The soviets used the parts they could get... This means that the resonance pot is inverted because they did not have reversed log pots. All soviet synths had a poor quality (ever played a Polivox?) but compared to other synths from the soviet era the keyboard is OK.
My Altair 231 was produced in April 1986 - the final inspection took place 11 days before the Tchernobyl disaster - 200 km south of the Tchernobyl nuclear plant!
The sound is excellent. No Voyager can touch the sound of just 1 VCO without the use of filter or modulation, while the envelopes of the Voyager are a little bit punchier to my ears.
Both synths are "Minimoog"-type and both sound very different.
For a dry bass sound (without much phasing) to be placed in a full arrangement and the Voyager wins hands down. The Voyager also has some really great modulation features you won´t find on an Altair 231... But for classic Model D sounds and slightly detuned basses and leads with a massive phasing the Altair 231 rocks the boat. And the analogue drum sounds I was able to produce on the altair appered to be more punchy than on the Voyager.
The Voyager and the Altair 231 complement each other very well.
Released: 1984 | 
