Axoloti as EURORACK Module?

modular
#1

I think I've worked out how I am going to use my axoloti now and was wondering if anyone was thinking the same or had tried it yet.

I want to mount the board on a 3U eurorack panel, add a display, some rotary encoders, a bunch of CV and trig/gate outputs and a couple of CV and gate ins and turn it into a sound source, processing and control unit as well as a USB/midi controller interface.

Has anyone else already done this?

Where can I find drawings and/or CAD models of the board to use to design the mounting panel?

#2

I know a guy have made a eurorack module for controlling Axoloti with a lot of inputs. Called Euxoloti:

But your project is a bit more interesting. To me it seems like you are going for a solution with a lot of outputs, which to me is also the setup that makes most sense. I dont care about the inputs. But I am not shure how possible it is to use many outputs from Axo. Read the link I posted. There are some info on output also.

BUT
I have been looking a bit on a solution using an Arduino board for midi>CV conversion. I think this is not mentioned in the Euxoloti thread. But IMO, I think it is the best solution to get many outputs and It can be done with out mangling to much with the Axoloti boards pins, etc. You just need to program the Arduino and hook Axoloti and Arduino up with midi cable. And if you do a lot of research online, you can probably find someone who have all ready coded everything you need, so you only have to get arduino board and do some basic setting up.

#3

Yes outputs are far more useful i would have thought, one CV and two gate/trigger ins for clock and to control virtual synths on axoloti would be enough ins

No need for an arduino, there is plenty of spare I/O already there on the board to drive a display, some encoders and the ins and outs to the modular i think, easy enough to wire up more I/O if needed with an i/o extended chip controlled via spi I2C or CAN, all of which are there on the st32 i think. I have to get more into the datasheets to see just how much spare i/o there is there though.

Trigger/Gate outs are really simple, just buffer a logic out pin.

For more CV outs an external DAC might be needed, that would be very useful anyway, could be used to make CV's and/or more audio out channels.

HIgh resolution DACs might not be needed for CV outs, 8 bit might be enough, arduino has a couple of 8 bit DAC's doesn't it?

My approach is to build as much of it I can myself on stripboard or breadboard rather than buy things, so much cheaper and you learn so much more.

#4

I just wanted to say that I would love if someone could finally adapt the Axoloti to the Eurorack format. This would be fantastic.

I will happily pay for aa Eurorack Axoloti, Euxoloti, or whatever its called. Please, make it a reality!!

#5

Well I have the concept clear in my head and Axoloti certainly has the hardware needed.

I got some blank 3U panels cut up today so should have it mounted in a rack in a few more days

I'll post the drawings for the panel when I finish them and updates on how it's going.

I've ordered a bunch of parts including rotary encoders and jack sockets and will build up the breakout board on a bread board then stripboard before I think about getting some pcbs made and make a proper product out of it, that'll be a year away though I'd say realistically.

If you want to work together on it that would be cool, even building your own and swapping ideas and experiences would be good.

I don't think I want the pressure of doing a kickstarter or something like that, I have other commitments and wouldn't want to have people waiting because I couldn't get things done on schedule.

Maybe when I get a working prototype PCB mounted version and the software sorted I might look at getting funding to mass produce it.

Thanks for your enthusiasm though, I'll keep posting as it evolves.

As for a name, because I think that's important, particularly if you want to sell it commercially, the first thing that came to mind was Axolotule, but something better just came to me then, Raxoloti.

Axoloti in a rack.

#6

yay for Raxoloti!!!!!!

#7

I would like to collaborate but I am not a DIY guy. And I don't know how to code. Maybe some beta testing?

But please do keep us updated with the progress!

#8

Electronics is not as hard as it it made out to be, and nowadays the tools and parts are cheap, besides I think every electric musician needs to have some basic knowledge, skills and tools to be able to get the best out of their gear and keep it working, it can also save you buckets of money. Many audio devices that people are paying big dollars for and often very simple circuits that a hobbyist can easily build themselves, have a look at what people are paying for boutique guitar effects, and it would seem it's even worse in the modular synth world as far as over inflated prices.

