[CLOSED] - Euro Panels for Ian Fritz Chaos Circuits

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frijitz
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Post by frijitz »

spotta wrote:How critical is the value of the Mod in Pot? - as I have a 9mm 50k that will fit without going over the edge of the panel.
50k will work fine.

Ian
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Post by frijitz »

zdarma wrote:Does anyone have some images that show how these two boards are wired up to the panels? I am a little confused by the documentation for the wiring? How is that dual 1M pot wired to the board?
I'm not exactly sure what you are refering to. The Bridechamber boards for ChaQuO?

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spotta
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Post by spotta »

Many thanks Ian, Mono

:tu:
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themanthatwasused
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Post by themanthatwasused »

SEEK AND YOU SHALL FIND
Edit: Sorry for the stupid question.
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synthcube
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Post by synthcube »

in the spirit of continuing to expand the availability of new and classic euro synth DIY, we are happy to say we are now carrying the ian fritz jerketr chaos and double well chaos panels by clarke68, as well as kits, PCBs etc.

http://synthcube.com/cart/ian-fritz-dou ... chaos-euro

Image

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Post by atari5200 »

Necro-bumping this thread as I'm building a couple of these. Everything looks pretty straightforward but I have a couple questions nonetheless

Wiring up R2, the dual-gang pot on the Double Well, I'm curious what the pinout is, I can't seem to find a datasheet for the pot. Is the first row of lugs closest to the shaft pins 1, 2, 3 then the second row, further from the shaft 4, 5, 6 or is it the other way around?


Also, the schematic does't show any wired ground connection for the input and output jacks and there's no sockets for them on the PCB wiring terminal. Are they just grounded through the panel?
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Post by trip »

Has anyone built these with the cheap bourns knock off precision pots from china? Any issues other than the tolerance?
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Post by synthcube »

we have not tried them...
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Post by trip »

Well can't hurt to try a few, I'll pick some up as they're only £2 on ebay - seems waaayy too good to be true! Will report back with findings.
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Post by trip »

My pots arrived from this seller http://www.ebay.co.uk/itm/291996363129? ... EBIDX%3AIT

They generally measure between 6 ohm - 100/101kohm which is almost within the 5% tolerance. Obviously can't speak to the lifetime of them yet, and they feel a bit rough to turn. Had one complete dud 100k that just measured infinity after a few turns, but for the price can't really complain! There are sellers which sell them with the dials for about £3 each, will order a couple of the cheap dials and see how they are as well.
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Post by synthcube »

thank you! please keep us apprised. Those bourns dials are insanely expensive.
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Post by acgenerator »

I just completed a build of the Double-well chaos and I think something may be slightly amiss. I'm using the Synthcube kit/good Bourns pots.

The module generates varying signals at X, Y, NL when a Drive signal is present. X has a larger range than Y but that can be adjusted via attenuation if needed. I'm an experience builder so I'm confident in the assembly itself.

Here's what I suspect isn't right:
I get basically one of two shapes from the X, Y run into an O'tool. First is a misshapen loop (single eye) which I can get at both positive or negative X values. The other is a horizontal "peanut" type shape (not quite a split into two-eyes). I can't seem to get a Lorenz-type attractor to form no matter the settings. It cycles and the pots have an influence (especially Rate) but I'm not sure it quite slips into chaos (regardless of the shape).

Before I get too far into trying to optimize resistors/caps, I'm hoping to get so feedback/advise from those with successful builds.

Here are may questions:
1) how hard is it to find "sweet-spots" for chaotic patterns? Am I just suffering from unrealistic expectations that I'd be able to find them with only a few minutes of tuning?

2) What Drive inputs are folks using? I'm using LFOs at various shapes and speeds. Should I be using something else?

3) If I were to start adjusting resistors or caps to optimize the build, where would you start? Are there particular ratios that have to be maintained to create chaos?
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Post by frijitz »

acgenerator wrote:I just completed a build of the Double-well chaos and I think something may be slightly amiss. I'm using the Synthcube kit/good Bourns pots.

The module generates varying signals at X, Y, NL when a Drive signal is present. X has a larger range than Y but that can be adjusted via attenuation if needed. I'm an experience builder so I'm confident in the assembly itself.

Here's what I suspect isn't right:
I get basically one of two shapes from the X, Y run into an O'tool. First is a misshapen loop (single eye) which I can get at both positive or negative X values. The other is a horizontal "peanut" type shape (not quite a split into two-eyes). I can't seem to get a Lorenz-type attractor to form no matter the settings. It cycles and the pots have an influence (especially Rate) but I'm not sure it quite slips into chaos (regardless of the shape).

