Alphatron is not just a simple VA synthesizer, instead, in using a 3rd oscillator with digital waves of single cycle type, it offers a lot more variation. Thus it can do pretty good analog-style sounds reminiscent of the old Moog and Prophet days but also merge this with the digital realm in various ways to achieve sounds far beyond.
Also, this 3rd oscillator serves as sync master for oscillator 2 thus offering much more sonic flavour. Amplitude Modulation has got a dedicated adjustable output and uses oscillator 2 as the main source being modulated either by oscillator 1 or 3. Oscillator 1 is a polywave oscillator with up to 5 additional waves, so you might have something like Super Saw, Super Pulse, Super Ramp, etc.
Another highlight of Alphatron is the versatile step sequencer with 8 + 4 pattern slots which can be selected in real time for instant pattern switching. Setting Note Seq to off it can serve as step modulator. The Gate length can be modulated by sources. Two play modes: normal with adjustable number of steps or Step Variation, which is in fact another 16 step sequencer to set different number of steps to be played in succession. Loops can be set to repeat up to 4 times, and two alternating semitone offsets can be set, e.g. for each 2nd, 3rd or 4th loop. There are 8 pattern slots per patch and 4 global pattern slots which can be used for instant pattern changes. Current pattern can be copied and pasted to a selectable slot, with the global slots even among patches.
Main features (based on Pro version):
1 VA Oscillator with up to 6 poly waves for Saw, Ramp, Sine, Tri, and Pulse.
1 VA Oscillator with single waves as above plus white and pink noise, Sync slave.
1 Sample Oscillator with fairly typical digital waves (single cycle type) with different harmonic content, Sync master.
1 Amplitude Modulation with dedicated output.
1 24 dB resonant Low Pass filter with dedicated ADSR EG, 4 mixable mod sources.
1 VCA EG. Note: Both EG have 3 modes: exponential, reverse exponential, and linear; and optional control for Attack and Decay by velocity.
1 Booster or Exciter selectable.
1 Mystify with three selectable types (Brite, Soft, Dark).
1 BPM synced Delay with adjustable Offset controlled manually or by modsource, Pan.
1 Bass Boost.
1 Pan for undelayed signal.
1 small Reverb for adding some nice flavour.
1 main Volume.
3 x LFO, 1 x Duo LFO (with two waves and phase control for 2nd wave), 1 x S&H.
1 Pitch LFO with option to speed up or down the LFO speed.
16 Step Sequencer (with Shuffle) for notes and velocity plus mute buttons for each step. Includes 8 pattern slots per patch and 4 global pattern slots for instant changes.
Aftertouch as selectable modsource.
8 Lazy buttons.
8 GUI variants selectable.
Both free and commercial versions are available. The major differences of Basic Free (less features):
Only 64 patches.
No Lazy buttons.
Only 4 Seq Pattern per patch & 2 global Seq Pattern.
No selectable GUI (instead there is a choice of four different dll to download).
No patch select on GUI, but a silly scroller reminder not to forget to support the developer.