Casio Magical Sound Dial SA-40 toy keyboard with effect sounds & bizarre dial controller

This is really an invention this mankind doesn't need - or did you ever feel the need to emulate the tempo behaviour of a crank operated music box on a toy keyboard?!

This strange little tablehooter from 1995 (embossed case stamp date) has 8 OBS preset sounds but no rhythms. The unique feature is that it has a dial controller which turning speed and direction modifies the sound. Beside the preset sound there are 10 (mainly movie- like) atmospheric effect sounds those turn the more dramatic or intense the faster the dial is turned, and also the direction changes the sound. But although this concept may appear exciting and the case style looks quite professional, the implementation is stubborn, rather boring and especially it is really nothing unusually great for tekkno performances. The 6 demo melodies have a mechanical music box timbre and their speed can be also manually controlled with the dial. The sound engine strongly resembles the classic Casio SA-series.

A light grey version of this instrument was released (later?) in the CasioClub series as Casio M-300.

main features:

notes:

The volume can not be set really low and in comparison to my Casio PA-31 also the bit resolution of the samples seems to be lower, because the SA-40 makes noticeably more aliasing noise. Like with My Music Center and similar toy keyboards, all OBS button presses play the selected sound as example. Also the volume buttons play a metallic noise (pitch depends on direction and range end).

The main voice sounds are made from low- res samples with very complex envelopes and mainly correspond to Casio SA-1. They can be modulated by turning the dial, but here only the speed and not the direction determines the intensity, and the sounds respond quite slowly by the low controller resolution. All sounds and atmosphere patterns of the SA-40 have only icons instead of names, thus the names were chosen by me. The music box resembles "elec piano" on SA-1 but plays 1 octave higher and clicks louder except in the bass range. The "piano" and "wood bass" sound like on SA-1 and the dial makes these all ring like a mandolin (faster = faster). The harsh trumpet is also the same. The bowed glass sound like "glass harmonica" on SA-1 but doesn't fade silent. The dial controls their volume (faster = louder, responds slowly, when not turned = full volume). The "violin" and "flute" are like on SA-1; the dial makes these in a strange way flutter and pitch up; when turned faster it howls slower with stronger modulation (like an US police car). When not turned, there is only a normal delayed vibrato. The organ sounds like "street organ" on SA-1, but with faster tremolo. The dial speed increases volume and tremolo until the tone purrs by the high modulation speed (when not turned = full volume). The dial effect may be also usable for tekkno, but IMO the Casio SA-35 is a way more fascinating tekkno instrument.

Each atmosphere sound has only the same fixed sound pattern on all keys (monophonic, no different notes, also played by the pattern's OBS select button) and the keys do nothing while the dial is turned. The sound pattern changes with speed and direction (up to 3 patterns per direction). The feeling of it resembles somewhat the "jog shuttle" wheel of some VCRs, although you can not play patterns backward. This is not the great DJ live performance thing you may expect, but a relatively boring sound toy. This is what the patterns do:
cats & dogs:
 
motion sound
key = cat + dog voices
right slow  = high dog bark
right mid = additional low dog bark
change to left = high cat mew
left slow = low bird tweet 
left mid = additional low bird tweet 
change to right = low cat mew
old gameshow:
 
motion sound
key = 2x ding dong, Hammond fanfare (winner jingle)
right = ascending Hammond portamento (speed sensitive)
right stop = 2x ding dong
left = ascending Hammond portamento (speed sensitive)
left stop = buzzer, organ portamento down (looser jingle)
steam train:
 
motion sound
key = train rattling
right start = train horn
right = steam train rattling (speed sensitive)
right fast = additional different noise
left start = 2x steam whistle
left slow = low steam train noise (speed sensitive)
left mid = additional ping noises (speed sensitive)
left fast = partly different steam train noise (tunnel?)
sirens:
 
motion sound
key = space siren up
right = tinny siren pitching up (speed sensitive, resembles motorcycle noise)
left = brassy siren pitching up (speed sensitive, resembles formula 1 car motor noise)
baseball organ:
 
motion sound
key = Hammond fanfare
right = 2 higher growing organ fanfares, brass fanfare, applause
right fast = starts applause after first fanfare
change to left = low whistle
left slow = low organ monoto
left mid = switch to 2 higher, brassier monotoes
left fast = winner fanfare, applause
change to right = high whistle
car race:
 
motion sound
key = low car motor pitching up
right slow = 4 start traffic light toots + car motors up (speed sensitive)
right fast = additional overtake(?) noises
right stop = high brake noise
left slow = car motors up
left fast = additional police siren, explosion
left stop = low brake noise
horror movie:
 
motion sound
key = e-bass + theremin + slow clock tic
right start = woody rattling, knock
right slow  = e-bass line
right mid = additional + slow clock tic
right fast = additional howling theremin track
change to left = mid church bell
left start = woody rattling
left slow = synth portamento down
left mid = additional steps (speed sensitive)
left fast = additional howling "synth- lead" track
change to right = low church bell
samba:
 
motion sound
key = main track with bass + agogo
right slow  = agogo rhythm (2 cowbells)
right mid = additional bass line
right fast = additional main track
change to left = samba whistle
left slow = base + snare rhythm
left mid = additional bass line
left fast = additional main track
change to right = low samba whistle
western movie:
 
