Demo 1981 Yamaha PS-20

Описание: Main features:
49 fullsize
built-in speaker
10 note polyphony (only 4 notes with accompaniment)
4 note polyphonic chords
monophonic solo voice
10 semi- OBS preset orchestra sounds {organ 1, trumpet, clarinet, piano, accordion | organ 2, string, oboe, harpsichord, vibraphone} selected by 5 OBS buttons + bank switch button
8 semi- OBS preset solo sounds {violin, trumpet, trombone, piccolo | saxophone, guitar 1, guitar 2, funny} selected by 4 OBS buttons + bank switch button
8 semi- OBS preset rhythms {march, waltz, tango, rhumba | disco, rock, swing, samba} selected by 4 OBS buttons + bank switch button
locking multi- contact push button switches to select sounds and rhythms
sustain switch
fingered & single finger chord
"chord memory" switch (means simply that chord is held when releasing keys)
2 bass variations ("multi bass")
2 arpeggio variations
rhythm "8 bar variation" switch (inserts a fill-in every 8th bar)
tempo slider
separate rhythm, chord, arpeggio and solo volume sliders
All main voice timbres seem to be made from a mixture of multiple analogue filtered squarewaves with a common digital envelope.
analogue percussion {base, snare, hihat, low & high tabla(?)} sounds rather unspectacular, although possibly more realistic than many other analogue percussions. The hihat is likely mixed from 2 digital shift register feedback noise outputs at the CPU. The base is a dull popping noise.
CPU "Yamaha YM1011, 16 2056" (40 pin DIL) + separate sound chip "Yamaha YM1101 E, 16 1853" (40 pin DIL).
solo voice CPU(?) "Yamaha YM1102 F, 1Z 2258" (24 pin DIL) + sound chip(?) "Yamaha YM-1002, 1Y 20 28" (16 pin DIL) + filter IC "1G02611, 112 400" (14 pin DIL)
solo voice tuning trimmer
jacks for AC adapter, headphone, cinch sound input(!) & output and "expression" volume pedal
internal power supply module that plugs into the battery compartment