Sony EM-2

The Sony EM-2 reel-to-reel tape deck is a portable monaural tape recorder designed primarily for professional use, such as field recording and newscasting. It features a Mono full-track permalloy head configuration and uses a single motor for tape transport. The deck is typically powered by batteries and outputs its signal through XLR connectors for professional audio use.

Key technical specifications include:

• Tape speed: 3¾ and 7½ inches per second (ips)

• Frequency response: 50 Hz to 15,000 Hz

• Head type: Permalloy

• Track system: Mono, full track (one audio channel)

• Power: Battery-operated

• Outputs: XLR balanced audio output

• Number of motors: 1 motor for drive

The most important technical shift from the EM-1 to the EM-2 was the move away from the spring-powered motor to an all-electric drive, reflecting improvements in motor and battery technology:

• Motor Type: The EM-2 uses an all-electric motor for the transport. This eliminates the need for the governor-controlled spring drive and the user's need to manually rewind the spring motor.

• Power Source (Battery Requirement):
  Motor Drive: The transport motor required a bank of batteries, typically 8 x D-Cell batteries (Motor).
  Amplifier/Electronics: The audio amplifier required separate batteries, typically 6 x C-Cell batteries (Amplifier).

• Design Rationale: By moving to an electric motor, the EM-2 was able to achieve superior speed stability (lower Wow and Flutter) and higher fidelity (better frequency response) than the purely mechanical spring-driven EM-1, all while reducing the overall weight. The multiple battery banks were required to provide isolated, stable power for the high-torque motor and the low-noise audio circuits.

In essence, the EM-2 sacrificed the absolute mechanical independence of the EM-1's spring motor for superior audio performance and reduced size/weight, making it a highly advanced, battery-powered portable recorder for its time.

This model continues Sony's line of portable, reliable reel-to-reel recorders designed for robustness and easy field use. Like the EM-1, the EM-2 is focused on professional audio capture rather than consumer stereo playback, with a frequency range suitable for voice and general sound recording applications.