NLC Dual LFO/VCO - part 2

 pART 2 of my NLC dual LFO/VCO build
Part one is here:
https://djjondent.blogspot.com/2020/02/nlc-dual-lfo.html

 This module is a DIY eurorack format module.

tHE  LM13700 op amp

DG 202

The DG202 is a CMOS switch. Its a quad SPST switch.
The DG 212 should also be ok to use.

The "DG " stands for double gate.
Double Gate CMOS  (DG)
 Traditional CMOS technology is approaching physicial limitations was we approach the nanoscale regime.
One such solution is the double gate transistor, proposed in the 1980s.
"Multigate transistors are one of the several strategies being developed by CMOS semiconductor manufacturers to create ever-smaller microprocessors and memory cells, colloquially referred to as extending Moore's law.^"

Time to build the top PCB

Re the LEDs
Andrews notes say
" Use 3mm LEDs, bipolar ones look good. If red/green use 1k for RL. If red/blue use 4k7 for RL"
I couldn't find suitable Bi-polars, so I used standard Red LEDs.

Links

+ NLC Wiki
+ NLC Build guide and BOM
+ NLC Blog (old)
+ NLC blog (new)
+ CMOS  info 
+ NLC DIY info 

 

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Hoi An - Vietnam - day pics

Hội An is a beautiful city on the Central coast of Vietnam.....about 100km south of Hue.

Its architecture is facinating ... its a mix of French, Chinese, Japanese, Portugese.
It's very well preserved. and the food is great too. tHESE pics are of the modern outskirts of the city where you will find cars & traffic.

Cars and bikes are banned from the city centre which sits upon the Thu Bon river.

...

The Japanese bridge.

For more travel postcards click here:

http://djjondent.blogspot.com.au/2015/03/travel-postcards-index-my-travel.html

 

Arp 2500 sequenced by a Roland TB 303

The 2500 is being sequenced by a Roland TB 303. 
This is the first of a series of experiments done during these COVID 19 lock down days.

The 303's Gate is triggering the 1046 quad envelope generator. 

The 1004-P VCO is sequenced by CV from the 303. 
A second VCO 1004-T is running in LFO mode and also modulation the 1046.

tHE audio is being filtered through a 1006 Filtamp module. 
The drums are from a Synthstrom Deluge. 

NIN Ghosts V & VI

Nine Inch Nails have just released 2 new albums:
GHOSTS V: TOGETHER and GHOSTS VI: LOCUSTS.  

 They are making  these available for free! These releases are part of the GHOSTS series

I'm sure these will help everyone during these difficult times.
They can be downloaded from the NIN website.
https://www.nin.com/

The Ship of Thesus

During this Covid 19 Epidemic I've started to repair some old synths.
With time on ones hands, I can consider the old question of the Ship of Thesus or the Theseus Paradox.
The story goes that after the Greek hero Thesus returned from slaughtering the Minotaur
his ship was left in the harbour as a memorial.
As it's timbers rotted, they were gradually replaced.

Plutarch, wrote about this boat:

"The ship wherein Theseus and the youth of Athens returned had thirty oars, and was preserved by the Athenians down even to the time of Demetrius Phalereus, for they took away the old planks as they decayed, putting in new and stronger timber in their place, insomuch that this ship became a standing example among the philosophers, for the logical question of things that grow; one side holding that the ship remained the same, and the other contending that it was not the same".

So after a few hundred years, when all the old timbers had rotted and been replaced, is the ship the same ship that Thesus once sailed. And if the old rotting timbers were kept safely and then in the future used to make a second boat, then which is the true ship of Thesus ??

So this makes me ask what is the limit one should repair a vintage synth.

 Old Serge Paperface

Do I let nature take its course and let it slowly decay ?
Do I replace some of the components? Do I replace all the old components?
Is the aim to make it sound like it did when new?
Does a synth with vintage components sound the same as the same modern synth?

In answer to the last question I think no.
I have an old ARP 2600 & a TTSH and though they are close , they don't sound identical.

The same is for my Korg MS20s (I have 2 vintage ones), and one modern.
In fact all 3 sound different (though you can hear that they are sonically all MS20s).
And I won't touch the insides of the MS20s as they sound great in their individual ways.

I'm divided about what the correct answer is when repairing historically important synths.
It really depends on how valuable to history, the synth is. 
I think if the synth is unique,  it may be better to simply maintain it until technology is available to restore the original components.

We can always build a modern equivalent that people can use in the meantime.

Arturia ispark

In these uncertain times every distraction is welcome.
To help you make music while in isolation Arturia are releasing their i-spark drum/synth for free.
It's for the ipad.
Free iPad app until Apr 30

Coco, my puppy is practicing his social distancing.

248r expander

This expander I think only works with the 248r mark 1 MARF

Some build pics.

CD 4051

HC595

Waiting for some parts.
To be continued ......................