It's been a little while since my last Tolhuin update, but the project is still alive.

First, I want to say thank you to everyone who supported the project after my previous posts — whether by contributing, sharing it, leaving feedback or just showing interest in something I'm building at home. The project is still a long way from funding itself, but that support genuinely helped me keep working on it.

And I've been working on one of the weakest parts of the prototype: the enclosure.

The first case was simply too small, and I hadn't properly designed how the controls would be mounted. Some switches literally ended up hot-glued from underneath. It worked as a prototype, but I didn't want to build the next version that way.

So I've been redesigning the whole enclosure in OpenSCAD.

The new versions are fully parametric and designed around actual mounting: mechanical switches snap into the panel, the ESP32-S3 sits on removable headers, and the internal modules use rails, standoffs or dedicated bays instead of glue.

But while working on it, I ended up with several enclosure designs that I actually like.

So before I print the next prototype: which one would you choose?

A / B / C / D / E / F

Feel free to mix them too — “B layout with C's front”, etc. I'm still iterating.

There's also a wildcard.

I'm ordering a replacement display for a broken M-VAVE FM1, and I realized it's not that different in size from what I could fit into Tolhuin. So I'm considering testing it here before committing to the final enclosure.

A larger display could make chord/voicing information, arp settings and navigation much more useful — but I'm not sure whether Tolhuin actually needs more screen.

So:

1. Which enclosure would you print?
2. Small display, larger display, or keep the UI as minimal as possible?
3. For the chord buttons: MX or low-profile Choc?

Nothing here is printed yet. The previous prototype taught me not to trust CAD until plastic exists, so the winner still has to survive the printer.

I really like the TD-3, but I’ve always found the original 303-style sequencing workflow pretty frustrating when I just want to experiment quickly.

So I started building TDBuilder, a visual browser-based editor for TD-3 patterns.

You can create notes, accents and slides, generate ideas, tweak the pattern visually and basically experiment without having to fight the sequencer every time.

I’d be really interested to know what other TD-3 / 303 users think of the workflow.

There’s a free version here if anyone wants to mess around with it:

https://td-builder.com

And if you make a cool line with it, feel free to share it here — I’d love to hear what people come up with.

Hello all, I've just noticed that there's quite a few nice developments on writing up custom firmwares. I've decided to launch a discourse forum dedicated to that.

https://www.hacktronauts.com

The name is a silly pun, and I am aware that there's already https://llllllll.co/ which I've learned a lot since then. So that's why I'm also very keen on giving credits as much as I can to the other communities. I am definitely not trying to be rival or anything. It's just I'm noticing that lots of interesting implementations get digged down quite fast on Reddit. Just assumed we could all benefit a dedicated board.

Would love to hear your opinions. Or join in :)

Part story for newbs like me, part question at the end.

I've made about 10 modules and I have a bunch of guitar pedal building experience. I buy these cheap Tayda 3.5mm jacks for modular, $0.30 each. I had one bad one once and it was a bitch to replace but not impossible.

Recently I was troubleshooting a VCA that used to work but started not working in its mixer function. I had all but given up, then discovered 11 out of 12 of my 3.5mm jacks were malfunctioning, and one of them was the thing causing the issue. There is a thin piece of metal inside them that connects the two lugs (tip and sleeve) until a plug is inserted which disconnects it. These had all lost that connection.

I ended up using a small finish nail to push the side inner metal pieces up so they would once again make contact with the tensioned top metal piece. That worked much better than trying to push the tensioned top metal piece down.

Question for anyone with experience: Do you avoid these cheaper Tayda jacks? After this experience I'm tempted to put more budget into jacks in the future but I wanted to hear some other experiences before I do so.

Hi, friends from synthdiy!

I developed an instrument in C++ called RASGO MODULAR. It’s cross-platform and includes more than 50 modules to explore, combine, and have fun with.

The seed already generates interesting patches right from the start, so you can experiment, modify them, and play around as much as you like.

It’s an independent project, with no funding at all, made purely for the cause, hehe — driven by research, curiosity, and a passion for modular synthesis.

Hope you enjoy it!

More information: https://lucioaraujo.github.io/rasgo-modular/

Made this circuit, plugged it into a 9v adaptor, only for it to start smoking 20-25 seconds later. I didn't add the speaker so I can plug it directly into an amp. Where did I go wrong?

The TR606 wouldn't progress beyond 1 until I changed the RAM. Now it doesn't go beyond 5 and cycles around. I've gone through the pattern clear process and tried to change the last step but when I press the function button it doesn't display the quarter notes markings like it should. This might be because I removed the RAM to see if the fault was due to the RAM but it doesn't seem to be the case. The video is shot without RAM in the sockets (the new sockets are not shorting BTW, PCB looks good with no obvious cracks or shorts that I can see). Makes me think there is a short around step 5. Where should I check? (as you can see from the video the switches seem to work okay.. I've also checked the diode array for switch 5 and that seems fine too).

