Yamaha HandySound HS-200

YAMAHA
HandySound HS-200

polyphonic squarewave mini-keyboard

Did you know that beside the famous PortaSound keyboards Yamaha also released an even smaller instrument series called HandySound?

This mini keyboard of 1983 (manual copyright date) has no rhythm, but features 4-note polyphonic squarewave sounds, which is quite unusual for such a tiny thing. The original German retail price apparently was 139DM (about 69€, mentioned in advertisement flyer).

main features:

25 mini keys
built-in speaker
polyphony 4 notes
5 preset sounds {organ, violin, clarinet, piano, harpsichord} (selected by slide switch)
volume slide switch (6 steps)
sustain switch
sound generator has waveforms like DSG YM2163, mostly based on bipolar squarewave with different digital envelopes, those get differently low pass filtered through capacitors. The digital envelopes (with mild zipper noise) are linear and thus sounds unrealistic because they fade silent too soon.
main ICs:

CPU= "Yamaha YM-10080, 23 16 21" (GH-1 | 16 pin DIL, crystal clocked @ 343.4 kHz)
standby IC= "IG06440" (9 pin SIL)
amp IC= "LA4142" (9 pin SIL)

jacks for AC-adapter & headphone

Like in the early Yamaha PS-2, the HS-200 still has its function sections written on the PCB.

eastereggs:

sliding the sound select switch into intermediate positions provides 3 additional preset sounds {brass, bright clarinet, bright piano}.

The main voice sounds of this instrument resemble Casio VL-1 but feature no multipulse squarewave timbres. The violin has a built-in vibrato. Unlike Casio VL-1, the harpsichord of the HS-200 has a fast attack rate and thus sounds more natural. The sound select switch internally selects the main voice sound and the corresponding capacitor filter through different contacts, thus setting the sound switch into intermediate positions play the preset sounds with "wrong" filter setting which produces additional sounds. This way between "organ" and "violin" there is a duller violin variant that resembles a dull brass sound. Between "violin" and "clarinet" a brighter clarinet (pipe organ?) appears. Between "piano" and "harpsichord" there is a brighter piano sound (like an e-piano or guitar?). The sustain switch adds a quite long sustain.

When I bought mine at eBay, the "off" position of the volume switch made a bad contact, thus the thing made funny blip noises when switched off. Playing "Decathlon" on the switch a few dozen times fixed this. The simple CPU is likely rather an LSI made from logic gates than an actual microcontroller. According to the service manual, the keyboard matrix (5 groups of 6) is fully used and thus has no eastereggs. (I haven't examined the hardware further yet.)

An almost identical variant of the HS-200 with additional audiogames and LCD was Yamaha HS-500. An ultra-rare variant Yamaha HS-400 (orange case looking like HS-200) even had an (according to a collector) great chorus style human voice sample despite it was already made in 1982. Not even Yamaha had its manual online, but I saw it a single time on eBay. Its instruments switch has the positions {do-re-me-fa, violin, clarinet, piano, guitar} and (according to icons on leftmost black keys) can play dog, cat and bird sounds. The rightmost 5 white keys {1..4, dot} are labelled "programmed music" and depict a girl face icon.

*removal of these screws voids warranty...*

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