Sandy Freckle

video upload by cirtcele

"Sandy Freckle was a wonderful villain played by actor Rock Hampton in the Kath & Kim series. He was sleazy and annoying but irresistible and funny at the same time, much like this module."

via nonlinear circuits

"In Australia, there is an entrepreneur called Dick Smith who ran a chain of electronic hobby stores in the 70s and 80s (now he makes breakfast cereal). He used to publish circuit books every year (and sell kits for them), I no longer have the issue but remember the finer points of a circuit for a burp/fart generator.

It was simply 3 transistor based multivibrators running at different frequencies. The trick was that they were loosely connected by low valued resistors causing them to influence each other. This would result in unpredictable sounds that rarely repeated. Don’t expect it to actually sound like gas escaping from an orifice, think of it is a random pulse/burst generator

This version has pots to adjust the frequencies of each section and an input for turning the sound on and off rather than a switch. It can be fed gates or envelopes, which give a more gradual onset and tail as the sound starts and drops off.

Feel free to build it with whatever capacitor values you like. The ones suggested on the PCB (and heard in the demo vid) get into audible frequencies, but in some ways it is more interesting to use larger valued capacitors to get just pulses that will then ping filters and phase-shifters.

It is also interesting to feed it audio rate signals and it becomes a waveshaper/distortion module.

Sandy Freckle was a wonderful villain played by actor Rock Hampton in the Kath & Kim series. He was sleazy and annoying but irresistible and funny at the same time, much like this module."

LDRama 1

cirtcele

Light from the film controls the patch.

"1st attempt to make a demo with this module, using an excerpt from the public domain film Daughter of Dementia to generate CVs. Yes my phone is a bit big (A21) but works fine, the design suits regular 5x2 inch phones.If you want to use your synth for making soundtracks, this module is pretty useful.

The video shown is playing full screen on my phone, which is sitting on a bank of LDRs (light dependent resistors). As the LDRs change corresponding to what is on the screen, the circuit generates a variety of CVs based on different sections of the screen."

nonlinearcircuits BBX291 VCF

Published on Apr 3, 2020 cirtcele

"Vari-bandwidth VCF based on the Buchla 291, tho the CV sections are completely different and it uses a black box between the PCBs instead of dual vactrols.
https://www.nonlinearcircuits.com/mod..."

Dual LFO VCO 1

Published on Oct 17, 2019 cirtcele

"Upgrade for the NLC thru-hole dual LFO. Now has CV and sync, sine, square, tri and stepped outputs. with switches it ranges from 1 cycle per 20 minutes up to 10kHz.

The stepped out is a S&H sampling the sinewave and clocked internally by the other oscillator.

In this vid the left side is supplying CV to a VCO, the right side is at audio rate and giving the VCO an FM signal. each side is CV-ing the other as well.

TBH it is a std module so I really just have a good play with the dog."

nonlinearcircuits Mobius PiLL - Audio rate chaos generator eurorack module

Published on Sep 7, 2019 cirtcele

"Audio rate chaos generator - contains two cross-coupled PLLs and two LPGs."

via nonlinearcircuits

"This is a chaotic noise module, it is generally not very nice unless you are into noise. In which case, hello!!

There are several papers describing ways to couple PLL (phase locked loop) ICs to create chaos. I have been sitting on a stack of them for years but found the actual circuits quite limited in a synth.

Eventually it clicked that the low-pass filter needed to be a bit fancier than a pot and a capacitor, so this version gets two Buchla style low pass gate/filters.

The circuit contains two PLL chips and two low pass filters. The PLLs are voltage controlled together, the filters are controlled individually.

Normally in a PLL circuit, the output of the phase detector goes thru a low pass stage and then the output of this is used to control the VCO. In this version, the low pass filter outputs are fed to the non-inverting input of an op amp for it's own VCO and the inverting input of an op amp for the other VCO. Maybe the pic describes it best, this is from Intermittent Chaos in a Mutually Coupled PLL’s
System (Shirahama et al), tho I have seen similar circuits in other papers.

It doesn't need an input signal to lock to, it can run on its own, but it can be fun to give it a signal anyway. The other inputs are for Freq CV, LPG1 CV and LPG2 CV. Two of the outputs are from the LPGs and two are from the PLL VCO, these two are pulse/squarewaves, very nice for feeding into filters.

The PLLs and filters are all vactrol controlled but the PCB is a unpatented NLC black-box design, so no need to buy any expensive vactrols.

PCB set = USD23
Panel = USD22
assembled = USD200"

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nonlinearcircuits VCAs fuzz/distortion

VCAs fuzz Published on Aug 23, 2019 cirtcele

"Short demo of the fuzz section on this triple VCA."

"This 8HP module contains 3 VCAs and a fuzz/distortion. The VCAs are similar to the ones used in the NLC Cluster; simple OTA based but work very well.

The fuzz/distortion is part of the bottom VCA and is a typical diode based affair, on the PCB the space for these are thru-hole so you can install Si or Ge diodes or LEDs. Turn the Fuzz pot to 0 if you just want VCA.

