Thursday, 3 October 2019

Jacks & sockets

This may seem simple, but its essential to building any synth these days.
They can be 3.5mm, tiny jacks (buchla), 1/4 inch, or banana.

Apart from the Serge banana & Buchla worlds you'll notice that nearly all the jacks
use "PJ" as part of their description.

The most common socket you will come across is the 3.5mm mono jack socket.
16PJ138 style
It's most often used in Eurorack.
It's also known as a switched socket.
This variety is classified as a closed frame.
The sleeve, is most often connected to ground.
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Here is another mono closed frame:
It's PCB mount also. Called a PJ302 3.5mm

These types of jacks are useful for connecting PCBs to faceplates at right angles


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This is a PJ301M-12 :Thonkiconn"

This is also PCB mount

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This is a PJ301BM 3.5mm.
This is mono
..


PJ301CM is the stereo version. Often used as a headphone jack.
I've also seen this used for mini-MIDI jacks
3.5mm






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PJ-320 3.5mm headphone jack socket




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5 pin Switched stereo. 3.5mm PCB socket




Buchla

"Switchcraft Tini-Jax” are the standard historical Buchla audio cable connections and are just slightly larger diameter and longer in length than 3.5mm connections. They are sometimes referred to as 1/8” in Don Buchla’s manuals, though they are actually .140” diameter connections".
 (Buchla 200e manual) 

This is the mono variety.
Mouser stocks them.
Mouser Part No

The Switchcraft data sheet says they are 0.141" diameter.
I often use eurorack cables in Tini jax sockets without any probs, but never the other way round.
If you plug a tini-jax plug into a 3.5mm euro style socket, you can damage the euro socket.

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1/4 Inch

This is a stereo jack.

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DC Power Jack PJ-20 

2.1mm Jack
3 Pin Contact
tayda a-4118


PJ-102AH
Mouser 490-PJ-102AH
2 mm




These are a standard PCB mounted power socket usually used for plugging in DC Wallwart PSUs

Friday, 27 September 2019

Model 155 - Dual Integrator

Some pics of a build I'm doing for a friend.

It's not a Buchla module.
It follows the same size, format & the circuits used are I understand based on Don's schematics.
This is the LA 67 version.

I hope one day I'll find a vintage original, or Buchla USA will release an official 155 module.


I am in no way affiliated with the manufacturer.
These are just my personal notes to help trouble shoot any problems I might encounter during the build.


.
A vintage Buchla 155 is super super rare. I have never seen a real one and can only imagine how it would function. My hope is that Buchla USA will reissue this module soon. (please Eric).
Or if you have one and wish to part with it, don't hesitate to contact me.

The module is described in some old 1992 docs as such:

"(The 155) produces continuous control voltage functions when used in conjunction with sources of discrete control voltages (e.g. keyboards, sequencers). Positive and negatives slopes may be individually varied from 15 volts in .0025 seconds to 15 volts in 10 seconds; either or both slopes may be voltage controlled. Particularly useful for generating complex voltage controlled envelopes, frequency glides, and repetitive control functions."

(from a catelog for the 1992 Ars Electronica exhibit Eigenwelt der Apparatewelt. Pioneers of Electronic Art, edited by David Dunn)

So it looks like it's an early form of function generator.

 The integrator is a very important electronic circuit. You will see this type of op-amp circuit again and again.

This is a common RC or resistor capacitor circuit.
It's also commonly known as a Op amp integrator circuit.

This module however doesn't use op-amps. 
Instead it uses transistors.
Google Miller integrator.




Wednesday, 18 September 2019

Synth Surfers - Bega Valley Synth Festival

Looking forward to the Bega Valley Synth Festival.
Just 1 month to go.

Workshops, demonstrations and displays in the day and OSCILLATIONS with live performances from local and interstate synth artists at night


There will be demonstrations/displays during the day and performances at night.
This is an inaugural event

The day is full of workshops to learn everything from DIY synth coding to Ableton Live to learning VCV Rack a free modular software synthesiser. There are displays of a variety of instruments and synthesiser formats all set up ready for you to try and play on.

10am - 12pm: Synthesis and sound design in Ableton Live
This workshop will give you a basic introduction into subtractive synthesis using the Ableton Live and the Simpler instrument.


12.30pm - 1.30pm & 1.30-pm - 2.30pm: Lunetta Synthesis
Join Adam Buckley as he gives you an introduction to the basics of creating your own synthesiser using the Lunetta Synth Cookbook.


3pm - 4pm & 4pm - 5pm: Intro to VCV Rack
VCV Rack is a free open-source virtual modular synthesiser:

  
10am - 5pm  - demo of the AE Modular from tangible waves.
See the latest modules from the newest modular format with demonstrations from tangible waves representative Carsten Eckelmann/The5thVoltScott Baker/Abre Ojos.

7.30 till late - OSCILLATIONS - Live electronia performances.
Local artists playing alongside artists from further afield. Featuring The 5th Volt . Myst Mach . Abre Ojos . DJ Jon Dent . Virus Installer . Vitals . DJ Hedge Zeppelin & more to be added!



When : Sat, October 19th.
Time: 10am till late.
Location: Murrah Hall 2989 Tathra - Bermagui Road

Links:
+ Murraha Hall
+ ACT Synthesizer Group
+ Facebook

Tuesday, 17 September 2019

211 power supply

Some pics of the Buchla Format 211 PSU

Perfect for a small system.
These are personal pics to help trouble shooting the build.
They are not official build notes.

The build however looks pretty straight forward except for one surface mount component (IC3).

Get those ICs on first.
There are 3 ICs
LM2575 IC1 1 926-LM2575SX-5.0NOPB
LM27313 IC2 1 926-LM27313XMF/NOPB
LM25575 IC3 1 926-LM25575MHX/NOPB

Some closeups:

IC 1: LM2575
 The LM 2575 is a switching, step down voltage regulator
The LM2575 and L3  inductor are used for the +5V supply.





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IC2


IC2 (LM27313) and the inductor L2 are used for the +15V supply.



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IC 3 


This IC is a voltage regulator. LM25575
It supplies -15V (along with the L4 inductor)

LM25575

Quite tricky to solder by hand.




Those inductors




fUSE


connect the external power supply to the +12V and Ground pads.
 I'm not sure why there are also 5+ and 15+ spots next to them.

Jantar Mantar, Jaipur, India

These astronomical instruments were built in 1734 by Sawai Jai Singh II, the founder of Jaipur.

Quite incredible structures.
There are 5 such monuments scattered throughout India: Jaipur, Mathura, Delhi, Ujjain, and Varanasi. 
This is the largest one.


This is very much like visiting a modern sculpture park

 
Nadivalaya
 There are a pair of these facing north and south.
They represent the Earth's two Hemispheres.

It's a UNESCO World Heritage site.
There are 19 instruments in total.


These super sized monuments allow observation of astronomical positions with the naked eye.

 Brihat Samrat.-- possibly the largest sundial ever built. Its 23m high. Apparently, it has an accuracy of 2 seconds.


The ramp of this sundial points towards the North Pole, hence Jaipur time can be easily calculated from the position of ramp’s shadow on the fine divisions of the carved scale. It calculates time up to the accuracy of twenty seconds.









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Jaya Prakash Yantra


 These two marble hemispheres detect elevation, azimuth and hour angles.




Ram Yantra

It measures the elevation and azimuth of the Sun and planets