OT modular integration with Magpie DoubleDecca!

looks really great. can’t wait to find out more. DIY project for eurorack integation.


already ordered

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i’m gonna have to track down a builder… hopefully they start shwing up FS by builders doing batches. really would be nice to design my own LFOs for the modular :wink:

Pardon my ignorance, but can someone explain me the benefits from using an Expert sleepers FH-1 (+ extension) and a Midi to USB in between ?

Ok the price is not the same but I’ll have no skill to built this alone :blush:

this is nuts. got one of these in the rack. set up the OT in a few minutes and had LFO designer going to the modular to control whatever. so stoked on the diy open source modular world for making this happen. OT + Modular will be good good friends soon.

make some short videos of it in action !

first steps… sorry for rapid camera pan!

nice! looks super fun

Woah! That almost makes me want to keep my OT!! Is someone doing a 5U build?! So rad!!

I’m very intrigued by this ( especially considering the coming trig conditions)

So, forgive the idiocy, but I’m confused about something: if 2 tracks are sending CC9 to MIDI Channel 1, how does the module decide which to output as CV?

Also, does it do polyphonic midi/cv? I would doubt it, but you never know…

you should check out the build guide… it has the set up for the OT in there and how it works.

no polyphony but modulars aren’t really about that anyway… though there are a couple people doing it. it’s complex to patch up a polysynth and you need one of each thing for each voice… so 1 oscillator/filter/envelope/vca for each voice so it gets complex and expensive… but modulars for me have always been about multitimbrality and complex mono voices/fx etc.

to answer your question though… the way the firmware is written in the dubledeca you get two independent voices (pitch/velocity/gate) and then 6 tracks of gates + CC and clock. you can pile CCs on one track but it’s more fun to have them on different tracks because then you can have them running different sequences and have them tied to different gates… but it’s trivial to assign an LFO to CC and have that output on the dubldeca

to have all the CC’s for every track show up in a jack you’d have a HUGE module not to mention all that going as modulation at once would likely be a big midi log jam.

but do check out the build guide at magpie modular to get the lay of the land for how the OT is setup to work w/the dubledecca. it’s totally open source so the firmware can be rewritten to work w/any midi device… i think someone is doing an mpc firmware… but i’d imagine a ripe candidate is the digitakt though i don’t own one so no idea how much LFO CC goodness is in the midi side of the DT.

anyway… the firmware/OT set up info is on page 15 of the 21 page build guide.


here’s magpie’s dubledeca page


Thank you. Ill give it a look.


how does it use 2 MIDI when there’s only 1 MIDI output on the OT (I need to use a midi splitter?)

one midi cable has 16 channels. so it splits out the midi data to separate jacks on the module.

but if you’re asking how to integrate w/the dubldecca and also sequence external midi gear then you’ll need a midi thru box like the kenton thru5 and you won’t be able to take advantage of all the dubldecca functionality because it uses all 8 midi tracks on the OT.

Got a PCB set on the way!

I thought I had to buy (2) of everything. So I bought two midi stereo jack things (like Beatstep uses) and I was thinking what is the 2nd used for if there’s only 1 MIDI out on the OT. I have a midi thru box so I’m good. I haven’t purchased the BOM so I’m sitting here thinking “why do I need 2 midi cables”

maybe I’m still not understanding. In the Youtube video I can see only 1 midi cable

yeah… one midi cable. one midi input. dubldecca uses all the midi tracks of the OT. so if you split the midi out of the OT to other midi devices you will lose some functionality of the dubldecca.

i didn’t build the dubldecca… bought it from a builder. i think it’s just two dodeccas and they’re connected behind the panel and have different firmware. though there’s probably other differences as well.