PCB = USD18
Panel = USD20
assembled = USD160"

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nonlinearcircuits 1U Signum 2

Published on Aug 21, 2019 cirtcele

via nonlinearcircuits

"In the simplest sense, this is a switching module. It is a little different though because it has 3 states rather than just on/off:
\operatorname{sgn}(x):={\begin{cases}-1&{\text{if }}x<0,\\0&{\text{if }}x=0,\\1&{\text{if }}x>0.\end{cases}}
In this case, the module uses approx 1V, rather than 0V, as the switching point, so that it can be controlled by gates. It is simple to bring it back to 0V for those who think it should be.
Also the '0' state is really a result of the diode voltage drops rather than any circuit design trickery.

The signal on the bottom input is fed to the switch of the Switch jack (oh yes) so the incoming signal can switch itself without any help.
The three states actually mean there is a flat spot at the switching point, so the circuit can be used for audio but at slow rates there is a click, so it is far better suited for CV processing.

This circuit originally was used as the nonlinear element in the Primal Hyperchaos and two of them in the Hyperchaos Deluxe. I quite like it on its own, so the Signum Hyperchaos brought the signum section to the panel where it could be used as a stand-alone module. This version drops the chaos and just has the Signum.
The switching is done by diodes rather than a dedicated IC.

The panels are available in white/gold and black/gold in both Pulp Logic and Intellijel formats. Please specify which colour and which format you want when ordering.

Also the PCBs are the same for both panel formats and use a standard Eurorack power connector. There is no provision for the Pulp Logic 3 pin power connector.

PCB and panel set = USD10
Assembled = USD55"

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nonlinearcircuits beat freq

Published on Aug 1, 2019 cirtcele

"Just trying out the proto-type. 2 beating VCOs drive the circuit, the output gate and CV are used to turn on and control a 3rd VCO."

nonlinearcircuits Cellular Automata 1

Published on Jul 14, 2019 cirtcele

"NLC Cellular Automata module demo. It can be used as a CV pattern and gate generator. There is little control over the patterns other than feeding signals into the 4 seed inputs"

via nonlinearcircuits

"This is a 16 cell gate and pattern generator using cellular automata rules 90 & 150. It will run thru a process driven by a clock signal and requires a signal on one of the seed inputs (anything crossing 1V) to start a new process or alter the current one.
A process without seeds may run for hours or minutes, depending upon the start point and clock rate.

There are 3 CV outputs, two based on what is happening on each half of the circuit, one reflects the pattern created by the active cells. Each cell has a gate output.

The circuit uses CMOS chips and op amps, no microprocessors. It is a big build!

PCB set = USD25
panel = USD23

assembled = USD280"

nonlinearcircuits Null A & friends

Published on Jun 27, 2019 cirtcele

"Not really a demo. I was testing a Null-A built for a customer and ended up with a fun patch. Added in a Doof, Badum Tiss and Resonate for persussive sounds. All gates and CVs from the Null-A"

nonlinear Dispersion Delay 2

Published on May 27, 2019 cirtcele

via nonlinearcircuits

"This module is based on ideas suggested by Lucas Abela.

It is three vactrol based bandpass filters in parallel, each filter is fed into a voltage controlled delay stage. The outputs are available individually or there is an OUT ALL where all 3 signals are mixed.

Me being me designed the delays to go into stutter/zipper/breakdown territory to create the usual noise I love. If desired the delays can be built to remain in their normal operating regions.

PCB set = USD25
Panel = USD26
Assembled = USD260

build info coming soon"

nonlinearcircuits Bi-di Choppers

Published on Apr 29, 2019 cirtcele

"Dual delta modulators that can be used as 2 into 1 or 1 into 2 CV controlled switches. The signals passing thru control the switching.....things can get out of hand."

nonlinearcircuits 1/n - 1 divided by n

Published on Apr 29, 2019 cirtcele

"1/n - can be patch-programmed to divide by 3-9, or match if you add another module. The other outputs will be at different phases to the 1/n out. Or use it to process audio. Jam and preset inputs let you create absolute mayhem."

nonlinearcircuits DelayNoMore3 - proto-type

Published on Apr 29, 2019 cirtcele

"Triple version of DelayNoMore (proto-type), can also be used as 3 individual CV controlled delay modules"

nonlinearcircuits Feague QUO VCF

Published on Apr 21, 2019 Ze Ka


Published on Nov 18, 2016 cirtcele

Note this module is from 2016.

"The Feague is a 4 pole VCF and quadrature oscillator with 0, 90, 180 & 270 degree outputs. It is based on the design in electronotes 41.

It features a lo/hi switch to run it at audio rates or LFO rates, plus a nonlinear Q pot which makes for interesting behaviour when using as a VCF.

When using as a QUO, the nonlinQ pot is used to increase the amplitude of the output signal, which is known to shrink somewhat at low frequencies in these kind of oscillators.

