ARIES MUSIC / SERIES AR-300 MODULE DESIGN INFORMATION

MODULE CONSTRUCTION
All Aries Music Series-300 modules have front panels of 3-inches x 9-inches x 1/16-inch black anodized aluminum. They are durable and rugged and cannot be scratched during normal use. Because all modules have identical dimensions, any system can be easily configured or re-arranged to suit each synthesist's preferences and needs.
The module frames are single pieces of 1/16-inch aluminum. There is a round hole in the rear of the frame and a 1/4-inch phone jack may be mounted so that a foot pedal controller can be patched into the back of the instrument.

Each module is inserted into a 22-pin edge connector; the distance between adjacent pins is 0.156-inch. The edge connector supplies the module with power and enables the normal connections to be made.
In a normal connection, the output from a module is wired from the tip of an output jack to one of the unused pins of the edge connector. This pin is hard-wired to another module's edge connector. This is, in turn, wired to the shunt of an input jack of the second module. When there is no plug inserted in this input jack, the shunt makes a mechanical and electrical connection to the tip of the input jack and the signal path from one module's output to another's input is complete. When a plug is inserted into the input jack, the normalled connection is broken. Normalled connections are usually made to attenuated inputs.

SIGNAL LEVELS
Aries Music modules are designed to be compatible with most synthesizers. All AR-300 Series modules require a +/- 15 Volt power supply. The VCO outputs, gate and triggers are 10-Volt peak-to-peak signals. Control sensitivity of all exponentially controlled modules is 1-Volt / Octave. The VCAs and VCFs are direct-coupled, allowing voltage control of the amplitude and waveshape of sub-audio frequency control signals as well as of audio signals.

INPUT / OUTPUT IMPEDANCES
Most module input impedances are 50k ohms minumum. This allows a single output to drive a number of inputs without significant loading. Most module inputs are summing nodes, which permits easy modification to accommodate additional inputs. Signals at control inputs are summed algebraically. Output impedances are nominally 1k ohms, allowing outputs to be shorted together and averaged at a set of multiple jacks. Some modules' outputs, notably the sequencer position gate outputs and the Switch's out/in jacks can be "wire or'd". This permits a multiple jack configuration to accomplish the "logical or" function.

PATCH CORDS
The standard Aries Music connector is the Switchcraft 42A subminiature phone jack. All patch cords should use the miniature phone plugs with pointed rather than rounded tips. Since there is no industry-wide standardization of miniature phone jacks, as there is with 1/4-inch phone jacks, using the correct patch cord is essential to making a dependable electrical connection even after hundreds of insertions. Using miniature jacks on our modules allows us to save front panel space, and to allow many dual and multi-function modules.