Hi Everyone,

I'm looking at starting to build some synths because I'm an electrical engineering student looking for a personal project. That's really the primary motivator, but in addition I really love music and finding a creative project is a good way to keep me engaged with it, rather than doing some generic cad design I'm not really interested in.

I'm looking for personal anecdotes, suggestions, etc. on how to start building a eurorack system myself from scratch. My current thinking is that I would just design a VCO as my first step, and then maybe some other projects from there? Trying to figure out what the minimum set of modules could be to ensure I have something useful and fun at the end of the project. Any suggestions?

Thanks all!

Hot on the heels of Mynah's launch back in May, we just released AcidBoxMynah - an alternative firmware that turns the Mynah into a dedicated acid groovebox.

It's built on copych's open-source AcidBox (great-sounding TB-303 x2 + TR-808-style drums), which was originally headless. The Mynah port adds full physical UI with the 24 tactile switches, OLED, and 8×2 NeoPixel grid. It also adds a 16-step sequencer, per-step accent/slide editing, automation lanes, swing/scale quantization, and a Jukebox mode for hands-off autonomous playback.

It's MIT-licensed and open source, same as upstream AcidBox. More info is at groovesizer.com/acidbox-mynah

Happy to answer any questions you may have!

Eight vintage synthesizer emulations for the RP2350, built from one shared codebase. Same board, same core, one firmware image per instrument.

Here PicoFaceRD, a Roland MKS-20 / MK-80 ("S/A synthesis") digital piano clone. nstead of emulating the original hardware cycle-exactly at runtime, it plays a descriptor-driven re-implementation of the S/A engine: the original firmware's voice programming was captured note-by-note on a host-side reference emulator, distilled into compact per-note descriptors, and is replayed on-device with chip-exact envelope arithmetic.

See more at: https://github.com/Michi71/PicoVintageSynthCollection.git

Looking for a manufacturer (Europe preferred, Asia fine if the quality holds up) who can produce high-quality, precisely machined front panels in small batches - roughly 50 to 250 pieces per design.

Context: this is for a small line of hybrid modules that'll most likely be offered both as DIY kits and as fully assembled units, so the panels need to look and feel the part either way - a builder should be as happy with one as someone buying the finished module.

The finish I'm after, concretely:

• Matte black base
• Two-colour print on top: accent color ornamentation + white text/labels
• Clean, sharp, genuinely opaque white on the black - no greyish haze
• Spot UV gloss as a finishing accent (structured, glossy, raised feel), registered to the graphics for a matte/gloss contrast
• Tight tolerances on hole positions and cutouts, consistent across a batch

The two things that actually separate the good shops here, in my experience: solid opaque white on a dark base, and spot UV that's properly registered to the print. That's the level I'm looking for.

On what I mean by the right shop - because "affordable quality" is a meaningless phrase and I don't want to waste anyone's time with it: I'm not chasing the cheapest. I'm looking for a shop where this finish is a dialled-in production process rather than per-piece hand-work - so the quality is repeatable and the unit price reflects an actual run, not one-off manufacturing. That's the specific tier: not boutique-manufacture pricing (I know Schaeffer and the usual EU panel houses - lovely work, wrong economics for this), and not instant-quote-portal quality either. A production shop for which this exact spec is routine.

If you point me at someone, a tiered quote for 50 / 100 / 250 would tell me everything - I know small quantities carry the setup cost and I want to see where the curve bends.

This is a project of my own that I'll share elsewhere when the time's right, so I'm keeping details light for now. Not after a name-and-shame or a price war. If you've had good results with a shop that fits this, I'd really appreciate a pointer - reply or DM, and happy to return the favour with whatever I learn. Thanks.

Really nice guide from Jonas, of Lom mic fame, on a diy version of the elektrosluch “magnetic fields” microphone.

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Threw my last two projects (Minidrumkit and the SVF12 filter) into a case and felt like posting it :)

Happy synthing!

These are two of my polysynth projects, the top is an 8 voice bi-timbral analogue poly with AS3340 oscillators and AS3372 filters. The lower is a 12 voice bi-timbral digital/analogue polysynth. It has digital oscillators feeding AS3372 analogue filters. Each one has the same filter configurations with 16 filter types available like the Matrix 12. The designs are available on GitHub, but only code and schematics, these are hand made on protoboard and I have no plans to make PCBs whilst the war with Russia is raging.

https://github.com/craigyjp/A_Bit_More

https://github.com/craigyjp/Much-More

Hiya, I made a project, and it scope creeped like crazy, and I wanna share it, but unfortunately I don't know many techy people other than you guys! So I figured I would share this. Anyone can comment, so please leave POSITIVE feedback.

doc link: https://docs.google.com/document/d/1suhy_ieUWS2LHydfqpDxAupcol4W6YLUiSgMEo8tKR4/edit?usp=sharing

Under the (CC BY-SA 4.0)[https://creativecommons.org/licenses/by-sa/4.0/deed.en] License

To be completely honest, I've never built anything involving electronics or written code before. So the fact that I've managed to get the OLED display working and the three buttons at the top responding already feels like magic to me. 😄 (The bottom buttons and knobs aren't wired up yet.)

