Akso as a eurorack module

Received my Akso the other day and more or less immediately 3D-printed a eurorack panel for it.

I haven’t spent too much time with it, but it’s already acting like a Disting-type module in my rack where it can quickly fill in holes in patches, be it as a vca, utility, clock or extra reverb!

Next up is adding some pots and perhaps a small OLED display…


Rad! Wanna share your model, either here or on Thingiverse?

@nsm Is there a way to get Thingiverse to do previews here like it does with YouTube, etc.?

Great. Does it survive -10 to +10V inputs? I don’t know anything about the Akso, but the ZRNA FPAA board’s audio inputs are specified for -5V to +5V. I want to integrate the latter board into my rack, but I think it would need a line level converter (aka voltage divider or level converter via opams) to make sure nothing gets destroyed. Or won’t this be an issue? @nsm

Hey @mcleinn. See my answer on the other thread for a deeper dive on the FPAA stuff.

Both devices have overvoltage protection on the inputs such that the downstream lower voltage devices only see signals that are in range. This is a codec in the Akso case and the FPAA device in the Zrna case.

Akso generates its own -12 and +12 rails internally so it can work with CV away from a Eurorack system if necessary. -10 / +10 on the inputs is just fine. Whether or not that is meaningful in the context of the patch you are running is another thing; it depends on what IO modes are in use.

Aside: we absolutely could make the FPAA technology work at full CV range. The Zrna tech came earlier, and it was just simpler to support -5 / +5. We could port over some of the ideas from Akso’s analog section in a future device.

I put the stl on prusaprinters!

The v2 print was decent, but not perfect. The tolerances for the jacks were a bit too snug, and the microSD card slot was slightly too small and skewed. I have altered the model but haven’t had the chance to print it yet, so can’t verify if it’s any better!


I’ve done a few updates! The button and SD slots were too tight so I loosened them up by .1mm and gave a chamfer to the buttons so you can fit a pencil or something in there. It would be neat to have a 3DP button that fits in a future version of the faceplate, but since the buttons are unreliable anyway in this firmware version I’m not too worried about it.

But the bigger change is to make it 10HP with a grill of 3.1mm holes that will fit an LED as-is or can be drilled to 6mm (Or whatever) to fit switches and pots in the pattern of your choosing!

I already printed one with the dimensions wrong so I redesigned it. If these dimensions are right, do you mind if I I’ll post it to Thingiverse with a link and credit?

Further edit!

Dammit, It’s 1.4mm too narrow! The SD card is also shifted toward the jacks still, too, by about (maybe exactly?) 1mm. There’s clearly something I don’t understand about dimensioning things in F360!

I’ll upload the .stl here if anyone wants to take a shot at it. I don’t think I have enough time to fix these errors today. Gotta do some shopping.


Looks nice!
I like the way you made it customizable & drillable post-print. It also looks way better in black than the orange PLA I had lying around :joy:

Feel free to post, share & remix however you like.

Other than me fully approximating the SD card slots position, I believe that some of the tolerance issues may stem from how the model is sliced, the resolution of the nozzle and possibly shrinking of the plastic. All eurorack panels I’ve printed from Thingiverse, for instance, have come in around 0.1-0.2 mm too short to be able to fasten both in the top and bottom rails – including my model, even though it’s done to the eurorack spec. I’ve had to take an x-acto knife to widen some holes here and there…

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I just had a new spool of filament show up. I’ll look at the dimensions and see if it’s actually designed right. There’s a goood chance it’s my arithmetic that failed here. Either way, I’ll print it again. If the model is right and it’s a printing problem, I’ll share it as soon as I’m reasonable confident that other people will be able to print a panel that works!

Looking good! Added a headphone icon, got the SD card slot in the right place. The buttons and USB ports could shift up by 0.1mm or so but it’s all basically in place. Everything measures to within .01mm so I think what’s going on is that the jacks are just very slightly small or low.

These knobs are just in place experimentally. I’m still not sure what I’m going to do with this module so I don’t know what configuration they’ll best fit in.

I think a similar grid layout with the Akso positioned orthogonally to the current arrangement with an assumed middle level shifting PCB would be great. This layout is a little tight for knobs this size and even with smaller ones it’s pretty tight for even my smallish fingers. Given the number of capabilities ones could build into an Akso, I think a 20HP module might be worth the rack space to some musicians.


Great Job, Looks Ace


I wish I had a 3D printer. Our library system has some, but COVID has library closed.

I can print you up one. Cover my shipping and I’ll crank one out for you!

I want to make a 20HP one if you’re interested in a wider one!

This is super rad. I’d love one or two of these panels.

Did you ever try making a 20hp version?

Thanks for all your hardwork @JoshuaACNewman

I haven’t done much programming with my Akso boards yet but having a panel like this may encourage me to set them up in my rack!

Something is wrong with my Akso right now that I have to deal with when Nic comes back to the world. When that happens, though, I’m probably going to make some variants including more HP and slots for sliders. With more HP I’ll also be able to loosen up the grid a little, which will both be better for aesthetics and for fitting your fingers.

I’d love to fit in a level shifter board so I can stick a bunch of CV ports in there, too. Two is good, but more is obviously better!

I went with the panel design I found somewhere on this forum (I think it was from here)


Unfortunately the holes on the design aren’t really placed for Eurorack. Plus I’m a bit bummed as I’m trying to find a solution for an addition TRS jack as a MIDI input but I’m not sure I’ll manage to pull it off in 2hp. We’ll see.

Oh, man! That design was supposed to have worked. It’s also available here.

My design’s dimensions match the modular Kastle module, fwiw. It’s what I checked it against before finalizing.

Yes, you won’t be able to ad another jack without making it wider. But then, if you need to add any sort of panel control, you’ll have to get wider anyway.

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Hi Joshua! Thank you for the design. I really appreciate it, so please don’t take the above comment as a a complaint. Here’s an image to showcase why the hole placement doesn’t really work:

Here it is compared to a 2hp sized module that has properly placed holes:

I’ll try to see if I can redo the design. I’m not familiar with 3D printing design, but modifying your work shouldn’t be that difficult.

I don’t have any specific aim to add extra control on the module, I just wanted a TRS for MIDI, but I’ll have to do with an expansion module or something. It’s a pity really, as there seems to be enough space for an additional jack if you eschew the stability screw which is close to the jacks, and don’t use the IO pins which are there. Here’s another photo:

Ah, I see!

This isn’t the one that’s my (re)design, but I’m surprised this one has that error! I thought they got it workin in their rack, but maybe I’m thinking of the one mine is based on.

Oh oops that’s my design. All my eurorack stuff is diy so I’ve never been able check vs a proper case if you give me the proper spacing I’ll correct that in the next week. Good idea in on the extra jack I’ll do a variant