Wednesday, 14 December 2016

Filters - Korg Electribe 2

I love the electribe 2
Its a wonderful and underrated synth for very easily creating your own sounds.
You can model your own unique drum and synth sounds really easily.
 
The filters are one of your best tools for doing this.
There are 3 basic types:
LP, HP, BP
They are virtual analog.
 
You can cycle through each sub group by pressing the LPF/HPF/BPF buttons repeatedly
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LPF
electribe LPF  
MS20 LPF
MG LPF (moog)
P5 LPF (prophet 5)
OB LPF  (oberheim)
Acid LP  (TB303)
 
 
HPF 
electribe HPF
MS20 HPF
P5 HPF (prophet 5)
OB HPF (oberheim)
Acid HPF
 
BPF 
electribe BPF
MS20 BPF
P5 BPF
OB BPF
Acid BPF
 
 
A good live performance trick is to cycle through some of the filters. 
 
There's  filter automation available so you can program in filter sweeps quickly and easily.
Press the record button, and then move the cutoff freq knob.
You will notice the record button starting to blink.
 
Experiment with the EG int (intensity) knob in the filter section.
Increase the EGint to let the Amp EG modulate the filter.

 
When building a baseline, I usually use the LP filter to cut out higher frequencies.
However, a cool live performance trick is to load identical copies of  your bassline
into parts 1, 2 & 3 , and give each a different filter. The mute/unmute each part
and tweak your cutoff freq, Q and EG int during the performance.
You can even automate some of the parts.
 
Remember you can also input external audio through the electribes filters.
 

Monday, 12 December 2016

Mutable Instruments - Clouds - drones - chords

Clouds is a great module to use for creating drones & chords.
 
 
Use Granular synthesis mode
First mode. 
You need to input a steady note, and then it's just a very quick sequence that transposes the pitch of the grains
 
Used the quantized output of the a sequencer.... a Rene for example.
program on each row four notes that form a chord.
Limit it to a C major scale, for example.
You can then turn the knobs freely on the sequencer and create chords on the fly. 
My Clouds tracks quite well 1v/Oct.
 
Links

Tuesday, 6 December 2016

Sauce of Unce - NLC - Build notes

This is a Eurorack module based upon the Buchla 265 Source of Uncertanity module.
The 265 is the first in a long string of modules bearing the name "Source of Uncertainity" which I
think is poetic and apt for such a module.


The Buchla 265 is one of  the greatest modules Don ever built.
However, the original 265 uses lots of rare and expensive parts and needs +24V to operate so is out of reach of most people.

The Nonlinearcircuit module though not a complete clone is very close.
The noise source uses a TL074 (quad op-amp). The 265 used four uA741s (single Op-amp).
The 0.05-50 Hz VCO is op amp based (again TL074).
The Sample & Hold sections are changed to use the hi-Z input of TL074 op amps (ie not uA741s). 
The 265 used an uA741 at the S/H output.

I've often wondered where did the name "unce" come from?
Maybe as it's the written form of the sound heard in most club music, Andrew named it from there? You have probably heard the sound unce,unce,unce,unce, etc coming from a club.


Andrew's build notes are here:
http://www.sdiy.org/pinky/data/Sauce%20of%20Unce%20build%20notes.pdf

NLC Blog descriptions:
http://nonlinearcircuits.blogspot.com.au/2014/04/sauce-of-unce.html
and
http://nonlinearcircuits.blogspot.com.au/2014/07/sauce-of-unce-in-eurorack.html

I'll be building two versions: one for the Buchla system & one for the Euro.

First the Eurorack one.
This is what the virgin boards look like.
There are four surface mount TL074 op-amps and some passive resistors in SMD format.
The rest of the build is through the hole.

There are two sides to this PCB

I like to get the SMD op amps onto the board first. Be careful there are no shorts.
Then the rest of the passive SMD stuff. The spacing is for 1206 SMDs.
I'm using 0805 SMDs. 
The 47K resistor  next to the 4u7 cap (marked in yellow) should be added last.
It sets the level of the noise output and determines the behaviour of the entire circuit.
It's value can range from 47K to as low as 12K if you have noisy transistors.
read Andrew's build notes for more info.

T1, T2 & T3 are test points.
T1: should just be noise like the three noise outputs
T2: a noisy approx 100Hz tri wave
T3: turn up the random pot to max, depending on your vactrol you should hear approx 30Hz +/-10V signal .
T3 is the output of the VCO that controls the S&H on the 'random' output, 

The orange & blue circles mark resistors that should be left out or changed. These set the output voltages.
Euro require voltages in the 0-5V range.
Buchla require a 0-10V or 0-15V range.

