TSynth is a Teensy 4.1 based synthesizer using PJRC Audio Board and Audio Lib

The pcb and front panel are available from with SMD 4067 multiplexers, 6N138 opto-isolator, capacitors and resistors fitted. The entire cost of parts to build TSynth will be around $99 if you buy components from the cheaper suppliers and the build time around two hours to solder. Plans for a 3D printed/laser cut enclosure are also available. Questions:


Coq au Lores Coq Au Lo-Res - Germany and Europe

ALS AnalogLabSwiss - Switzerland and Europe

Inpublic Inpublic - NY, USA

Bulk orders for resellers available on Tindie Bulk orders for resellers available on Tindie

Discussion forum

Facebook Users Group

Go to Troubleshooting common problems

Github has source code, model files and documents

Build Guide and User Manual for T4.1 (PCB Rev 1.3) are here - Docs
T4.1 firmware (PCB Rev 1.3) is here - Firmware



  • 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


  • 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…)


  • 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


  • 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