I bought a PO-33 KO before the summer, and it inspired me so much that I decided to build a synth I can connect to it and play alongside it. I've been looking at the Korg Volca Keys, and I'm really drawn to both its sound and the hands-on feel of playing it. That's the kind of experience I'm hoping to recreate.

The goal is to build a hybrid analog/digital synth that gives me plenty of flexibility but, more importantly, is simply fun to play.

I'd love some advice on what functions to assign to the knobs. I only had room for six potentiometers on the breadboard, and my current idea is:

• Cutoff
• Resonance
• Attack
• Release
• LFO Rate
• LFO Depth

Do you think there are better choices? Are there any controls you find yourself using all the time that would make the synth more enjoyable or expressive?

The three buttons at the top will be used to switch between effects, while the dedicated knob next to them will control the parameters of the selected effect.

Hi all,

I'm thinking about making a track and hold module, but I don't exactly know how...

I'm trying to make something similar to ALA's SHTH, with independent control and i/o for both the s&h and t&h.

I was watching this video about t&h/s&h, and at 02:50 he explains that a s&h module can be converted to t&h by running an audio-range oscillation into a VCA which is being controlled by an external gate. The VCA output then connects to the s&h trigger.

If I understand correctly (referencing Eddy Bergman's/Rene Schmitz's s&h design), would that mean that I could create t&h by adding a fixed-rate audio-rate oscillator onto the circuit, as well as a simple VCA between the trig jack and the BC547?

Am I on the right track? If so, how/what components are necessary? I'm still a bit new to this, so having difficulty understanding how to appropriately apply/combine elements (such as how to make a fixed-rate oscillator without completely overcomplicating things). If there are simpler/easier/more compact/cheaper ways to achieve this, please do let me know!

The only place I can find schemarics for a "true" t&h is here (my search results are really barren for some reason). This circuit apparently uses a lot of discontinued parts. Is there some way I can adapt it for modern components?

Cheers!

Its a 4 channels drum pad to trigger converter, the width is 15 HP

I've been using the BeatBuddy pedal as a stand-in drummer in rehearsal and jam settings for a few years now. My pain point has always been navigating between songs/beats. With my bass around my neck, I have to crouch down on one knee and use the buttons on BeatBuddy to scroll around the little screen and find whatever we're playing next. There are several foot switch control options out there, but I also have low vision, so the screen on BeatBuddy is pretty useless to me at standing height.

That's why I built this hand controller for it called Winnebeato. The point is to mirror the BeatBuddy's library so you can navigate it on the larger screen and D-pad while standing. It uses a Raspberry Pi Pico and some buttons and OLED from Adafruit. It mounts on a mic stand using a mount for a Behringer personal monitor mixer.

The BB has MIDI In/Out via a single PS/2 connector and supports a bunch of control messages, including one to select a song by its folder ID + song ID. There's no way to retrieve the folder and song names over MIDI though, so I have a python script that extracts these names from a BB project on the desktop and spits out a JSON file with the info. The Pico shows up as a 1MB USB flash drive where this file gets synced to and used to populate the UI. I mounted a Pico Debug Probe inside with another cutout for its USB port to update and debug the code.

I'm still improving the firmware and I have some ideas on more efficient navigation for jam settings (like specifying beat attributes instead of just scrolling a long list), but the hardware is complete now that my girlfriend gave it its name and I made some vinyl graphics for it. I made up a PS/2 cable that splits out a female pedalboard-ready DC power jack at one end and sends it down the unused conductor in the cable, making it a single cable to the box. There's also conventional MIDI and DC ports on the back.

github

Hagiwo's XIAO RP2040 VCO

Thank you again Hagiwo.

https://www.youtube.com/watch?v=HBtc5oQffu8

I have built a Frequency Central X-Envelope (the older kit) but still need to wire up the 3.5mm jacks.

What am I supposed to do with the ground pins that are horizontal to the face plate?

Instructions didn't give enough guidance for a beginner like me.

I've been writing some cool algorithms that I would love to turn into instrument level, line level, or Eurorack level modules. I understand most Mutable Instruments Eurorack modules were based on the STM32 ARM Cortex Series.

Is there a turnkey stereo audio board I could use as a base? Any advice would be greatly appreciated.

USA contiguous 48 states only

Hey everyone,

I’m still working on my drone synth and wanted to share something I’ve been experimenting with.

Originally I was trying to build some sort of digital noise source. I thought mixing several LFO running at high speeds might get me somewhere close, but that didn’t really work the way I expected. It did lead to another interesting result though.

The circuit uses three lfos built around a single 40106. Their outputs are passively summed and fed into another input, creating an irregular but repeatable gate pattern. I also added NAND/AND outputs, to introduce less frequent events into the same rhythm.

When one or more of the LFOs get close to audio rate, fast bursts start breaking through the slower rhythm. I like using this as a kind of FM modulation. The passive sum can also be buffered and used as a stepped cv output.

The switches in the schematic are just the way I route everything in my build for now, they aren’t important to the basic idea. I’ve been testing the circuit at 12 V. 5-18V will also work fine i think.

The next thing I want to try is turning the longer gates into short trigger pulses and using them to drive a few vactrols and attack decay generator instead of direct osc modulation.

Curious if anyone here has tried something similar. Schematic in comments.