Monday, 1 February 2021

Eurorack Jam at Elk Elektronik

..

Nice one Ed.

The system uses many NLC modules. Esp like the Null-A
NULL-A Build notes

Nelson Falls - Mt Field - Tasmania

 Located in the Franklin-Gordon Wild Rivers National Park.
 


West Coast region of Tasmania
 




The landscape ranges from eucalyptus temperate rainforest to alpine moorland, rising to 1,434 metres at the summit of Mount Field .
Mount Field National Park was the first national park created in Tasmania.
Established in 1916.  It's 64 km northwest of Hobart.
 It's part of the homelands of the Big River nation of Tasmanian Aborigines.
 


The largest trees here were growing when Abel Tasman first sighted Tasmania in 1642.
Many are over 100m high.

 




 
 

Saturday, 30 January 2021

Monday, 25 January 2021

NLC Mobius Pill - Build notes -part 1

 These are my build notes for the Nonlinear Circuits Mobius Pill.
 
The MP is a chaos - noise module in Eurorack format.
So if you like chaotic noise this is for you.
 
The BOM looks pretty standard with no rare or hard to find parts.
You will need two 4046 ICs. 
These are your PLLs (Phase Locked Loops). 
(These PLLs create the chaos.)

There are also two Op-amps. These are standard 072s.

In addition to the two PLLs the circuit also has two vactrol based  low pass filters 
These filters are in the Buchla style... I think they are 292 inspired gate/filter combos.

The vactrols are all DIY (black box design) using LEDs and light dependent resistors.
The PLLs have a single combined voltage control input.
Each filter has it's own voltage control input.

 
 
Thanks  to Andrew for supplying this diagram.
It explains what's happening in this circuit.
There are two TL072 op-amps, two VCOs, two filters , and two PLLs


The phase detectors feed into the LPFs and theirs outputs are fed into the non-inverting inputs of one and the inverting input of the other.
The outptuts of each control VCOs.


There are 4 inputs & 4 outputs.

Inputs:
Input signal, Freq CV, LPG1 CV and LPG2 CV.

Outputs
Two of the outputs are from the LPGs and two are from the PLL VCO










Some pics of the virgin PCBs.


LEDs go here. These LEDs are part of the vactrols.

---------

The 4046 IC -- it contains a VCO, two phase comparators & a zener diode.

The zener diode acts as a voltage regulator, setting the voltage at 5.1V. across it, for voltage input into pin 4. This is the voltage that controls the number of oscillations for the output digital signal of the chip
  
The oscillator will produce a digital square waveform .
Analog input to the VCO is at pin 9.
Digital output of a square wave is at pin 4. 
This is fed into an op-amp and becomes the VCO 1 & 2 outputs.
 
PC (Phase comparator) 1 out (pin 2) becomes the LPG output.
Hopefully, this will help you trouble shoot, should you run into any probs.

The 4046s




First place the ICs,
 
 
Now the  nineteen 100k resistors.

Rest of the resistors... Caps next.
 
 
the

 The 1uF and 10uF need to be 25V or more.

To be continued ......Waiting for those diodes 

Links

 
---------------------------------------------------------------------------------------------------
Click here to return to the NLC Build Index:
http://djjondent.blogspot.com.au/2015/03/non-linear-circuits-ncl-index.html 
 

Andromeda A6 - Alesis Part 2 - Ribbon Controller & Performance Wheel

 The Ribbon Controller

 

 The Ribbon controller can be thought of like a pitch or mod wheel stretched across the keyboard.
As it has a much longer travel, its more accurate than  a mod wheel.

It can be assigned to any of the A6’s mod destinations and is programmable per Program like the wheels.
The MIDI Controller Number is user selectable


The ribbon can be assigned to multiple destinations at the one time and has 3 configurations.
1. Ribbon Value
2. Ribbon Left
3. Ribbon right
 
 
 
1. Ribbon Value
This assigns continuous values over its entire length.
 
2. Ribbon Left
This divides the ribbon in half.
The left becomes a self contained ribbon.
(There is a centre line).
 
3. Ribbon right
This divides the ribbon in half.
The right becomes a self contained ribbon.
 
The ribbon can also be a control route source .
Can be used to rescale any other modulation in a live performance
 

Ribbon HOLD Buttons 

On each side of the ribbon there are HOLD buttons. 
 
