Revox B77

The Revox B77 is a high-fidelity, professional-quality reel-to-reel tape deck produced from 1978 to 1983, designed as a successor to the renowned A77. It is celebrated for its precision engineering, robust build, and excellent audio performance.

Mechanical and Drive System

• Motors: Three-motor drive system with two AC coil reel motors and one electronically controlled AC capstan motor.

• Capstan Motor: Features a precision-machined toothed circumference read by a tachometer head, enabling fast servo feedback and exceptional speed stability. The capstan shaft is hard chrome-plated and machined to an accuracy of one-thousandth of a millimeter for long-term stability.

• Tape Speeds: Supports 3¾ ips (9.5 cm/s), 7½ ips (19 cm/s), and 15 ips (38 cm/s) speeds.

• Reel Size: Accommodates reels up to 10.5 inches (26.5 cm).

• Tape Slip: Maximum slip of 0.2%.

• Rewind Time: Approximately 135 seconds for 3,600 feet of tape.

Audio Performance

• Frequency Response:
  3¾ ips: 30 Hz – 16 kHz (+2 / -3 dB)
  7½ ips: 30 Hz – 20 kHz (+2 / -3 dB)
  15 ips: 30 Hz – 22 kHz (+2 / -3 dB)

• Wow and Flutter:
  <0.1% at 3¾ ips
  <0.08% at 7½ ips
  <0.06% at 15 ips

• Signal-to-Noise Ratio:
  Better than 64 dB at 3¾ ips
  Better than 67 dB at 7½ ips
  Better than 65 dB at 15 ips

• Crosstalk: >45 dB at 1 kHz

• Distortion:
  <1% at 0 VU (3¾ ips)
  <0.6% at 0 VU (7½ ips)

Electronics and Features

• Heads: Three heads (erase, record, playback) made from Permalloy or Revodur alloy for excellent electromagnetic properties.

• Equalization: NAB standard (3¾ ips: 90/3180 µs; 7½ ips: 50/3180 µs).

• Inputs: Microphone (low and high impedance), radio, and auxiliary inputs.

• Outputs: Line outputs (1.55 V), headphone outputs with volume control.

• Meters: VU meters with LED peak indicators for precise level monitoring.

• Additional: Infrared sensor for automatic shut-off; optional fourth head for audio-video synchronization or slide projector control.

Physical Specifications

• Dimensions: 452 mm (W) x 414 mm (H) x 207 mm (D)

• Weight: Approximately 17 kg (37.5 lbs)

• Power Consumption: Up to 80 VA

Variants and Upgrades

• The B77 MKII adds a variable speed control allowing ±10% tape speed adjustment for pitch correction and creative effects.

• Variants include quarter-track and half-track versions, with some models supporting additional tape speeds and professional features.