The alphaSyntauri was originally developed to work with Apple's IIe computer, but for its first "true" synthesizer, Audio Damage has modelled it, put it into a VST/AU plug-in and called it Phosphor.
This is a digital additive instrument that features two 16-partial additive oscillators, each with its own amp envelope. Although Phosphor is based on the alphaSyntauri, Audio Damage has also furnished it with many modern features that weren't present on the original instrument - here's the list from the company's website:
• Two complete oscillator/envelope sections modelled on the original topology of the alphaSyntauri.
• Each set of partials can run in "lo-fi" mode, emulating the original, or in a modern mode for alias-free sines.
• The noise can be either "lo-fi" digital shift-register noise, or modern white noise.
• Two complete delay sections with LP/HP filtering and cross-feedback.
• Two tempo-syncable LFOs with multiple modulation destinations.
• 80 presets included that show off the extensive sound generating capabilities of Phosphor.
• Full MIDI Learn.
Phosphor costs $59 and is available now.