Neutral Labs SCRAT Steiner Parker Filter Overview

Elk Elektroniks workshop this Sat - 27th Aug

 Elk Elektroniks are holding a workshop this sat.

The Neutral Labs Scrat Steiner-Parker filter.

This is a eurorack DIY kit.

 

" You can change the resonance flavour by plugging in components like diodes, capacitors or resistors (even LEDs and/or light-dependent resistors) directly to the front panel. A set of preset cartridges is also available, which gives you instant access to a variety of filter sounds. You could even make your own. Or go all in and connect some jumper wires to a breadboard for pretty much endless possibilities."

https://www.elkelektronik.com.au/ 

https://www.facebook.com/elkelektronik/ 

 

The suppository of All Wisdom - NLC - Build notes

These are my build notes for the "The suppository of All Wisdom" module

TSOAW is a Eurorack module from Nonlinear Circuits in Western Australia.

The name of the module comes from the words of one of Australia's ex PMs, Tony Abbott.

https://youtu.be/oep_DPDy6xw

Andrew's module is supposed to be a (phaser) phase shifter, but in his own words "is so badly designed that it spits, sh!ts and burps all over the place. It can even do it without even using any CV signal."

 

So it sounds like it would be good for randomly 

phase-shifting an input.

 

This module combines circuits from two of Andrew's fav shifters.

the Steiner Phaser and the  Lovetone Doppelganger.

The Steiner phaser uses diode strings as variable resistors.

The Lovetone Doppelganger is a  4 stage LDR based phaser.

 

Andrew has replaced the Steiner diodes with LEDs which 

modulate LDRs as in the Lovetone.

You will need to build a light tight box using headers. 

The module is one big vactrol. 

Links

+Wiki

+BOM

Some pics of the virgin PCBs

This module doesn't look like it has any hard to find parts

The ICs are all TL047 op amps

You will need 4 LDRs

Some NLC words of wisdom :-)

I'm surprised Andrew reckons Tony was only the second worst PM

But I've got a pretty good idea who Andrew thinks was the worst :-)

To be continued...

Part 2 is here;

The suppository of All Wisdom - NLC - Build notes ...part 2

 

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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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Noiro-Ze VCF & VCA

These are my build notes for the Nonlinear Circuits Noiro-Ze VCF/VCA

This looks like a fusion between the VCF based on the Steiner-Parker diode VCF and a Korg PS3100 VCA.
The the Steiner diode VCF uses diodes of course, but Andrew has substituted LDRs.... you are basically
making vactrols. You will build a light proof box on the PCB.

The original Steiner filter is so very different from all the other filters that I've used. I first heard this on my Arturia Minibrute.  According to Vintage Synth, it can self-oscillate like the Minimoog, but has an opposite polarity so it doesn't lose any volume when resonance is increased

"The nice thing about this filter is you can feed different signals to the LP, BP & HP inputs then 
surf between them with your CV, quite different from regular filters."

"issho ni karaoke ni ikou ka:
 translates to

Let's go out together

karaoke (カラオケ) is a Japanese word. 

It's a blend of two words — kara (“empty”) + oke (short for “orchestra”).  

I'm using 2n2 capacitors for the LDRs.

tHE 180K resistor is here

RL resistor -- 10K

Headers to connect the two PCBs
A bit fiddly. Start with the vactrol box

"You may need to adjust the 2n2 capacitors to suit your LDRs. For GL5516, 2n2 are

fine. For GL5539, which has a higher on-resistance, I found 1n caps worked well." Andrew F

I'm using GL5549 LDRs ... so i may need to tweak the capacitors.

I'm starting with 2n2 for now.

I'm using all b100K pots.
So the top 3 will need the log conversion treatment.

Sounds great !!!

Another finished NLC Module. :-)

Links
+ NLC Blog
+ NLC Wiki
+ Module Info - wiki
+ BOM & Wiki
+ YuSynth Steiner VCF
+ Ken Stone's Synthacon VCF
+ Build notes for the CGS synthacon VCF
+ Potentiometers - convert Linear to Log

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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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DIY - Eurorack

This page is my index for all Eurorack related DIY.
It includes build notes, hacks, etc

GENERAL
+ Small Euro drum - version 1

Barton Musical Circuits (BMC).
+ BMC 037 - EuroBuffer (Buffered Multiple)
+ BMC - FM Drum - build notes

Bastl

+ Grandpa

+ Grandpa Spa

+ Grandpa - adding samples

Beast-Tek
 + Microbe 
 + Pixel Drum 

Befaco

+ Eurorack Power Supply - Lunchbus

+ Percall - build notes  

Cat Full Of Ghosts

+ XCHGN - video exchange - buil...