motion sound
key = fast banjo + horse gallop
right slow  = fast banjo track
right mid = additional horse gallop
right fast = additional pistol shooting
change to left = pistol shot
left slow = slow banjo track
left mid = additional slow horse walk
change to right = pistol shot
rap music:
 
motion sound
key = e-bass + rhythm + scratching
right slow = drum kit rhythm with scratching
right mid = additional e-bass
right fast = additional e-piano
change to left = additionally 1 low scratch
left slow = drum kit rhythm with scratching
left mid = additional e-bass
left fast = additional "synth- lead"
change to right = additionally 1 high scratch
The 4 music themes are only short repeating monotoes and always play in the same key; it would be much more interesting when the keyboard would be usable to transpose them like with a single finger accompaniment, but on this boring instrument the keys do nothing in this mode.

With the atmosphere sound I called "baseball organ" I first thought it would be a 2nd gameshow sound track, but according to some old movies, such hammond organ fanfares and ascending monotos seem to be traditionally used in USA to accompany baseball or ice hockey matches in the stadium - similar like in Europe there is the tradition of circus bands those  accompany the performance of acrobats etc. in the circus with brass and drum kit music to increase suspension. Later both traditions obviously contributed strongly to the style of bonus fanfares and level end jingles of historical videogames.

The concept of the sound dial controlled sequencer is partly described in US patent 5350882; it even suggested a motor driven dial to mimic the behaviour of a turntable as scratch disc for DJ consoles, which over 20 years later got implemented in Casio XW-DJ1.
 

hardware details

The Casio SA-40 is built around the "OKI M6387-22" CPU. Thus technically this is a basic SA-series keyboard that only differs in software. Interesting is that the power amp IC AN8053N (16 pin DIL) also contains the 5V voltage regulator for the CPU. (I haven't analyzed this hardware further, but only read the service manual.)
The dial controller internally pushes down 3 plastic buttons with silicone rubber contacts.

keyboard matrix

This keyboard matrix is based on the Casio SA-40 service manual. I haven't analyzed this by myself, thus there may be still unknown eastereggs.
 
11 KI0
12 KI1
13 KI2
14 KI3
15 KI4
16 KI5
17 KI6
18 KI7
 
CPU pin
in 0
in 1
in 2
in 3
in 4
in 5
in 6
in 7
in / out
 
o
F3
o
F#3
o
G3
o
G#3
o
A3
o
A#3
o
B3
o
C4
out 0
30 KO0
o
C#4
o
D4
o
D#4
o
E4
o
F4
o
F#4
o
G4
o
G#4
out 1
29 KO1
o
A4
o
A#4
o
B5
o
C5
o
C#5
o
D5
o
D#5
o
E5
out 2
28 KO2
o
F5
o
F#5
o
G5
o
G#5
o
A5
o
A#5
o
B5
o
C6
out 3
27 KO3
O.
music box
O.
glass harp
O.
piano
O.
street organ
O.
trumpet
O.
flute
O.
violin
O.
wood bass
out 4
26 KO4
 
 
volume
+
FX.
train
FX.
car
FX.
quiz
FX.
cheer
FX.
animal
out 5
25 KO5
 
volume
-
stop
FX.
siren
P.
horror
P.
country/western
P.
carnival
P.
rap
out 6
24 KO6
dial
SW-A
dial
SW-B
dial
SW-C
 
 
 
 
 
out 7
23 KO7
D.
song 1
D.
song 2
D.
song 3
D.
song 4
D.
song 5
D.
song 6
 
 
out 8
22 KO8
 
The input lines are active-high, i.e. react on +Vs. Any functions can be triggered by a non- locking switch in series to a diode from one "out" to one "in" pin. All matrix lines have a 2.2k serial resistor. The inputs have behind that additionally a capacitor array "CNB8X101K" against GND (8x 100nF? - likely against EM interferences).
 

legend:
"o"
 = keyboard key
O.
 = preset sound ("orchestra")
FX.
 = sound effect
P.
 = phrase
D.
 = demo songs
orange
background 		 = easteregg (unconnected feature)
 
On Casio SA-40 the 6 demo melodies play polyphonic in a lovely mechanical musicbox style. Once the dial is turned, the demo speed becomes proportional to the turn speed (i.e. stops when you don't turn the dial, direction is ignored). The demo tunes are:
  1. Twinkle Twinkle Little Star
  2. Pop Goes the Weasel
  3. Lullaby (Brahms)
  4. Old MacDonald had a Farm
  5. Clap Your Hands
  6. O Christmas Tree
As far I know, no other Casio keyboard was ever equipped with a "magical sound dial" controller. The big dial on Casio Rapman RAP-1 instead simply simulates 2 button presses (playing 2 scratch noises) and also the big red knob on Casio PA-31 has nothing to do with it but is simply a pitch knob (potentiometer) for its effect sample buttons. A bigger keyboard with similar atmospheric sound patterns like Casio SA-40 was the Casio MT-540. A My Music Center variant in a case imitating SA-40 (with 2nd speaker instead of the dial) was released by Medeli as MC-27.
 
 removal of these screws voids warranty...    
WarrantyVoid
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