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

Tuesday, 28 November 2017

Brain Custard - NLC Build notes

My notes for the Nonlinearcircuits Brain Custard Eurorack module.
This version of the module will be for audio rates, but you can also build this to produce CVs.



It's kind of like the Jerk Off module in that it uses chaotic oscillators.
The Brain Custard has "9 audio rate chaotic signals mixed to form 'neuron clusters'
The idea is that the low frequency patterns will emerge from the mayhem.
Really it will be vaguely controllable noise and lots of it.....with LEDs."

No rare or hard to source parts. Yah !!!
Just four TL074s & one TL072
Mostly SMD passives.
"c" = 100K
"1" = 1K


For the Audio version install all eighteen 10K resistors.

For the CV version six of the 10k resistors need to be replaced with 47k resistors
You will also need to Replace the 47nF (473), three of the 100nF(104)(see pic) and the 220nF (224) capacitors with 1uF capacitors

 
Some very good advice. :-)

I like to install the ICs first.



"Inputs can be anything; audio, gates, triggers or CV. Depending upon the pot settings, the input signals may do a lot or do little. The X, Y & Z outputs are mixes from the same stages of different oscillators, consider them minor Σ (sum) neurons. Custard is just everything jammed in together, so the main output neuron. Blend is the X, Y & Z outputs mixed together via the Blend pots, these pots have +/-1 gain, meaning when the pot is at 0 the signal is inverted and if the pot is at its mid-point the signal is off."


Links
+ NLC Build notes
+ NLC Blog


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Monday, 27 November 2017

CEM3340 VCO - NLC - Build notes

These are my build notes for the CEM3340 VCO module. It's a  Nonlinearcircuit eurorack module using the CEM3340.

The CEM3340 is a completely self contained VCO on a single chip.


It featured 4 waveforms : triangle, pulse, square & sawtooth (though they are at different levels). The VCO is extremely stable eliminating the need for a temperature compensation tempco resistor.
The CEM3340 is extremely unusual in that it offers both Hard and Soft Sync inputs (pin 6 and pin 9).

It has featured in many famous synths of yesteryear including Roland's Super Jupiter MKS-80 & SH101, Sequential's Prophet 5.3, The ProOne, the OB-Xa & Prophet T8 and Moog's Memorymoog,

sOME nlc words of wisdom









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There are 3 trimpots:
10k trimpot 10 turn - Tadya A-586
20K single turn - A 2504
100K single turn  A 2506
I only had the 20K on hand so used some non tayda pots for the rest. I'll see how this goes.
Might have to replace them in the future.

There are 10 X B100k linear pots .


 Mount the switch, jacks & posts loosely, then solder after securing into place with the panel
This is what the rear looks like.


Another happy customer.

Links:
* CEM 3340 data sheet
* NLC Build notes 
* Electric Druid - VCO designs
* gear junkies - Update about the new Curtis CEM 3340
* NLC Blog

To be continued.....

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NLC - Envelope follower - build notes


These are my build notes for the NLC - nonlinearcircuit Envelope follower. It's a eurorack module but it's design was based on the Envelope Detector of the Buchla 208 (Music Easel).

The 208 has a a hi/lo switch. Andrew has substituted a gain pot.
The NLC version also has a additional comparator stage to give a gate output.
The NLC build notes are here:
http://www.sdiy.org/pinky/data/ENV%20follower.pdf

The module uses just two op-amps (TL 072)


I mixed the 101 (100pF) and 2M2. - it does not matter as they are in parallel anyway.

The BOM requires:
a S1JL rectifier
Mouser No: 821-S1JL.
There is a long waiting list for this.
A replacement is  Mouser Part No: 583-FM4005-T.
The rectifier is polarized. The cathode end is marked with a band. 
This replacement is slightly too big for the PCB. so i had to solder it on its side.

NLC words of wisdom
I think what I do is positive. in its own way. GG Allin


Jacks, pots, LED

tHE Envelope Follower is ideal for instruments at line level such as guitars, mics and Buchla audio signals.
Synth levels (eg Eurorack) can be a bit hot.
Turning the gain to zero and a input from a VCO seems to trigger the envelope and gate quite well
and doesn't seem to harm the module.
However, I think an additional attenuator in the signal path will give more control over the envelopes produced.

