[sdiy] Re: [AH] CEM / SSM Chips used in non-synths? ~``~

[Travis Shire]

> I've also seen reference to the CEM3394 as the Bally/Sente chip.  I
> think they may have been used in some video game machines?  The 3394 is
>

Yep. They were used in the sound generator board for the Bally/Sente SAC-1
cartridge system. Basically the mid-80s predecessor of the Neo Geo
replaceable cartridge (field convertable) arcade game.

The cabinets looked like
this:http://www.arcadeflyers.net/?page=flyerdb&subpage=flyer&id=3059&image=1

It was a 6 voice digitally controlled analog synth. Pretty much a six trak
board without the extra circuitry for interfacing to keyboards and buttons.

I'm in the process of building a synth out of one of these boards. They can
be easily modded to accept midi input (adding an opto isolator).

Analog sound circuitry was very common on most early arcade games. Asteroids
used 555 timers and filters to generate sounds. Space Invaders, Vanguard,
and Stratovox used discreet analog circuitry along with SN76477s for sound.
Star Castle was especially impressive with its 2 oscillator detuned drone.
I was an arcade game technician for many years and got to know most games
sound generation circuity very well through troubleshooting "missing" or
"just wrong" sounds. Still have a large collection of old games and boxes
and boxes full of boards.

Fun stuff!