Showing posts with label Eurorack. Show all posts
Showing posts with label Eurorack. Show all posts

Wednesday, 7 November 2018

LZX Castle Video Synthesizer - 000 ADC


Some build pics of the first module in the Castle series.
This module is in Eurorack format.
iT'S 4HP and all through hole.
Quite an easy build

I must thank the entire team from LZX  and Philip Baljeu for making this DIY system possible.
Building these modules from scratch is a great way to learn.
 tHESE are not official build pics and I am in no way affiliated with LZX.

 The Castle 000 ADC is an Analog to Digital Converter. It's used to change an analog input signal in to a 3-Bit data stream.  You will see on the module a single input on the top and 3 outputs below, labelled D0, D1, D2.

"The ADC will take an analog signal and split it into 3 bits or zones, the separate outputs kind of look like a square wave version of staircase, the first output D0 has 4 lines, d1 has 2, and D2 has 1".
 (facebook post from Philip)


The main IC is the SN74HC148N
The SN74HC148  features priority decoding of the  inputs  to  ensure  that  only  the  highest-order data
line is encoded. These devices encode eight data   lines   to   3-line   (4-2-1)   binary   (octal).

The SN74HC148 features ‘priority encoding’ where, if more than one input is active at the same time, the output will select only the most significant active input.

The internal logic is shown below:





The voltage regulators

tHIS is the underside of the voltage regulators. Be careful not to short circuit.


 tHERE  are six LM6172s


Finally done.

Troubleshooting:
There appears to be a sweet spot when adjusting the Bias & Gain knobs.
I'm not sure if this is normal behavior. Outside this narrow range the output signal disappears.
The schematics indicate that the Bias/gain 10K pots effect the first 6172 op amp.

Possibly tweaking the value of those 10k pots or the associated resistors might give a better outcome ??????
I received an email from my friend, Chris who directed me to some info regarding this:
"The bias range is pretty wide, maybe too wide. I wanted enough range to mess with many signals, not just 1V. The controls aren't really something I see people changing a lot, more of just to get the settings right in to the ADC and set and forget. But if people think the range is unusable I can look in to limiting it. In the meantime, anyone who wants to try for themselves, R10 would be the thing to change. its 4.99K right now.” (Philip B).

The Gain control on the ADC goes from non-inverted on the left through zero to inverted on the right. 


LZX - Castle
Introduction
00_000 ADC - Analog to digital converter
01_001 DAC - Digital to Analog converter
02_010 Clock VCO
03_011 Shift Register
04_100 Multi Gate
05_101 Quad Gate
06_110 Counter
07_111 Flip flops

Links
+ ADC overview - LZX
+ LZX industries 
+ Bit numbering
+ CMOS
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Video Index page

Monday, 5 November 2018

LZX - Castle -Modular synth

Some notes before I begin building The Castle.


The Castle synth is different from the Cadet synth which I have recently been putting together.
These modules were designed by  Philip Baljeu of Toronto and were inspired by early digital hardware video synths.
The main difference seems to be that the castle is a system of binary & logic modules.
Binary = on/off or 0/1
It processes 3 bits in parallel....  3 bit data streams
The 3-bits give 8 possible combinations.....Black, Red, Green, Yellow, Blue, Magenta, Cyan, and White.

I'm guessing that these modules will be good for producing computer graphics and pixels ??... but maybe more. I wonder what it will be like when you mix these with the analog Cadet LZX.
It seems that any signal can be used as an input, it doesn't need to be binary logic signals. 
There are 8 modules in this video synthesizer. Everything is through hole, and 4HP

LZX - Castle
Introduction
00_000 ADC - Analog to digital converter
01_001 DAC - Digital to Analog converter
02_010 Clock VCO
03_011 Shift Register
04_100 Multi Gate
05_101 Quad Gate
06_110 Counter
07_111 Flip flops



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Saturday, 3 November 2018

Modular in the Lounge V

Yah. Sat 2nd November
Modular in the Lounge V is here.
 The day began with the best scampi ever.

The night was all modular. Thanks to Paul, Dee, Adam, Ben, Terry & Andrew for some
 some great stuff.

Allinaire

The 5th Modular in the Lounge.

RENE mark II

Ben




Post Global Disorder
..


VirusInstaller - 1st performance


Adam








Virus Installer --- 2nd performance



Past Modular on the Lounge gigs:
+ Modular in the lounge IV
+ Modular in the lounge III
+ Modular in the lounge II
+ Modular in the lounge I
+ Modular in the Car Park

History of Buchla, Eurorack formats & the origins of names.

This post was inspired by a discussion with my friend Adam over the confusion of naming Buchla modules. I have 2 vintage Buchla systems along with what many refer to as "Buchla Clones"

and lots of 3rd party 4U modules which make no attempt to pass themselves off as Buchla apart from the fact that they are 4U and share the same voltage specs.

I love all these modules. ... for different reasons and am happy to use vintage alongside modern modules.
This format has been steadily growing over the years and I think this momentum will only gather pace.

Should they all be called Buchla ????
How do we make the distinction between vintage Buchla modules, their "clones", and modern manufacturers who use the format invented by Don Buchla?
I have recently started describing only vintage Buchla modules as Buchla, and the rest as "Buchla Format". Is this distinction good enough? Should the word Buchla only be used with modules that Don Buchla himself made or commissioned?
I think making this distinction is important to avoid confusion for musicians and their audiences.

