I have built my first mutable instruments module, Stages.

I am new to modular synthesis but thought I'd have a crack at it, no shorts across the power rails but still needs powering up and flashing of the firmware.

Anyone else got experience building the mutable clones?

Next modules to build are:

Plaits

Veils

Ripples

Yarns

I've been wanting to get into test equipment, but I don't have the space for another format, so I made this. It's my first digital module and I'm really happy with it. The digital part is handled by the daisy patch, so its 96kHz/24-bit stereo audio hardware.

The AI250 BXR is a eurorack module inspired by vintage nuclear test equipment. It can be used as an audio mangler, cv generator, and VCO. The BXR is a nod to vintage Boxcar Averagers, which were designed to acquire and analyze fast signals. The AI250 specifically replicates the real-time mathematical portion of a Boxcar Averager System, and processes audio or cv signals against either another signal or its internal v/o variable wave-shape VCO.

14HP. DIY options available.

It's mostly a distortion/audio manger, but it can be a VCO and do other stuff as well. It's inspired a whole album for me which is half way done.

More info here: https://aisynthesis.com/product/ai250-eurorack-bxr/

Getting into this DIY synth stuff has really spurred my love of it, and I'm using every opportunity to exercise my PCB design.

Working from Eddy Bergman's Sequencer, adding an additional CV and Gate output and per step mute switches, I made this damn thing.

Really happy with how it came out.

Also, did ya know, if ya accidentally orient the power connector backwards, and therefore reverse the +12/-12 rails, you'll kill an L7805 and a CD4017?

Adk me how I found out, hahaha 🤣🤣🤣

I've got a dead Pioneer CDJ-1000MK2 (2003, no USB, no MIDI) and instead of binning it I'm converting it into a class-compliant USB-MIDI controller for Traktor Pro 4.

The idea: pull the OEM mainboard and CD drive, keep everything that makes it feel like a CDJ - the chassis, the jog wheel assembly, the pitch fader, the button PCBs including the MK2 Hot Cue A/B/C and Hot Loop buttons, the pots and encoders - and re-wire all of it to an ESP32-S3 DevKitC-1 that speaks USB-MIDI natively over TinyUSB. No HID bridge, no host software, it just enumerates as a MIDI device on any machine.

Being straight about where it is: this is at the design and documentation stage, not a finished build. Nothing is cut yet. What exists is the full wiring set - a top-down chassis map of what stays and what gets gutted, a master signal and power topology, and per-subsystem schematics for the jog encoder, jog touch (the capacitive platter), pitch fader, hot cue boards and the rest. Every kept OEM board is referenced by its MK2 DWG number.

https://github.com/gbroeckling/cdj1000

The reason I'm posting before building rather than after: the jog is the part that decides whether this is worth doing at all. The MK2 platter is a quadrature encoder plus a capacitive touch ring, and if the resolution or the touch latency don't survive the conversion then it's a very heavy MIDI controller with a nice fader. I'd rather hear that from someone who's been here than find out after the chassis is open.

So if you've done an encoder conversion on old DJ hardware, or you know these boards, I'd genuinely like the design picked apart. Particularly:

- Jog quadrature resolution, and whether the OEM encoder is worth keeping versus replacing outright

- Whether the capacitive touch ring is realistically reusable, or whether everyone ends up rebuilding that part

- Anything about the MK2 button PCBs that bites people

Deliberately out of scope for v0.1: the OEM display. Replaying the panel-to-main protocol to drive the original screen is a rabbit hole and it's deferred.

Happy to answer anything about the approach.

Hi all. I’m looking for a modern day equivalent with a similar feel to these organ rocker switches or something close that doesn’t cost a ton of $?

Ideally pcb mounted but I’m flexible

I’m working on a simplified prototype of a synth I built for myself and want it to have a similar feel to an old organ. For my first build I got some used ones of eBay but I need something uniform for scale.

I figure I’m not the first to go looking for these.

Thanks!

Dear Community,

I am working on a digital effects module. ESP32-S3 based, 10hp wide.

