Prototyping Nearness, a minimal panning mixer module


#61

I imagine the easiest option for a one-off would be Front Panel Express, and the cheapest to get a 3 or 4 HP blank and drill holes in it.

I have access to a CNC machine at my makerspace, and so cut the panel myself from aluminium sheet, and then used a vinyl cutter to make black vinyl stickers to mark the outputs.

You can open the SVG with a text editor to see the exact dimensions and locations of everything. In case it’s not obvious: the red outlines in the SVG are for cutting, and the black ones for printing, if applicable.

Hrm, looks like both Digikey and Mouser are currently out of stock. GRM21BR61E226ME44K is the same component in different packaging… and also out of stock. Any ceramic capacitor with the same footprint, capacitance and temperature coefficient, and the same or better voltage rating should work fine, though.


Thanks for the kind words, everybody!

Anyone looking to build a few extra modules for other people: please do! It’s a good way to bring the unit cost down a bit. But, please make at least one for yourself before you commit to making any for others, and do note that the design is currently in, let’s say, public beta. It could conceivably interact strangely with some other modules. If that sounds fine to you, and you’re okay with possibly desoldering and replacing a few components later, go for your life. If not, wait a bit.


#62

I’m just curious - is there a need to use 0.1% resistors as spec’d? I feel like I typically only see that choice made in designs meant to handle 1V/oct CV processing.


#63

Possibly not.

The resistors are what determine the gain per-input and per-output. Their absolute values are not too critical; the actual values used (in the BOM) are up to 1% off the ideal values (in the schematic) for a -3 dB pan law.

The values should be well-matched, though. For instance, the two 140k resistors can’t be too different, or the center channel will sound, well, off-center. Would using 1% resistors be good enough? Maybe! Try it and see what you think?

(I did a quick experiment in Audacity, but there’s too much confirmation bias at play for me to know whether I can hear a difference or not.)


#64

This is a great idea! I’m going to order some boards this weekend, and maybe knock up a pcb panel for it too. If anyone in Australia wants a spare let me know


#65

@bmoren and I are working on a 2HP version!
Here is the front panel design:


#66

thanks for the tips! I was mostly trying to be cheap, but the necessity of somewhat rare values means that I can’t get all the parts from Tayda anyway so might as well get the good stuff :slight_smile:


re: panel - I may not use this myself, and it is definitely not tested, but I made a FPD layout for the panel to see how much it’d cost, so here it is. looks like it’d be ~$33 per panel base price. I haven’t ordered from Front Panels Direct before, but I believe I correctly set this up so that the name/black rings around the output jacks would be printed rather than milled, but of course you can change that if you like. there is also a version
without any printing/etching (~$20/panel) These can also be exported as svg/dxf from the FPD software:
nearness panel.fpd (975 Bytes)
nearness panel no etching.fpd (843 Bytes)

again, double check the measurements before you commit, but I’m pretty sure I got it right. if you decide to order, please report back! :smiley: If anyone decides to make a PCB panel, please share! I’d just as soon go that route, personally.

edit: I was curious about other types of FPD machining costs, so here’s a bronze color, etched one with no printing (but since it’s bronze, anything etched/machined will be silver. looks like it’d be ~$25:
nearness panel bronze.fpd (1007 Bytes)


#67

Beautiful! Could use 2 of those. Will it be DIY only as well or option for a built module?


#68

We were not quite all the way there with the 2hp prototype. Since the 3HP is all laid out and available, we are going to make these 3HP ones for now, and still look into refining the 2HP version.
Meanwhile the 3HP front panel (in black and gold) will look like this:


#69

as in a PCB panel, and therefore hopefully not too expensive? if so, sign me up for sure! also, if you are ordering PCB panels and would be interested in some sort of group buy for the actual PCBs, I’d happily order a set of boards and a panel from the same place :slight_smile:

if a 2hp version gets made eventually, that’s cool, too!


#70

I was a bit coy above, but I’ve got a 2HP remix brewing as well. I should know if it worked out in a week or so. I already have my first prototype boards on the way from OSH. I’ll share more details when I get them built and tested.

That said, I don’t imagine that it will be a very fun DIY build at 2HP. Parts are smaller. Jacks are stuffed in like sardines. Assembly is tricky and will take a lot more time.

I’m doing it for one of my massive TXo rigs that has tons of oscillators that I want to mix and pan (and thus will use several of them). In general use, I’m not sure if saving the 1HP is really worth it as it is an amazingly feature-packed module at 3HP.

