DIY ElectroTechnique TSynth V1.3 : Super affordable DIY desktop 12 notes polyphonic synthesizer


Shipping to United States: Free

Note : Due to Covid situation and Postal delays the shipment is done in "Priority" & Tracked.

TSynth V1.3 is now available !

The TSynth is a little beast made by an enthusiast electronic guy as an open source low cost D.I.Y. (do it yourself) project. This is an impressive looking machine at a remarkable price !


The PCB + PANEL order option contain :

1 : The Green V1.3 PCB with pre-assembled SMD components : two 4067 multiplexers, 6N137s based MIDI In optocoupler, buffer for MIDI through and all resistors and capacitors.

2 : The Front Pannel of your choice (Blue, Red or Black)


The ESSENTIAL KIT option contain :

1 : The Green V1.3 PCB with pre-assembled SMD components : two 4067 multiplexers, 6N137s based MIDI In optocoupler, buffer for MIDI through and all resistors and capacitors.

2 : The Front Pannel of your choice (Blue, Red or Black)

3 : 4 special 2mA LEDs

4 : an 24 pulses per rotation Bourn incremental encoder

5 : an 0.96" RGB screen.

6 : The 3D printed stand for the screen

You have to collect other part by yourself (look at the bill of material at the bottom of this page).


The ESSENTIAL KIT SELECT option contain :

The same parts as the "essential kit" but you get the best printed panel available.


The TSynth PCB we sell is safe RoHs compliant (Lead Free).

The final prodcut size is about 320mm x 150mm x50mm


You’ll need to source and buy a Teensy 4.1, an Audio Board, pots, encoder, buttons, connectors and few other bits and pieces (look at the BOM list at the bottom of this page) that are detailed in the build guide. There are also plans for building a suitable enclosure although it will work fine with just the front panel.

The Teensy firmware offers 12 voice polyphony with 2 oscillators per voice, individual LFOs and pitch envelopes, lots of pulse width modulation and noise generation. The state variable filter has its own envelope and LFO. You can stack the oscillators into dynamic or chord unison and there’s plenty of cross-modulation on offer. At the end of the chain is a stereo ensemble chorus effect. It comes with a bunch of presets and you can save and recall your own.

SPECS (Firmware 2.20) :

Oscillators :

- 12 voice polyphony (last note priority), two oscillators per voice, velocity sensitive, detunable with +/- 2 octaves range, Sine/Sample & Hold (like tuned noise)/Square/Sawtooth/Ramp/PWM/Var Triangle/User waveforms and level. Square, Sawtooth and Pulse waves are band-limited.
- Pulse Width/Var Triangle can be set for each oscillator with PWM by dedicated LFO or from the filter envelope
- Pink or white noise level
- Dedicated LFO for pitch mod (can be retriggered by note on), Sine/Triangle/Sawtooth/Ramp/Square/S&H waveforms
- Pitch can be modulated by filter envelope (+/-)
- Oscillator FX - XOR creates lots of harmonics with certain waveforms and X Mod ‘Cross Modulation’ bell-like sounds.
- Dynamic Unison with all 24 oscillators detunable from each other - one, two, three or four notes can be played with oscillators distributed among them
- Chord Unison with all oscillators playing a chord selected from detune control - major, minor, diminshed…
- Monophonic mode - first, last, highest, lowest note priorities.
- Polyphonic Glide with variable time

Filter :

- State variable 12dB filter (SVF) with continuous mix between LP and HP (provides notch filter) and BP
- Cutoff freq and resonance
- Cutoff can be modulated by dedicated exponential ADSR envelope (+/-), dedicated LFO
- LFO has same waveforms as pitch LFO (can be retriggered by note on) and rate can be set to match MIDI clock (tempo) with variable time division (1,3/4,1/2,1/4,1/8…)

Amplifier :

- Dedicated ADSR envelope with exponential attack (adjustable), decay and release stages
- Volume
- Effect amount and mix - currently for stereo ensemble chorus rate and mix but could be set up to allow choices in Settings menu

Patch & Program Buttons

- Encoder with button for data entry, Back button for menu navigation
- Save and Delete buttons for storing patches
- Holding Settings initialises the current patch to match the panel controls. Holding the Save button takes you into a patch deletion page.
- Settings Menu - Velocity curve, Pitch Bend and Mod Wheel range, VU Meter, oscilloscope display, bass enhance, MIDI In, Thru and Out options.