 
When ribbon hold mode is on, the ribbon value will be “sticky”. 
That is, when you lift your finger from the ribbon, it will hold its value. 
When you exit ribbon hold mode, the ribbon value will snap back 

Programming the Ribbon Controller

1. Press the RIBBON button to the left of the ribbon controller.
    This displays its control routes (CROUTES).
     In the CRoutes display a Mod Route can be assigned only one controller at any time.
     Also, only 35 of the Mod Routes can be controlled from here.
 
You can see in the above pic, that the ribbon is not connected to anything.
 
2. Press soft button 1 (CROUTE). 
You’ll now see a list of SOURCES on the left, going through a LEVEL and ENABLE control, to a list of ROUTEs on the right.
 
 
3. To change the sources on the left (to either Ribbon Value, Ribbon left or Ribbon right),
    turn the soft knob 1 or  press the up or down keys when SOURCE is highlighted.
 
 
4.  Turn soft knob 5 (ROUTE),
 (or press the up or down keys when ROUTE is highlighted), 
to display the destination.
To highlight ROUTE turn soft knob 5 very gently, then use the up/down keys.
 
 
 
 ---------------------------------------------------------------------------------

 The Performance wheels.

The A6 has two performance wheels.
They are incredibly flexible. 


These are mainly used for pitch bend (PITCH) and vibrato (MOD). 
The Pitch wheel is on the left. It is a spring-loaded wheel that snaps back to its center or neutral position when released.
The Mod wheel is on the right. It is not spring loaded and must be manually returned to its off position. 
It is normally used for vibrato.

Of course, you don't have to use these two wheels as described above. Eg you can make both pitch bend , both vibrato, swap them, neither,  etc.
You can assign these wheels to modulate any parameter that is designated as a mod destination. 
You can even assign the wheels to perform multiple modulations at the same time.

The pitch wheel is usually set up so that pushing it away from you bends played notes up in pitch and pulling bends them down. This setting can be reversed.
It can also have a different type of modulation on either side of the center stop.
 

Programming the Wheels

 
To make changes to either wheel, press the PITCH (“Pitch Wheel”) ASSIGN 
or the MOD (“Mod Wheel”) ASSIGN button. 
The parameters for that wheel will be displayed 
--------------------------

CHORDS 
 
The CHORD button allows you to play a chord with a single key. 
To define a chord, hold down the CHORD button until the chord LED starts to blink. 
Then, play the notes of the chord and release the button. 
After the chord is in memory, playing a single note on the keyboard will play the chord relative to the note you played. To toggle chord mode on and off, simply press the CHORD button.
 
 
 
 

Saturday, 23 January 2021

Elk Elektroniks - synth meet 3 - 23rd Jan, 2021

 Thanks to everyone who attended the synthesizer meeting yesterday.
 Thanks also to Ed of Elk Elktronics for organising these events.



LOts of fun.
 
Lots of old and new toys.
Sorry about the background noise.

''




tHIS Korg Sigma is a really beautiful synth.


Underrated for sure







 

Hopefully, these meetings will grow as covid restrictions decrease.
NSW recorded no new local cases in the last 24hrs, and there is no one in ICU. 
;-)
 
I think this will be a second Elmyra workshop . 

Time: 10am - 4pm

Location: Elk Elektronik - Shop 3, 266-268 Crown St Wollongong



Wednesday, 20 January 2021

Korg miniKORG 700 - vintage vs reissue

..

KITARO meets miniKORG 700FS 
 
Kitarō (喜多郎), born Masanori Takahashi (高橋 正則) (February 4, 1953), is a Japanese musician noted for his electronic-instrumental music. He is really famous for using this instrument.
 
Among his many achievements, in 1980,  he received a Galaxy Award  for the score of the The Silk Road: The Rise And Fall Of Civilizations It was a documentary on how ancient Japan was influenced by the Silk Road trade route.
The music was composed mainly using a Minimoog, Minikorg 700, and Maxikorg DV800.
 

I'm so looking forward to this re-issue of a classic.
 

I've had my old miniKorg 700 since 2011 and today decided to re-explore it in preparation for
the re-issue coming out soon. My version doesn't  have midi, or CV control. There isn't USB connectivity, a sequencer, memory, or even a second oscillator. 
It was released in 1973, retailing for $500 USD. (I paid $500AUD for mine in 2011).
 
The 700 was Korg's first monosynth but was released under the UNIVOX brand in the USA.
It has 37 keys, a 2-speed phaser, and a variable pitch slide.
 
