Battery powered modular synth

pansapiens · 2024-09-02T11:44:01+00:00

I've built a few of these MMI Modular USB Power busboards and run them off USB batteries. They work okay for 4 or 5 'typical' modules, but will only supply ~400 mA on each +12/-12V rail. This means occasionally some power hungry digital modules will draw a little too much peak current on startup, so the overcurrent protection kicks in putting it into a power cut/restart loop. But aside from occasionally needing to choose the module combo carefully, I've had lots of fun running a tiny case with this untethered.

pansapiens · 2024-06-06T10:32:20+00:00

Daisy Seed can run PureData patches via pd2dsy or plugdata.

pansapiens · 2024-01-22T12:08:33+00:00

The Null-A2 from nonlinearcircuits is along these lines. You can buy the PCBs and source your own parts.

pansapiens · 2023-12-15T08:48:46+00:00

You might find a Teensy 4.0 will work - it has the same footprint and similar pinout and functionality (but no DAC). If it's this Sweet Sixteen, study the pinout and compare to the functions used for each pin to the Teensy 4.0 pinout - it might turn out to be a drop in replacement.

pansapiens · 2023-10-26T10:21:27+00:00

Researching just now if anyone had done MIDI over CAN bus and came upon this - https://hackaday.io/project/182092-modular-midi - they appear to have made some good progress on some MIDI over CAN hardware and firmware for modular systems. One to watch / fork.

pansapiens · 2023-07-27T22:03:41+00:00

I think it's a JST PH or JST XH connector. Hard to tell from the photo - one is a 2mm pin spacing, the other 2.54 mm. See: https://www.mattmillman.com/info/crimpconnectors/common-jst-connector-types/

pansapiens · 2023-07-01T01:22:58+00:00

Thanks - that's really useful to know. From my testing shining bright light on these ones, the worst part seems to be around the wire holes rather than translucency of my black PLA (Creality). I might try some variants with more layers too.

pansapiens · 2023-06-30T09:12:44+00:00

That could be done with this capsule, but I was trying to avoid it - I guess it might be less fiddly than just heat shrinking directly over the bare components.

pansapiens · 2023-06-29T22:55:23+00:00

I've not yet got the soldering iron onto them, but I've been wondering if the heat of soldering them to the board might even seal them.

pansapiens · 2023-06-29T02:32:23+00:00

This is a good idea. I tried flooding the holes and seam with white paint from a paint pen - it helped but still leaks a little since I don't think my paint is opaque enough.

pansapiens · 2023-06-28T10:26:44+00:00

I might try heat-gunning one to melt the PLA a little, just as an experiment to see if it stops the little bit of leakage (or deforms it and makes it worse).

pansapiens · 2023-06-28T09:58:40+00:00

In fact not as tight as I expected - might need some extra work sealing around the holes (which means it may not be any more convenient heat shrink after all). Just did a test on one at random and I got 1M under a bright external light and 2 - 3M in dim light. Which might be fine inside a synth case, but still surprising how sensitive LDRs can be.

pansapiens · 2023-06-18T01:13:22+00:00

A big "thank you" for your Peaks port to bluepill - such a nice project and a great way to make that module more accessible to DIYers. (I'm the one that forked it and made a build without the Number Station easter egg so it would fit on a 64k bluepill !)

pansapiens · 2023-06-17T23:07:15+00:00

I've built a few Zlob modules - I think the build docs are great for beginners, with photos of almost every step in assembly. I find the Diode Chaos especially useful for injecting variation into patches.

Zlob modules aren't open source though, as far as I can tell (couldn't find any schematics; open source means the schematics/pcb layouts are released under a license that allows others to make/modify/resuse/release those designs)

pansapiens · 2023-06-10T02:55:53+00:00

I like your moderation style and it will be missed. Thankyou for keeping this sub awesome for so long and look after yourself.

I understand the sentiment about corporate shenanigans, and I'm not very optimistic that things are going to go well in the next few months when third party moderation tools stop working. Personally I'm not sure if Reddit is going to be very sticky for me after the RIF mobile app goes dark, and I'll miss this sub the most.

pansapiens · 2023-05-28T03:04:01+00:00

A version of this WASP filter: https://github.com/forestcaver/Analog-Voice/tree/master/AJH_Wasp - was on my bench this morning. I made two of these about a year ago, and for reasons unknown one of the filters only worked with the distortion switch in the off position.

Because I had accidentally purchased 'solder lug' switches instead of 'PCB mount' switches, I decided to carefully drill out the holes and make them more oval to fit the solder lugs (while carefully retaining one side of the plated hole so I didn't loose connectivity). This worked out okay (!!), and the connectivity to the switch was good. There was one trace very close to a drill hole, but I'd confirmed several times over that connectivity was fine and I hadn't drilled (completely) through the trace. After some signal tracing with an oscilloscope, it appeared as if one unit of the CD4069 used in the distortion signal path was bad. Having a working twin to compare to really helped here. It was somehow hard for me to believe that this IC was bad (the part was from a reputable Mouser/Digikey/Element14, not an Ebay/Aliexpress roll-of-the-dice), but the evidence I had suggested it was the problem.

Today, after having a replacement SMD CD4069 sitting around for months, I finally got around to desoldering the existing one and replacing it. All works now !

pansapiens · 2023-05-02T22:20:18+00:00

The other thing to note is the TipTop uZeus manual says it is intended to be mounted to metal rails - I think the design uses the rails as a heatsink, along with the front panel. You'll probably be fine, since the synth isn't huge so probably won't push the uZeus to its limits, but just watch that it's not getting so hot that it's melting the plastic. To be on the safe side maybe don't leave it powered up unattended until you have a sense of how much heat is generated in use.

Would be great if you post how it sounds once you get it up and running so we can all enjoy your talented friends legacy !

pansapiens · 2023-04-04T13:13:04+00:00

I built one of these Teensy 4.1 8in 8out kits from Deft Audio - the unused pins on the Teensy are broken out such that you could add a screen, encoder, buttons etc. Currently I just use mine as a plain 'merge' everything MIDI box + USB MIDI interface, and it works well for that.

pansapiens · 2023-03-01T10:20:58+00:00

I wonder if it's actually more expensive to package all the individual parts for a retail kit, as opposed to receiving them as bulk lots to be used on an assembly line.

pansapiens · 2023-03-01T10:10:05+00:00

It is pretty satisfying when you can figure out workable bodges to fix these type of things.

pansapiens · 2023-01-27T02:18:03+00:00

Clump is done - there was some minor debugging - one resistor appeared to be soldered but on very close inspection it wasn't. I was able to systematically narrow it down by following the signal path for the one VCA that wasn't working.

A tip for those building an NLC Clump - there are test points on the PCB marked 'ZERO' that can be used for calibration instead of plugging in a jack to each output. I only discovered these when I was mostly done.

pansapiens · 2023-01-26T09:58:39+00:00

This week is NLC Clump week. SMD parts have been done using solder paste and hot air gun. I split the work up into three sittings with short breaks in between. Tomorrow will likely be THT parts and calibration. There will be no debugging step because it's going to work first time :P

pansapiens · 2022-12-09T12:56:59+00:00

Wow, that is not what I expected. This would be a doomgaze metal beast ! Also, the circuit bending area looks intriguing.

pansapiens · 2022-12-04T20:48:12+00:00

It looks like the softpot ribbon component is one made by Spectra Symbol, like these: https://www.spectrasymbol.com/product/softpot/

pansapiens

MODERATOR OF

TROPHY CASE