XVA1 Synthesizer

High-end DIY subtractive, ‘virtual-analog’ sound generator.

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What is the XVA1 Synthesizer?

The XVA1 Synthesizer Module is a high-end DIY subtractive, ‘virtual-analog’ sound generator. XVA1 is 32-voice, 4-oscillators per voice, with a powerful parallel built-in effects processor, completely built on an FPGA chip.

XVA1 uses the same hardware platform as XFM2, so both synthesizers can be easily interchangeable.

The Hardware

XVA1 is based on the Xilinx Artix-7 35T FPGA chip, and its build is very simple as it relies in two tiny pre-assembled development boards: the Digilent CMOD A7-35T (FPGA, FTDI, SRAM), and the Adafruit UDA1334A (96kHz, 24-bit DAC), plus a few discrete components.

This selection allows to get the module running with less than 10 components (about $99 total cost).

XVA1 FPGA Synthesizer

Feature Set

  • 32 stereo voices polyphony
  • Polyphonic/Monophonic Legato modes
  • 4 oscillators per voice, capable of saw stack, saw up, saw down, pulse (with adjustable width), sine and noise
  • Saw stack creates up to 20 individual oscillators per voice, spread in tune and in the stereo field
  • Two independent stereo filters, with 20+ filter types and configurations
  • Oscillators Ring-modulation
  • A 7-segment, loopable Envelope Generator for each operator
    (DAD1D2SR1R2, with time and level controls for each segment)
  • 7-segment loopable Pitch Envelope Generator
  • Two per-voice LFOs with eight waveforms each.
  • Per-oscillator adjustable LFO sensitivity for pitch and volume
  • Per-oscillator adjustable velocity tracking, keyboard tracking
  • Polyphonic /Monophonic portamento
  • Pitch bend range adjustable independently for up and down directions
  • Extensive MIDI implementation (pitch bend, mod wheel, aftertouch, sustain pedal, breath ctl, foot ctl, volume, pan, chorus, reverb, delay, tremolo, etc.)
  • Two analog CV inputs
  • Internal temperature sensor can be used as modulation source
  • Eight per-program assignable Performance Controls, which allow any parameter to be controlled by MIDI continuous controls messages.
  • All synthesizer and effects parameters (400+) adjustable via MIDI system exclusive messages.
  • A complete stereo-in/stereo-out effect processor, featuring:
    • Bandwidth limiter
    • Distortion
    • Decimator
    • Bitcrusher
    • Low/High Pass Filter
    • Chorus/Flanger
    • Phaser
    • Amplitude Modulator
    • Delay
    • Early Reflections
    • Reverb
    • Gate
    • All of above effects can be run simultaneously
  • Built-in Arpeggiator and Step Sequencer
  • 128 programs memory (EEPROM)
  • MIDI in, optional out/thru
  • Samplerate-grade modulations
  • 96KHz/24-bit Stereo analog out
  • 96KHz/24-bit Stereo SPDIF digital out
  • Battery friendly, low power operation
  • Fully programmable (connecting it to a PC via USB)
  • 256 microtuning scales
  • Nearly zero latency (< 100 microseconds)
  • Extremely fast boot time (< 100ms)

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Get XVA1 Binaries and Documentation