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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
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Uncle Krunkus
Moderator
Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
Audio files: 52
G2 patch files: 1
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Posted: Sun Nov 08, 2009 12:12 am Post subject:
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Those screen shots of the CRO are beautiful. _________________ What makes a space ours, is what we put there, and what we do there. |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
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Posted: Sun Nov 08, 2009 2:37 am Post subject:
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cheers - this is an excellent cct for studying chaos, simple to build and responds very differently to the amplitude, frequency and format (tri, sq, trapezoid, etc) of the input signal.
good aggro filter too..........Tim E. is a genius |
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frijitz
Joined: May 04, 2007 Posts: 1734 Location: NM USA
Audio files: 54
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Posted: Sun Nov 08, 2009 12:42 pm Post subject:
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andrewF wrote: | cheers - this is an excellent cct for studying chaos, simple to build and responds very differently to the amplitude, frequency and format (tri, sq, trapezoid, etc) of the input signal |
Amazing work. If I had any idea there was such a rich variety of attractors there I might have worked on it more.
Those are some of the coolest bottlenecks I ever saw! Do you have a simple explanation as to why you get three scrolls out of the system? I never would have expected that.
Ian |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Sun Nov 08, 2009 4:56 pm Post subject:
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bottlenecks! Thanks Ian - I was actually spending all my time trying to get an image like the one you posted on pg 1 of this thread, that one is quite stunning.
To get these the input is a low frequency trapezoid around 20-30Hz (Don Tillman's VCO). They are great to watch, the 3rd bottleneck is quite unstable as you can see it looks quite scratchy. It gets spat out, wobbles around for a few seconds and is gone.
I'm getting pressured to work out the maths for this circuit, not exactly my favorite job, but will post it here when (and if) it happens. |
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frequencycentral
Joined: May 25, 2008 Posts: 186 Location: UK
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thepaddiscuile
Joined: Jul 11, 2007 Posts: 28 Location: ireland
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Posted: Fri Jul 23, 2010 10:46 am Post subject:
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Hi guys.. Anyone know how you.d get a highpass response from this..
Be cool to have both running in series lp-hp |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Sat Jul 24, 2010 8:51 am Post subject:
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In a sense it already has the hi-pass.
In a regular twin-t filter, the two sections deliver a low-pass and a hi-pass function, combined the result is a notch filter.
Of course the added diode means the Q&D is not normal.
From http://en.wikipedia.org/wiki/RC_oscillator
The second common design is called a "Twin-T" oscillator as it uses two "T" RC circuits operated in parallel. One circuit is an R-C-R "T" which acts as a low-pass filter. The second circuit is a C-R-C "T" which operates as a high-pass filter. Together, these circuits form a bridge which is tuned at the desired frequency of oscillation. The signal in the C-R-C branch of the Twin-T filter is advanced, in the R-C-R - delayed, so they may cancel one another for frequency f=\frac{1}{2\pi RC} if x = 2; if it is connected as a negative feedback to an amplifier, and x>2, the amplified becomes an oscillator.
Hope this doesn't put you off, I'm quite interested in the Q&D and would love to learn any new tricks with it. On my breadboard at the moment I have a version with the op-amp replaced by a 4009 inverter, it filters but no chaos yet. |
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kurodama
Joined: Jul 23, 2010 Posts: 15 Location: Italy
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Posted: Sat Jul 13, 2013 5:26 am Post subject:
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Sorry to revive this old thread, but this filter design kind of struck me and I tried to build it on breadboard. I admit that I'm not the most experienced synth maker, in fact I'm a total noob. I currently try to understand how OpAmps work and this seemed like a nice project to try some things out.
I've built the original version from the gif file, and so far the filter seems to work, the audio gets through and the pots do change the signal. Also I can modulate it using an LFO from the modular.
The only thing is that it does really not sound like a filter, more like a distortion. I guess it's supposed to sound like that, it's the "chaos" part isn't it?
I can't tell from the mp3 that has been posted at the beginning if my circuit is sounding similar or not...
The Vr thing confused me too btw. What I did was to connect the 1M resistor right after the IN to ground. Also I've connected the V- on the OpAmp to ground. Is this how it is supposed to be?
I'm currently running this off a 9v battery, but I'm thinking about making it on perfboard to be used in my eurorack modular... so I could also adapt it to +/-12v... just not sure how I should do that...
Well, if anybody has some tips for me on this, it would be really appreciated! thanks! _________________ www.papernoise.net | kvsu.net |
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kurodama
Joined: Jul 23, 2010 Posts: 15 Location: Italy
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Posted: Mon Jul 15, 2013 12:26 pm Post subject:
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I've made some recordings of how this filter sounds in my breadboarded version. You can find them here:
http://papernoize.tumblr.com/post/55448137952
One thing I noticed is that, despite this being a lowpass filter it does not really attenuate the high frequencies that much... _________________ www.papernoise.net | kvsu.net |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Mon Jul 15, 2013 6:43 pm Post subject:
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The PDF has no CV in.... |
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kurodama
Joined: Jul 23, 2010 Posts: 15 Location: Italy
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Posted: Tue Jul 16, 2013 1:07 am Post subject:
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no but if you check Andrew's post, he mentions where to add it. Or you can just compare the two schematics... _________________ www.papernoise.net | kvsu.net |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Tue Jul 16, 2013 6:05 am Post subject:
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Someone else was asking what was the difference between a couple versions posted, but those posts appear to be gone now? That'll show me for not quoting |
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Moosgummi
Joined: Feb 01, 2015 Posts: 15 Location: Hiltown, Germany
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Posted: Tue Jun 14, 2016 7:25 am Post subject:
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Does this work for audio only only, or can it do CV without the caps? |
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