Adam & I decided to compare this format to Eurorack.
 Original photo by Nina Richards


The Eurorack system was originally specified in 1996 by Doepfer Musikelektronik, but history could so easily have gone another direction.

Doepfer Musikelektronik GmbH is based in Gräfelfing, Germany and was founded by Dieter Döpfer.
Dieter developed a voice modular system in the early 1980s (the VMS) but with the advent of MIDI in 1983 & the release of the Yamaha DX7 again in 1983, it seemed that the world of the modular synthesizer was over.
In 1992 Doepfer developed the MAQ16/3 Sequencer which was heavily influenced by Kraftwerk.
He developed the Mogli Midi Glove and the MIDI-to-SYNC interface MSY1 in 1994.
Around this time second-hand Roland TB303s began to inflate in price and Dieter decided to develop a
 TB 303 inspired synth... the MS 404. 1995 was a big year. The MS404 was a huge success. It was a 1U rack mounted synth.
After this success, Dieter decided to try to develop a new modular system and by Autumn of 1996 he released the A-100 system. " The first A-100 modules were nothing more than circuits from the MS-404". (DD)

It had only 10 modules at the time. It's part of the history of Eurorack now.
I understand that the Eurorack name originated from the computer Eurocard systems which were developed by Acorn computers between 1979 to 1982.

This decision to use a standard 19" rackmount enclosure was critical.

 It looks very much like the modern Eurorack modular synth system of today.

At the time there were other manufacturers like Analogue Systems (AS) that used a similar rack system. AS had small technical differences such as the power connectors but they later adapted some of  their products to offer "Eurorack compatibility".
Over time more and more manufacturers adopted this system.

The module height was three rack units and the width varied depending on the specific module
Width was measured in the Eurocard-specific Horizontal Pitch standard. Here 1HP = 0.2 inches, or 5.08 mm. 

 This 3U system is now the largest format with hundreds of manufacturers from all over the world. What makes it so popular I think is it's open source nature.
 The A-111 is a doepfer module. It sits happily along side two US manufacturers.

There is of course strict adherence to the format size/and voltage specs, but manufacturers are free to
name their modules what they like, using their own distinctive panel designs and names.
These module manufacturers are fortunate to have the name "Eurorack" to use. It's a generic title.

Is there a generic name that could be applied to all modules using the format invented by Don Buchla?  BF (for Buchlaformat)?, 4U? , 4UB maybe?
I don't think 4U is sufficient as there are other module manufacturers using the 4U size.
4URack ?
4rack?


Links:
+ What U is that synth?
+ Eurorack - Wikipedia
+ Doepfer - wikipedia
+ Eurocard -wiki
+ Doepfer time line History

Wednesday, 31 October 2018

Vector Rescanning - Rutt Etra - Tek 620 monior - first attempt

Initial efforts on getting some vector rescanning.
I'm using a LZX video synth and a Tektronix 620 monitor.

...


 tHE patch is very simple.
Horizontal ramps into the X input.
Vertical ramps into the Y input
Video from the camera into the LZX "Color TBC" and out via the Color video encoder.
This video signal is then plugged into the Z input

 The Passage, Bridge are boosting the signals
-------------------------

Patch 2

Slight variation on the first patch.
I'm now mixing the video signal into all 3 inputs.
Ramps and still going into the X & Y ins

....

Links:
LZX official
Muffs - Cadet series DIY/assembled

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LZX Cadet X - DIY Video synthesizer - Multiplier

There is a old saying in the audio world: "You can never have enough VCAs"
Maybe this is a bit simplistic, but I'm seeing the Multiplier as a VCA for video.
(its much more than this too).

These are some pics of the Cadet DIY modular video synth build.
I am an independent builder and have nothing to do with LZX industries.
These aren't official build notes, just my records to help me trouble shoot.
It's a work in progress.
Do let me know if you spot any errors or omissions.
This is module no.10 (Multiplier X).
It doesn't require the 14 pin sync cable.

It's described as "Cadet X Multiplier is a variation on the Cadet VI Fader circuit,
 configured as a switchable 2-quadrant or 4-quadrant multiplier".
So if I understand this correctly, in 2-quadrant mode it it acts like a VCA and in 4-quad mode it behaves like a ring-modulator..... "it crossfades between an inverted version of the input signal
and a positive version of an input signal"

2-quadrant mode = VCA.
You can control the amplitude with a control voltage (0 = no signal & 1V = max signal)

4-quad mode = Ring Modulator
The amplitude of the output is again controlled by CV.
When CV is negative ( -1V for LZX = max inversion) signal gets inverted.
When CV is positive  ( +1v on LZX = max amplification) signal is non-inverted.







This video amp ic is out of stock at mouser. (marked U2 on the PCB)
584-LT1251CN#PBF
LT1251CN#PBF 

I'm using this instead:
584-LT1256CN#PBF
LT1256CN#PBF

LT1251CN#PBF - iTS a 40MHz Video Fader and DC Gain Controlled Amplifier
It's probably the core component of this module. Looks very useful if you are designing your own circuits like the fader and amp below. But its not cheap. Mouser sell them for $16 AUD each.

And yes, this same chip is used in the Cadet VI Fader module.





ICs and special parts:
TL072IP
LT1251CN#PBF  ---- 40MHz Video Fader and DC Gain Controlled Amplifier
LM6172IN/NOPB
TL431BQLPR

to be continued ... waiting on some parts

Links:
LZX official
Muffs - Cadet series DIY/assembled

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