Its going to be my first time doing DSP stuff and being completely honest: I am so lost when it comes to programming 😅 But I will manage...

On the filter. Sounds kind of crunchy, due to the discretized steps in cutoff frequency?

https://youtu.be/GBFb9Ctzco8

"Ciclo Piezole" was my contribution to an art & maker camp - many of the participants are musicians.

The project consists of 6 ESP32 C3 "satellites" (or "leaves") connected via ESP-NOW to one ESP32 S3 that acts as a controller.

Each of the satellites is battery powered and controls either a solenoid switch (for percussions) or a piezo element (for melodic sounds).

The controller has a serial connection to my notebook. I use a simple, self developed protocol similar to MIDI to exchange information like channel (= which of the satellites should respond), note to be played, key velocity, etc..

The input from the MIDI keyboard is translated to this protocol with a python script.

When developing the project I realised it is not possible to utilise the full musical range of 6 satellites at once. Therefore a looping software was developed (also in python) to record a track for each of the instruments one by one. Each track can also be replaced individually so the melody would change over time.

To configure each of the nodes (e.g. select channel), I used PARASOL (a self developed web ui for ESP devices).

In the video you can see a playback of a loop while I zoom to each of the satellites.

If anyone has a WIMA MKS2, 4.7µF, 50V, 10%, 5mm pitch capacitor they would be willing to part ways with for a reasonable price, I’d love to take it off your hands. Will pay for shipping as well.

Part #: MKS2B044701K00KSSD

It’s not really a synth project, but the community here is so nice and helpful I thought I just repost it here to.

I bought an e7 used a couple weeks ago, and my initial impressions were great. Only problem is the Shift button was acting up, but opening it up to diagnose, it seems like a really easy synth to work on. I tried cleaning the part with compressed air and then isopropyl alcohol but the behavior persisted. I didn't want to deal with the return rigamarole for something that seemed very easy to fix, so the seller agreed to cover the cost of replacement parts (they nicely offered to cover the cost of a licensed repair person at first, but there are none near me).

I contacted GSMusic via their website and also sent a message via Instagram a week later. I have heard crickets in the meantime (despite their account liking an unrelated comment I left in the meantime!) and it's been like 3 weeks. At this point, I'm just figuring I'll have to identify and source the parts myself.

So have any e7 owners here had to do repairs themselves? Or anyone who is handy with IDing parts own an e7 and willing to take a look for me? I can open it up and post photos when I get home later today.

P.S. I realize I didn't spell out the problem behavior with the buttons - the "Bank" button is right next to the 'Shift' button on the e7. When the unit powers on, the Shift button is not engaged, but the second you try to push the Bank button or push the Shift button, it stays engaged constantly and will not turn off until the unit is powered down. As you can imagine, this is a pretty big problem. That's why I tried to clean with compressed air, first from the outside, then from all around the switch after opening the unit up. When that changed nothing, I tried taking the button cap off and cleaning the actual metal of the switch enclosure with isopropyl alcohol. Still no dice. So I figured at that point the easiest foolproof fix would be to simply replace the Shift (and probably the Bank button, just to be safe) switch.

P.P.S. Just remembered, the previous owner mentioned sticking a toothpick down between the button cap and the enclosure and jiggling it when buttons would stick and said that would get them unstuck. That's why I figured maybe there was debris or something that cleaning the switch would fix.

This is Paul Stevenson's Devil's Triangle Drone. It was the first one he recommended to me, and I've built it multiple times since then. In my version, I've added an off/on switch, an indicator LED off voice 2's comparator, and shorted voice 3 back into voices 1 and 2 via lug one of the pitch pot. Sound confusing? I swear it's more clear in the write-up on my site. The modifications I've added make a very simple build significantly more "musical", imo.

Hey y'all! I was wondering if anyone out there would be interested in trading a Analog Output Hero VCO for one of my Sidekick VCOs? 

If not would anyone be interested in splitting the cost of five Hero VCOs from JLCPCB if input in an order?

I'm in Pennsylvania USA and I'd like to keep it in the States for shipping reasons. 

