THC Recursive Machine

this looks so interesting but over my skill level as far as soldering is concerned.
does anybody know if there is someone building these currently?

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Anyone have a lead on the GW22LHH rocker switch? It’s the only part that’s non stocked on mouser and digikey

I found an alternative in grey. Will post when I’m on my laptop again.

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Huh, it’s available now:

Are you creating and updated mouser BOM with all the backordered passive stuff as well?

As of right now this cart is fully stocked

I should mention doesn’t include ic socket and pots. I would suggest finding an alternative like Tayda for a much better price than mouser/digikey


ummmm is this project dead?
I just wanted to buy one on thonk and im seeing this:

And the 73-75 says: Sorry, this product is outdated and no longer active

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it looks like they’re working on a different approach to the same concept. this was posted on instagram a few weeks back…

Hmmm seems bulkier and less modular :confused: Does anybody know a place where i still can get some pcb’s?

Patch Point appears to have PCB kits in stock here


Interesting, the Thonk notice is clear about it being discontinued. Maybe (hopefully) a revision of the pcb is in the works? It’s also possible the next version will be the Recursive Apparatus.

Sort of like the 73-75, TTSH kits, availability and support from THC is never ideal. It’s exciting because you are sort of diving into the deep end with these projects but it’s more experimental than some established DIY synth projects.


In the process of putting this together, just a quick note the supplied cart has a couple of errors/omissions. You’ll need to add 1 x 1uh inductor, 3 x 27k resistors, 1 x 150uf electro cap, and the speaker appears to be the wrong footprint (too big for the PCB)

more update

Here are replacements for the missing parts

1 x RLB9012-1R0ML‎ inductor edit apparently both will work
1 x UPM0J151MED1TD Capacitor edit nvm apparently THC recommends 120uf
3 x CFR-25JB-52-27K Resistors
1 x CLS0201MP Speaker

I also noticed that many of the resistors in the BOM are 1/3w, I can’t specifically think of a reason for this. 1/4w will also work and in most cases will be slightly cheaper

more and more edits

THC recommends changing the top plate SMD resistor from 10k to 0k (aka jumper) to allow the filter to self resonate. They also posted a mod that transforms the wet/dry knob to a feedback knob. Posting it here for the non-swedish speaking crowd


Just finished building the Recursive Machine tonight. Hopefully a demo soon. Initial reactions are very positive :smile: reminds me the most of the Bastl Softpop. Not in sound but in technique and philosophy. I’ve decided not to use the case for now. I think I’ll try to redesign a back plate to protect the PCB traces.


Ack… pulled the trigger on the PCBs - despite expense of shipping…
Now to start pulling together the BOM…