Casio SA-1, 100 sound ToneBank mini keyboard with complex lo-fi wavetable sounds

the Casio SA series

The Casio SA series ToneBank keyboards were the first cheap sound bank instruments with up to 100 PCM preset sounds based on samples using a single- chip CPU. They were initially released as competitor to the Yamaha VoiceBank FM instruments those also had up to 100 preset sounds.

All Casio SA keyboards sound very similar and employ a wavetable synthesis engine that mixes 2 looped samples using independent, partly very complex algorithmic volume and pitch envelopes (made by program loop synthesis?). Most samples are of low resolution and typically short looped static waveforms, which gives these instruments a characteristic cheap and cheesy digital lo-fi appeal; the sounds tend to be cold, harsh and have much digital aliasing noise, which is very different from the always quite warm, bassy, smooth and noble sounding Yamaha FM timbres. The Casio SA tablehooters instead sound tinny, squeaky, thin and kazoo- like - it's exactly that sound you likely would have hated in the early 1990th, when it was the over- glorified, over- used and almost only available timbre in consumer home keyboards and PC wavetable soundcards. (When it would be my only sound source, I also would hate it.)

But nowadays in the age of high quality sampling and modern software synthesizers the trashy sound style of the Casio SA wavetable squeakboxes sounds special again, not least because they include certain characteristic algorithmic sound effects; many sound presets contain reverb or echo effects (simulated by envelope) and there are even melodic arpeggiator loops and disharmonic and atonal effect sounds like wicked sirens, sci-fi- and tekkno noises and also various drum kit modes with low- res percussion samples. Also the incredible static and naughty tooting "brass ens" and the squawky "elec organ" are very remarkable timbres of this hardware series. Unfortunately some effect sounds play the same pitch on many keys, which makes them less useful because it prevents melodic playability. But many preset sounds are time- dynamically playable, i.e. the sound of the release phase (often reverb or echo) changes with the key press duration (Yamaha FM keyboards do this also), which makes the sounds behave less static than normal sample based sounds. Important is not to confuse this hardware family with earlier Casio instruments, those usually had much warmer sounding semi- analogue sound generators based on multipulse squarewave timbres (see e.g. Casio CT-410V). I don't know if the SA sound generator has internal technical similarities with the Casio CZ and VZ series phase distortion synthesizers, since the CZ synths (e.g. Casio CZ-101) are famous for characteristic nasal timbres and can do detuned chorus sounds and rather complex 8 step envelopes with simulated echo effects, which are also typical elements of the SA series sound style. But at least with my Casio CZ-230S only few of its 100 preset sounds resemble the SA- series, and CZ synths have no programmable algorithmic envelopes. Older Casio PCM keyboards with only 20 or 30 preset sounds (like my Casio MT-540) had a higher timbre quality than the SA-series and its relatives; especially the percussion sounded by magnitudes better. Possibly Casio squeezed the 100 ToneBank and up to 100 rhythms of newer keyboards into the same amount of ROM space like the only 30 preset sounds and 20 rhythms of the older hardware. But the MT-540 CPU also employed an external ROM chip (with higher capacity?) while with these later keyboards it became fully integrated into the CPU to reduce manufacturing cost.

The Casio SA series also introduced silicone rubber buttons and various other cheap construction details into Casio keyboards, and the speakers of some specimen distort because they tend to rumble loosely inside the case since they are only held by both case halves without any additional screws. (Add some hotglue to the speaker chassis rim to fix this.) Fortunately at least they all have a polarity protection diode. Casio SA keyboards are common victims of circuit bending because when crashed by a shitshot they often produce bizarre drum loops and some even quite complex semi- random musical arrangements. Some models are still made and also most others are very easy to find on eBay.

