Rare Vintage Casio PT-7 Synthesizer Keyboard W BOX

via this auction

"Casio PT-7 (instrument with tiny polyphonic touch sensor keypad & analogue rhythm)

This is clearly one of the most bizarre and innovative instruments created by Casio, because this tiny thing has a detachable keyboard with 29 soft touch foil keys, and this is not just a monophonic toy tablehooter but a real 8 note(!) polyphonic instrument with analogue rhythm and a small but high quality loudspeaker that makes a very respectable organ sound.

This strange Casio invention permits special play techniques with very rapid glissandos and was one of the forgotten milestones in the struggle of overcoming the clumsy piano key relic on electronic consumer instruments.

main features:
* 29 tiny soft touch foil keys on a detachable slim line keyboard with short cable
* built-in astonishing reasonable sounding small speaker
* 8 notes polyphony
* separate knobs for main and rhythm volume
* tempo knob
* 6 preset rhythms {waltz, samba, swing, slow rock, pops, rock} selected by a slide switch
* 8 OBS preset sounds {piano, elec. piano, organ, pipe organ harp, accordion, clarinet, violin} selected by a 4-step slider + switch
* main voice CPU "HD44140, 3G 13" (56 pin SMD) with timbres based on multipulse squarewave tones with different digital envelopes, those are differently low pass filtered through capacitors. It makes very warm and pleasant timbres, but envelope release phase is truncated too soon, which makes piano- like tones less natural.
* rhythm IC "NEC D8048C 316, 8322X7" (40 pin DIL, same like in Casio MT-40) that outputs trigger pulses for analogue drums
* analogue percussion {base, snare, open cymbal, close cymbal, clave}; cymbals and snare use transistor noise.
* jacks for AC adapter & headphone

eastereggs:
* vibrato and sustain switch addable
* up to 8 additional keys addable (makes no sense here)
* holding down multiple sound select buttons during play makes wild cacophonic sounds (likely keyboard matrix mess by missing diodes).
* possibly bass accompaniment (with additional keypad) addable
* rhythm shitshot button addable

notes:
The main voice sound chip of this instrument is the same like in the Casio MT-45. It plays high quality analogue timbres, those although not always natural, reproduce a warm and pleasant sound; it does not sound typically C64- like thin, but resembles rather full- size home organs of that era. Like with Casio VL-1, the release phase of main voice envelopes seems to be linear and thus sounds unrealistic since it fades silent too soon with an audible end click. When sustain is switched off, all sounds stop almost immediately after releasing the key. When sustain is on, sounds with decay envelope (piano, elec. piano, harp) ignore the key press duration and sound always with a fixed duration instead. The "elec. piano" sounds like a banjo, and also the normal piano resembles more a picked string. The "harp" and "organ" sounds seem to add a bit of analogue distortion (or a mixed suboscillator with very short independent envelope??) during attack phase. All sounds include a mild vibrato. The smooth touch sensor keypad responds quite sensitive and permits special play techniques with rapid note clusters and polyphonic glissandos (but no portamento - this is not a theremin!).

Attention: Never play with sharp, spiky or rough objects (like finger nails) on the sensor keyboard surface - the foil may get damaged easily.)."