ALTAIR-231 SN 2863 3-OSC ANALOG SOVIET SYNTHESIZER

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"Monophonic synthesizer Altair 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

Altair 231 is an almost identical copy of the famous Moog Minimoog, made in the former Soviet Union. Biggest difference in sound is caused by different brand of components: Russian equivalents are used everywhere.

The oscillator board is based on the older version. However, the Russians were clever and used multi-turn potentiometers for the scaling controls. Result: Synth stays in tune better. The Russians didn't seem to have reverse log pots. Because of that, the resonance control was wired backwards and a regular logarithmic pot was used instead. Other than that, the synth seems to be very robust and easy to service - the real Mini schematics come for good help when comparing the component numbers etc. It sounds like a Mini! I heard a Mini with the newer oscillator board and I think that's the reason for minor differences in sound between it and the Altair.

It is a monophonic 3 OSC analog synthesizer. Synth has 4-oct keyboard (F-C) with velocity (sensitivity assign to vibrato effect). The synthesizer has based on 3 VCO (osc. No.3 can work as the modulator), 1 VCF (lowpass 24dB/oct)with ADSR, 1 VCA, 3 LFO, noise generator (white/pink), portamento, memoryloop. It has an EXTERNAL INPUT allowing to use FILTER and GENERATORS with external audio INPUT.

OSCILLATORS section: - osc 1,2,3 registers - 2", 4", 8", 16", 32", LF - osc 1,2,3 waveshape select - triangle, saw, square, pulse, sine - osc frequency - freq 1..3, freq 2, freq 3 -linked to keyboard pitch on/off (osc 3 ONLY) MIXER: - osc 1,2,3 on/off, level - ext input level, on/off - noise generator level, on/off - noise mode switch: white/pink MOD section: - portamento on/off, rate; - mod mixer knob: balance between modulated by OSC3 and noise, depth amount; - pitch wheel (glissando)

FILTER: - mod on/off - cutoff, resonance, brightness - attack, decay, sustain - keytrack on/off

AMPLIFIER: - attack, decay, sustain - key hold memory on/off Next - global section: main volume, phones volume, phones out (5din), A-440Hz tone on/off, power. Connections :

Audio OUTPUT, Audio INPUT on standard 1/4''jack, pedal input on 5-Din socket , power wire connection (220/240V), fuse (0,5A) ."