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Tuesday, 7 November 2017

Greyscale Algorythm - Firmware 2

This module is a 1 to 8 channel step sequencer.
It can be a 1x64 step, 2x 32 step, 4x16 step or a 8x8 step sequencer.
 
The new firmware is a bit tricky to decipher initially.

There are 3 global menus
(access these menus by holding the Start/Stop button for about 450ms.)
 
1. OVERVIEW MENU (Loop/End switch)
2. MODE RESPONSE MENU (Seq/Rand switch)
3. CHAINING MENU (Gate/Trig switch)
 
Tap any of the right top white LED switches (excluding the left most Start/Stop LED switch) to change to a different menu.


 
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1.OVERVIEW MENU (Loop/End switch)
 The Overview menu always appears when the module is powered on.
It displays what's happening with each of the 8 channels.
 
The 1-8 LEDs flash brightly when an output voltage is high, and glow dimly when an output voltage is low. 
 
You can also mute channels from the Overview by tapping the specific channel button really quickly (just a light tap). 
 
Holding the button down for longer will allow you to see what steps are on/off for that specific channel.
To return to the Global view/menu, hold down the "Start/Stop" button.
 


 
Muted channel LEDs still flash (albeit less brightly) during playback so that you can keep track of what muted channels are doing before un-muting them. Mutes are applied on a per-segment basis, meaning that you can mute any segment within a chain while the other segments continue to play.
 
 
2.MODE RESPONSE MENU (Seq/Rand switch)
controls whether or not a channel will respond to a pulse at the Mode input jack,
 


 
3. CHAINING MENU (Gate/Trig switch).
( Switches 2, 4, and 7 have no function in this menu.)
 
Tap switch 1 for a 1x64 chain, where each of the 8 segments play in series. 

 
Tap switch 5 for a 2x32 chain.   (Switch 1 & 5 are lit)
 

 
Tap switch 3 for a 4x16 chain (switches 1,3,5,7 are lit)
 

 

tap switch 8 for an 8x8 setup, where each channel is independent (chaining is off). 

 

 
All the 8 LEDs are now lit.
 
 
Pattern Editing
You can change between channels/segments at any time, from any menu, by holding down one of the 1-8 switches for 450ms.  
you will then enter the editing mode and see the LEDs light up sequentially.
video 6
 

 

To return to the global view hold the Start/Stop button for about 450ms.

Links
 
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Thursday, 19 October 2017

Doepfer Module A-188-1

Still on the search for the perfect Bucket Brigade Device module.
I just purchased these two on Ebay.
The A-188  series of Doepfer Eurorack modules are great value. They use the Panasonic BBD chips and as always with Doepfer, the build quality is excellent.

The A-188-1 X uses a MN3009. Its a 256 stage IC. These are getting hard to find.

The A-188-1 Y uses a 512stage BBD.




This module happens to be using a newer Panasonic MN3204 IC. These 32xx ICs are lower voltage than their 30xx cousins.

You can read the manual here:
http://www.doepfer.de/A1881.htm


Thursday, 14 September 2017

Numberwang - NLC - Build notes

These are my build notes for the Numberwang Eurorack module by nonlinearcircuits.
The Numberwang is a 4:16 decoder using the CD4514 CMOS logic chip.
I plan to use this for triggering drum modules.
It takes 1-4 gate signals and converts them into a 4 bit number, the corresponding output goes high.
It means you can mix clock signals to get complex timing structures and patterns.
There is also an overall sync input.

This is not to be confused with the Wangernumb module which I built earlier .(See previous notes).

The Numberwang is a 4:16 decoder. I plan to use this for triggering drum modules.

The Numberwang is also great for triggering the ARP2500's envelope generator module .. the 1046.
It appears to output gates with sufficient voltage. (The 2500 usually needs between 7V & 10V gates).
It also triggers the ARP 2600's ADSR envelope generator.
My voltage measurements from the Numberwang - Gates of approx 7V.
Use a Gate booster if your ARP doesn't trigger.

Andrew's build notes are here:
http://www.sdiy.org/pinky/data/Numberwang%20BOM%20guide.pdf


...




The CMOS 4514
I like to get the passive SMDs in next
The through hole stuff.
Jacks next:

Now the LEDs. They are loosely placed. I'll only solder when the panel is on.

Yah, it works.


 Links:
++Andrew's build notes are here:
    http://www.sdiy.org/pinky/data/Numberwang%20BOM%20guide.pdf 
++ NLC Blog


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