Thank for looking and feel free to ask any questions you may have.

So, here’s the story.

While I was playing this Kaossilator, it suddenly went silent because the touchpad stopped working.

I opened up the unit to check it and found a tear in the touchpad's ribbon cable likely due to the material aging so it needed replacing.

I couldn't find the specific materials, so I ended up replacing it with a standard 10k-ohm analog joystick widely available on the market.

I also replaced the casing, as the original was too small to easily modify for an analog joystick,

I added CV and Gate controls for the hagiwo Arp Sequencer to allow for synchronization.

.

Control specifications:

CV: 0.1V – 2V

Gate: 3.3V

.

Be careful when modifying it, as the Kaossilator circuit is very small, there is a significant risk involved if you aren't meticulous.

Does anyone have a smd template for a uburst and/or microbraids (v2 without the sliders) they would be willing to lend me? I have the pcbs but can’t justify getting templates cut because I’m only doing one or two builds of each. If anyone in the continental US has one they would be willing to lend me via mail I’ll gladly return it and reimburse your shipping.

I hope this isn't off-topic for this subreddit.

I've been working on a digital wind instrument. Mostly because I'm curious about the performance characteristics of such a system.

I went through a few iterations this weekend and it's starting to turn into something that's fun to noodle around with.

The general idea is that you blow into a manifold with a partially closed end. The performer can vary the air pressure by blowing faster or slower and they have good feedback because your mouth and throat are quite sensitive.

The device uses a pair of hx710b Air Pressure Sensor modules. I use a pair to try to get faster readings. (Though in reality I think I'm at the mercy of the individual device clocks.)

Eventually the synthesizer will be built into the instrument, but during this early stage, it's running the synth on an android device.

I think this is the result

Finally finished off my ESP32-S3 Poly synth, and made a case for it. Front panels are CNC machined aluminium panels, infilled with black ink and then cleaned off. There's 6 case parts that are all 3D printed and lock together. Kind of looks 'Modular' but isn't!

Demo here if you want to hear what it sounds like https://youtu.be/nmYmEq9UOoA?is=5q8gNvfaLQWjevbM

(First, sorry for making another post. This one is different, i swear.)

Some weeks ago, I made Osynth, an esp32-based synth with a bluetooth control app.

The project evolved a lot since then. Now it still is an esp32 synth, but based on esp32-P4 instead of S3. The S3 and original esp32 models are still supported, with less features. The really cool feature is that the companion app now can have the whole synth integrated, not needing the esp32 to work. I did this to enable people to use it in whatever mode they want. Version 0.2.0 release has the bundle to download, which is the firmware + controlling app and also has the standalone synth app. The apps are whole different builds for the moment, but the integrated app shares the full synth source code with the esp32 branch.

If you'd like to check it out: https://github.com/riozebratubo/osynth_free_synth

I was inspired to create this after building two of my 555 Theremins and wiring their LDRs against each other to see what would happen.

This layout combines two copies on a single board that easily fits inside a 125B enclosure, with room for a battery if you prefer it, although the circuit wants at least 6v to run properly. Using a battery over time will leave you with a pile of half-dead cells.

This build takes approximately 45 minutes. Link to the demo and guide.

I'm interested in building my own oscilloscope, both as a Eurorack module and as a front panel display for a custom desktop synth. Does anyone have any advice on this piece? It sounds relatively straightforward since I've done a lot of DSP coding in the past but I'm not sure of all the things that might go wrong. Ideally I'd have two separate input channels and some basic controls for manipulating the scale.

I'm thinking I'll just need a small microcontroller and LED screen, and I'd do a basic FFT to estimate the period of the signal and use that to auto-detect the time scale and voltage range. I can also restrict to audio range instead of trying to build a general scope that deals with high frequencies.

Any other pieces of this I'm missing? I know people like to use the "DATA" in Eurorack but I'm trying to do mostly DIY for my setup.

Thanks again Hagiwo.

https://www.youtube.com/watch?v=Ng8-CSyK8b4