Otari MX-55

The Otari MX-55 is a professional ¼-inch, 2-track, 2-channel stereo reel-to-reel tape recorder designed for studio use, known for its rugged construction, precise tape transport, and high-fidelity analog audio performance.

• Tape Width and Track Configuration: ¼ inch (6.3 mm) tape, 2-track, 2-channel stereo system, compatible with NAB or DIN equalization standards.

• Tape Speeds: Switchable speeds of 15 and 7.5 ips (38.1 and 19.05 cm/s), changeable internally to 7.5 and 3.75 ips (19.05 and 9.5 cm/s).

• Speed Accuracy: Within ±0.2% with a pitch control allowing ±20% continuous variable adjustment in 0.01% increments via a multiturn encoder servo system.

• Reel Size: Accepts reels from 3" EIA up to 11.8" DIN hubs, with different reel sizes usable on supply and take-up sides.

• Tape Length: Supports tape lengths up to 3,280 feet (at 50 μm tape thickness).

• Motor Configuration: Three motors — a DC brushless capstan motor with quartz PLL controlled direct drive and two AC induction motors for reels.

• Heads: Three heads (record, playback, erase) made of permalloy, in a stacked/inline configuration with plug-in head blocks allowing independent height, tilt, and azimuth adjustment.

• Frequency Response:
  15 ips: 30 Hz to 20 kHz ±2 dB
  7.5 ips: 20 Hz to 18 kHz
  3.75 ips: 20 Hz to 10 kHz

• Signal-to-Noise Ratio (unweighted):
  MX-55N: 71 dB at 15 ips, 69 dB at 7.5 ips, 64 dB at 3.75 ips
  MX-55D: 72 dB at 15 ips, 69 dB at 7.5 ips, 65 dB at 3.75 ips

• Wow and Flutter:
  ±0.06% at 15 ips
  ±0.08% at 7.5 ips
  0.12% at 3.75 ips

• Total Harmonic Distortion: Maximum 0.3% at 1 kHz, 250 nWb/m, 15 ips.

• Bias and Erase Frequency: 150 kHz.

• Equalization: Switchable NAB or IEC.

• Inputs/Outputs: Balanced XLR connectors for line and mic inputs and outputs, transformerless active balanced circuitry.

• Additional Features:
  Front panel pitch control with fine resolution.
  Built-in tape timer displaying hours, minutes, and seconds, with search-to-cue locator and memory functions.
  Optional Voice Edit Mode (VEM) for double-speed playback without pitch shift.

• Dimensions and Weight: Approximately 440 x 222 x 488 mm, weighing about 30 kg (67 lbs).

• Power Supply: Multi-voltage support (110-120V and 220-240V).

• Build: Rugged die-cast aluminum alloy deck plates and side frames for mechanical stability.