Besides the Casio SA-65/ 67 and SA-40 there are basically only 2 different Casio SA hardware families with each a fixed set of 100 preset sounds and a corresponding fixed set of rhythms. (Specimen of both are cheap and easy to find on eBay.) The 1st one (like Casio SA-1) selects its sounds by entering 2 digit numbers and its rhythms through keyboard keys. The 2nd one (like Casio SA-35) instead selects sounds and rhythms by pressing buttons multiple times. (One button per sound group.) Both have only 32 keys and some of their rhythms include fixed- key accompaniment. Of both families exist 4-note polyphonic midsize key and 2-note polyphonic mini key versions (the latter apparently with lower sample resolution) but the sounds and rhythms stay always the same because they contain the same CPU. Some cheaper models (e.g. Casio SA-2) had less preset sounds by omitted cipher buttons, but these buttons can be re- added easily as keyboard matrix eastereggs. Not all Casio keyboards with such sound hardware have "SA" in their name; e.g. various toy keyboards were named differently. Similar sounds like in the SA keyboards (see SA-1) exist also in the Casio MA (midsize 49 keys, e.g. MA-130, but not MA-150/ MA-170) and CA (cheap fullsize) series instruments, although these have different rhythms and also the sound set is a bit different. Higher quality variants of these Casio PCM sounds exist in many modern Casio keyboards (e.g. last CT series instruments and most CTK series), unless they have General MIDI with its standardized (and thus boring) sound set.

Casio SA-1

This instrument from 1989 (embossed case stamp date) was the first Casio SA series keyboard with mini keys.

A white version with blue control panel (and possibly different demo by newer Casio SA-21 CPU) was later released as Casio SA-7.

main features:

SA-1, JASRAC T-3B0593 (+ Japanese characters) This odd sticker says: "SA-1, JASRAC T-3B0593" and has some Japanese characters. Someone wrote me that JASRAC is the Japanese music authors copyright organization, similar like the German GEMA. Most later sample based Casio keyboards (since Casio MT-540) have such a sticker. I don' know if only the demo melodies or the accompaniments or even the samples itself have been registered there. Older Casio keyboards with only few (like SK-1) or no samples have none, independent from there accompaniment complexity.



Although I normally don't go that far into details with 100 sound bank instruments, I have explained in the following almost all of the available sounds, because unlike with modern sample based instruments the presets here typically don't sound like what their name suggests. The sounds of this instrument are made from low resolution samples and thus partly have quite funny timbres. There is a reverb in most percussive and many other sounds, that was likely added to hide the aliasing noise of the low sample resolution and to sound differently than Yamaha. I thus don't mention the reverb in the following anymore but only its absence or when it sounds special.

