ROM EXPANSION – For EPROM Drum Machines by DUCKTRONIC

DUCKTRONIC has made a ROM Expansion currently compatible with Oberheim DX and Linn drum machines. You can find the user manuals for each on a Google drive here.

The following is the intro in the DX manual: "The ROM EXPANSION extends the Oberheim DX with 104 sounds, most of which originate from the early 1980s. This makes it possible to recreate the sound of drum machines from that era. It is also possible to save custom-assembled soundsets and load them again at a later time.

Installation requires the CONTROL BOARD with the "Sound Control" software, the CONTROL PANEL, and six EPROM BOARDS with EPROMs. If only individual instruments are to be modified, fewer EPROM BOARDS are required accordingly.

Installing the ROM EXPANSION does not require any mechanical modifications or irreversible changes. The original state of the Oberheim DX can therefore be restored at any time."

You can find a YouTube playlist with demos here.

CLICK FOR MORE »

Treasure Hunter Optical Theremin

video upload by Tim Kaiser

Behold DigiTaur - a DIY digital bass synthesizer

video upload by Mute State

"A teensy based digital bass synth heavily inspired by Moog Minitaur, with a few twists of my own."

Note Mute Synth brought us the Semiotic Sequencer – Online Text Based Sequencer just posted below.

ESP32-S3 Polysynth Complete and looking sweet!

video upload by Bad Dog Designs

"The final video for the build of my ESP32-S3 poly synth, shows it fully cased in its 3D printed houses! I also mixed the OSPRAY-8 percussion synth I made last year into some of the tracks.

Did a full write up here:

https://esp32polysynth.blogspot.com/2...

Explains what everything does, how it works and how it's put together. Links to the project files:

https://github.com/Bad-Dog-Designs/ES...

https://github.com/Bad-Dog-Designs/Os...

Need a new project...!"

just look at the past (Yamaha YM2151 + Yamaha YMZ280B)

video upload by Vivi The Pumpkin King

Fun video featuring the Yamaha YM2151 + Yamaha YMZ280B voice chips. Interstingly, you'll find previous posts mentioning the YM2151, but not the YMZ280B. This simply implies the YM2151 is more comonly used in DIY projects.

"The Yamaha YM2151, also known as OPM (FM Operator Type-M), is an 8-channel, 4-operator sound chip used for frequency modulation (FM) synthesis in 1980s arcade games, home computers, and synthesizers."

Key Features

Voices:

Plays up to 8 simultaneous sounds or channels.

Data Formats: Supports 4-bit ADPCM, 8-bit PCM, and 16-bit PCM waveform data.

Memory: Connects to up to 16 MB of external ROM or SRAM for storing sound data.

Output: Delivers stereo output with 4-bit/16-level panning for each individual voice.P

rocessors: Links with an external digital-to-analog converter (DAC) and can connect to a Yamaha YSS225 effects processor for extra channel processing."

"The Yamaha YMZ280B, also called PCMD8, is an 8-channel PCM and ADPCM sample-based sound chip made by Yamaha Corporation in the mid-to-late 1990s.

Key FeaturesChannels and Operators:

It supports 8 simultaneous channels of 8-note polyphony with 4 operators per channel.

Sound Generation: It includes built-in noise generators, LFOs for vibrato and amplitude modulation, and timer circuits.

Companion IC: It requires an external digital-to-analog converter (typically the Yamaha YM3012) to output stereo audio.

Common Uses

Arcade Machines: Atari's Marble Madness (1984) was the first arcade game to use the YM2151 for FM synthesis, leading to widespread adoption in arcade hardware.

Home Computers: It powered the sound boards in sharp computers like the Sharp X68000 and the Yamaha CX5M music computer.

Synthesizers: Yamaha utilized the chip in early budget keyboards and sound modules like the DX21, DX27, and DX100."

Benjolin X by Before Void || Modular Demo

video upload by bajjjan records

"Rob Hordijk Benjolin with Before Void mods

A deep dive into chaotic synthesis using the Before Void Benjolin X as the only one sound source.

All effects are generated within the Eurorack case: Before Void Trigonometry (Wave Shaper), Shift Line Astronaut (Reverb), Catoff 100FX (Reverb/Delay)

What you hear is the raw character of these modules. Post-processing is limited to mixing and compression only. No external EQ or VST plugins."

