Casio SK-1  (first home keyboard with sampling)

This keyboard from 1985 was the first affordable home instrument that could record and playback samples. It also includes an additive synthesizer that can generate Hammond- like organ drawbar sounds by mixing sine waves. The rhythms are made from very recognizable semi- metallic blip percussion.

All sounds can be combined with 13 preset volume envelopes. Also the portamento (glide tones) button is really fantastic, because it can make the instrument howl like a theremin when switched into a monophonic mode. The SK-1 has cheesy single finger accompaniments and great digital blip rhythms. The blip percussion sounds very unique and has been used in many tekkno, acid house and pop musics. Very annoying is that the sample-, synthesizer- and sequencer memory is always erased by auto power- off. (As a temporary fix for this, simply start a rhythm and set volume to minimum when you need to make a pause.) This instrument was also released as Realistic Concertmate-500.

main features:




The sampling feature of the SK-1 sounds extremely lo-fi (rather 4 than 8 bit?), but is nice for tekkno; also the "synth. drums" (synth tom loop) and blip rhythms are interesting for this. It is strange that this thing has only a standby mode instead of a hardware power switch (noticeable by the strange power supply bug) and a rather complex sequencer despite it has no persistent memory and the annoying auto power- off. Likely Casio originally intended to equip it with battery backed- up RAM, but considered it too expensive, too battery consuming or discovered in the last moment a hardware bug that prevented it from working properly and thus disabled this feature. The SK-1 PCB is a quite complex multi- chip design.

The preset sounds are made from looped medium resolution samples. This instrument has an astonishingly natural sounding piano, that sounds better than many modern mini- keyboards.  The "trumpet" has delayed vibrato and apparently produces an artificial wind noise during its attack phase by a rapidly stuttering zipper noise envelope. The "brass ensemble" is a nice synth brass. The "human voice" sounds like a child voice singing "tong"; the entire sample repeats in a loop and slowly fades silent like an echo (ignores key press duration). The "synth. drums" is a tekkno drum loop sample (alternating base + echoing synth tom) that slowly fades silent (like an echo). All sounds can be combined with the 13 preset envelopes. The vibrato button adds a vibrato (quite weak, about 5Hz) and the portamento button makes the tone bend from one note to another (like a slide trombone, takes about 0.5s) when a note is held and a new key is pressed. (The held old note stays audible unless you select monophonic play by setting the "mode" switch to "solo 1" or "solo 2".)  You can play fantastic theremin- like howling effects this way.

The rhythms sound quite unique due to its digital blip percussion; they were already used e.g. in various early acid house musics. The drums are made from unique rough and blippy digital waveforms (possibly these are extremely low- res loop samples with decay envelope). The cymbals employ a rough and semi- metallic digital waveform.

When the "mode" switch is set to "chord", all keys play single finger accompaniments (with rhythm, 1 chord per key - a similar concept like the chord button field on Casio PT-30, "nc" mutes accompaniment). The accompaniments consist of a monophonic e-bass line and a (monophonic?) sort-of e-piano; they all sound cute and cheesy and most contain typical arpeggio patterns. There is no manual chords mode (without rhythm). With accompaniment you can not play the main voice, but you can record a chord sequence in the built-in sequencer and then play to it. But due to the memory gets erased by auto-power-off, the sequencer is unfortunately almost useless despite it can be edited and records on 3 individual tracks.

The synthesizer feature is great for organ tones and gentle pad sounds, although it can not be programmed in realtime. To program a timbre, press "synthesizing". A continuous sine wave tone starts now. You can now use 9 of the white keys to change the timbre; each key behaves like a Hammond organ drawbar and adds an overtone; the more often you press it (up to 14 times), the louder turns the overtone. You can not reduce the overtone volume again, but only clear all overtones by pressing "synthesizing" again. When the timbre is finished, press the blue button in the preset sound row to select it. You can add a preset volume envelope for it  by pressing "envelope select" followed by a black key. The envelopes are slow and sound quite similar; short ones play a fixed time (0.15s?) and then end with an audible click.

Successors of the Casio SK-1 include the Casio SK-5 and SK-8. These all had real persistent memory (could even store 4 samples), but unfortunately the synthesizer and portamento is gone, envelopes work only with sampling and the drums are different (plain ordinary samples). The Casio SK-2 is a crippled variant of these (only 5 sounds, 6 rhythms).

Much info about these instruments can be found on the internet.

 removal of these screws voids warranty...    
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