ALTAIR-231, vintage soviet analog synth

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via this auction

This is the one from this video posted earlier today.

"Monophonic synthesizer Altaiir 231 (Estradin factory, Zhitomir city) is intended to play different sounds from the imitation of natural instruments to complicated synthesized electronic timbres, sound effects, percussion sounds & so on. There are a four-octave keyboard & a wheel to pitch control. There are also controls for parameters on the front panel, an output for phones, an input for a pedal. The instrument consists of four main blocks of sound synthesis - Generator, Mixer, Filter and Contour.

Synthesis is based on 3 master oscillators (each of them with different parameters of registers) waveform, frequency modulation. There is also a generator of white & pink noise. Low-pass filter with main parameters gives the possibility for keyboard tracking. Portamento adjustment knob is provided. To tune a pitch the tone signal is used (440Hz) It provides a linear input to connct an external sound source to Altair. Output and input sockets are 1/4" jacks

Specifications:

Mains voltage of alternating current, V 220
Frequency band 0,3 - 25000Hz
The range of musical tones 9 octaves
Relative generator drift over 4 hours continuous work is within, % max +/- 0,3
Number of generators - 3
Number of waveform generators - 6
Frequency change range of the cutoff frequency of the filter, Hz min 40 + 20000
The presence of 440Hz tone generator (for tuning) - YES
Dimensions of the synthesizer, mm 750х360х200
Weight, less than kg 15"