September 2014 — The Model 47A Interface builds on the strengths of the popular Model 47 and offers significant improvements:
- Smaller and Lighter
The Model 47A is smaller and weighs considerably less than the Model 47. The overall depth of the unit has been reduced by almost two inches (5.1 cm). The Model 47A is 8.4 inches (21.3 cm) deep while the Model 47 was 10.3 inches (26.2). Changing most of the material used in the enclosure from steel to aluminum has reduced the weight by almost 4 pounds (1.8 kg). The Model 47A weighs only 4.7 pounds (2.1 kg) but still maintains a steel front panel for rugged performance in rack-mount applications.
- Party-Line (PL) Output Current
The Model 47A's four party-line DC power sources have been slightly improved. The maximum current is now 315 milliamperes (mA), a small increase over the 300 mA that the Model 47 provided. While not significant, this 5% increase will provide extra "margin" for supporting the connected party-line user devices.
- Improved Circuitry and Software
The internal switch-mode power supplies were revised to provide increased efficiency. The audio level meter circuitry was completely re-designed using state-of-the-art components to offer improved flexibility and enhanced performance. A new-generation of microcontroller integrated circuit was included allowing faster and more-accurate software performance.
But what's stayed the same?
The Model 47A maintains the "look and feel" of the original. All inputs and outputs from the Model 47 are present in the new unit and, of course, use the same type of connectors. For ease of service, maintenance, or updating a Model 47A is directly "pin-for-pin" compatible with the Model 47. The Model 47A can be a "drop in" replacement for a Model 47. The front panel is essentially identical to the Model 47 so users will have the same positive experience that they've become accustomed to: flexible configuration, intuitive controls and displays, and great audio performance.