[net.rumor] Computer music from RFI

grt@twitch.UUCP ( G.R.Tomasevich) (03/22/86)

> > The TRS-80 Model 1 used to put out so much RF interference, that one
> > way of adding sound to ANY program was to put a small AM radio right
> > by the machine, and listening to the electronic "music".  Some

The IBM 1620 was RF noisy, too, and of course it had no such thing as D/A.
We would put am AM radio by it, too.  Someone had written several pieces
of music, which were available on decks of cards.  Someone had even written
a music compiler, which took notes, spelled out on cards, and produced
the notes.  I think, but am not sure, that that is how the composed pieces
were done.  This was at the Harvard Chemistry Dept.  Many computers
emitted a fair amount of RF from their console lamp drivers, including
the HP 2115A, the Data General Nova 1200, PDP-11.

Even modern equipment makes noise, sometimes audible.  We have an 8088
processor pack in a frame powered by a Western Electric 484AA power converter.
One can hear what the 8088 is doing by listening to the 484AA.
-- 
	George Tomasevich, ihnp4!twitch!grt
	AT&T Bell Laboratories, Holmdel, NJ