Mobenthey/Ciat-Lonbarde (synthmall) thread

[wheelersounds]

On this note, when I built my Lil’ Sid I found different types of capacitors, even of the same value, made a difference in tone (ex. old stock mylar, new polyester, ceramic, etc). Trial and error was fascinating and valuable in making my cap choices.

[jlmitch5]

@sbaio

Finally finished my version of the “poor man’s Rolzer”: Eight paper circuit Rollz PCBs in a guitar pedal case. The orange outs are taken from behind the 220K resistor where it seems that there is always a positive voltage, and even a positive pulse on the even rollz. That’s also what drives the LEDs. I found the MC Escher “Stars” sticker on Etsy and thought it to be very fitting (geometry!).

Incredible! wanted to ask a couple questions:

you mention 220k resistor…looks to me like the resistors for the rolls are 22k and 470k, so I think you mean 22k? When you say you tap the jack from behind do you mean, one of the jacks/led is pulled from here (red = removed that trace, green = added).

Also I wonder if it would be fine to have an orange jack in addition to the brown jacks, (so for example, a 3-roll has 4 jacks, 3 brown, 1 orange). I feel like this would be a lot easier to do on the meng qi board.

EDIT: found @corpusjonsey’s schematic, so I understand now. also I don’t think there should be any problem doing it as an additional jack based on what i understand

[Justmat]

Does anyone have a CL Rolzer, and maybe a second or two to answer a question? If so, send me a dm!

[mlogger]

This is some info from Martin Freeman -

If you measure the voltages coming off a Roll node it has a swing of something like -3v to +2v but it tends to hang around in the minus region. If you take a measurement where the 22k meets the transistor and the cap you have a positive voltage rectangle wave that you can use as a CV output or to drive LED’s etc

I would also ask this guy what method he used to add LED to his build. I think the best way is to use a separate LED driver circuit based on Ken Stones design

http://www.instagram.com/p/CCTxiikhfuC/?igshid=1f78cwfur7x1p

[jlmitch5]

Thanks for the info! I have learned there are a couple of different ways to buffer an led so it’s not coupled to the output impedance of whatever that part of the circuit would be plugged into…basically if you just tapped that spot, put the led and a ground resistor, the led could be variable in relation to the out connected near it. I believe the schematic @corpusjonsey shared “buffers” using the transistor, you could also use an op amp circuit.

[laihalll]

hey hey - just used the ken stone LED driver. i had a weird time the other day trying to put an LED to each node so i could watch the whole sequence but it didn’t work. maybe too much current drain even with the seperate circuit? only one output was a dedicated CV out, the rest were still androgynous with the driver on the cv out junction

[mlogger]

I haven’t added leds myself but have been following other peoples builds. If you look at the Rolzer he’s only adding 1 led per Rolls set. So maybe is a current draw thing or adding too many interfering with the Rolls feedback loop circuit.

[mlogger]

The 5 holes on the lower part of that photo - the middle hole between the 2 on either side is a grounding banana socket - the one with no trace

[sbaio]

Thanks!

Yes, that was the 22K (not 220K) resistor I tapped. Unfortunately I can’t seem to edit the post anymore to correct this.

I see you already discovered the schematics posted further down the thread and that’s definitely the way to go. I still have to upgrade my Rollz with an LED driver circuit. Currently the LEDs are just connected with a resistor to ground, which is of course less than ideal.

[crucFX]

Hi All,

I am newer to Ciat-Lonbarde circuits and brand new to lines.

I have been a lurker on this thread for quite some time now, and finally decided to create an account and contribute a bit to this thread and others

I have been working on PCB’s for a few various Paper-Circuits as well as Panels to accompany some of them to make small desktop units

Rungling is what seems to be Peter’s newest Paper up on his IG, aside from the weird Quad Norton Op-amp Paper that he has a couple of obscured photos of.
I am working on making this a mini desktop unit with a panel as well.

Once all of this stuff is finished, built, and tested - I will sell some of the PCB’s, but will also make all of the Gerbers available for those who wish to build their own.

I have some of Meng Qi’s Gerbers that he made available on his site (which only seems to be active at certain times) - here are the Links.
Meng Qi Boards
Rollz-5 (Converted right from Peter’s files)

Hope to see more in this thread

[crucFX]

Here are some quirky little power boards to hook up to any paper circuit

BIRD (My Version)
Lil Sidrassi (Converted right from Peter’s files)

[jlmitch5]

very nice, this looks very similar (possibly identical) to the power regulator mentioned here: https://pugix.com/synth/rollz-5-schematics/

I saw an article for a completely different project that implemented something similar too…maybe this is just a standard design for the lm7809 regulator?

[crucFX]

Very standard! but yes! I’ve checked out Richards Page a couple times!! So much information
Just wait til I post my 2-Roll LFO x8 Desktop Unit here… lol It is based on Richards 2-Roll Schematic!
He actually recently corresponded with me and cleared up some stuff about the output mixer for me
I have a Twin 6-Roll Board, and a 543-Roll board finished and ready to fab, as well as some other fun stuff like Mourning Dove

[crucFX]

Roll circuit w/ LED Driver Example - 2-Roll & 3-Roll

[jlmitch5]

Also an update on my gerassic organ project…got the buttons/gate ins bread boarded up and working.

The buttons xor to their respective gate in. I’m definitely promoting thresholds to pots on the panel…you can get some cool patterns by setting different thresholds for the channels.

The one thing I need to figure out is if I somehow need to buffer the inputs…it seems like the led of one channel being on or not can cause another channel on the threshold edge to trigger or not if they are using the same signal. I’m gonna see if using a buffer mult for the gate signal makes that go away and I think that should give me an idea if that’s the problem or not

IMG_6197

[barrford]

@jlmitch5 looking / sounding good! Do you need pull down resistors on the inputs of the CMOS chips (inputs for the XOR and the A, B, C, D inputs of the multiplexor)?
If any of the inputs are left floating then you can get unpredictable behaviour on these 4000 series chips.

[barrford]

Good work! I’m looking forward to seeing the mini desktop unit, as I always struggle with the enclosures for my circuits, and usually end up putting them in guitar pedal boxes.
For the 8 x Rollz 2, rather than having multiple battery connections, why not just connect the power traces around the circuit? It would look a bit neater. If you’re making single layer boards then you might need bridging wires for one of the power lines, so you’d need to put pads in for those as well.

This rungling paper circuit is from the 3rd Edition of “Handmade Electronic Music” by Nic Collins.
The original paper circuit can be downloaded from the accompanying website:
Rungling paper circuit

[jlmitch5]

Ah good question! I’m not using the 4th channel of the quad xor…I’ll ground those and see what happens

EDIT: I don’t think grounding that not-used channel or switching to buffered mult did anything. maybe it’s the led that needs to be buffered, gonna try that later

[crucFX]

They are all connected on the bottom copper I am making everything Dual Layer - same with my 543 Roll and Twin 6-Roll - dual layer - powers connected on the bottom and bottom is also a ground.

I mostly left the obelisks there for aesthetics haha.

That Rungling link… WOW - that would have been SO MUCH EASIER TO DO… if I had had that picture 2 days ago, lmao.
I made mine completely off of the Instagram pics lol.
Hey, at least now I can check my work, so a huge Thank You
Here is the little Panel I made for Rungling.

[Cementimental]

@crucFX

Quad Norton Op-amp Paper

excited for that, I have tonnes of those I’ve never found a use for… bought to try and build a matrix mixer without a dual power supply but in the end designing a norton mixer seemed more confusing than just building a little power supply