Frankly, the design that @billyhologram put together is quite wonderful and very thoughtful. It will be a super-fun thing to build - even for SMD beginners. I’m building three of them to start for myself. I’ll also be doing a run at 3HP for others as well (if folks need it). :slight_smile:


#71

Great update. Keen to get a 3hp one when you build a batch.


#72

Please count me in for one as well


#73

3hp is out of the question for me, but I’d be interested in what people cook up for 2hp!


#74

I’d love to see your approach for the 2hp (and am happy to share where we’re at – many heads are better) My main question is, did you fit in 9 thonkiconn jacks? If so, what was your strategy!?

Here’s our REV 2 : https://oshpark.com/shared_projects/JhDnxTrd
but, DON’T ORDER THIS, rev 1 is tested (and obviously needed adjustments), but not this one yet. We’re using PJ301CM STEREO Jacks for compactness, but honestly they are a pain to solder and are no-good with oshpark (or other cheaper services) because the footprints need to go over the edge of the board. And, in addition they are so darn stiff it makes the whole thing flex when removing a cable. Quite problematic!

We’ll be getting the 3hp panels done in black PCB with gold ENIG, they should be under $15 a piece (likely closer to ~ $7) I’ll get a group order together when I’ve got it ready to go.

b.


#75

you can check/ask which jacks are used for this multiple https://www.modulargrid.net/e/other-unknown-seamoss-instruments-mul-70
They managed to fit 10 of them in there, so I assume they’re quiet small :slight_smile:


#76

I did … I think. I’ll be honest, I was delirious on sleep aids in jet-lag hell in the middle of a 26 hour travel day when I did it, so I guess the proof will be in the boards when they get here. (I accidentally ate breakfast twice during my first, thirteen hour flight.) :slight_smile:

I’ve seen a number of strategies in the past. From sharing the ground hole to using more compact stereo jacks like you guys did. The one I decided to try was to make a derivation of the part and slightly bend the lead for the ground wire to the right. This part is very flexible and should be accepting of this contortion. When rotated, this allows me to stack a few next to each other more closely than before.

(You need to zoom in order to see that part of the image. Not sure why. But that’s how the forum software cropped it. )

I’m sure it could go even closer together with the pots. But for this remix, this is all the extra room that was needed. I think this will be easier than trying to share the hole which has been a PITA to deal with in some builds I’ve done in the past.

Clearly, I’m pushing design tolerances in other places (things are damn close to the edges of the board with even a little slight overhang of the outer pots). For my previous tests on another module that is in the works, this has worked acceptably.

I should know shortly. :slight_smile:


#77

This is what I was thinking, or to run them all common and then to a single ground hole ‘hovering’ above the PCB. Commoning the grounds 2 into 1 didnt seem like a good idea due to the even spacing that the jacks would need. I eagerly await your report! Perhaps we could join forces if you’re interested in the 2hp version panel @laborcamp and I are working on.

It is damn tight to the edge!


#78

Here is a mouser cart for the original 3hp version from @billyhologram. I haven’t tested this yet (had to replace some out of stock parts), so use at your own risk!

https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=be78cae6c0


#79

I’m very keen too. I would build myself if I had time but please count me in if possible/still available


#80

Really excited to see people interested in modifying, building and playing with this thing! I’m away from home at the moment, but, a few scattered thoughts:

If you’re making a panel, open the SVG in the repo in a text editor to see the precise measurements (in mm) for everything. If you can import the SVG into whatever layout program you use, great. If not, it’s just a rectangle and 9+2 circles, so shouldn’t be too tedious to copy manually.

As you might have noticed, the build guide in the repo is, uh, terse. I’ll try to get something more helpful written soon, and post some photos too. But, for now, I think the only gotcha is that you really need to solder the pin headers connecting the boards before you do the jacks.

Thanks for posting a Mouser cart, @bmoren. Looks reasonable to me. For what it’s worth, both Digikey and Mouser let you upload a BOM.csv file (like the one in the repo), which is a good way of making sure you’re getting exactly the parts specified (as long as they’re in stock, of course).

To the folks working on 2 HP versions: hey, godspeed! It’s not for me, but I can see why you’d want it. And it can probably be done, if you’re willing to compromise on ergonomics and ease of assembly a bit. (If I were to remix my own project, I’d probably make it 4 HP instead, so I could fit some bulky AC-coupling caps in there, but hey.)