The blue circle marks the 12K resistor which I'm changing to 6.8k to give a Euro voltage output (0-5V).
The Orange circle marks the 10K & 33K which I'm changing to just a link (on the 10K) to again give out Euro voltages.



I'm using a J112 for the FET.
 Caps next.
 I'm using 68uf ceramics for the decoupling caps.

I used a 10uf 50V non polarized electro here.
The remaining 10uf Electros were 35V
 Vactrol time.
Using a VTL 5C3/2 for the dual vactrol.
It's what I had on hand at the time.
Probably a VTL 5C2/2 would be better ??
The VTL 5C2/2 has slower attack and decay response times.

For the single vactrol I used a NSL 32.

Almost there.
Pots, LEDs & jacks now.
I used 510 Ohm SM resistors for the LEDs.
Before setting the noise levels with the resistor marked "47K" I had a listen with just headphones.
Yup !!! lovely noise.

I measured an average of 0.175V at pin 1 of the TL074.
It fluctuated  quite a bit.
So the resistor value was 62K
11000/0.175 = 62.857



I blew the 10 ohm resistor in the lower right corner of the pic. It's now replaced with a SMD 10Ohm.
The culprit was I think a short  between the dual vactrol and the resistor (now covered with plastic shrink).



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For the Buchla module:
To get approx 0-10V, install the 10k and 33k resistors as described. To get it up to 15V, replace the 10k resistor. Use 0805 smd (which will fit nicely), so you can easily remove them, try 22k for starters.

Similarly, on the smooth output you can change the 10k resistor to increase the output voltage.  
The build guide I suggests using 6k8 to 8k2 instead of the 12k. "The output still gets pretty hot but very rarely clips, this depends a lot upon your dual vactrol, so some experimentation is needed. I (Andrew F) used a rare dual Silonex. "Best to use 0805 resistors which can be easily installed and removed".

Another way is to use 6k8-8k2 as suggested to keep signal levels at comfortable (for the op amp) levels and then adjust the '10k*' resistor at op amp C1 to get the range you want, higher resistance = higher voltage.

 
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Links:
Muffs- 265sou

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sAFI - Morocco

Safi is a port city on Morocco’s Atlantic coast. 




Ksar El Bahr, a 16th-century fortress built by Portuguese colonizers, is on the waterfront. In the old town





These pics were taken in 2004




safi is famous for pottery.
This is a kilm


Lovely, lovely place.


Wednesday, 30 November 2016

Squid Axon - NLC - Build notes

These are my build notes for the Nonlinearcircuits Squid Axon Eurorack module.

The Squid Axon is a circuit based on the Hodgkin- Huxley
 equation describing the chaotic behaviour observed in giant
squid axons.


Andrew's Build notes are here:
http://www.sdiy.org/pinky/data/Squid%20Axon%20build%20and%20BOM.pdf

Andrew's Blog info:
http://nonlinearcircuits.blogspot.com.au/2016/03/squid-axon.html

Basically it's a 4 stage analog shift register with two feedback paths, one nonlinear and one linear.


 I like to get the surface mount ICs on first.


I'm using this DG411 - from mouser.
 According to the specs, it requires the 100K & 120k resistors.

See Andrew's build notes.

 Get the rest of those SMDs on the board.
You're nearly there.





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Monday, 28 November 2016

Pauline Oliveros RIP

Pauline Oliveros will be sorely missed.


The picture above is of her with a Buchla 100.
She was a central figure in the development of experimental and post-war electronic art music.


Pauline was born on  May 30, 1932 in Houston, Texas.
She passed away on November 25, 2016.

Oliveros, along with Morton Subotnick and Ramon Sender, formed the San Francisco Tape Music Center
in the 1960's.
She made a huge contribution to the development of Electronic Music.
Her legacy will enrich the lives of generations to come.

Fairlight CMI IIx - Demo - Locust

This is one of the demo tracks that was released in the 1980s for the Fairlight.
The Fairlight I'm using is vintage 1982.

All sounds are from the fairlight with no added effects, etc

 It's important to load the instrument file (LOCUST.IN) first, then load the .RS file (LOCUST.RS).
The image above is a pic of page3 (Keyboard Control)

This is really important. For PageR to work correctly, you must set up page 3.
+ All loaded voices should have a NPHONY of 1.
+ Each register must have its own keyboard.

To load an instrument file type:
L,filename.IN<return>
or
L,IN,filename<return>

An IN file is a collection of VC (voice) file names & keyboard tunings.

 Opening page for the Locust tune.
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