+ Cat full of Ghosts - Video Equations

 

CGS

* Serge Resonant EQ/Filter - Euro format (CGS 202)

     Audio Equalizers

 

Division 6
+ Dual Sequencer

Doepfer
+ module 128 modification - Fixed filter bank

Duskwork

+ self tuning VCO

+ Faderbank -16n 

 

Greyscale

+ Greyscale Algorhythm - Firmware 2 (Polyrhythm)

+ Greyscale Algorhythm - build pics

hEXINVERTER

+ mUTANT Bass Drum

+ Midi2CV - Hexinverter - build pics

+ Mutant Hot Glue - buildnotes - part 1  

+ Mutant Hot Glue - part 2 - build notes

Ian Fritz

+ 2xAD/AR - envelope generator 

 

Klee Sequencer

      Eurorack format build - part 1

      building of the Klee sequencer - part 2  

      Building the Klee sequencer - Part 3

L1

+ MicroCompressor - build notes 

+ Compressors for Audio

Liquid Foam

+ herbs and stone - liquid foam 

 

Ljunggren Audio

+ RYO Penta sequencer 

+ AmpMix - RYO - Build notes

LZX Video Industries
 + Function Generator - build pics & notes

LZX - Cadet
 + Cadet I - Video Sync Generator - Build notes
 + Cadet II - RGB Encoder - Build notes
 + Cadet III - Video input - build notes
 + Cadet IV - Dual Ramp generator - build notes
 + Cadet V - Scaler - build notes
 + Cadet VI - Fader - Build notes
 + Cadet VII - Processor -Build notes
 + Cadet VIII - Hard Key Generator - build notes
 + Cadet IX - VCO - build notes
 + Cadet X - Multiplier - Build notes

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

Manhattan Analog
  + CVP (Control Voltage Processor)

Meng Qi
 +Passive Dual LPG

 + Voltage memory - Meng Qi - build notes

Metromodular

+ Metromodular Eurorack Power system 101

 + Metromodular Eurorack Busboard MM1521A 

 + Metromodular Eurorack Power system 202 

 MI

+ Mutable Instruments - Grids Hack for clock & random gate.

+ Links - DIY build pics 

+ CV Pal - build notes - Mutable Instruments

MFOS (Music from Outer Space)
+ Bi-polar Power supply

Music Thing Modular

+ Radio Music - build pics

+ Radio Music - Chord Organ - SD card 

 

Neutral Labs

+ Nermal -- build notes

 

NLC - Non Linear Circuits:

        + All NLC pages are here  

 

Ornament & Crime - O_C

+ Piqued - envelope generator 

Snazzy Effects
+ ArdCore -Installation Demo

Sonic Potions

  - Penrose Quantizer

 

ST-Modular

  - ST-Modular EFI filter

Steiner-Parker
Steiner-Parker MicroCon Voice - Eurorack - Build notes

SynthroTek  

1U stereo mixer  

Roboto  

LPG build notes

MST MIDI to CV Converter part 1

MST MIDI to CV Converter - sYNTHROTEK - part 2

Synthrotek Power supply - 5A build notes

 

 

Temps Utile - Build notes

 

 Westlicht

+Westlicht Performer part 1 - build notes

+ Westlicht Performer part 2 - build notes

Zlob
Minimixer
Dual VCA
Dual VCO
Clock divider
Zlob SVF (State Variable Filter) - build notes

Steiner-Parker Microcon - Euro module - Build notes

These are my build notes for the Steiner MicroCon (Eurorack format).
The original Microcon was a full voice module.
It's very rare & was first produced between 1977 & 79 as a complete synthesizer in a single module with its own power supply less keyboard. It has its own LFO, Filter, EG & VCO.
The original module measured 4 x 6 inches.

I purchased this modern eurorack kit from SynthCube.
The circuit/PCB was recast by David Ingebretsen in 2012, with permission from Nyle Steiner.

The euro format panel is designed by Clarke Robinson and produced by synthCube.

Muffs has a very useful thread here:
https://www.muffwiggler.com/forum/viewtopic.php?p=1047995&sid=d261297539ec4b711819800a9b1a5c93

David's L's Microcon post is here:
 https://www.muffwiggler.com/forum/viewtopic.php?t=42415&highlight=micr ocon

It might me fun to install the PCB in a box of the same dimensions as a homage to the original
module, though for the moment, I'll keep this in Eurorack format.

