New Teensy 4.1 DIY Synthesizer

Hi friends..

We're almost there. My friend Andre now orders the new circuit board and if it works he will order the housing and components for a pilot series.

For my part, I'm still writing around the operating instructions and programming a few "weird" demo sounds. I'm curious..

Hello there..

After minor technical difficulties, we are now in the final phase of our development.
We still had some problems with the FV-1 DSP chip for the effects. But we were able to solve that.
The procurement of components is still a minor problem. We try it through Chinese distributors.
The housing construction is ready and will be ordered in the next few weeks. It becomes a transparent one
and colored housing with support feet (similar to the one in the picture).


More informatin here:

I can already reveal a few technical details about the Jeannie ..

  • 8 voices polyphoner DIY Synthesizer
  • ARM Cortex-M7 Prozessor 816MHz mit 1MByte Ram
  • 2 digitale Oszillatoren per voice with PWM controll for Variable Pulse and Variable Triangle Waveform
  • 1 PWM LFO
  • Pitch Envelope für beide Osczillatoren
  • 2 LFOs für Pitch und Filter
  • Osc FX (XOR, XMOD, MOD, AND, OR, FM) with OSC-Mix function
  • 12 Standard Wellenformen (zum Teil bandlimitiert)
  • 500 User Wellenformen
  • Noise Generator (White or Pink)
  • Digitaler 12dB Multimode Filter mit Resonanz und Überblendfunktion (LP/HP/BP)
  • 2 ADSR Envelopes max 12sec für Amplifier und Filter mit positiver und negativer Steuerung
  • Waveshaper mit verschiedenen Kurvenformen
  • Unisono Modes
  • 15 DSP Effekte mit einstellbaren Parametern
  • Farbiges TFT Display mit 128x160 Pixel
  • 16 Step Sequencer
  • SD Karte fürs laden und speichern der Sound Programme max 2048
  • Externer Netzteilanschluss 12 VDC/1A und Netzschalter
    und einiges mehr..

Sound Demo:

Gruß Rolf
In summer, too? (well, a real summer, not this summer here in Germany) :) Teensy reboots or switches off if the die temperature is too high (but you can set the "panic" temp higher)
A very very nice project.
Do the same again on Youtube if it doesn't work on Soundcoud. Everyone has.
In the future I will only upload the sound to Youtube. I am not aware of any other free,
unlimited and free platform for music.


Regards from West germany :)
Hello dear Synthians

The new Jeannie Panel Board has arrived from China. Andre has now soldering the board and
tested. It all works wonderfully. The DIY manual is also almost ready. Now that's all that's missing
Housing and then we're done.

Greetings Rolf
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Hi Rolf,

i have no idea about synthesizers, but your GUI is beautiful, i appreciate every pixel ;o)

Hello Rolf,

in #187 you show a picture which says FXDSP Phaser.

In Green it says DEEPTH, should this not be DEPTH

Regards, Otto
I changed the filter page a bit. Instead of "AMT" I have "ENV" as
Parameter designation selected. The red marker for CUT is now also available.


FilterMix LP / HP (LP red / HP yellow)

A filter submenu can be reached using the Shift key. Then you can
Set the filter velocity, key tracking and LFO modulation strength.


Software changes in the sequencer
The sequencer record function now records velocity values when playing the notes on the keyboard.
The volume of the notes corresponds to a color. The lighter the color, the louder the note.


A poly-mode sequencer is also planned. After all, we have an 8-voice synthesizer.
A maximum of 4 notes are saved in one step at the same time.

Greetings Rolf
Hello Paul :)

I have a problems with the releaseNoteOn function (5ms) in my polyphonic DIY Synth.
If the releaseNoteOn phase were the new note will be played (see picture).
I'm using Teensy 4.1 and the latest Audio Lib. Release Phase is 4.4sec long.
Play 8 voices is good and Click the 9th note and the following :(

Envelope curve

1. Voices block

Thanks for help :)
Small video about the polyphonic sequencer ..

The sequencer now has a mode function.
In mode: REC, notes are received from a connected midi keyboard.
The pitch of the notes can then be edited with pitch or muted with mute.
In mode: TRP, the sequencer notes can be transposed using a midi keyboard.
In mode: KEY you can play additional notes via a midi keyboard.