DIY 12-voice virtual analogue polyphonic synthesizer based on TSynth

Available as a kit and fully built on Tindie

Momentum User Manual and Build Guide

Latest firmware


  • Teensy Micromod-based 600MHz MCU
  • PCM5102A 16 bit, 44.1 kHz analogue stereo out
  • USB client (power in), USB Host
  • MIDI TRS In and Out/Thru (In is type A and B, Out is type A)
  • Four encoders, 10 buttons
  • 320x240 TFT colour display
  • SD card socket


  • 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 a 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…)
  • Key tracking adjustable up to full


  • Dedicated ADSR envelope with exponential attack (adjustable), decay and release stages


  • Stereo ensemble chorus - very good quality with mix and rate control
  • Simple reverb with mix and size

Patch storage

  • 8 user-nameable banks with 128 patches in each, stored on SD card


  • 128 user-nameable performance memories allowing patch, MIDI settings and assignment of the four encoders to the patch parameters


  • Six styles (up, down, bounce, up & down, random, play order), choice of ranges, base octave, tempo and tempo divisions
  • Syncable to incoming MIDI clock


  • Simple step sequencer, length up to 64 notes,
  • Syncable to incoming MIDI clock
  • 128 user-nameable sequences stored on SD card


  • USB HOST MIDI Class Compliant (direct connection to MIDI controller, no PC needed)
  • USB Client MIDI In from PC
  • MIDI TRS In (type A and B)
  • MIDI TRS Thru/Out (type A) - configurable as a thru with filtering options or an out


  • PCM5102A 16 bit, 44.1 kHz analogue stereo out
  • USB digital audio out, appears as 16 bit, 44.1 kHz audio interface on PC