The "piano" is well recognizable, also the "honky- tonk piano". The "elec piano" sounds metallic. The "harpsichord" is even very metallic and the envelope gets shorter(!) with held keys. The "jazz organ" and especially the "elec organ" have a unique tinny and squawky digital timbre. Although it was likely designed to imitate a Hammond organ tone, the timbre is different and rather somewhat reminds to an "ah"- voice through a telephone or a cup- muted trumpet or the like. The "pipe organ" is a metal pipe organ rank while "church organ" sounds more like a wooden pipe rank. The "brass ens" is a tinny, brassy and dry toot with chorus but no reverb. It resembles rather a car horn or pneumatic fanfare and sounds incredible artificial and static. The "warm brass" (with reverb) sounds more natural while "tuba" has chorus but no reverb. The "trumpet" is way too harsh. The "brass hit" is a percussive short brass note with reverb and 2 echoes after key release. The "wind ens" is rather natural. The "english horn" sounds hollow and more like an oboe (no reverb) while the oboe is brassy (with reverb). The "bassoon" and "clarinet" are ok (no reverb), the latter with delayed vibrato. The "samba whistle" plays only 2 different pitches. The "whistle" sounds nice, "quena" and "flute also (slow vibrato). The "flute- vib" starts percussive like a vibraphone. The "ocarina" has a percussive attack phase (delayed vibrato). The "bagpipe" quickly howls up to the played note (woodwind timbre). "harmonica" is a harsh tone that resembles more a trumpet ensemble or fanfare. The "chorus" is rather a silent fading high flute with vibrato. "brass- strings" resembles "brass ens", but with echo after key release. "strings" and "warm strings" are a bit harsh. The "violin" is rather brassy with delayed vibrato and reverb (Casio VL-Tone did it better). The "cello" is similar and rather a harsh tuba. The "elec guitar" is more a koto or picked violin or harp. The "jazz guitar" may be a nylon one and the "mute guitar" blips short with the same timbre (intensified by the reverb). The "metal guitar" shall be a distorted one but resembles a very harsh and distorted church organ or the like. The "metal lead" is similar but less harsh and with delayed vibrato. The "snare bass" is a layered snare and e-bass sample, which sounds grainy in the bass range and may be nice for tekkno. The "ukulele" is harsh with an echo during key release. The "banjo" has reverb except with held keys. The "sitar" is a harsh sound with chorus (fairly realistic). The "mandolin" rings. The "harp" blips short and has 3 slow echoes after key release. The "taishokoto" quickly rings during attack phase and has reverb except with held keys. The "shamisen" sounds like a short, distorted e-guitar without reverb. The "synth- celesta" is rather a harsh picked string with chorus and an echo during fast key release. "synth- clavi" has no reverb. "synth- accordion" is a harsh tone with chorus. "synth- brass" is a lower variant of it. "synth- reed" is a squarewave lead synth with vibrato (chorus?, speed varies with note pitch). "synth- lead" is a harsh timbre with delayed vibrato, which reminds to Rob Hubbard's C64 lead synth timbres. The "pop lead" is a harsher and more massive variant of it and sounds like exactly copied from the "magical wind" sound on Casio CZ-230S. The "synth- strings" resembles a cello ensemble. "synth- guitar" is a harsh short e-guitar. "synth- bass" sounds like a slap bass. "glass harmonica" is a bowed glass. The "fantasy" sound has nothing to do with the famous Casio VL-Tone timbre but is a strange howling harsh brass chorus timbre that resembles much a sitar. The "wah voice" is a male chorus which howls up during attack phase and has a nice bass range. The "twinkle echo" is a harp with 3 echoes after key release (and reverb). "cathedral" is a disharmonic mixture (major chord?) of church organ and 3 church bell clangs after key release (long sustain). "cosmic dance" is another characteristic timbre; its a disharmonic strum of 3 muffled picked strings those simultaneously sound again during key release (going "drripp... bimm", on a major chord?). The "plunk extend" is a buzzy bubbling sort of synth e-bass which bass range reminds to a buzzing ruler. The "pearl drop" is a water droplet with melodic echo during fast key release. There are also 4 key split combinations: "bass/ piano", "bass/ trumpet", "piano/ flute", strings/ oboe".

The "airplane" is a buzzing propeller plane with rising pitch (key pitches are assigned narrower than normal notes). "ambulance" toggles between 2 notes (narrow key pitches, long sustain). "insect" chirps like locusts (only 2 pitches). "emergency alarm" is a fast siren in the right and slowly rising buzzing tone (like motor bike) in the left keyboard half. "laser beam" are 2 siren- like buzzing space sci-fi tekkno effects: the first howls 2 times and goes up while it fades silent, the 2nd toots high and then goes down like a siren and stays at a low tone while it is rhythmically chopped. "cosmic sound" is a slowly down and up fading, harsh and thin purring chirping (both only 1 pitch). The "telephone" plays to the right a phone touch tone and to the left a phone toot (both melodic playable). "car horn" sounds like expected (but only 2 pitches). The "computer sound" is a melodic pattern like a siren- like glissando that plays on "c" e.g. "c" followed by "g, f, g, f..." on a xylophone- like timbre, which note sequence continues in the reverb. "typewriter" is a sample of a mechanical typewriter. The "marimba" rings fast. The "church bells" clang disharmonic with 3 slow echoes. The "bells" timbre resemble more ceramic bowls or a toy piano. The "gamelan" sounds a bit disharmonic (like intended?, using a special tone scale?). "afro percussion" resemble a marimba - unfortunately only 2 pitches.

"ethnic percussion" rings buzzy and grainy like an old alarm clock. The "sample percussion" is a gong or cymbal which pitch ascends during the attack phase (sounds like from a Peking opera). The "matsuri" sounds like hammering nails into a wood box full of bottles or the like (only 2 pitches). The "wadaiko" is a wood drum (only 4 pitches). The "triangle" has only 1 pitch (but short and long version). "conga/ agogo" is a percussion kit sounding like 2 wood drums and 2 pinball bells (cowbells?). "cowbell/ clave" is a kit of 2 cowbells + 2 claves. "tom" is a synth tom (4 pitches). "rock drum" is {base, snare, closed cymbal, open cymbal}. "swing drum" is {base, very short snare (or rimshot?), woodblock, cymbal}. All drum samples have rather low resolution, but still high enough to sound recognizable.