- USB HOST MIDI Class Compliant (direct connection to MIDI controller, no PC needed)
- USB Client MIDI In from PC
- MIDI In 5 pin DIN
- MIDI Thru/Out 5 pin DIN - configurable as a thru with filtering options or an out

Audio :

SGTL5000 Audio Shield 16 bit, 44.1 kHz Stereo out
USB Audio in/out—appears as 16 bit, 44.1 kHz audio interface on PC


What's new in V1.3 ?

- The 6N138 optocoupler is now a 6N137. JLCPCB ran out of the previous (half of them went on TSynths) and they have plenty of 6N137s.

- MIDI thru is now a software thru/out with filtering options. V1.2 PCBs can use this if they are simply modified by cutting a trace and soldering a wire.

- The display SCK line has been re-routed with a series 100ohm resistor to get rid of noise coming through the analogue audio at high volumes.

- The display backlight is connected to pin 6 of the T4.1, so it could be turned off or PWM dimmed. This is in anticipation of a possible soft on/off switch or power saving mode, which requires the display backlight to turn off. Again, V1.2 PCBs can easily be modified by users, for this.


You can find detailed information about the project at or on the GitHub page of the project


Please note that this is a low cost, low volume DIY project where the build quality may reflect the low price, meaning there may be minor cosmetic inaccuracies / imperfections! Cosmetic defects (thin scratches, dents or similar defects that do not affect the basic functionality of the product) are not valid grounds for a refund complaint and will not be considered. Please do not order if you do not agree !

Due to the Covid situation, some delay may occur on delivery.


The BOM list:

Components available on AliExpress :

0.96” Colour IPS Display 80 x 160 with ST7735S SPI interface 1

Components available on :

LTL-4251NLC Lite-On 2mA LEDs - Through Hole Yellow or Red 4
PEC11R-4215K-S0024 Bourns Encoders 15mm SHAFT w/SWITCH (24 pulses/rotation) 1
DEV-16771 SparkFun Electronics Development Boards & Kits - ARM Teensy 4.1 1
485-4384 SparkFun Electronics Audio IC Development Tools Teensy Audio Adaptor Board Rev D 1
PTV09A-4025U-B103 Bourns Potentiometers 10K LINEAR 20% 33
B3F-4055 Omron Tactile Switches 12x12mm Std Ht .3 High-force 260g 7
AKTSC22K Apem Switch Bezels / Switch Caps ROUND BLACK CAP 7
SS-52100-001 Bel USB Connectors USB 2.0 R Angle Recpt Type A solder 1
SS-52300-001 Bel USB Connectors USB 2.0 RA Receptacle Type B 1
161-3507-E Kobiconn Phone Connectors PHONE 3.5MM STEREO 1
KCDX-5S-N Kycon Circular DIN Connectors 5P R/A PCB NON SHLD 10mm CIRC DIN RECPT 1
NYS216G REAN / Neutrik Phone Connectors 1/4" STEREO JACK .322" GOLD REAN 1
R30-1002202 Harwin Standoffs & Spacers M3 x 22mm THREAD HEX BRASS 5mm A/F 7
R30-3000802 Harwin Standoffs & Spacers M3 x 8mm HEX 5mm A/F 6mm ML/FML NICKEL 7
1227-L Davies Molding Knobs & Dials S/T Control Knob 6mm Interference Fit 34

Legal imprint