Subdecay EZ MIDI 2

The Subdecay EZ MIDI 2 is a DIY board that serves as both the brain for an effect pedal and a programming interface via a web-based MIDI editor¹. In other words, it is not a pedal you plug a guitar into on its own: it is the control board a builder puts inside a homemade or custom effect to give it presets, MIDI control and digitally generated control voltages for the analog circuit around it. Subdecay uses the platform internally for its own pedals and sells it as a product².

The current firmware is version 2.0.0, which moved customization to the web-based MIDI editor and added comprehensive control re-routing³.

What it does and how it is controlled

The board's job is to add digital control to an analog circuit. It reads up to six pots, labeled Pots 1 to 6, all assignable in the web editor, and it can drive up to 7 PWM/Control Voltage outputs at 3.3V with 62.5kHz PWM¹. A MIDI input gives full control of all parameters from outside the pedal, and a signal input supports envelope-based modulation, expecting a 1.65V-biased input signal¹.

Firmware version 2.0.0 offers three operating modes¹:

Control Voltage Array mode is the one aimed squarely at dirt pedals and switching circuits. You store an array of control voltage values, select a row with Pot 7, and map the columns of that row to the PWM outputs, which can then control analog switches or tone-shaping circuits in the analog path around the board¹. Subdecay also lists PT2399, BBD and PWM Synthesizer modes as coming soon, which points the platform at delay chips and synth-style builds¹.

Trying it on a Blue Pill board

A builder who wants to evaluate the platform before committing can run the demo firmware on an STM32F103C8, the inexpensive board known as the Blue Pill, without the programmer board. The demo runs full-featured for about 90 minutes¹. Loading it takes a parts list download and the STM32cube programmer software, available for Windows, Mac and Linux¹. Subdecay's documentation for the platform is written for the STM32F103 Blue Pill board³.

Earlier and later versions

The EZ MIDI platform's current release is EZ MIDI 2, which runs firmware version 2.0.0¹. Its six pots are assignable in the web-based MIDI editor, so a player can map each control to the parameter of their choice rather than working with fixed assignments¹. The programmer board is powered with a 9V supply and connects over MIDI¹.

The line has since branched in several directions:

• EZ MIDI Control: a 1-square-inch circuit board with 36 breakout pins, customizable with the EZ Wizard Programmer board, no coding required⁴
• EZ MIDI PRO: based on the EZ MIDI Control board but with more customization and support, adding control inputs, PWM/CV outputs and digital pots; MIDI out is possible by contacting Subdecay, and pricing depends on microcontroller cost and availability⁵
• EZ MIDI MCP: adds presets, MIDI and an OLED display to a pedal with up to 8 digital pots, with a KiCad demo board adapted from the EZ MIDI Programmer board that Subdecay notes has not been tested⁶

Subdecay also offers an EZ MIDI PRO variant, and the company says MIDI out is possible on the platform; builders interested in that option are directed to contact Subdecay for more details⁵. Documentation for the platform is available as a downloadable user guide covering setup and use⁴.

Editing settings

All customization happens in the EZ MIDI web editor, which Subdecay states is for EZ MIDI 2 only⁵. Pots 1 to 6 are assignable there, and the v2.0.0 re-routing means a builder can change how controls map to the board's functions without writing code¹³. This is the main practical difference from the earlier EZ MIDI Control approach, which used the EZ Wizard Programmer board for customization⁴.

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