Before Void Benjolin X || First Jam

video upload by bajjjan records
"First Jam with Before Void Benjolin X and Roland TR09"

"Based on forestcover Benjolin

+clock rungler input (any signal such as puls, trigs, gates, clock)
+band pass filter output
+high pass filter output (capricious output, starts cutting low frequencies only when the resonance is raised from 30%)

Open-Source:
https://github.com/BeforeVoid/Chrongler

CC-By-NC 4.0, 2026.
Strictly for non-commercial use."

MNX - Patent | Live analog synth performance

video upload by Beuk Bunker

"One take live analog synth jam.
No presets, no structure, just creating a beat as it goes.
Using self-built analog synths."

Gilded Synthesizer Sound Demo

video upload by GraveyardWifi

"This is a diy analog digital 8-voice paraphonic synthesizer I designed and built over the past year. It features external midi control capabilities as well and an integrated keyboard.

More information on the circuit and build process can be found here: https://drive.google.com/file/d/14EuB...

All audio is captured directly from the synthesizer through an M-Audio profire 2626 interface and has no post processing aside from gain matching."

CLICK FOR MORE »

Transposition and Patch Switching Box by The Electronic Peasant

video upload by epeasant

"A very useful modular synthesizer utility for VCO transposition and octave switching, as well as audio and CV signal switching.

The Transposition & Patch Select module features two six-octave switch banks, a one-octave keyboard, and four independent analogue signal switches. External volt/octave CV signals can be summed with the transposition controls, making it easy to change octaves or keys while playing or sequencing without repatching. The built-in keyboard also provides a gate output and can be used on its own as a simple control keyboard.

The four analogue switches can be used to quickly change audio or CV signal routing at the push of a button, making the module particularly handy for live performance and experimentation.

Constructed using discrete logic and analogue ICs with no microprocessor or programming required.

Complete construction details, photographs, circuit description, and the full schematic are available at The Electronic Peasant: www.epeasant.com/transwitch/transwitch.html"

"Changing keys, octaves, and patches at the push of a button!

A handy utility module for volt/octave transposition and audio/CV signal switching. Many modular synthesizer VCOs don't have built-in octave switching capabilities, which are useful for extending the range of a keyboard. Dynamically changing keys and octaves while using a sequencer is often not an easy or ergonomic process. Unplugging and plugging cables to modify a patch while playing can be cumbersome and inconvenient as well. This project provides the capability to easily and automatically do all of those things in one handy box.

The module includes a pair of six-octave latching switch banks, a one-octave switch keyboard, and four SPDT analogue switches. There is a combined output that mixes one of the octave switch banks with the keyboard output so that they can be used together, and the keyboard has a gate output included as well, so that it can be used as a freestanding keyboard. The keyboard circuit itself is adapted from Ken Stone's CGS10 Pedal board/Mini Keyboard project. Both of the octave switches and the keyboard include a CV input for precision summing of external volt/octave signals with each switch output."

See The Electronic Peasant for additional details.

The BOTANICA Sequencer: First Look

video upload by human.motives

Playlist:

1. The BOTANICA Sequencer: First Look at My New Project

0:00 Intro
2:35 What is BOTANICA
4:00 Sequencer features
12:17 Jam demo
17:29 Outro

2. Botanica: Live Demo of My Custom MIDI Sequencer 3. BOTANICA - Sequencer Prototype | Try It Now

"I've been designing and building my own midi sequencer called BOTANICA. This hardware midi sequencer creates expressive sequences from simple patterns.

In this video I tell you about how I started this project (learning electronics and pcb design), a demo of the sequencer and the project status. You can get involved by playtesting, discussing in my discord channel and stay up to date.

Go to https://humanmotives.org/ for more information and links.

Timestamps:

A first look at the Botanica midi sequencer prototype. See how this custom hardware controls generative sound design.

I have been refining the design and interface of this new project for quite a while now. This device features a custom pcb and a tactile front panel, allowing for hands-on control over complex musical patterns. It is built for anyone interested in diy electronics and the process of creating custom musical tools from scratch.

Watching the digital display react to each knob turn is satisfying. Botanica is designed to push my generative music performances further, giving me more control over the output. It is a work in progress, but seeing it come to life on the workbench is a major milestone for this modular synth project."

"BOTANICA is in prototype phase with a small group of testers. After that, the first 5–10 units get built for sale."

"A natural sequencer that grows simple patterns into whole compositions."

FEATURES
Sculpt intricate sequences from 1 to 64 steps. Add, trim away, create space to add fills and variations.

TIMED PHRASES
Add timed phrases and variations to from 1/2/4/8 bars to continuous chance-based evolution.