Specs

HP: 10

Inputs

SIGNAL: audio input
CV: for controlling cutoff in VCF or frequence in LFO/VCO
SYNC: sync in/freeze/hold control
1V/OCT: for controlling cutoff in VCF or frequence in LFO/VCO

Outputs

Each ouputs are 90 degrees in out of phase : 0, 90, 190 and 270.

In VCF, the two outputs closest to the side edge of the panel are low-pass outputs, and the other two are band-pass."

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nonlinearcircuits I can't believe it's not a VCO

Published on Apr 10, 2019 cirtcele

"VCO/VCF based on concepts presented in Electronotes #132."

via nonlinearcircuits

"PCB set = USD20
panel = USD20
assembled = USD180

This module is based on ideas presented in Electronotes #132. It is a VCF with a 'filter exciter' section to allow a wide variety of acoustic, semi-acoustic and not-acoustic-at-all sounds. In a sense it takes the concept of pinging the LPG or ringing a VCF one step (or 2) further. The decaying sound is fed back into the input via a VCA. The VCA can be controlled by a gate or an envelope (or both).
Another interesting point is higher frequency sounds tend to be louder.....which is what happens naturally in the big room."

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nonlinearcircuits SPASM - LDR controlled (!) chaos

Published on Jan 4, 2019 cirtcele

"This module takes the classic Sprott jerk circuit and replaces all the resistors with LDRs.....a 7 way vactrol."

"This module takes the classic Sprott jerk circuit and replaces all the resistors with LDRs.....a 7 way vactrol. This means the brightness of the LED in the giant vactrol controls the frequency of the circuit.

It is a very easy build and will give you a very flexible chaotic circuit. The CV inject jack allows you to control the chaos with gates and CV, some signals will cause it to pause or stall, others will make it glitch & freak out. CV freq controls the LED which, in turn, controls the resistance in the LDRs.

It is a very flexible build; you can use any LDRs you like, so long as they are the same. You can also use any capacitors you like for CAP, so long as they are the same.

Of course, the LDRs and capacitors you choose will affect the behaviour & frequency range of the circuit. GL5516 LDRs go to 500kΩ off resistance whereas GL5549 go to 10MΩ+ (anywhere from 10MΩ to 20MΩ), so will be a lot slower but will give a much wider frequency range and some very unpredictable outputs. Similarly with capacitors 10uF will be a lot slower than 10nF.

If going for the more extremely slow values, GL5549 LDRs and 10uF caps, the module will stall at minimum pot settings and generally needs a CV on the CV freq input to make it operate. This is actually a good thing as you can turn the signals on and off with CV or gates.

PCB set = USD20
Panel = USD20
assembled = USD160"

nonlinearcircuits Signum Hyperchaos 1

Published on Jan 4, 2019 cirtcele

"This is an expansion of Primal Hyperchaos, based on the description in a paper by C Li, et al. The internal signum switch has been brought out to the panel. It can be used as a stand-alone switch (don’t expect it to be clean and nice) or it can be used to inject signals into the hyperchaos circuit or control the switching of the hyperchaos."

See this post from 2017 for additional details.

nonlinearcircuits Digital Filter Simulator 1

Published on Jan 3, 2019 cirtcele

"Analogue circuit designed to simulate a digital filter....sort of. Starts slowly, jump to the 2nd half to get a real taste for it."

via nonlinearcircuits

"This module is based on ideas presented in a 1969 IEEE paper titled - Hybrid Implementation for Sampled-data controllers. The paper presents the canonical form of a generalised digital filter made using analogue elements.....yes this is an analogue circuit; all CMOS and op amps. I played around with various versions for a few years and, as usual, settled on the simplest and cheapest version.

Incoming audio signals (or CV if you want to use it as a pattern generator) are fed to a 4 bit A/D stage, these 4 bits then go thru a 4 stage delay (shift registers). Each delayed bit is re-united with its siblings via four D/A stages and the stepped signals are then fed back to the input via an attenuator/inverter stage and are fed to the summed output, again via an attenuator/inverter stage.

The circuit is controlled by the clock input that ticks over the shift registers. CV controlling the VCO that supplies the clock signal will in turn control the filter. The Range pot needs to be set to a suitable level, I like it when the peak LED is flickering. Range can also be controlled by CV which will allow you to shift from a 1 bit signal to a 4 bit or overdrive the crap out of it and lock everything up. It is interesting to supply clock signals that are multiples or divisions of the audio signal, but like all NLC modules, feel free to do whatever you like. As mentioned, supplied with a gate and a CV it will perform as a complex pattern generator as well.

I will get a demo up soon, but will promise this doesn't sound like a filter......it is very noisy and splatty.

PCB set = USD22
Panel = USD22
Assembled = USD220"

nonlinearcircuits bad digital filter simulator proto-type 1

Published on Nov 12, 2018 cirtcele

"Various snippets from testing and honing this circuit over the past few weeks. As the name describes, it is an analogue circuit designed to simulate a digital filter - badly. It is not capacitor based but uses shift registers and feedback to do its thing. More info and the module coming soon."