Before I get too far into trying to optimize resistors/caps, I'm hoping to get so feedback/advise from those with successful builds.

Here are may questions:
1) how hard is it to find "sweet-spots" for chaotic patterns? Am I just suffering from unrealistic expectations that I'd be able to find them with only a few minutes of tuning?

2) What Drive inputs are folks using? I'm using LFOs at various shapes and speeds. Should I be using something else?

3) If I were to start adjusting resistors or caps to optimize the build, where would you start? Are there particular ratios that have to be maintained to create chaos?
Thanks for you interest. Sorry you are having trouble. Folks have been building this unit for 10 years now, and this is the first I have heard of any serious difficulties. Typical patterns in the chaotic regime are shown on my website:
http://ijfritz.byethost4.com/Chaos/ch_cir1.htm
It's not a Lorenz system, so there is no reason the attractor should look the same.

In any system, chaos is only observed over a limited range of parameters. I choose this particular system because it is easy to build and easy to get chaotic signals. Please try something like this to observe the chaos.

1. Drive with a +/-5V Tri wave at, say, 50Hz.
2. Set Drive at about 2/3 fs.
3. Set damping at about 1/3 fs.
4. Tune the Rate until you see a strong signal.
5. Experiment with different Damping and Drive to see the various patterns.

I don't have a working unit in front of me right now, so I can't give you more detailed instructions. If this doesn't get you going, please let us know.

Ian

(This is my second attempt to post this, so apologies if it turns up twice.)
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acgenerator
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Post by acgenerator »

Thanks Ian! I'll give it a whirl with those settings and see If i can get results that more closely resemble what I see on the site. I was getting something along the lines of the outside orbit for the middle image but no time spent forming eyes/wells.

Update:
using the settings suggested (largely the LFO speed/shape combo) I was able to find some distinctly Chaotic single well instances. (distinct loop variation /slightly evolving shape over time). I'll be able to spend more quality time with it later this week to find more "sweet spots" for different shapes. I'm finding much better success in the 40 to 60 Htz range.Thanks again.
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Post by frijitz »

acgenerator wrote:Thanks Ian! I'll give it a whirl with those settings and see If i can get results that more closely resemble what I see on the site. I was getting something along the lines of the outside orbit for the middle image but no time spent forming eyes/wells.
From that point, probably you want less Drive. Try reducing it a bit. Then tune through the Rate range. If that still gives just limit cycles, then reduce the Damping a bit, tune through R again. Keep creeping down like that and you should easily get into the chaotic regime.
Update:
using the settings suggested (largely the LFO speed/shape combo) I was able to find some distinctly Chaotic single well instances. (distinct loop variation /slightly evolving shape over time). I'll be able to spend more quality time with it later this week to find more "sweet spots" for different shapes. I'm finding much better success in the 40 to 60 Htz range.Thanks again.
From that point you probably need more Drive. Remember again to tune through the rate range. Cut back the Damping if you are still just getting loops.

I'm afraid I cannot give more precise settings because every build is a bit different, mostly due to non-idealities of the opamps. But at this point it doesn't sound like there is a major problem with your unit.

Please let us know how it goes.

Ian
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Post by acgenerator »

I'm finding a bit more "tune-ability" of shape by sending the LFO to a VCA (2.5x) then damping the signal a lot. I've gotten a little bit of separation into two loops like that. Previously it'd take multiple rotations to see significant change.
I'll pull it our this weekend and check resistors along the "drive" path. If I'm getting my best responses when Drive is maxed out or the signal is boosted, I suspect I need to look there.

on a side note - I just finished the Jerk Chaos and that came out great. Lots of shape movement from the pots, easy to find chaos.
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Post by frijitz »

acgenerator wrote:I'm finding a bit more "tune-ability" of shape by sending the LFO to a VCA (2.5x) then damping the signal a lot. I've gotten a little bit of separation into two loops like that. Previously it'd take multiple rotations to see significant change.
Yeah, sounds like a problem with the build. Shouldn't be too hard to track down. Be sure to check the zeners for part number and orientation. The layout graphic is not too clear -- they need to be toe-to-toe (or heel-to-heel).

Ian
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Post by trip »

The cheap vernier dials from china were too small for the precision potentiometers I have, I haven't found any other alternative to the Bourns ones. I've built up my jerkster and the cheap pots are working fine though.

Still need to order the 50k dual pot for the double well, is it best to use a lin or log pot? Does anyone have a part number with suitable shaft for the clarke panels for that pot?
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