Lil Sidrassi Paper Circuit

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thresholdpeople
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Lil Sidrassi Paper Circuit

Post by thresholdpeople » Sun Apr 05, 2015 11:38 pm

A friend and I built our first paper circuits today.

The Lil Sidrassi seemed like the first one to build, as it has descriptions for what all of the symbols mean, unlike other paper circuits.

It went well, and was a lot of fun. Paper circuits are a great idea.

Image

Image

Image

Image

I found following the traces on the back intuitive. I used hook-up wire where the leads did not reach in order to make the connections. I think I printed the paper out with the wrong size image, because a few of the through-holes did not match the component, but it was no biggie.

The hardest part was deciding which tuning capacitors to choose, and which would complement the others. Also, for some reason, the ultrasound node sounds like it is lower in frequency than the treble cap that I used.
Last edited by thresholdpeople on Mon Apr 06, 2015 1:13 am, edited 1 time in total.

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Post by Dirty_Bill » Mon Apr 06, 2015 1:04 am

Double Double Post Post
Last edited by Dirty_Bill on Mon Apr 06, 2015 1:05 am, edited 1 time in total.

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Post by Dirty_Bill » Mon Apr 06, 2015 1:04 am

:deadbanana: Looking Good,don't know why I never thought to use colored paper... :hmm: what were your cap value choices, BTW?

Also, here is s a link to the Symbol Legend that was posted in the NABRA Users Google link:

Master Legend

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Post by thresholdpeople » Mon Apr 06, 2015 1:12 am

Thanks for that link!

I used two .1uF caps 'bass', one .01uF 'treble', one .001uF ultrasound, and 110uF for some low frequencies.

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Post by ClausF » Mon Apr 06, 2015 3:00 am

Thanks for the nice and detailed photos! Yes, the paper circuits are fun. And there are many of them...

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Post by windspirit » Mon Apr 06, 2015 4:25 pm

Looks great! Are you going to put it in a case or leave it bare?

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Post by thresholdpeople » Mon Apr 06, 2015 4:39 pm

I have the paper pasted around 1/8" chipboard so it's quite sturdy, but the battery and jack are a bit unwieldy. I might build a little frame for it which is tall enough to fit the 1/4" jack. I'll probably end up switching to a 9v power supply instead of the battery as well to keep things small and easy to deal with. It's nice at the moment, it's very handy and small.

I'm curious where in the circuit the barres come into play on a big Sidrassi.

Variable capacitors would be really nice for this as well, but they drive the price up a lot to build the circuit.

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Post by windspirit » Mon Apr 06, 2015 6:12 pm

It seems like the barres in the sid control a vca which attenuates the output of each oscillator, whereas this circuit just always has all 7 oscillators playing?

Edit: nvm, you just attach the output of each osc to the soeaker amp inout manually.

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Post by ClausF » Tue Apr 07, 2015 2:21 am

thresholdpeople wrote:I'm curious where in the circuit the barres come into play on a big Sidrassi.
Maybe the Lil Sidrassi is a precursor of the Sidrassi, but there are more differences than only the barres: The big Sidrassi has seven "tone generators" with barre and 7 "connection points", screws or bananas. The circuit of the big Sidrassi is a lot more complex, the pcb is around 20*20cm.

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Post by thresholdpeople » Tue Apr 07, 2015 11:09 am

http://soundcloud.com/thephantasm/lil-sidrassi-test

First recording. Raw mono audio, with a touch of light compression after.

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Post by ym2612 » Tue Apr 07, 2015 1:00 pm

Interesting, yours sounds totally different to mine. It must be down to choice and arrangement of capacitors. Mine sounds full of chaotic feedback:

http://soundcloud.com/ym2612/first-conv ... l-sidrassi

(Not sure why the SC tag wasn't working, seems a bit silly, so there's the clickable link)
Last edited by ym2612 on Wed Apr 08, 2015 5:23 pm, edited 4 times in total.

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Post by thresholdpeople » Tue Apr 07, 2015 3:37 pm

Wow, yeah, totally different!

Which caps did you use?

What do the wires lead to?

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Post by ym2612 » Wed Apr 08, 2015 9:54 am

I'll have to take a look at it to remember the values. I think I used a range from ultrasonic to LFO-rate, and I added a couple of switches to switch between different values. The wires lead to brass hooks that I screwed into a cheap plastic art case for storing it. I have the hooks in two rows with the cap switches at the top.

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Post by fluxmonkey » Wed Apr 08, 2015 5:20 pm

it also matters what order (progressing around the ring) you put the hairy caps in. i try to make sure adjacent caps are different.
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Post by Dirty_Bill » Thu Apr 09, 2015 10:53 am

fluxmonkey wrote:it also matters what order (progressing around the ring) you put the hairy caps in. i try to make sure adjacent caps are different.
Mine is somewhere in between these two... I'll have to get it up and recorded...

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Post by thresholdpeople » Thu Apr 09, 2015 11:29 am

Mine jumps around, but has two bass caps next to each other.

