Mobenthey/Ciat-Lonbarde (synthmall) thread

this is a Gerassic Organ i made


it looks like you have a hairy cap device that is pretty smart

I just ordered a pcb for that from the Facebook group. I might hit you up for build tips once I get it :slight_smile:

I think you can basically do whatever you want with these modules :slight_smile:

The Swoop is one of my favourites… part VCA, part function generator, lots of crazy. I could see having two of them for sure, and I totally understand why Peter includes three in his set.

If I were doing this I’d probably do 2 Denum, 1 Fourses, 2 Swoop, 1 Dunst, 1 Sprott…

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Interesting. So wouldn’t double up on Fourses then. (I guess it is 4 osc in one, in a way).

I’ll have a rethink and perhaps double up the swoop and leave a bit of space from there.

At the moment I have one of each in my setup… and I keep waffling between keeping it like it is so that everything fits in one big case, or breaking out my individual “instruments” into small cases. If I do that, then I’d probably build up the IFM set I mentioned in my last post.

Do you have a Swoop already?

its a 1 pole 12 rotary switch i made


yes no problem - i used the Gerassic notes / schematic plus the Lil Sidrassi docs regarding the caps and symbols.
Heres a cross post :

Having played with it more, theres a few things i just realised that might not be obvious to some.
Switches labelled 1, 2 and 4 on the circuit board each have 2 tuning.
Switch 1 corresponds to both tuning pots 1 on the board. Switch 2 corresponds to both tuning pots 2 on the board. Switch 4 to both tuning pots 4.
Tuning pots 3, 5, 6 and 7 have no effect.
I see no need to put pots on these.
I’ll probably take those off and put on mini trimmers.
Both tuning pots 0 chooses the master note that effects all 3 switches.
The sustain pot marked x on the board i have a 500k pot - this works well to go from long notes to plinky plucks to off (no sound).
If this had switches for 3, 5, 6 and 7 then that would be a bit special - thats why i bought 2 boards :slight_smile: The cap switch works really well and i’m liking the bass 0.1uf (104) and 1uf (105) subbass the best for plumbutter like clicky bass drums, with a little treble .01uf (103). The treble is good with short sustain for plucky sounds. The ultrasound annoys the dog and without fm it just sounds like i high pitched whine and i usually pitch down but makes a nice clicky sound. If that could be FM’d somehow, it would be great :slight_smile:
I think 6 x 100k sliders would be good for the trim pots 1, 2 and 4. 3 big knobs - 2 for pot 0 plus another for the sustain plus an additional one for switchable knob for the capacitors. Also if you didn’t want a 1 pole, 12 position switch you could always do something similar with an on/off/on switch


What is the purpose of these connection on the board? If they have no effect, could they be replaced by static resistors? You also mention putting switches on these instead, what would that do? Or am I missing something? :slight_smile:

I’ve not cut the wires to these pots yet so was afraid they could break the circuit somehow. If it did i would just put the mini trimmers on those ones.

I love this very much!

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But there’s no noticeable impact on the sound when turning those pots? (assuming it would work the same with trimmers).

What would the switches do for this part of the circuit? (you suggested you might put switches in 3,5,6,7)

Thanks again for the insight. I’m planning my build now. I also got two boards, thinking I might build a double enclosure and tune one side for high pitches and the other for bass.

there is nothing on the circuit board to trigger 3,5,6 and 7 - only 3 switches to trigger 1, 2 and 4 (they are the castle shaped ones) . I only suggested i would be great if you could trigger the other ones but you can’t. That would mean redesigning the circuit.

The original design has mini trimmers for 0 - 7 on one side and 0 - 7 on the other side of the chip. All i did was substitute the 100k trimmers and use 100k pots. If you remove the pot or trimmer, who knows what will happen - if theres nothing in there, the circuit may not work even though i know the pot does nothing when its in there and its turned.

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you could do something like this for switching capacitors if you didn’t want to make a big rotary switch


you can see all the trimmers are connected

I was just reading Peter’s one-sheet for the Gerassic Organ and it says:

“There are three buttons: 1, 2, and 4. When you have buttons 1 and 2 down, you are playing note 3, which you can tune with trimmer pots 3 and 3.”

This implies that you can play the notes associated with trimmers 3,5,6,7 by playing it like a trumpet, where different combinations of the “keys” play different notes.

Have you tried that at all?

yes i tried it but got no joy on mine. You are correct that is the way it is supposed to work - About the other tuning pots: the switches connect to 1, 2 and 4. To activate 3, you press 1 and 2 at the same time. For 5, press 4 and 1 at the same time - binary arithmetic. So all the different notes should definitely be activated. I have a second one to build so will try with all the pots again.
Heres a pic of bonomos build - note the key presses on the lid


Hi. I’m interested in the Cocoquantus 2 and wondered if anyone had any sounds to share to get an idea of what it can do. I’ve trawled you tube but wondered if anyone had anything else that could be highlighted. As well as ITB stuff I use an octatrack and effects for manipulation and looping but often leaves me a little flat. Thanks

Check out Hainbach’s youtube channel for a lot of coco videos. He’s going to make a coco tutorial video soon as well. Think the OT and Coco would be best friends!

That would most useful thanks for the heads up