GENERATIVE MELODIES
Seed melodies and dial in Root, Semitones and Range to taste. Color them with a preset scale (Seasons)

EXPLORE WITHOUT RISK
Turn knobs, modulate, experiment. Dial everything back to return to your original sequence and tones.

EXPRESSIVE REPEATS
Blossom adds timed MIDI repeats at varying intervals and velocity curves

TONAL OPTIONS
Pattern, Arpeggiator and Chord modes

CLICK FOR MORE »

AI250 BXR Eurorack Test Equipment Demo Video

video upload by AI Synthesis

"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."

AI250 BXR Eurorack Test Equipment Build Video
video upload by AI Synthesis

Press release follows:

Portland, OR, USA September 2, 2026 – New for Knobcon, AI Synthesis has released the AI250 BXR in both a built and guaranteed version, as well as in kit and PCB/Panel format.

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. The internal VCO has 11 different voltage select-able wave shapes and can be played v/O.

It's also our first digital module, and runs on the Daisy Patch.

Depth: 39 mm
HP: 14
-V mA: 11mA
+V mA: 120 mA

“In the year 2000, I was in college and obsessed with modular synths, but could barely afford to eat. I knew it was possible to build your own synth, but there wasn’t anyone, or anywhere to turn to for advice. In the past decade, much more information has been published online, and in 2013 I started down my path to DIY modular. Even with all of the information online, there still lacked a single, simple, comprehensive guide for those looking to build their own synthesizer. I want AI Synthesis to be that guide. Prior to building my own synth, I was a dreamer, after building my modular, I felt I had awoken. I want to help others do the same.”

-Abraham Ingle

Founder, AI Synthesis

In addition to providing step by step build instructions, schematics, and circuit explanations, the site also includes a guide for getting started in modular synthesis, and a series of DIY Guides, with information regarding how Resistors actually work, and how to integrate a $26 scope into your Eurorack system.

EMS 256 Sequencer repair Part 5 Finale

video upload by Really Nice Audio

All parts

"Join me in this final video restoring this EMS 256 sequencer.

Watch me fumble around until I finally get the I/O scaled correctly!

Thanks to PCBWay for making the extender boards https://www.pcbway.com

This sequencer is part of the Pete Townshend Studio ay the University of West London.

https://www.uwl.ac.uk/study/study-fac..."

MoCM Fragments - DIVISION #short

video upload by MOCM (A. Monopolis)

"#moçm #arduino based #synth. compiled with cv divider function, effects, #tvoscilloscope ++"

Building a Noisferatu from schematic. Show-and-tell with brief demo

video upload by MIDI IN

"I've built a Noisferatu. I'm not really sure whether noise machines are my bag but I wasn't expecting some of the more melodic possibilities and I've found it way more addictive and enjoyable than I expected.

Hack Modular breadboard:
https://www.tindie.com/products/hackm...
Rob's Noisferatu kit:
https://www.thonk.co.uk/shop/scaepe-n...
Rob's own site:
https://www.robertheel.com/++/
My stuff:
https://peacockmedia.software/hardwar..."

See the announcement post for Noisferatu here.

Playing Light Like an Instrument — Open-Source LED Synthesizer

video upload by engmung

Note 1:43 in the video. Patternflow can be used as a controller via OSC.

"Patternflow is an open-source LED synthesizer — a 128×64 HUB75E matrix driven by an ESP32-S3, with four knobs wired straight into the pattern math. Turn a knob, and the pattern bends with your hand.

▶ Get one — Patternflow on Crowd Supply: https://www.crowdsupply.com/engmung/p...

Everything is open source: STL files, Blender sources, PCB gerbers, and firmware. The full build runs around $100 depending on where you order parts.

— What's in the video —
0:00 This is Patternflow
0:08 How it works
0:26 Build your own (~$100)
1:04 Make patterns in your browser
1:42 OSC — a pocket-size VJ rig
2:03 Why it's open source

Patternflow began with Nam June Paik's Participation TV (1963), the first work where the audience could touch the image. I wanted to go one step further — so I built an instrument where you make the image yourself.

The full story, from Paik to Patternflow:
https://patternflow.work/journal/nam-...

▶ Try it in your browser (no hardware needed): https://patternflow.work
▶ Build one — all files + build guide: https://github.com/engmung/Patternflow
▶ Join the builders — Discord: / discord
▶ Patterns, daily: / patternflow.work


Patternflow is sponsored by PCBWay.

#esp32 #ledmatrix #opensource #synthesizer #diy #maker #hub75 #mediaart"



Details:

Standalone LED visual synth with 4 rotary encoders and 128x64 RGB LED matrix (8,192 pixels).

