Maddie Synths

Open-source DIY Eurorack modules I have built and sell.

These are my open-source Eurorack experiments — mostly small, cheap boards where the firmware defines the module. Each card below is a single firmware build / module. This is inspired by things like the WGD Modular melon.

The MOD1 and MOD2 hardware is an open designs by Hagiwo — see the original build guides for MOD1 and MOD2. All firmware lives in the maddie-synths repository.

Maddie MOD1

Maddie MOD2

808 Clap panel

808 Clap

Drums · Percussion

A TR-808-style digital hand-clap: gated noise bursts into a band-passed exponential tail.

Acid 303 panel

Acid 303

Bass · Sequencer

An 'acid' 303-ish bass voice with a built-in Turing-style generative sequencer.

Breakbeats panel

Breakbeats

Sampler · Drums

A PCM break-beat player with CV-selectable slice points, variable speed, length, and loop mode.

Claves panel

Claves

Percussion · Voice

A tunable claves/woodblock voice with morphable sine↔triangle waveform and 1V/oct tracking.

Flux panel

Flux

Noise · Physical Modeling

Seven modes from tuned resonance to pure chaos — modal, Karplus, noise colors, Lorenz, and drone.

FM Drum panel

FM Drum

Drums · FM

A two-operator FM percussion voice — six parameters across two modes with smooth pickup switching.

HiHat panel

HiHat

Drums · Percussion

A white/blue-noise hi-hat with adjustable decay, decay curve, and band-pass frequency.

Kick Drum panel

Kick Drum

Drums · Percussion

A sine-based kick drum with six parameters and soft-clip drive, switchable via the button.

🎛️

Radio

Sampler

A long-form sampler for vocals and speech — up to ~130s with variable speed and direction.

Sample panel

Sample

Sampler · Drums

A one-shot PCM sample player — up to 18 samples in flash, selected via two-stage CV.

Spirals panel

Spirals

Oscillator · Experimental

Auditory illusions and impossible sounds — Shepard tones, Risset rhythms, and tritone paradoxes.

Square VCO panel

Square VCO

Oscillator

A V/oct square-wave oscillator with vibrato LFO and chiptune-style octave toggling.

Tiny Braids panel

Tiny Braids

Oscillator · Macro-oscillator

A Mutable Instruments Braids macro-oscillator port — dozens of synthesis models in 4 HP.

Tiny Tides panel

Tiny Tides

Oscillator · Function Generator

A Mutable Instruments Tides port — a tidal wavetable generator and function source in one.

VCO panel

VCO

Oscillator

A six-waveform oscillator with PolyBLEP anti-aliasing and negative-slope 1V/oct CV.