Connections
All signals within the system are patched with 4mm Banana cables and sockets. All signals, being
voltages, can be freely patched, but it can help to distinguish between the two major groups of
functions:
•
Main Path
– Typically a signal input / output functional block to which some form of
process is applied. A Filter, for example, could have one Main Path input and one Main Path
output and within the functional block the process of filtering is applied. I have previously
called this the Audio Path, but most modules are DC-coupled, meaning that they can equally
process audio or sub-audio voltages.
•
Control
– This is a signal which combines with the settings of the function control dials to
automate processes and is the basis of 'voltage control'. Again taking a Filter as an example,
the Frequency CV input (attenuated and/or inverted via the modulation depth setting) is
summed with the setting of the main Frequency control dial to determine the operating
Cutoff Frequency. You can think of a Control signal as being an automated knob twiddler
and these can work at sub-audio or audio rates.
If you consider a module as a functional block, it will generate or process an audio (or sub-audio)
signal via the Main Path, with the behaviour being governed by combination of knob settings and
any Control signals applied.
Colours play a key role in helping to quickly identify functions within the system. Sockets can
generally be classified as follows:
Main Path
Control
Input
Yellow
Blue
Output
Green
Red
Colours also help identify the function of dials:
•
Red/Orange – for the main module control functions
•
Yellow/Green – for input/output level control (eg. Mixing)
•
Blue – solely for CV modulation depth
In all areas there can be exceptions and blurred boundaries – full details are given in individual
Module sheets. Simply note that voltages can function as Main Path and/or Control signals
depending on what they are patched to – a VCO can be sound source and a modulator, for example.