Overview
The Graphic VCO from Erica Synths is a 16HP oscillator built around drawing. You draw one period of a wave on its screen with the two encoders, edit it in line-sketch mode, or shape it by its first 32 harmonics in a spectral view. Waves can then be arranged into wavetables and wavetable banks, and everything is saved in the module’s memory. A newly drawn wave is named on the module and added to the end of the waveform list.
It has four main modes. The basic one loads two waves into an A and a B window and morphs between them with a knob or CV, giving in-between shapes along the way. The others are playing a wavetable, a wavetable matrix, and a drum mode that builds percussion from its wavetables. On top of those, an FX section adds FM, phase distortion, ring modulation, wavefolding, wavewrapping, bitcrushing and overdrive, and a second output carries a configurable suboscillator. Snapshots store whole sounds for recall, including FX and settings. When you recall one, the knobs (except Tune) only take effect once you turn them to the position saved with it. The Device Configuration menu adds CV gain and bias settings, calibration, and a quantizer with 9 scales.
Wavetables on the Graphic VCO
Each wave is 1024 points, played at a 96 kHz sample rate. In Wavetable mode you pick a wavetable of 16 waves from the bank list and sweep it with the Morph knob or CV, and Erica Synths says waves added to a wavetable are morphed automatically. In Wavetable Matrix mode the module shows your wavetables as rows and their waves as columns. The default matrix is 8 wavetables by 8 waves, you can resize it, and two controls with their CV inputs move through it as X and Y. The CV range always spans whatever size you set.
What’s missing for WaveStack is a way in. The manual documents a mini-USB port, but only for firmware updates with Erica Synths’ firmware updater app in Chrome. It mentions a Graphic VCO app for designing wavetables without describing it, and Sound On Sound’s July 2018 review said wavetable upload would come through an app that hadn’t been released yet. We couldn’t find documentation of a file format the module imports, so WaveStack can’t target it.
For now, the Graphic VCO’s wavetables are made on the module, which is the workflow it was built around: you can load any existing wave into the A or B window, edit it, and save it to a wavetable, and the Manage menu reorders, renames and deletes wavetables. Drum mode then reuses those same wavetables for percussion, with amplitude decay, pitch decay and a pitch envelope. If Erica Synths publishes an import format, we’ll look at adding it.
Specifications
| Wave resolution | 1024 points |
|---|---|
| Sample rate | 96 kHz |
| Waves per wavetable | 16 |
| Matrix | 8 wavetables × 8 waves by default, resizable |
| USB | Mini-USB, documented for firmware updates |
| Width | 16HP |
Frequently asked questions
Can I upload WAV wavetables to the Erica Synths Graphic VCO?
Not in any way Erica Synths documents. The user manual covers drawing waves on the module and updating firmware over mini-USB, and it mentions a Graphic VCO app for designing wavetables without explaining it. Sound On Sound’s 2018 review described wavetable upload through an app that was still to be released. With no published file format, WaveStack has no way to write files for it, and waves have to be drawn on the module.
How many points does a Graphic VCO wave have?
1024 points per wave. That’s the wave resolution in Erica Synths’ specifications, and the module plays it at a 96 kHz sample rate. Each wavetable holds 16 waves. The spectral editor works on the first 32 harmonics of a wave, which is a small slice of what 1024 points can hold (freehand drawing can reach the rest), as explained in frame size.
How does the Graphic VCO’s wavetable matrix work?
Matrix mode lays your wavetables out as rows, in the order set in the Manage menu, with their waves as columns. The default view is 8 wavetables by 8 waves. You can resize and move the matrix with the encoders, and X and Y knobs and CVs pick a position inside it. A CV swing of −5 V to +5 V covers the whole matrix, whatever its size.
Does a firmware update erase my Graphic VCO waves?
No. Erica Synths’ manual says waveforms and snapshots saved on the module aren’t affected by a firmware update. Factory wavetables can’t be overwritten either: you can edit them, but you have to save the result under a new name. The Memory Clear menu deletes user wavetables or snapshots, but never the factory set. It asks you to confirm before anything is removed.