Runs on ESP32-S3 with all generative visuals rendered live in real time.

Bidirectional wireless OSC support for Ableton (Max for Live) and TouchDesigner.

Internal hidden battery bay for cordless portable performance.

Over 150 community-created patterns and browser simulator.

CLICK FOR MORE »

He made a turntable synth & Built a DIY Drum Machine

video upload by Daisy

"Can I build an instrument with a turntable-inspired interface? Let's make a sampler synth that can record a sound and play it back as I spin a disc.

Documentation (parts list, schematic, software, & more): https://daisy.audio/blogs/seeds-n-cir...
Daisy Seed: https://daisy.audio/products/seed3
plugdata: https://plugdata.org/

About Daisy
Daisy is an embedded audio platform for creating musical instruments, effects, synthesizers, and other audio projects. Learn more at https://daisy.audio

Credits
Production team: Michael Corell, Andrew Ikenberry, and Takumi Ogata
Presenter: Takumi Ogata
Music: Eugen Schott (bensound)
Stock footage: Pexels

Chapters:
0:00 Intro
0:39 Designing the turntable interface
2:48 Rotary encoders are useful and surprisingly easy to program
4:09 Controlling the pitch of a sample
5:11 Controlling the position of a sample
6:46 Time to build!
8:42 Demo
10:36 Outro"

Building a DIY Drum Machine

video upload by Daisy

"Let's build a standalone drum machine using the Daisy Seed!

Blog version: https://electro-smith.com/blogs/seeds...

Get the Daisy Seed: https://daisy.audio/products/seed3

plugdata: https://plugdata.org/

Join the community:
/ discord
https://forum.electro-smith.com/

Sections:
0:00 Overview
3:37 Switch & LED Test
3:58 4-Step Sequencer
6:40 Hardware
8:01 Programming"

SpaceAxe - Recreating Retro Arcade Sounds ;;;;;Space Invaders;;;;;

video upload by TronixSynth

"Reproducing sounds from vintage arcade video games such as Space Invaders, Pac Man, Asteroids, Atari 2600, etc."

You cand find a previous model here, and the SpaceBass here.

Update: one more video:

CLICK FOR MORE »

KNOBCON FOURTEEN GUEST OF HONOR & an Update on Workshops and Informative Sessions

via KNOBCON

"We are delighted to announce Terry Michaels as our esteemed guest of honor. Join us at the annual banquet for his keynote address and to help us honor him.

Terry Michaels, AKA Terry Mikulic, designed the seminal relaxation-core oscillator published in Electronotes 62 by Bernie Hutchins: the highly accurate ENS-76. It is the most influential analogue oscillator design of the modern era. This circuit became the heart of hundreds of synthesisers, including Gene Stopp’s ASM-1, the Synthesizers.com Q106, and the muSonics Vanilla Oscillators. Through his synthesizer work, Terry founded a laser light show company called Laser Artistry in 1976. The company operated as one of America's elite laser show outfits until its final performance on December 31, 1999.

The annual catered banquet will be held Saturday, September 12, 2026 at 7pm in the Sapphire Pavilion. Tickets are available as an add-on to your Knobcon attendance. Seating is limited."

CLICK FOR MORE »

Soviet RITM2 Repair

video upload by Really Nice Audio

"Join me on this nice repair of a RTM2 soviet era synthesiser.

The music in the video is from my ATMOS album 'Height Supremacy'.
This track has plenty of my own RITM2 on it.

When the power supply fails a great substitute is the Velleman project
https://whadda.uk/Item/velleman-k8042...

And if you experience the pitch gong flat no matter how you set the calibration, adding half a volt to the positive power rail can really help."

DIY Lo-Fi FM Drum Machine with Arduino Nano on Breadboard - A Few Beats

video upload by Waiting For Zyo

"Another DIY instrument! This time I used a famous microcontroller: an Arduino Nano (compatible, tbh), a few buttons, and some code to made a really basic (lo-fi) FM drum machine with a built-in sequencer.

Here are some of its features:

• 4 instruments: kick, snare, hi-hat, and tom
• 4 main sound controls: tune, decay, FM amount, and FM ratio
• 4 secondary sound controls: balance, pitch envelope decay, pitch envelope range, and FM feedback
• A full 16-step sequencer with swing and basic parameter locks and on-grid rolls

At the moment, it only has a basic audio output, so I recorded everything into Ableton and added a bit of filtering and some reverb.

These are four beats I made from scratch using only these basic parameters and the internal sequencer.

Enjoy!"