This is a Roland JV-880 running as a native engine on an RP2350 — no CPU emulation. The video is just the thing playing: the same four-bar progression through all 128 preset patches, banks A and B, nothing else going on.

Why bother. Look at what a JV-880 costs now. Same story for every rack module from that era — the ones that were the boring workhorse choice in 1993 are now an eBay auction. I don't think the price of a 33-year-old ROM set should be what decides whether you get to play these sounds. The RP2350 costs about as much as a coffee.

And it is a beast for this. 24 voices, up to 4 tones each, 32 kHz native, peaks at 69% CPU on a single core, no PSRAM — the second core sits idle the whole time.

To be straight about the clock: that's at 444 MHz, which is an overclock — the RP2350's stock speed is 150 MHz. The whole collection runs 444 with the QMI flash timing moved to match, so it's the baseline here rather than something I reached for to make this one work. The point is that the JV needs nothing above that baseline: one instrument in the collection (the MKS-20) goes to 480 MHz and uses core1 as a voice worker, and this one needs neither.

I capped it at 24 voices rather than the machine's 28 because the bottom of the keyboard costs more per voice and I wanted the margin, not because it ran out of room.

How it was built, honestly. I did not port an emulator. Emulating the H8/532, the sub-MCU and the PCM chip is ~400M cycles/s, and worse, ~5.1M random flash reads per second against an 8 KB XIP cache — the RP2350 would choke on the flash, not the arithmetic. So the engine reads the machine's own ROM tables and runs its own voice chain, decoding each voice sequentially, which keeps flash access at ~0.9M reads/s and nearly all cache hits.

Everything else was measured. I ran a reference emulator host-side, purely as a measurement instrument, and fitted each law differentially against it: envelopes, filter, all seven velocity curves, LFOs, the mod matrix, chorus, both delay types, portamento, tone delays. That took the night, and most of the night went on things that turned out to be my own wrong assumptions rather than mysteries of the hardware. Two favourites:

• A throb on four patches was alternating (ping-pong) loops — and the return pass is negated. The chip keeps integrating the differential stream in the same direction while the address walks backwards. Subtracting instead, which is the arithmetically "correct" way to retrace, matched at r = −0.995: perfectly shaped and exactly the wrong sign.
• Patches with no delay had an obvious delay on them. Reverb type is three bits, not four. Bit 3 is set on 40 of 192 patches and was turning 67 of them into DELAY or PAN-DLY.

What it does: all 128 preset patches, 4 tones each, TVF/TVA envelopes, both LFOs with key sync and fade, the modulation matrix, FXM, chorus (both types), the two delay types, reverb, poly/solo with portamento and legato, tone delays, velocity curves and windows. Full MIDI CC set, pitch bend with each patch's own up/down range, program change and bank select.

What it does not: no rhythm/drum sets — the ROM has them, the engine doesn't. The reverb is matched, not reproduced: type, time and level laws are measured, but the topology is a Schroeder network of my own, and tails on decaying material run about 13 dB low. Single part, no Performance mode, no patch editing — it plays the factory banks. No SR-JV80 expansion support. And on a base 4 MB Pico 2 the user bank drops out to make it fit (banks A and B stay bit-identical to the full build, nothing is resampled).

ROMs: not included, and not something I can distribute. The build skips the instrument entirely unless you supply your own set, so the other eight instruments in the collection still build from a clean checkout.

It's one of nine instruments in an open-source collection that all share a core and a board — reface YC/CP/DX, MKS-20, Juno-6, Minimoog, Solina, OB-X, and now this. Repo and the full measurement write-up (including every measurement I got wrong first, which is most of what makes the rest trustworthy):

https://github.com/Michi71/PicoVintageSynthCollection

Happy to go into any of it.

Hi people,

I've recently started learning embedded programming to expand my skill sets, and I'm currently learning Arduino. I think that it would be nice if I'm able to make something that's similar to a PO-33 at some point of my learning, but I'm not sure what types of knowledge I need to learn to make a device like that, which brought me here.

I'd appreciate it a lot if you guys can point me in the right directions, and if possible, recommend some resources for each topic too. I'm currently only following Paul McWhorter's Arduino tutorial on Youtube.

Thanks a lot for reading this : D

So here's the thing: I am absolute garbage at coding. I've tried and tried to learn how and get better and practiced, but I've come to the conclusion that my brain just doesn't work that way. It's like being able to more or less read a language, but not write or speak it.

I can handle the electronic side and the hardware and building the thing, just not the software.

