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Post by keurslagerkurt on Apr 3, 2021 13:37:06 GMT
Hey all! Was in search for a chaotic modulation source, and saw a lot of people online loving the Triple Sloth eurorack module from Non-linear Circuits. So I tried making the 'fastest' sloth modulator with this official schematic that i found online:  I made it on the breadboard with an MCP6004 instead of TL072. I also swapped every ground on the schem with 2.5V (buffered 2.5V from another MCP6002 opamp). I was lucky to find some 2.2uF box caps in my parts bin dating from an old function generator board i cannabalized on a year ago. So I used one of those instead of the 2x 1uF in parallel, and put two others in series to get the 1uF  It works like a charm! Really fantastic and useful circuit for modulation. Maybe I should contact NLC and ask if I could make an AE adaptation on pcb.. saw the creator (andy) replying on muffwiggler and it seems to be a really nice and helpful guy. Here a video from him of what the module does. Below some pics of the breadboard!   |
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Post by pt3r on Apr 3, 2021 15:42:31 GMT
Why did you swap the gnd for 2.5v?
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Post by keurslagerkurt on Apr 3, 2021 15:47:48 GMT
Why did you swap the gnd for 2.5v? In Eurorack the output of the sloth oscillates around 0V (Gnd), so it goes negative and positive around that value. In AE most oscillators and LFOs oscillate around 2.5V. It was a bit of a guess as the circuit is quite complicated and I don't understand it's working process really (chaos is hard!), but in general adaption to AE requires to swap most/all ground Points with 2.5v (Often refered to as 'virtual ground' in this case). |
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Post by pt3r on Apr 3, 2021 15:50:42 GMT
I actually guessed that would be the answer as I posted the question  . |
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Post by NightMachines on Apr 3, 2021 18:25:45 GMT
This is really cool! I’ve been hoping for a chaos module to come out!
Now, the question is if it would be possible to put several different chaos generators and speeds in the same module - maybe even through digital generation?
Here are some Snazzy FX Chaos traces (Kitty Eyes is based on the Chua Algorithm I think):
... and the Klangbau Logistic Equation (digital version using an Arduino, although he also made an anlog one), which I find very musical:
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Post by pt3r on Apr 3, 2021 19:45:39 GMT
Here's another one 5v based.
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Post by keurslagerkurt on Apr 3, 2021 20:02:30 GMT
NightMachinesDamn those look fancy! Would need someone to collaborate for the digital side tho, i'm really only versed in analog 😅 digital is on the wishlist, but still need to take the first babysteps on An Arduino even. pt3rDamn nice visuals and minimal parts! So the circuit as is oscillates at 45kHz they say, I wonder if it's possible to get it into lfo rate with reasonable Cap sizes (<1hz is a long way from that 45k tho). Something to experiment with!
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Post by funbun on Apr 3, 2021 20:35:04 GMT
Finally! Woot!
Yeah, as the answer to the 2.5v thing. That the same way WAVETABLE has a bipolar, just op amps circling around 2.5V. Looks like a simple circuit.
The Chaos poles look like two black holes fighting over a start that it has ripped apart.
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Post by NightMachines on Apr 3, 2021 21:01:27 GMT
Damn those look fancy! Would need someone to collaborate for the digital side tho, i'm really only versed in analog 😅 digital is on the wishlist, but still need to take the first babysteps on An Arduino even. The Logistic Equation is quite easy to code. I’ve tried it once and as far as I remember it worked I used this formula here: bendov.info/cours/chaos/logistic.htmEDIT: While I’m dreaming up this wild AE Modular chaos module with multiple switchable algorithms, CV control and super wide frequency ranges (sloth to cheetah), it would also be cool to have a S&H feature in there to hold values on incoming triggers. This would also be easy to code ... hmmmm ... I don’t have any experience with the microprocessor hardware past the stock Arduinos unfortunately. It’s not economical to put a whole Arduino behind the panel though. As far as I understand, robertlanger just takes the flashed Arduino/ATMEL processor ICs and builds only the required circuits for the module around them. |
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namke
wonkystuff
electronics and sound, what's not to like?!
Posts: 686
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Post by namke on Apr 3, 2021 22:08:01 GMT
Sounds like a job for GRAINS  |
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Post by funbun on Apr 4, 2021 0:21:07 GMT
Sounds like a job for GRAINS Will that 8-bit chip do the job? |
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Post by keurslagerkurt on Apr 4, 2021 6:09:06 GMT
NightMachinesWell i didn't even do blinky lights on Arduino, so anything digital is really for further down the line. I'm also having tons of fun doing analog, as it gets me away from the screen 😊 but surely a digital path would be much more potent for this kind of modules. Ooh and also a quick flex, the logistic equation for growth was developped at my university 😁 so when studying we really had to study it a million times haha en.wikipedia.org/wiki/Pierre_Fran%C3%A7ois_Verhulst
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Post by pt3r on Apr 4, 2021 8:36:32 GMT
Sounds like a job for GRAINS Will that 8-bit chip do the job? The only problem with grains is that the outputs is not real analog voltage but rather a pulsewidth modulated approximation smoothed out via a capacitor, I wonder how well that will work to generate continuous cv signals. |
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Post by NightMachines on Apr 5, 2021 17:05:33 GMT
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namke
wonkystuff
electronics and sound, what's not to like?!
Posts: 686
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Post by namke on Apr 6, 2021 7:05:34 GMT
Will that 8-bit chip do the job? The only problem with grains is that the outputs is not real analog voltage but rather a pulsewidth modulated approximation smoothed out via a capacitor, I wonder how well that will work to generate continuous cv signals. I expect that the answer will be ‘good enough’ it won’t be identical to a purely analogue implementation, but it could be tried and then used or discounted based on results… Note that the FMOS, SAWOSC and rbss modules use this PWM technique. |
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Post by keurslagerkurt on Apr 6, 2021 9:20:29 GMT
NightMachinesWow, that kitty eye module looks super super cool. I like that you can go from the seemingly 'stable' region into this beautiful chaotic circling region. Will def look into the circuit. It's a good way to refresh my bifurcation knowledge from Uni  Considering the Sloth circuit, I contacted Andrew from Nonlinear Circuits and he was super nice & gave me permission to try & implement his circuit in AE Modular (of course if I manage to create a kit, he will get a commission for each sale!) So who knows, maybe we'll see some Sloths hanging out in AE racks later this year! I would love to fit two sloths in 1U, but not sure whether they will fit (the slower ones need huuuuuge caps)
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Post by NightMachines on Apr 6, 2021 9:37:43 GMT
Those are great news! I'd assume that Dan from Snazzy FX would also grant you permission regarding the Kitty Eyes. That one doesn't need big capacitors, so maybe a Kitty Sloth crossover could work in 1U  |
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