Though not quite a quartet in number, the digital “musicians” behind the chance music generation of a bent Casio SA-2 are similarly focused in that, once the keyboard’s Change Trigger is pressed, a cohesive composition is performed by this small, but introspective, group. Their performance might evolve through astounding changes, instruments limited to, say, piano, drums and flute, all players continually sensitive to each other’s work. Or so it seems.
Built for David Harrington, founding member of the Kronos Quartet, this aleatron follows my original SA-2 chance-triggering system but with the modifications in the following notes…
The blue Power LED is housed in a 1960’s mini-incandescent pilot lamp hacked to accept the tiny LED.
Vintage red calibration dial is adjusted to increase/decrease the Chance Trigger’s power threshold.
Spherical Body Contacts are chrome balls with threaded holes for mounting and electrifying. These are more sensitive than the lightning BCs.
The last three (red) keyboard keys have been re-assigned, now devoted to the chance triggering routine:
A – Starts Demo tune.
B – Chance Trigger (deconstructs Demo into aleatoric sound movements).
C – Reset (tap after a crash, tap A to begin Demo and start routine again).
Chance triggering is now refined to a smooth and efficient operation, all important controls grouped within 1/2″ of each other. No push-button switches added to the instrument.
Casio’s strange color scheme of grey/orange/green has been replaced with a simple gloss red and textured gloss black. Bottom of case is finished in “nickel-satin” and looks very aluminum.
The re-assigned keys are game-changers. Simple. Powerful. Fun.
This Error Lamp turns on whenever someone in Congress makes a mistake. But it did go dark once. To protest a Congressional consideration to weaken the Clean Air Act I’d stopped paying my utility bill.
Custom Reset Switch finished in Cautionary Red with vintage gold hardware.
Vintage Green Glass Photo Cell Lens. This is an adjustable-shutter pilot light lens, military-spec avionics, 1950’s surplus, used here to vary ambient light reaching the vibrato photo cell behind it. Activated via toggle switch to left, vintage gold hardware.
Custom Light Show. This is a three-layer rotating fractal mandala backlit with color changes and a central violet sound-envelope LED (pulses with the chants as colors/patterns change around it). This animated lighting system is based on my Starve & Share Voltage Flanger. Once the associated DIY film is ready I’ll get into that here.
Brass Body Contacts. Instead of wiring these to the usual pitch points (raises freq) these are connected to SPK (-) and Song push-button frame. These contacts lower the pitch when touched, nice in contrast to the raised pitch of the photo cell (increases circuit stability, too).
Custom “OM” Frequency Dial. Behind this dial is a 5-Meg mini-pot allowing passage into “sub-sonics,” the freaky re-resolved chants that reside below basso. The reference gnomon is inset with a turquoise bead.
(DIY: Any such thing can be used as a dial. Find a plastic knob with brass sleeve and set screw. Crush it in a vise. Salvage the sleeve; epoxy it to the back of your object).
Custom Song Button. Matching turquoise.
Vintage White Milk Glass Pilot Light. White lens is mounted in brass and is back-lit with changing hues of red-violet-purple (again, part of the voltage-flanger circuit).
Speaker Switch with vintage gold hardware.
Full-sized 1/4″ output jack wired to audio section of board (line-level is constant regardless of volume dial or speaker switching).
Aesthetics were guided by existing color scheme and music (all my added components followed the bronze/gold theme where possible; the beautiful green of the adjustable lens was picked-up by the light show discs and turquoise stones).
In use, the instrument is set on its back, controls arranged accordingly with dial, sensor and contacts facing upward toward the musician. The potentiometer has super-smooth action. It can be easily adjusted with one finger while the other hand plays BCs and photo cell.
Via the pitch dial, all 29 chants have several viable, and very different, iterations. Very fun, very psychedelic sound machine.