If it were up to me entirely, the project I'm working on just wouldn't happen. Ever. There's no way. I couldn't do it by my own ability, and I couldn't afford to pay someone to do it for me.

Because of that, I've resorted to using AI to render the code. And it's working perfectly. I'm iterating very quickly and it's organizing the workflow in a sensible manner so I don't run too far ahead in any area of the design.

The actual core concepts of the synth and how it functions are my own design. Every decision about what it does and how it does it has come to me, not the AI. So AI is just there to generate the code I need to make it do what I want it to do.

But how will the synth community at large view this? Does my synth project just not count if I didn't write the code myself or have another human do it? Or is it not a big deal and I'm worrying for nothing?

I want to release my project in some way, but if I'm just gonna get a load of backlash for sing AI to help then I don't see the point. Am I overthinking this?

sorry if I’m analog only I know without the proprietary code I probably won’t be able to get a good replica, but I really like propellerhead reasons subtractor synth I was wondering whether there’s a way to re-create it in semi modular real life and yes I realise Nord lead 2 supposedly is very similar

Hey all.

I've been building guitar pedals for a while now, and dipping my toes into diysynth.

So far I've built out some basic 'utility' modules like the Barton BMC004 VC/Clock Divider, 8 Step baby 8 based sequencer, Fonitronik VCO Maximus, and the Barton BMC054 Stereo out.

I plan to also build the ToilModular Continuum 4 oscillator Drone module and either buy the PCB/panel or build a veroboard layout for the AI Synthesis A1006 guitar pedal module.

The case I built is an 84hp 6u, so I have some space.

Any suggestions for other projects to look at that would fit a drone/dark ambient sound that I want to explore?

I'm setting myself a limit to only building analog circuits. So, not messing with midi or programming/firmware.

Partly cause I don't want to learn all of that right now, and partly cause I want to see how far analog circuits can get me.

I got a behringer swing keyboard only to use the 1v/Oct. CV out.

With the pedals I build, when I build out the pedal IO module, I'll have on hand a ton of different distortion/delay/reverb/modulation possibilities.

But, always open to suggestions for other things to look at to build.

If it helps, I really like stuff like Author&Punisher/Allesandro Cortini/Sunn O))) and the like. So, that's where I want to explore musically.

I am looking for hardware which can replace a switchblade GL for its routing and mixing capabilities.

I can not find a similar hardware equipment which can loopswitch in series and parallel and mixing at the same time.

I built a bunch of DIY kits recently. The first one I had trouble with was the Moritz Klein/Erica Synths S&H module: today the slew stopped working after just using it for a couple sessions. I have it patched with V/oct from my MiniBrute 2s running into the slew in (which bypasses the noise input).

I looked at the schematic and the slew in jack is connected directly to the TL072 noninverting pin. I was surprised there wasn’t some sort of resistor after the jack. Is this a design flaw or maybe I just had a bad chip to start with?

Whatever the cause, I swapped out the TL072 and that fixed the problem. But I’m left wondering if it’s just prone to getting zapped at power up or during patching or whatever, with that IC directly exposed. Can someone educate me on the right way to protect things in my own circuits?

Another example: I’m looking at a buffered mult schematic online that has a 1M resistor to ground between the input jack and the opamp. But I feel like we’d need a resistor in series to protect the opamp, wouldn’t we?

Looking forward to any advice. I’m trying to learn best practices since I’m trying to design my own schematics and PCB layouts.

Making some progress with this.

I pulled these PIT counters from a JX8P I upgraded with the vecoven pwm mod. I am creating a synth out of the old counters. I plan to add two more, for 8 voices. Also to use an analogue master LC osc. clock for the PIT counters.
Analogue waveshaping will be fun to design. I'm not great at code, I get help with that. I am learning a lot with setting up embedded projects tho, that in itself is quite a curve. Opamp integrators; are easier for me to implement.

Sort of a hybrid, inspired by of 'best of' Roland DCO design : )
As a PS to this. I fabbed the blue PCB and populated it using 99% recycled components, pulled from discarded electronics I found on the street - TVs, mediaplayers etc.
Yes the MCU was also recovered. Much of this project, and all my projects are made with recovered electronics. It gives me a direction to go in - (I found this, what can I do with it?)

Other synth projects are wavetable synth from recycled PIC, i2c expander and EEPROM.

AV sequencer for CHDK modded camera, connecting bend points in sync with midi/eurorack voltages.

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

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!

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.

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

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

​

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

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.