Casio SK-5

CASIO SK-5

small keyboard with lo-fi sampling & effect sounds

This lo-fi sampler keyboard is a close variant of the Casio SK-8; unlike the latter it lacks ROM-Pack and key lighting, and it has a different set of preset sounds and rhythms including some trashy lo-fi effect noises. There are also 4 additional drum/ effect pads.

The SK-5 is quite well known on the internet. Technically it is basically an SK-8 with changed ROM, thus I only explain here the differences to the latter:

different main features:

neither ROM-Pack slot nor key lighting
different preset sounds {piano, vibraphone, dog, surf, trumpet, pipe organ, chorus, flute}
different preset rhythms {rock 1..2, disco 1..2, 16 beat, march, bossa nova, samba, slow rock, waltz}
4 additional drum/ effect pads {lion, laser gun, hi bongo, low bongo}
7 demos (complex polyphonic arrangements)

modifications:

polarity protection diode added & AC adapter jack polarity changed to standard

notes:

The main PCB of this instrument has strong similarity with Casio SK-8; only the section for the key lighting LED driver transistors is unused and not drilled, despite the traces are still there. Unfortunately the control panel PCB lacks the slide switch traces for the Casio SK-8A oriental keyboard easteregg, but I guess that it can be added despite this by adding an external slide switch. Strange is that the button shape of the Casio SK-5 corresponds to the Casio SK-1 and not to the SK-8. My SK-5 also distorts a bit more than my SK-8; which may be caused by a damaged speaker or amplifier.

Some of the preset sounds differ from the SK-8. "chorus" is a short looped sample of a dull human chorus. "dog" is a low dog bark. "surf" is an ocean wave sound made from digital noise with a well audible loop point. It fades louder and quieter again by a slow 0.3Hz volume LFO. When no samples are recorded, the 4 sample pads here trigger the default preset sounds {piano, vibraphone, dog, surf}. The percussion pad "lion" plays a short and grainy lion roar sample. "laser gun" plays a short zap noise than reminds to a short looped bullet ricochet sound. "hi-" and "low bongo" are what the name suggests.

The rhythm patterns differ from the SK-8 and also some percussion sounds are changed; e.g. the longer hissing metallic cymbal is gone (to save ROM memory?). Most remarkable are "rock 2" and "disco 2", those use effect sounds. "rock 2" employs the high pitched "dog" sample (sounds like a cuirca). "disco 2" is rather a lo-fi oldschool hiphop rhythm with intensive rhythmical use of the "laser gun" and some "lion" noises, which reminds to trashy Chinese toy tablehooters from 1990th like Gogo-Train. But most rhythms keep the characteristic woody knocking style of the SK-8.

The demo section proves that this instrument is still a very close relative of the SK-8 ROM-Pack hardware. The song selection works exactly like there and even the "part tone" slide switch still exists to change the "melody", "obligato" and "accomp" voices during playback. The ROM for the 7 demo songs is technically nothing else than an internal ROM-Pack and it even sits on a separate small PCB. But the demos itself were likely especially composed for the SK-5 because they intelligently use the particular effect sounds those do not exist in standard ROM-Pack keyboards.

The 7 demo songs are: (according to the manual)

Picnic (English folksong) [with dog bark]
Turkish march (Mozart)
Claire de lune (Debussy) [with "surf" waves and "chorus"]
Eine kleine nacht musik (Mozart) [with "dog" voice and "lion"]
Surprise symphony (Haydn) [with "surf" waves and "dog" rhythm]
Jingle bells (Pierpont) [with "dog" voice, very short]
American patrol (Meacham) [with "dog" voice, "laser gun" & "lion" rhythm fill-in]

The demos with their strong use of effect sounds resemble the "Stereo Playkeys!" toy keyboard.

*removal of these screws voids warranty...*

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