So if you want to beta test you will need to build a copy of what I build and help test the code when we get the hardware built.

I'll post the drawings as I do them, I'm working on the panel layout, art work and drilling pattern right now.

Start with buying some basic electronics tools, soldering iron, pliers, cheap digital oscilloscope etc, shouldn't cost more that $100-200 for cheap gear, it's enough to get started, get on ebay or DX.com and check out how cheap a hobby it is to get into now.

A gram of knowledge is worth a kilo of brute force.

Fight your gear acquisition syndrome and learn how these things work before just throwing money around.

I don't know I have the time, skills or inclination to be making kits or build modules to sell right now, though that maybe a possibility at some time in the future it will be 2 years at least I'd say. So if you want one to beta test on you'll have to build your own from my plans, and I'll share code with you, and the rest of the community.

Thanks again for your interest and enthusiasm.

#9

Ok here is a link to the first panel layout drawing

https://drive.google.com/file/d/0BwUUyc6HJZwUT09Edm1JeWZqOTA/view?usp=sharing

Still waiting on encoders and jack sockets so I may adjust spacings or even the overall layout if they wont fit as expected.

I'm using an old version of Rhinoceros CAD to draw things but I'm having trouble getting it out into a good format for working from like SVG, I'll try and sort something out so I can post it in a vector format rather than this JPG but it's getting late and it's been a long day.

I used the hole placements from the front panel of the case by the guy who posted on here, don't have the link to hand, thanks .

Does anyone have a either a drawing or 3d with the physical dimensions and placement of mounting holes and sockets?

#10

I dont promise anything. But I will try to do it!

Thanks for sharing your experiences!

#11

It's the trying that matters

#12

Just wanted to let you know that euxoloti is up and running. Here is a bunch of information on the project.
http://build.irieelectronics.de/
I´m not affiliated with the project but one of Paul´s first customers. I was lucky and to get a kit of the first run.
As far as i know there is another run available soon. All the info is on his site.
At the moment my kit is in the making and i hope to be up and running in a couple of days. The kit is pretty straight forward to build (mostly through hole, only the gat8 has some smd resistors) and the build documentation is excellent.
I´ll definitely report back when its ready.
As mentioned before this project is very input centered but as Paul explained to me he wanted to create a rock solid platform for possible expansion first. Which i personally believe he has achieved.
I am 100% for expanding the Euxoloti for more CV output capabilities and creating a monster!
@strum I think you should contact Paul for some knowledge exchange.
He has put a lot of work and effort in the euxoloti and told me he is working on an expansion module based on the MAXIM MAX11300 20 I/O IC.
I see great potential in this.
That´s it for know. Here is a nice video for the meantime.

Happy Halloween and don´t go outside...
because CLOWNS!

#13

Thanks , I have looked at that project, honestly I don't see the point of it and don't understand why he has hidden the axoloti front panel ins and outs.

That CV control chip looks interesting though, I had thought of doing it with discrete components but an integrated IC might be a better solution and would free up a bunch of io pins on the board.

Made a rack mounting front panel for it and have it mounted and in a rack, waiting on encoders and jack sockets so can't do much more with the hardware yet, but I have downloaded the code and have started trying to get my head around it. Not so easy when there is no documentation though.

#14

Really interested in checking out how you mounted yours. Did you diy the frontpanel or got it made?
Maybe you can show us some pics sometime.
The way i see it with the front panel in and outs is that the big in and out jacks are not necessarily useful in an eurorack enviroment, the headphone jack is something were i d say maybe, usb and midi are accessible as is and the sd card gets mounted once and is never to be seen again. Then there is the usb host port which coud be usefull to have but might also consume a lot of power. Depending on PSU and mounted modules thats something to think about. The usb host function in euxoloti can be used with a dc/dc converter.

