into the main motherboard.

The cards are very tight to plug in.

One of the main difficulties was sourcing rare components from all over the world.



The partly populated front panel.

The original Buchla used plastic slider pots (above module). For this new version, I've substituted modern metal pots.


Almost finished.

The LEDs are a bit tricky to install.


You can buy the PCBs for this project from "The Electric Music Store".
ModularSynthesis.com is another very useful site - awesome build notes.

Wednesday 18 May 2016

Song View - Basic


The Mute & Launch button is also the solo.

To Solo.
1. Press the Left/right knob + Mute button
2. The button should turn blue.

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

To add another track, just press an empty track.

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

To change section colours.
1. Shift
2. Press the Audition button. (you will see the colours change).
'








Tuesday 17 May 2016

Crystal Oscillators

You will often find these used with microprocessors & microcontrollers.

Its an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a precise frequency.
(Wikipedia)
They are a type of linear oscillator made of quartz.

This is a 16 Hz quartz crystal. It uses a HC-49/S package.

This is also a 16Mhz crystal . The package is a HC49/U


These oscillators are not to be confused with your usual analog VCOs.
The crystal oscillator provides a fixed frequency. They often are the clock for a microprocessor, UART, etc. 

Through Hole Crystal (THD)Package types vary.
They include HC49, HC50, UM, AT26, AT39

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







 Model                         Frequency Range Mode of operation

HC49/US                     3.0 MHz ~ 54.0 MHz Fundamental 36.0 MHz ~ 150.0 MHz 3rd-overtone




HC49/U

HC-49/S package.



UM-1 UM-5 UM-4    8.0 MHz ~ 70.0 MHz Fundamental 35.0 MHz ~ 200.0 MHz 3rd-overtone
This is a UM-1 low pass filter

A UM-5



AT26                            6.0 MHz ~ 27.0 MHz Fundamental
The AT packages are cylindrical in shape.



THey of course also come in SMD packages.

This is a ABLS7M2-12.288MHZ-D-2Y-T - 
Crystal, 12.288 MHz, SMD,
7mm x 4.1mm, 30 ppm, 18 pF, 20 ppm, ABLS7M2 Series



KORG PS 3100 - GEG - General Envelope Generator

This has 5  KBD Trigger Selects.
The knob setting determines the number of keys you must press in order for a trigger signal
to be sent to the GEG.

It's a second modulation source for the SGs.

The GEG is a 3 stage envelope generator: Delay-Attack - Release.
Similar to the GEG in the PS 3200

There is also a Auto switch -- when on, the envelope will automatically loop.

There is a switch that connects the GEG to VCA 1



Monday 16 May 2016

kORG PS 3200 - preset sounds

These sounds are a good starting point if you are trying to learn how to program the PS 3200
They are from the manual.
The sound quality is just ok ....from a mobile phone, but  you should get an idea.

Steam Pipe Organ


------------------------
Echo... one of my fav patches



-----------------------------
Harpsicord



Sunday 15 May 2016

Voltage regulators (series)

 These are really useful in synths where we need reliable, stable voltages.
 
They come in many packages 


Here is a transistor regulator
It's a TO-92 package

Here is one with a IC package

In synths common operating voltages are 3.3V, 5V and +12V, -12V.
The most common series of voltage regulators is the 78XX series.  

the 7805 is a 5V regulator
The 7812 is a 12V regulator
 
For negative voltages use the 79XX series
 
The 7912 is a -12V regulator 

For building a +/- 15 PSU you will need a
LM7815 +15V Voltage Regulator      LM7815
LM7915 -15V Voltage Regulator      LM7915  
 
 This is a pic of a NLC eurorack PSU.
It uses two regulators
The 7812 is a 12V regulator
The 7912 is a -12V regulator 
 
 
These can handle up to 30V on the input and depending on the package, up to 1A output current.
 
Arduinos, and many other microcontrollers use 3.3V
 
The LD1117V33 voltage regulator, is a low drop positive regulator with a 3.3V fixed output voltage. 
Making a 5V regulator is very useful in the Euro world.
It's easy too.
Below is a LM7805 voltage regulator.
Notice the two decoupling capacitors:
The capacitors are placed between the power line & ground.  

 
The 0.33uF helps to smooth out any low-frequency changes in an input voltage. 
The 0.1uF helps to smooth out any of the high-frequency noise at the output.
Combining these two caps helps to deliver a smooth uninterrupted voltage to your circuits.
 
The decoupling capacitors are connected between your power source, whether that’s 5V or 3.3V, and ground. (Generally it's recommend to use a 100nF ceramic capacitor and a larger 0.1-10uF electrolytic capacitor for each integrated circuit). 
 
-------------
 
Shunt Regulators
The other type of voltage regulator they you may come across is a shunt voltage regulator.
The main difference between a series and a shunt is how they are connected to the load.
 
 A series regulator is connected (as the name implies) in series with the load to stabilize the regulator's output voltage. 
A shunt regulator, on the other hand, is connected in parallel to the load.
 
 
 
This is a TL431 shunt regulator.
It's used along with a series 78L05 voltage regulator  in a Midi to CV converter.
 
The TL431  acts almost like a Zener diode except for that the voltage rating of this IC is programmable. 

Saturday 14 May 2016

Korg PS 3200 - 14. Volume outs (D vol,P vol,F vol).

The PS 3200 has 3 outputs
1. Direct output
2. Headphone output
3. Final output.

The direct out is the signal formed by the SG, filter, the EM (VCA & Envelope Generator)
& the Balance Mixer
It is not effected by the equaliser, the amplitude modulator, the ensemble, VCA 1 & VCA 2 etc.
 The headphone out and Final Out are effected by the equaliser, the amplitude modulator, the ensemble, etc

Many people complain about the lack of a resonator in the PS-3200.
There are quite a few manufacturers who have attempted to reproduce this circuit.
I have purchased a MAM RS3 Resonator.
I think the best place to park this is from the direct output of the PS 3200.

Friday 13 May 2016

Modded DJ decks

What to do with your old CDJ decks.???
If you're like me, you probably have lots of old CDJs lying around in the garage.
As technology moves on, the old decks become yesterdays gear that nobody wants.

This is a awesome idea. Time I got a 3D printer.
This is a modded Nexus 2000. It's fully functional.

 It's a beautiful job. Such attention to detail.

And Chewbacca loves it too.




As do the rest of the crew on the Millenium Falcon.
They can't wait to get their decks modded.