A voltage-controlled oscillator module for modular synthesizers, offered in kit or assembled form by Aries during the mid-1970s.
Overview
The Aries AR-317 is a modular synthesizer VCO (Voltage Controlled Oscillator) that was sold in the mid-1970s. It provides four simultaneous waveform outputs and features VCO sync to an external square wave. Designed for a 10V signal level standard, it includes six internal trimmers for calibration of 1V/octave response, initial frequency, sawtooth amplitude and offset, and sine wave purity and symmetry. The module has two unused front panel jacks, which can be repurposed for functions like linear FM input.
Specifications
| Frequency Range (Manual Control, 2 ranges) | 0.03 Hz to 30Hz |
| Waveform Outputs | Four simultaneous outputs |
| VCO Sync | External square wave sync supported |
| Inputs/Outputs | Two unused jacks on front panel |
| Adjustments | T1 (1V/Octave), T2 (Initial Frequency), T3 (Sawtooth Amplitude), T4 (Sawtooth Offset), T5 (Sine Purity), T6 (Sine Symmetry) |
| Signal Level Design | 10V signal levels |
| Original Price (1975) | $69.50 (kit), $139.00 (assembled) |
| Original Price (1977) | $125.00 (kit), $182.00 (assembled) |
Design
The AR-317 was available as a kit or factory-assembled module. Its PCB is single-sided tin with no solder mask, making pads prone to lifting. It includes a potted exponential converter module (U8) with three transistors and a tempco resistor, where the NPN transistor is known to fail. The PCB mounts in two plastic rails secured by angle brackets and screws. Build notes suggest adding linear FM via a 330k resistor from an unused jack to pin 4 of U8, with AC coupling possible using a 0.1 µF capacitor. Options for the unused jacks include AC or linear FM inputs, or small 1/8" potentiometers. Restoration reports note clean waveforms, excellent stability, and no drift. However, original builds show non-uniform components, wiring inconsistencies, cold joints, solder bridges, tin whiskers, and mechanical issues causing shorts.
Market
Common issues include kit build errors, improper repairs, lifted PCB pads with cracked traces, and mechanical interference. The restorer observed that transistor pinouts on the PCB (E-B-C) conflict with datasheet specifications for some types like the 2N3393 and NTE85 (E-C-B), leading to incorrect installation. NPN transistors fail more frequently than PNP. The performance of each module depends heavily on the builder's skill, as most units appear to have been assembled from kits with variable quality.
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