DIY polymorphs?

Wondering if there’s any more modern open source polymorphic synth modules out there along the lines of Ardcore or Ornament and Crime. Ardcore is very long in the tooth and limited. o_C uses the unobtainium Teensy 3.2, except there’s the Squares and Circles firmware which targets Teensy 4.0 but I’ve read 4.0 is marginal at best (worse than 3.2) for what o_C tries to do.

There is EuroPi. Unfortunately I consider Raspberry Pi a garbage company and will not use their products.

So are there any other DIY polymorphs for the 2020s? I’m more interested in CV applications than audio, but both I suppose.

OK, there’s the patch.init() based around the Daisy Patch module.

One downside is the limitation to 2 CV outputs and 2 gate outputs.

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The Daisy Patch has more IO, if that is what you are after.

Patch — Electro-Smith

I have been meaning to build a Kosmo Module around the Daisy Seed to experiment a bit, but I haven’t gotten around to it yet. I have played around with the Daisy for my interactive flower synth project, and I am just finishing up a guitar pedal powered by the seed. It is a great platform for DSP.

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The Daisy Seed has 12xADCs and 2xDACs, so you can build a module to use all of that. Note the 2xDACs are shared with the ADCs, so if you use those you get 10xADCs. On top of that you have stereo in and out audio lines.

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Yeah, as I understand it the Patch adds Eurorack interfacing to the Seed and the patch.Init() packages up the Patch as a Eurorack module. Or something like that.

I built a couple of Patch.Init()s and have one of the adapter PCBs and a few faceplates left over if you want to DIY one? You’d need to add a patch_sm, which is basically the seed but with eurorack power and signal conditioning.

I haven’t used them for any sequencery type things yet, mostly running faust dsp code on them for filters and reverbs at the moment.


Thanks, no, not looking to acquire anything but information at this point.

The patch submodule, not to be confused with the patch I linked above (easy right?), adds the circuitry to the Daisy Seed platform to make it eurorack friendly. It can be powered with +/-12v and adjusts CV and gate levels. It saves a bit of circuit work for $10 more cost. The Patch I linked is a Eurorack development module based around the Daisy Seed. The patch.init() you linked is a Eurorack development module based around the patch submodule. They could have done better with their naming conventions. I am still undecided on which platform I will base my Kosmo module around, the Daisy Seed or the patch submodule. The patch submodule would be easier, but I already have several Daisy Seed boards to play with.


I find that hard to believe, given that the 4.0 is significantly superior to the 3.2 in pretty much every spec.
Only point where the 3.2 wins is that it’s got a DAC, but the Ornaments & Crimes uses an external DAC anyways.

Where does the 4.0 fall short?

Max (mxmxmx) and I were investigating porting to Teensy 4.0 in 2019, I think - Max had a few pre-production T4.0s and I bought a few just after they were released. It turned out that there was a problem with the SPI bus, at least at that time. The SPI hardware on the T4 chip is actually slower than on the MPU used by the T3.2, and as a result the display and DAC weren’t working correctly. If the display was disabled, then the code ran OK, iirc, but that’s not much use. We were intending to wait for better SPI drivers for the T4, but decided it was better to work on a successor to O&C. We got as far as hardware design and proof-of-concept for that, then COVID-19 hit and the wheels fell off. We may get back to it at some stage… I think that a Teensy 4.0 port which worked as a “brain transplant” for O&C is still a worthwhile project, if the SPI bus performance issues have or can be solved. I’ haven’t been watching the teensy forums for the last year, so not sure what has been going on there wrt this issue. Note the SPI i=on the T4 is fine for all reasonable purposes, it’s just that the O&C design pushed the SPI bus way beyond reasonable in order to get decent DAC sample rates, due to the single bus architecture of the O&C hardware design (given the the O&C firmware took that hardware design into places it was never intended to go).

The [Squares and Circles] project was originally a kind of research that I did over half a year. The current O_C hardware could certainly be optimized. As you know, the DAC and the display share the SPI port - this is not ideal for simultaneous operation. Furthermore, the Teensy 4.0 does not have “high-end” ADCs - my focus here was to achieve operation at audio rate (aux input) - the issue of noise has not been the focus so far.

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Weaker SPI and ADCs, interesting, thank you.

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is this along the same lines?

Reading about this led me to find the teensy audio gui and that looks pretty cool, I think! People made cool stuff with that, like a drum computer or a whole synth. It also works with teensy 4.1, which is still available (but more expensive). If anyone is about to develop a KOSMO module for that, I would be very interested!! :slight_smile:

Oh well I guess there’s this