Rob Hordijk Active Matrix: Difference between revisions

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[[File:Hordijk am.png|thumb|right|200px]]The 4U [[MU]] or 5U [[MOTM]] '''Rob Hordijk Active Matrix''' module is a fully buffered eight by eight matrix where any one of eight input signals can be added to any one of eight outputs. By using ¼-inch tip-ring-sleeve insert jacks for the matrix nodes (equal to stereo jacks) a whole range of applications ecome possible. First the column input signal is buffered and then routed to the tips of the nodes in that column. The ring signals of the nodes are basically summing inputs and summed to the final output signals at the ends of the rows. By connecting a stereo jack where the tip and the ring are connected directly together, a connection with unity gain is made from a column input to a row output. If the tip-ring connection in the jack goes through a resistor an additional attenuation can be accomplished. E.g. a 30k resistor will attenuate by 6&nbsp;dB and a 91k resistor by 12&nbsp;dB.<ref name="rh">Rob Hordijk</ref>
Contact Rob directly for details about his designs: rhordijk@xs4all.nl.


[[File:Hordijk mb.png|thumb|right|200px]]When a stereo audio cable is soldered to a jack plug and on the other side of the cable a potentiometer is attached the potentiometer will act like a pot on the node, enabling to set the mix level by the pot. Basically each node is an insert, just like the inserts on a mixing desk. And can thus be used in the same way. So, using a jack with a pot means to ‘insert’ the pot into the signal path. This means that you can insert any other outside world device in the signal path by using an insert cable with a stereo jack on one side and two mono jacks on the other, provided signal levels match of course (e.g. 5V pp oscillator output signals will severely overload line level inputs on e.g. a digital effects rack or the guitar input of a stompbox). One could also connect a resistive sensor like a light dependent resistor (LDR) to a jack and make the node light sensitive.<ref name="rh" />
Rob also has his own subforum at the Electro-Music forum site:
http://electro-music.com/forum/index.php?f=185


Each column also acts like a multiple. When a mono jack is connected into a node it will pick up the column input signal from the tip. But the ring input is now short circuited to the ground through the sleeve of the mono jack and will so disable any input from this particular node to the row output. This will not interfere with any other nodes in the same column or row, because of the full buffering of both the column inputs and row outputs. So, any node that is not used to route a signal to a row output can be used as a multiple output. Meaning that the matrix is also eight multiples with one buffered input and eight buffered outputs on each multiple.<ref name="rh" />


Matrices with bigger sizes can be built on demand. Input columns come in multiples of eight and any number of output rows are possible.<ref name="rh" />
Most of Rob's module designs use SSM quad VCA chips, possibly the Analog Devices SSM2164 (?)


== Mini Bay ==
The 2U wide MiniBay is a smaller version of the Active Matrix. It has a four input by six output fully buffered matrix plus two passive multiples with five jacks each. The matrix section works exactly like the 8x8 Active Matrix.<ref name="rh" />


== Mini Mix ==
<b>HRM VCO</b><br>
Mini Mix is a mixer module to turn patch points into mixers like a matrix mixer.<ref>Mod Wiggler forum:[https://www.modwiggler.com/forum/viewtopic.php?t=32246&start=all&postdays=0&postorder=asc Rob Hordijk Phaser Filter demos]</ref>
The HRM VCO module can morph from waveform to another because it builds up the harmonic content from a sine and cosine waveform.
You can morph with CV from sine to triangle.


== References ==
{{From Mod Wiggler Wiki|Rob Hordijk Designs}}
{{reflist}}


== External links ==
<b>Dual Phaser </b><br>
* Rob Hordijk explains the [https://www.youtube.com/watch?v=kSKp2q3LlUE&index=6&list=PLAC347DE38ABA9E8D Active Matrix] at the European Electro Music Event 2012, Mallorca, Spain.
Price: 385 Euro.
The phaser module can do waveshaping and ring-modulation, and can also act as a VCF. It can perform spread-modulation.
It is an OTA phaser (8 pole and 2 in a module.)
When nothing patched into phaser 2 the second phaser goes parallel to phaser 1 with the input inverted.
With the same settings, you get almost full cancellation from the output.


[[Category:Original Rob Hordijk Design]]

[[Category:5U modules]]
<b>Active Matrix</b><br>
Price: a little under 500 Euro.<br>
The Active Matrix module is buffered and works similar to the EMS Synthi.
It comes with mono plugs and some have built-in resistors for -6db or -12db signal reduction.
Every point is an insert, and with an insert cable, you can patch whatever you like into that point.

<b>Dual Envelope Generator</b>

Latest revision as of 18:09, 24 April 2021

The 4U MU or 5U MOTM Rob Hordijk Active Matrix module is a fully buffered eight by eight matrix where any one of eight input signals can be added to any one of eight outputs. By using ¼-inch tip-ring-sleeve insert jacks for the matrix nodes (equal to stereo jacks) a whole range of applications ecome possible. First the column input signal is buffered and then routed to the tips of the nodes in that column. The ring signals of the nodes are basically summing inputs and summed to the final output signals at the ends of the rows. By connecting a stereo jack where the tip and the ring are connected directly together, a connection with unity gain is made from a column input to a row output. If the tip-ring connection in the jack goes through a resistor an additional attenuation can be accomplished. E.g. a 30k resistor will attenuate by 6 dB and a 91k resistor by 12 dB.[1]

When a stereo audio cable is soldered to a jack plug and on the other side of the cable a potentiometer is attached the potentiometer will act like a pot on the node, enabling to set the mix level by the pot. Basically each node is an insert, just like the inserts on a mixing desk. And can thus be used in the same way. So, using a jack with a pot means to ‘insert’ the pot into the signal path. This means that you can insert any other outside world device in the signal path by using an insert cable with a stereo jack on one side and two mono jacks on the other, provided signal levels match of course (e.g. 5V pp oscillator output signals will severely overload line level inputs on e.g. a digital effects rack or the guitar input of a stompbox). One could also connect a resistive sensor like a light dependent resistor (LDR) to a jack and make the node light sensitive.[1]

Each column also acts like a multiple. When a mono jack is connected into a node it will pick up the column input signal from the tip. But the ring input is now short circuited to the ground through the sleeve of the mono jack and will so disable any input from this particular node to the row output. This will not interfere with any other nodes in the same column or row, because of the full buffering of both the column inputs and row outputs. So, any node that is not used to route a signal to a row output can be used as a multiple output. Meaning that the matrix is also eight multiples with one buffered input and eight buffered outputs on each multiple.[1]

Matrices with bigger sizes can be built on demand. Input columns come in multiples of eight and any number of output rows are possible.[1]

Mini Bay

The 2U wide MiniBay is a smaller version of the Active Matrix. It has a four input by six output fully buffered matrix plus two passive multiples with five jacks each. The matrix section works exactly like the 8x8 Active Matrix.[1]

Mini Mix

Mini Mix is a mixer module to turn patch points into mixers like a matrix mixer.[2]

References

This page uses Creative Commons Licensed content from Mod Wiggler Wiki:Rob Hordijk Designs (View authors).

  1. ^ a b c d e Rob Hordijk
  2. ^ Mod Wiggler forum:Rob Hordijk Phaser Filter demos

External links

  • Rob Hordijk explains the Active Matrix at the European Electro Music Event 2012, Mallorca, Spain.