 

Install the resistors first.
There are 10 Diodes - Switching vR/100V Io/150mA (standard 1N4148)
And two 1n4001 Rectifiers (Vr/50V Io/1A T/R)

Headers & caps next.

The two trimmers and that tempco .... needs to be in contact with the IC.(SSM2210).
It's a dual matched transistor.

The Microcon uses two vactrols : VTL5C3/2. These are the same type used in my Buchla.

The original BOM uses a 74c14n Inverter - It's a Schmitt trigger.
This part is obsolete and has been replaced with a CD40106.

It's time to wire everything up.

     More Links:
1. SynthMuseum

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For more Euro DIY builds click here:
http://djjondent.blogspot.com.au/2017/12/diy-index.html
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The Synthacon - Steiner - Parker

On this page are my blog entries on all Steiner-Parker / Synthacon related subjects.

1. SYNTHACON VCF - CGS 35 build notes
2. Steiner-Parker MicroCon Voice - Eurorack - Build notes

   External Links  
1. Yu Synth VCF
2. Analogue Realities
3  Steiner Synthasystem DIY
4. The Synthesizer Network

SYNTHACON VCF - CGS 35 build notes

These are some build notes for the Cat Girl Synth (CGS) tribute module
of the Steiner-Parker synth VCF. (CGS module # 35).
My thanks to Ken Stone & Nyle Parker for making this possible.

This filter is so very different from all the other filters that I've used. I first heard this on my Arturia Minibrute.  According to Vintage Synth, it can self-oscillate like the Minimoog, but has an opposite polarity so it doesn't lose any volume when resonance is increased as do the Minimoog and Odyssey's filters.

If I'm not mistaken, the original multimode synthacon filter had a knob to change between high, band and lowpass filtering.

The 4 toggle switches at the bottom allow the VCF to be controlled by Keyboard, Envelope 2, Sample and Hold, and VCO3.To the left the toggle switches select inputs for VCO1, VCO2, VCO3 and Noise. There are 3 knobs for frequency, filter type and Resonance(Q).

Ken's version allows all three to be used simultaneously.

The simplicity & elegance of  this filter always amazes me. The circuit seems to be based on your standard non-inverting amp LP / Sallen Key type filter design

 Sallen Key filter

 If the resistors (R1 & R2) are voltage controlled (eg with vactrols or OTAs), then we have a voltage controlled filter. (OTAs = operational transconductance amplifiers can be found in Korg MS-20 type filters & vactrols can be seen in many Buchla filters).

In the Steiner- Parker VCF, a string of eight (1N4148) diodes morphs into this voltage controlled resistor. How ???

And all 3 filters (BP, LP, HP) are obtained simply by injecting the audio signal into different parts of the circuit.

Take the LP filter as an example.
The LP filter is obtained by injecting the audio into the 47k resistor at the top. There it enters the diode string (1N4148) and the 2n2F capacitors.

Those three 2n2F caps are v important.
Also notice the two 2n2222 transistors that sit on either ends of the diode string. They form a voltage differential across the diodes.
The diodes need to be fed current if they are to act like a resistor......
By varying the voltage we can produce different effective resistances in the diode string as we force current through them.
The whole idea of the diode string is based on Ohm's Law & the equation R=V/ I   (R= resistance, V= volatge & I= current )

I've chosen to use 3 x 2N2222 trannies.(Mouser). 

 The pic to the left is the view of a NPN 2n2222 from the underside.
 I didn't match these. I wonder if you can use any standard NPN transistors?
 Maybe BC 547s ???

In Nyle Steiner's 1972 article it looks like he used 2N5174 transistors instead of the 2N2222 . On Analogue Realitie's site, they use two monolythic matched SSM2210 pairs.

The PNP Transistor 2N2907 - mouser Part No.
 Alternatives ??? - 2N5138 or BC 557 - I might try these in future versions of the filter

"Original transistors as per Nyle Steiner's schematic are 2N5138 and 2N5172"

Hope I've got their orientation right.

Simple = Beautiful 

8 diodes, 3 caps & 2 transistors = a multi-mode VCF.

Some more Links:

1 YuSynth.net

2. Vgermuse Youtube

3. SynthMuseum

4, m.bareille (Papareil Synth Labs)

5. Doepfer 

6. Great synthesizers 

7. Cynthia - Synthacon Filter

8. Nyle’s 1974 paper on his VCF

9. AnalogueRealities