Audio boards with SC-01


MA-216 advanced boards

Presentation of our work and clarification on the operation of the audio card with speech synthesis.


Sound cards MA-216 (B-20887) are equipped to some pinballs of a VOTRAX SC-01 speech synthesis circuit. There are several variants of these cards, but are easily recognized by those with this circuit, as for example the model below for Mars (# 666) with the SC-01 located at lower-left:

Audio board with SC-01

We improve these cards, replacing the amplifier and using a single PROM as we can see below, this model for the Mars with the two sets of voice in French and English:

Audio board with SC-01


Advanced sound cards are totally autonomous systems, with their own CPU 6502. The program flying these boards is specific to each model, even if we find some common features. According to the pinballs, sounds or voices are not generated in the same ways and are organized with different priorities. Thus, some sounds correspond to mood music that are played in a loop, other one-time sounds, finally others like the TILT cancel all other current sounds.

SC-01 is in principle a circuit for speech synthesis by phonemes, but on some pinball machines, it is also used in the generation of some sounds.

Features of cards with SC-01

When a card is expected to work with the SC-01, the presence of this circuit is mandatory. Indeed, one might think that in the absence of this component, the map could operate normally, except much hollowing out of voice messages. But, it did is nothing and without this circuit the card will end up to crash.

The reason is the CPU expect the SC-01 acknoledge after each issued phoneme. As long as the signal is not received, the CPU is stuck in a loop to wait.

If the SC-01 is not mounted, as long as the sounds playing card do not appeal to this circuit, the operation seems normal. But as soon as the SC-01 will be sought, the map will remain blocked in an infinite loop (because not acknoledged).

This is exactly what is happening on a Black Hole, if it tries to use the sound without the SC-01 card. As long as the ball is on the top Board, sounds are normally issued. However, when the ball passes on the lower playfield, the emitted sound is then "vortex". This particular sound uses the SC-01, and therefore non-presence of this circuit caused crash of the sound card.

Pinball machines using the MA-216 cards with SC-01
(and examples of voice messages)

Mars God of War
SYSTEM 80 #666

A French version was produced for export.

playShoot stargate for hyperforce playBattle is over Mars is supreme
playAbattez stargate pour obtenir force supreme playLa bataille est terminée Mars est le vainqueur

SYSTEM 80 #667

The French version for export remains to the prototype stage.

playIt's gonna blow playFire pit
playCa va exploser playLa pluie de feu

Black Hole
SYSTEM 80 #668

The export version has only a simple non-talking MA-55 board.

playDo you dare to enter the black hole playTILT

Devil's Dare
SYSTEM 80A #670

The export version has only a simple non-talking MA-55 board.

playDanger playSLAM

SYSTEM 80A #672

A French version was produced for export.

playToo bad you lost ah ah ah playRound ten
playToo bad vous perdez playRound dix

The translation of the export version is sometimes partial ("Too bad, vous perdez").

SYSTEM 80A #675

A French version was produced for export.

playNice move playNational hymn
playBeau joue playHymne national

The translation of the export version is sometimes approximative ("Beau joue" for "nice move").

Q*Bert's Quest
SYSTEM 80A #677

Generated voices are a sequence of random phonems.

playQ*Bert 1 playQ*Bert 2


playCaveman wake up playDon't eat me

Pinball machines using the MA-216 cards without SC-01

This models are initialy expected to speak and has been shipped with a full MA-216 board.
For costs reasons, this option has been abandonned and the SC-01 has not been installed.

Haunted House
SYSTEM 80 #669

Not speaking initially, but can become (read this article).

SYSTEM 80A #676

Not speaking, but have some pleasant musics.

playMusic 1 playMusic 2

Only 10 models produced.


The MA-216 boards with SC-01 have, in the GTB PROM test, a message to check the quality of the voice:

playPlease listen to be sure I'm speaking correctly

About the VOTRAX SC-01

The documentation on the SC-01 are relatively rare and difficult to find. We provide below, most useful.

Dictionary (maybe incomplete, but can serve as a reference):

Originally VOTRAX first started by building the ML-1 which was a rack driven by RS-232C and equipped with eight boards (including some protected by molding epoxy). This module built in analog technology was designed in order to be incorporated later into a single chip. In fact it is the prototype of the SC-01.

Although this circuit appeared as early as 1980, its principle was the subject of a patent application until 1982, which finally published in 1984. One can verify that this document uses effectively, the schemas of the ML-1.

SC-01 patent:

Last update of this page: December 11th, 2019

French Tech


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