Soleil Lo-Fi MIDI String Synth Chip

Make your own simple DIY “Lo-Fi” MIDI string synth with this cool 28-pin chip.


In stock



The Soleil is a Lo-Fi MIDI String Synth chip 28-pin DIP package, capable of playing 4 paraphonic notes with 2 oscillator ranks per note.  The second rank can be detuned.  Waveforms are continuously variable from sawtooth thru variable pulse widths. All sounds share a single A/R envelope.

Many parameters are controllable via 0 to 5 V CV inputs.

Soleil responds to MIDI Pitch Bend and Modulation, and has a built-in modulation / vibrato oscillator, the depth of which responds to the MIDI Mod Wheel.

MIDI Channel Assignment

Soleil’s MIDI channel defaults to Channel 1 but can be reset with a simple sequence from your MIDI keyboard.

To assign a new MIDI channel to the Soleil, first unplug / power off your Soleil and connect your powered-up MIDI keyboard, set to the desired MIDI channel.  Now hold down any note, apply power to the Soleil. During the first 2 seconds while the MIDI LED is flashing, simply release the key you’re holding, which causes a MIDI NOTE OFF on the desired channel.  Your Soleil is now set to your keyboard’s MIDI channel.  The new setting is automatically stored in the chip’s non-volatile memory for the next time.

The audio outputs are PWM DACs (filtering required) and the chip runs standalone from a 5 volt power source.



Feature Summary 

4 note para-phonic
2 oscillator ranks per note
Second rank detune
Global pitch bend and modulation via MIDI
Waveforms continuously variable from sawtooth thru variable pulse width
Single A/R envelope generator / VCA
Internal LFO for pitch modulation
Gate output for interfacing to external synths

Technical Specifications 

DSP platform: ATMEGA
Audio output: PWM DAC, 1 channel mono audio
Gate Output: 0 to +5 V
Fine Tune Range: Approx. +/- 1 semitone
Pitch Bend Range: Approx. +/- 1 semitone
Modulation Range: Approx. +/- 1 semitone
Detune Range: Unison to about 1 semitone
Supply power: 5v DC
Supply current: <50mA


Note On, Note Off, Running Status
Mod Wheel: 176 (B0 hex)
Pitch Bend: 224 (E0 hex)


(Due to continual product improvements, specifications are subject to change without notice.)

Product Manual

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