User Manual

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System A - 100 3. A-100 signal flow

Trigger or Gate Signals, which start a process or

function, are typically from 0 V to +5V or 0V to +12 V,

with the trigger occurring as the leading edge of the

waveform shoots up from 0 V to +5V/12 V. The A-100

modules usually output +12V, but the corresponding

inputs of A-100 modules (e.g. Gate, Clock, Reset) will

also work with lower levels (typ. +5V).

These definitions of the various signals, and the di-

stinctions between them - sound sources and modula-

tion sources - are right in principle, but a modular

system like the A-100 often makes a mockery of them.

In a modular set-up, all of the modules produce volta-

ges, and can be used as control voltages or triggers,

thus blurring the distinction between the various types.

For example, the output from an LFO can be used as

an audio signal, as a control voltage for a VCF or VCA,

or as a trigger signals for a sequence.

It’s just about true to say that anything can be modula-

ted by anything else, so that a modular system gives

the musician extraordinary flexibility and individuality.

3.3 The System Bus in the A-100

The A-100’s System Bus supplies power to the modu-

les. It also carries the internal control system

(INT.GATE and INT.CV), which some of the modules

(such as the VCO A-110, or ADSR A-140) can tap into.

You can choose whether these modules receive these

signals, by altering an internal jumper.

Fig. 7: The A-100 system bus

If you use the A-190 MIDI-/CV-Interface in your sy-

stem, when you press a key on your MIDI keyboard,

the gate and CV1 signals from the A-190 will be sent

via the INT.GATE and INT.CV to all modules on the

bus.

The INT.GATE and INT.CV signal busses can be split

into two equal halves by removing jumpers J1 and

J2 (see Fig. 7), so that for each whole bus, you can

have two separate CV/GATE subsystems.

INT. Gate

INT. CV

+5 V

+12 V

GND

-12 V