Electro Technique TSYNTH, A $99 Teensy-Based Open Source Polyphonic Synthesizer

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Electro Technique TSYNTH is Teensy-based polyphonic Synthesizer that is open-source, powerful and cost less than a plugin on average

A weekly look at the DIY platform Tindie is always worthwhile, especially if you are looking for a nice DIY project. The South Korean developer Electro Technique introduced TSYNTH, an open-source polyphonic Synthesizer based on the Teensy board. For this purpose, they have developed a PCB on which the tiny Teensy is attached but also where all controllers of the synth are located. It has plenty of controls for a $99 synthesizer project: 33 knobs, 6 buttons, and a small screen.

TSYNTH is a pure DIY project. From the developer, you get the PCBs, display, and a 3D printed standoff for the display. Small parts like knobs, buttons, etc. have to be purchased from other shops. According to the developer, all of this will cost you around $99 what would be a great price for such a fully controllable synth.

Electro Technique TSynth


The engine is pretty impressive: six-voice polyphony (last note priority) with two oscillators per voice (+2/-2 octave range detunable) including sine/S&H (like tuned noise), square, sawtooth, ramp, PWM, Var triangle, user waveforms to select from. Further, there is pulse width/var triangle for each oscillator with a dedicated LFO or filter envelope, pink/white noise, pitch mod, XOR (ring mod), unison, and polyphonic glide with variable time.

On the filter side, it comes with a state variable 12dB filter (SVF) with a continuous mix between LP and HP (provides notch filter) and BP. A bit like an Oberheim SEM filter. The cutoff can be modulated by a dedicated ADSR envelope (+/-) or LFO. The latter has the same waveforms as the pitch LFO (can be retriggered by note on) and rate can be set to match MIDI clock (tempo) with variable time-division.

Further, there is a dedicated ADSR envelope for the amp and an effect section with a stereo ensemble chorus. The synth has a built-in USB host connection that allows you to connect a MIDI controller via USB with no PC/Mac required. Plus, it has a MIDI in via 5 pin DIN. It also includes a built-in audio interface that is based on an SGTL5000 Audio Shield 16bit, 44.1kHz stereo.

Electro Technique TSYNTH

The synth comes with a programmer that allows you to save/recall patches but also to update it with new user waveforms, new features (alternative filters, effects, parameters…), and firmware updates.

Sold Out Why?

The first batch of TSYNTH is sold out but there is one main reason why it’s sold out. The developer has announced that Teensy 4.1 was recently released. This information is important because the synth is based on the previous version of Teensy (3.6). So the PCB doesn’t support the new version so the developer decided to update the main PCB of it with a new firmware. The new version will offer more polyphony (16), quicker note on response, and MIDI thru. A nice upcoming update for TSYNTH which will probably be released later this year.

At first glance, an impressive DIY Synthesizer with many features that can be operated without sub-menus and a great sound for little money.

The TSYNTH PCB and front panel kit will be available from the Electro Technique Tindie shop for $36 USD that includes SMD 4067 multiplexers, 6N138 opto-isolator, capacitors, and resistors fitted. The other parts must be purchased from other shops. Plans for a 3D printed/laser cut enclosure will be available soon. The synth with all the components will cost you around $ 99 in the end.

More information here: Electro Technique

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1 Comment

  1. Honestly, as such DIY projects go, this one is rather impressive. A certain attention to details as well as a nice integration of diverse features, quite a winning combination even for a commercial product coming from a full R&D team. For instance, the polyphonic glide demoed in the orchestra patch is quite revealing. It also sounds like the overall device is quite fun to use. Plugging controllers through USB is one of the showcased features of the Waldorf Iridium (rumoured to be “affordable”, revealed at 2k€).
    Soooo… If this were released commercially as a piece of pre-built hardware, it could gain quite a bit of traction.

    Wouldn’t say that the sound is mindblowing. That can be solved with just a bit of FX, as what happens on the (monophonic) Korg Nu:Tekt NTS-1.

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