TEAC A-4010S

The TEAC A-4010S is a mid-high fidelity, 4-track, 2-channel stereo reel-to-reel tape deck produced in Japan from around 1966 to 1971. It is notable for its advanced features for the era, including a 4-head design and foil sensing auto-reverse playback.

Track and Head System

• 4-track, 2-channel stereo system with four heads: erase, record, playback, and a special reverse playback head for automatic tape direction switching.

• Heads feature a hyperbolic surface with a 3-micron gap for playback, precision-machined for wide frequency response and low crosstalk.

• Head material is permalloy with a complete front shield to enhance performance.

Tape Transport and Motors

• Three independent motors:
  One 4-pole/8-pole, 2-speed hysteresis synchronous capstan motor for precise tape speed control.
  Two 6-pole eddy current outer rotor reel motors developed by TEAC for stable rotation and tape tension.

• Tape speeds: 7½ ips (19 cm/s) and 3¾ ips (9.5 cm/s) with ±0.5% speed accuracy.

• Supports reels up to 7 inches (No. 7 size).

• Wow and flutter: 0.12% at 7½ ips, 0.15% at 3¾ ips.

• Rewind time: approximately 90 seconds for 370 meters (1200 feet) of tape.

Sound and Signal Features

• Frequency response:
  30 Hz to 20 kHz at 7½ ips (50 Hz to 15 kHz ±3 dB)
  40 Hz to 12 kHz at 3¾ ips (50 Hz to 7.5 kHz ±3 dB)

• Signal-to-noise ratio: approximately 50 dB.

• Crosstalk: 50 dB channel-to-channel at 1 kHz, 40 dB track-to-track at 100 Hz.

• Equalization follows NAB standards (50 µs at 7½ ips, 90 µs at 3¾ ips).

• Bias oscillation frequency increased to 100 kHz to expand recording frequency response and reduce FM broadcast interference.

Inputs and Outputs

• Microphone input: 0.25 mV minimum, 10 kΩ impedance.

• Line input: 0.14 V minimum, 100 kΩ impedance.

• Line output: 1 V at 10 kΩ load or more.

• Headphone output: suitable for 10 kΩ or higher impedance headphones.

• Connectors include RCA and DIN types.

Controls and Features

• Symmetrical push-button control system arranged in a T-shape for forward, backward, fast forward, rewind, and stop.

• Foil sensing device on tape enables automatic reverse playback at desired positions.

• Back tension adjustable to two levels for tape thickness.

• Automatic stop function linked to tension arm to stop transport at tape end or rewind completion.

• Independent microphone and line input level controls with mixing capability.

• Monitor selector switch to toggle between source and tape monitoring.

• 4-digit analog index counter for tape position tracking.

• Optional remote control compatibility.

• Power: AC 100V/117V/220V, 50/60 Hz, 110 W power consumption.

• Dimensions: 443 mm (W) x 442 mm (H) x 216 mm (D).

• Weight: approximately 20 kg (44 lbs).