To put this in context, the early 1970's was an important period in the development of the synthesizer.
The ARP 2500 came out around 1970, as did the Moog MiniMoog & the Buchla 200 series.
1971 saw the ARP 2600, the EMS Synthi 100 & Synthi A.
1972 saw the Buchla Music Easel, the ARP Odyssey (Mark 1), the Moog Sonic Six, The EMS Synthi AKS & Synthi E.
1973 saw the Moog Satellite and modular 15/35/55.

The Korg company had been around since the 1960's. They mainly made drum machines.
As mentioned earlier, this was their first mass produced monosynth. They were probably trying to cash in on the craze for pre-patched performance instruments like the Minimoog and Odyssey.
It started Korg's journey to become one of the world's great synthesizer manufacturers.

The knobs and dials share a common style with the minipops 7 drum machine.
Thanks bdu808

The Korg700 was meant to sit on top of a larger keyboard (usually an organ). Thus most of the controls have been placed under the keyboard, not above as is usually the case.
 
 
At first glance the 700 seems basic.
It has just one oscillator, a HP / LP filter, a simple EG.

But it delivers with style & has oodles of character.  The filter (traveller) is fantastic.
Even with just one oscillator, it still can make some fat baselines. 

 The MiniKorg 700 was replaced a year later by the 700S.
This added a second oscillator and ring modulator.

Korg is remaking the 700S but calling it the 700FS. 
FS = Full Size. ??? Does this imply there will be a MiniKorg  700mini in the future ??
The FS has a second oscillator.
It also has a ring modulator, a spring reverb, joystick controller, patch memory, aftertouch and an arpeggiator.
I'm seriously tempted to buy this. 



Some interesting features of these synths are the Traveller filter, the Percussion/Singing envelope, and the function switches.
 

The Filter

 
The Traveler is the Filter.
It's typical of early Korg filters seen in the 700, 700s and dv800 Maxikorg.
Korg also used this design in their FK-1 effects pedal.
These early filters consisted of high pass and low pass stages in series.
The top section is the LPF.
The bottom is the HPF 
(interestingly, the Korg MS20 also used two filters - high pass and low pass in series).

Korg used the Keio IC TS201012 for the VCF.
It's a custom sealed IC. There are 2 of these.
The "Traveler" filter was used in the Korg 900PS, 700, 700S and 800DV.  


To aid the filter there are 2 switches -- 
expand & Bright.
 
These add resonance 
The "bright" adds additional high-frequency harmonics.
 
 
 
 
 

The Oscillator

 
Scale of course is the Oscillator Pitch.

You can choose waveforms with the mode switch on the right. You get Triangle, Square, Saw and Chorus I & Chorus II waveforms. 
 
The Chorus I sound is described in the manual as a "Slow rotating sound with duplicating effect".
The Chorus II sound is described in the manual as a "Fast rotating sound with intensified duplication effect".
 
I understand that this single oscillator uses the KEIO TS200011 IC.
This is a Korg custom VCO core integrated circuit. (look for a sealed black box).
 
Check out Colin Fraser's website:
 
Colin Fraser in 2010 began reverse engineering these modules. Before this you had to "sacrifice" old Korg synthesizers to get spare parts. 
 

The Envelope Generator

 
This is a basic AD envelope.
Attack on the left. (forms the beginning of the note)
Decay on the right. (Forms the end of the note).

The Decay range is from 
Short (Percussion) to long (singing).

The envelope is triggered by the keyboard.
When a key is pressed the cycle is initiated.
 
The envelope is disengaged when the key is released. 
To enable a show release when a key is released, 
activate the the sustain switch.
The sustain level is fixed.






 
The Bender provides added slide to the beginning of each tone... such as Glissando and slur. 
It glides into the current note, from a whole tone below.

The Portamento switch in comparison glides the previous note into the current note. (A bit like a slide).

Repeat - this repeatedly triggers a held note.

Vibrato - It modulates the pitch of your current note.
Delayed Vibrato - applies vibrato with a slight delay.

The amount of these last 3 effects (repeat, Vibrato, Portamento)  are controlled 
with the slide modifier group below. The green slider adjusts the portamento speed.
The two blue sliders control the speed & depth of vibrato.

 
The pitch slider on the far right on the above picture is the master  tuning.
 
Just two audio outputs - High & Low.
There is no CV control or midi of course.
Also no external filter input.
 

Links