Clockwise from the top -- bass, bass, treble, mountain sub, ultrasound.

I wonder if this is why the ultrasound sounds somewhere between the bass and treble...

I primarily tried to use poly caps, but ran out for the bass, so I used ceramic. For the mountain sub poly caps are extremely expensive, so I used electrolytics. Would this have an effect beyond extreme subtlety?

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Post by Kalerne » Mon May 11, 2015 12:03 am

Hello - i'm preparing to build one... (still newbie in paper circuits and diy)

May I ask a few questions...

Concerning the IC LM386, is there a recommendation about which 386 to choose, I saw some 1W or some 0.325W...
I'm planning to use both a little speaker (8 ohm) and a connect a jack plug.

Also, I'm wondering, why those caps are called "hairy" ? What does that means in CL terminology ?
And how did you guys choose the value ? Just random and experiment ?

Thanks !

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Post by thresholdpeople » Mon May 11, 2015 12:28 am

The LM386 I ended up with is this one: LM386N-4. But I didn't get good results with standalone speakers. The ones I had laying around I had ripped out of desktop speakers I found on the street, then kept them in boxes through a few moves. I attributed the failure this more than the choice of opamp. I replaced the speaker wires with a jack output, and it sounds good as a line out.

Hairy caps are the tuning capacitors. Changes these values will change the tuning of each node, and ultimately the entire Sid, as all the nodes interact.
In the paper circuit documentation, it says what the values mean, some are LFOs (sub and mountain sub), some are low frequencies 'bass', some higher, some very high frequencies. In the end I decided that I wanted some two low end nodes, 1 middle node, an very slow LFO, and a very high frequency, as Peter seems to do a lot with those, so I was curious. For these I tried to use poly caps, but as I placed a huge mouser order for other stuff along with this, and things got weird while modulating my cart for quantity discounts, and ended up not having enough of some caps or others. For these I substituted a ceramic cap for the bass. The lowest value caps are very expensive as poly, so I used electrolytics in series.

The order in which you arrange them around the ring also makes a difference.

If you listen to my example as opposed to ym2612's -- they sound completely different. My friend who built this with me, ended up switch out her caps a few times until she was satisfied with the result. To do this though, you need to have the rest of the circuit built.

Goodluck with the build! It's a fun one, and there's nothing too strange to worry about with it either. I recommend laying out all/most of the components first, then soldering them all.

Let me know if you have more questions!

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Post by Kalerne » Mon May 11, 2015 2:23 am

Thank you very much thresholdpeople ! I'll try it.
Concerning the caps, I still don't understand the vocabulary "hairy", but it's not important ! ;-)
I'll try to do it this week - will share here when done.

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Post by thresholdpeople » Mon May 11, 2015 10:37 am

Kalerne wrote: Concerning the caps, I still don't understand the vocabulary "hairy", but it's not important ! ;-)
I think that's a part of it. I've attributed the meaning to either being in a hairy situation.

ym2612 had the good idea of using switches to change between different values of capacitors. I think this is an awesome idea. I'd also be curious about using two caps with slight differences in capacitance, I have a big love for frequency beating, and I wonder if it can be tuned to get that sort of rhythmic response.

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Post by thresholdpeople » Mon May 11, 2015 10:37 am

Can't wait to hear and see your Lil Sid build!

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Post by Kalerne » Wed May 13, 2015 11:03 am

I did it ! And I'm quite confused of course ! :eek:
But I like it.

Image

Image

[soundcloud url="https://api.soundcloud.com/tracks/205298733" params="auto_play=false&hide_related=false&show_comments=true&show_user=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]

Actually it took me a bit more time and was a bit more uneasy that I thought, but I want to build other paper circuits now !

My choice of caps are all ceramics amongst the treble and bass range. I have no idea if it is a good choice. And I'm thinking I should replace some just to try...
-> 0.1uF + 0.22uF + 0.01uF + 0.44uF + 0.022uF

So... to be sure, is that "normal" that when I don't touch anything it makes a sound ?
And when I touch the speaker sensor, I have a big hum, which is not nice alone, but makes interesting modulations with I thouch it while touching other pins, is that also "normal" ?

Okay, the concept of normality might not apply here.

:-)

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Post by Kalerne » Wed May 13, 2015 11:48 am

I changed two caps : now with 10uF + 0.22uF + 0.0022uF + 0.33 uF + 0.022uF

[soundcloud url="https://api.soundcloud.com/tracks/205305143" params="auto_play=false&hide_related=false&show_comments=true&show_user=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]

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Post by thresholdpeople » Wed May 13, 2015 8:05 pm

Awesome Kalerne!

Mine also makes sound while nothing is touched, and hums when just the speaker peg is touched. It also picks up radio broadcasts when I've used it in my studio.

I like the bleed of the oscillators when the speaker peg isn't touched. I sometimes just play the nodes, and use the speaker peg for extra tonal timbral possibilities.

Did you get a speaker working, or just a line out?

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Post by fluxmonkey » Wed May 13, 2015 9:01 pm

Kalerne wrote: Image
nice clean build! good job!
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