The digital volume control steals bit resolution from the main voice, which truncates the decay phase of the sounds at low volume and thus can be rather regarded as a sound effect. But while this is still a common phenomenon, very bizarre that the volume control also changes the speed of algorithmic sound patterns; the lower the volume, the faster e.g. the "mandolin" rings. (Especially at fast ring speeds these sounds turn quite buzzy.) My conclusion is that the volume control internally does not change the output volume of the generated tones, but instead modifies the start time of the individual envelope phases, and because each phase still counts down with its fixed rate, it thus faster reaches zero and in algorithmic sound patterns this event apparently triggers an interrupt that immediately starts the next sound of the pattern instead of waiting on a central timer, which makes the entire pattern run the faster, the lower the volume is set. You can even play the same pattern with multiple speeds simultaneously by holding down a key, selecting a different volume and than pressing another key, which makes the previously held note keep its old speed and volume while new notes respond to the new volume setting. Annoying is that any successful button press makes a typewriter noise, which disturbs live play.

The rhythms use a lot of different percussion samples including various latin and synth tom sounds. The cymbals use a looped hissy metallic waveform. The rhythms "pops 1" and "tango" add a nice sounding varying phasing effect to the base drum by layering its sample with itself. The rhythm tempo can be set quite low, but not extremely high.

The additional "super accompaniment" rhythms contain great sounding and partly unusual accompaniment patterns. Unfortunately they play only in a fixed- key and can not be switched off, which severely limits their use for melody play, and many are rather monotos (short melody loops) than accompaniments. E.g. the "jungle" is a aboriginal rhythm played on a metal can and 2 xylophone notes. "orient" is a Chinese monoto with gong, "bagpiper" is a snare rhythm with constant tooting bass drone and "fanfare" repeats a "winner" fanfare (or similar) in a loop. "child's play" is a chinking glockenspiel monoto, "computer" is a disharmonic down tumbling percussive synth loop.

Technically it is likely possible to upgrade the SA-1 with the 4 note polyphony found e.g. in the Casio SA-10, because regarding my other SA keyboards both likely contain the same CPU. But for this a diode would need to be soldered into the line of each key, and also the CPU needs to be switched into SA-10 mode (likely by a permanent diode somewhere in the keyboard matrix).

A cheaper variant of the SA-1 with only 16 sounds (4 cipher buttons, white SA-1 case) was released as Casio PK-1. Midsize key variants of the SA-1 with 4 notes polyphony were the Casio SA-10/ SA-11 (with 1 speaker) and Casio SA-20 (with 2 speakers). The direct successor of this hardware class had the same sound and rhythm set like SA-1, but 5 different demo melodies and 4 additional drum pads. Its 2 note polyphonic mini key version was released as Casio SA-6(?) and with only 25 sounds (omitted buttons) as SA-8 and with 16 sounds as SA-2, while its 4 note polyphonic midsize variant was the Casio SA-21/ SA-38/ SA-39 (2 speakers). This hardware class was also used in the great Casio PA-31 and the toy keyboard Casio KA-20 (only 16 sounds by omitted buttons). The same sound set (but different rhythms and user interface) has also the Casio SA-65/ SA-67 (37 midsize keys, LCD display). Also Casio PT-88 (polyphony 2 notes, mini keys) and PT-380 (polyphony 4 notes, midsize keys) employed this sound set; these had additional drumpads, ROM-Pack and key lighting feature (see Casio PT-80) but only 12 plain rhythms (resembling Casio ML-1).

The same sound style but with the subject more on algorithmic synthesizer patterns instead of natural instruments are the Casio SA-5/ M-100 (polyphony 2 notes, mini keys) and Casio SA-35/ M-200 (polyphony 4 notes, midsize keys). These great keyboards are almost synthesizers because their 100 preset sounds are sorted into groups with "tone edit" variation button and the pattern speed and timbre can be drastically changed by the digital volume control. Another great hardware family with similar cold and grainy digital lo-fi sample sounds is My Music Center.

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