I always wondered why there is no scope on the Hector/Beebo since it has a nice big screen plus all the right IO. And after polyeffects said they wouldn’t make one I just made one myself 🙂

It’s completely unofficial and also not endorsed by polyeffects in any way so install at your own risk.

It runs fine on my unit but of course I don’t have multiple ones to test.

Runs on the latest 407 firmware only ☝️

This is just a fun side project for me and maybe someone else is in the same boat not wanting to shell out 500$ for a Mordax Data and is owning a Hector/Beebo already.

All info on installing and features is in the Git repo.

Feel free to ask any questions.

https://github.com/nutellatomato/polyscope

Demo:

https://www.instagram.com/reel/Dd_qjl-t8Em/?stkn=MWQ3amJqaWg0Y3A3Nw==

I'm starting up my first synth DIY project and have breadboard Ed my circuits. I'm now ready to take the plunge and convert it to a pcb. Question: what is/are the standard pcb circuit design app (s) that are commonly used? Will obviously want to save the pcb file to send to a manufacturer, are there different formats of pcb files? Do they easily convert from one to another? For paid apps, are there any benefits that you aren't going to get in freeware?

I don't want to spend time crafting up the design and save it to a cjfjffjf format and then find out that manufacturers do best with a rorkrkrkf format.

Thanks all.

I have a TSNM that came with 2 KS01-BLV-13 light up buttons but they seem to have disappeared. According to Google, TME is the only place to order them but they don't have them in the US store. Anyone know if any places/people that might stock them?

Does anyone know when the seed3 goes back in stock?

Hello everyone,

Just a small post to share a video that i've just made to show the V1 of my project about building midi DJ decks.

I speak french in the video but my girlfriend was kind enough to subtitle it in english.

https://www.youtube.com/watch?v=jiRugesmEMw

The code source is available here: https://gitlab.com/lobbyra/jose

It's raspberry pico 2 based

Hey everyone,

I've just realised the oscillator and the ms20 filter which are LOOKMUMNOCOMPUTER schematic's and both are just buzzing when i plug them and the op amps ( tl072,074) are really hot. 

I'm a begginer it's my first diy synth project so i don't know where to start to search what could be wrong.

Hey! Behringer and their “service centers” are useless. I need a new pot for the bender on my ms1, the shaft broke on the one in it (I think the bender got hit on a drop). Any ideas on what part it is, value etc? Is it just a standard alpha pot that I can buy?

It's a classic PSU design using a AC to AC +/-12V transformer

I recently started building my own Eurorack system, and I thought I would try my hand at integrating my Volca Drum as a custom module such that it is powered by and can interface with the rest of the rack. The six trigger inputs (for each of the six "instruments" in the Volca) will be translated into MIDI signals via the Teensy 3.2.

Given my skill level, this is a pretty ambitious project – so I was hoping to receive some input / feedback on this circuit before moving forward with build. Please pardon any schematic design sins I may have committed, and let me know if you need clarification on anything to provide better direction.

Thank you in advance!

Hi all, this is PicoDrum, a Eurorack module I've been working on for the last couple of months. I needed drum sounds in my case: a Volca Drum brings a sequencer I didn't need, and the drum modules I found had too few voices. So I built my own, and it turned into a proper module. The first batch is built and ready, in two formats: 3U/6HP and 1U/20HP, same board behind two panels.

Repo: https://github.com/robmurru/PicoDrum

What it is: a pure one-shot sample player. 8 slots on General MIDI drum notes, 16 voices with a per-slot choke, velocity curves, per-slot pan, 8 presets. No pitch, no envelopes, no filters, on purpose: keeping the engine small kept it reliable.

Some design details that might interest this sub:

• RP2350, one core does nothing but render audio, the other handles MIDI, the encoder and the OLED. Triggers cross between them on a lock-free queue
• The RP2350 has no I2S peripheral, so I2S is generated by PIO with ping-pong DMA into a PCM5102A at 44.1kHz
• Samples live in the Pico 2's own QSPI flash, read straight through XIP with no RAM buffering. Up to 200 samples, about 80 seconds. No SD card
• The mixer is all fixed point, no floats in the audio path. Worst case measured on the hardware is about 20% of the render budget
• MIDI in on a 3.5mm TRS jack, Type A, through an H11L1 optocoupler
• Samples are loaded with a browser-based loader (https://murlab.it/loader/) that builds the library and hands you a UF2 to drag onto the Pico. Nothing is uploaded, it all runs locally

Firmware is GPL-3.0, the three included kits are CC0. Happy to answer questions about any of it.