My build is stalled too at the moment because i m also waiting for components. Sometimes those parts from china take forever :wink:
If you have any questions i m sure you can drop @paul a mail.
I ll report back when i made some progress...

#15

I'll take some pics tomorrow and post them.

I got some 3U * 19in panels cut by a local sheetmetal shop and cut a piece 160mm long, about 32 HU for the Axoloti panel.

I tried using toner transfer to put the drilling guide and other text but it didn't work so I just printed the panel graphics onto a label and applied that, then drilled the holes and filed the slots for the USB and leds and the display.
The label got a bit torn up but it's securely mounted and in the rack case I built on my desk and working.

I posted the panel graphic, I'll put it in a vector format when I get some time.

Also waiting on parts from china to add encoders and the sockets for the ins and outs.

you can get adaptors for the 6.25 mm jacks to 3.5mm. I'm using insert leads to break out the stereo into separate channels.

I'm hesitant to plug anything into the audio in without a preamp and maybe a hard limiter, 2v pp limit is not going to like potentially 24v pp levels coming out of a module.

I'll keep posting as I progress, got lots of other projects on the go and regular gigs so the time needed to get into the software is hard to find right now.

#16

I have been planing on making a Eurorack module for my own rig by combining a Doepfer a-192 voltage-to-midi interface module and an Axoloti wired together behind one panel. The A-192 gives you 16 CV inputs (via MIDI) and is programmable (what input produces what MIDI CC command). I would modify the A-192 if given the chance, but a basic prototype unit would be as easy as just measuring the jack positions and laying out a panel in Front Panel Express. If I had the chops to design the interface PCB myself, I would probably do that, but this is a simple solution for me.

The mods to the system would be CV offset and gain controls since the A-192 just responds to 0-5V CV inputs range. There are som better CV to MIDI CC modules out there too but the A-192 is only $175.

#17

Why the need for so many inputs? wouldn't outputs be more useful?

I'd use the Axoloti for control more than for sound generation, I guess I'm a bit of an analog purist though.

Did you see the posts about the CV chip people have been using for eurorack integration?

that or something like it looks like the go to me, more flexible and far cheaper than buying doepfer modules, though more work, you don't need PCBs you can do it on strip or vero board, or even bread board.

#18

My main purpose would be to use the Axoloti as a synth voice or sound maker so the more CV inputs the better. The choice for A-192 is just for simplicity. Basically just connect the MIDI together and there you go. You don't even have to make one panel for it. I could save some more cash by using their "Pocket Electronics" PCB which is just the electronics part of the A-192 but then I would have to make the limiting circuit for the CV in (the PCB doesn't want to see over +5V and need protection). Basically is it an ease thing for me. Also the A-192 would be useful for driving other MIDI boxes I have already, like my Nord G1 and G2. If you set up the Axo to be 2 independent voices (Left and Right) and wanted a decent amount of CV and panel controls for initial settings like PW and wave shape (bias DC voltages normalized into the jacks) you could easily use up 16 inputs so that is not too much for me. Also if programmed as a sequencer, all those knobs could easily be used as step pitch controls for live use. There are never too many CV inputs on a synthesizer for me.

I personally would love more Audio inputs and outputs from the Axo but that means a new Axo design.

#19

Why not just use MIDI controllers to control synth parameters on the Axo?

#20

I have over 100 modules in a Eurorack modular rig already. The goal is to integrate the Axo with the modular to expand that rig. I make and sell CV controllers under the company name Synthwerks so CV control is more important to me than MIDI control at this point. I want to use my current CV controlled modular and CV controllers with the Axo. Just a different direction. The goal is to make a module that I can just put in my Eurorack rig and doesn't need anything else after programming. I have an iPad and Audulus and other programs. a laptop with Reason, Max for Cats and more too. All of these are great alternatives for the Axo but the Axo driven by CV control is the goal. I might just connect directly to the Axo board with CV circuitry too. This was just easy. Nothing wrong with MIDI controllers, I have more than one.