Chopper/Bi-Di router - NLC build notes.

These are the build notes for the nonlinearcircuits Chopper / Bi-directional module. 
So what is it?
It's a eurorack format voltage controllable electronic switching module.

The bottom section is similar to your old fashioned gate controlled bi-directional router. Functionally, it behaves very much like the Serge triple bi-directional router, though the circuit is very different.

The top section is based on a 70's delta modulator, (at least in concept). Delta modulation (DM or Δ-modulation) is an technique of analog-to-digital and digital-to-analog signal conversion. It's used for information transmission where quality is not of primary importance.

The signals being switched are also sent through a comparator & they control the switching. Plus you can add CV to all of this. Cool !

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Muff's thread is here:

https://www.muffwiggler.com/forum/viewtopic.php?t=124048

Andrew's build notes are here:

http://www.sdiy.org/pinky/data/Chopper%20BUILD%20NOTES.pdf

Andrew's Blog:

http://nonlinearcircuits.blogspot.com.au/2014_12_01_archive.html

 I have  2 versions of the PCB.

I'm currently building Version 2 (on the left).

Version 2 has corrections (mods) already done which you will read about in Andrew's build notes.

Mostly replacing some resistors (470K & 22K) & the addition of the 10K .

A 10 k resistor needs to be soldered from the left pad of the 470k resistor to +V, easiest is the closest pin of

the nearby transistor - the collector of BC547.

I've used two 68uf ceramics for the decoupling caps.

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I've used 510 ohm SMD resistors for the  LED resistors.

You need to experiment with this. I might go to a 1K for the next build.

Mount pots & Jacks. I used a 1M & a 100K pot ... using this for CV.

Cool. Looks like it works. 

Links

CGS - Bi-Directional switch.

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You can find more NLC builds here.

http://djjondent.blogspot.com.au/2015/03/non-linear-circuits-ncl-index.html

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