TEAC AL-700 (1976) | Esoteric Series

The TEAC AL-700 Elcaset Deck was introduced in 1976 as TEAC's first—and only—Elcaset deck. Developed around the ambitious "Open reel sound on cassette" concept, it combined 6.3 mm-wide tape, high tape speed, and sophisticated open-reel-derived mechanics in a cassette format.

TEAC AL-700 Specifications

Model: TEAC AL-700 Elcaset Deck

Release: 1976

Track format: 4-track, 2-channel stereo

Head configuration: 3-head — erase, record, playback

Tape: Elcaset LC-60 / LC-90, Type I, Type II, Type III

Tape speed: 9.5 cm/s

Capstan motor: FG servo DC motor

Reel motors: Coreless DC motors ×2

Wow & flutter: 0.04% WRMS

Frequency response: 25 Hz–20 kHz ±3 dB, Type I; 25 Hz–22 kHz ±3 dB, Type II/III

Signal-to-noise ratio: 59 dB Type I; 62 dB Type II/III

Total distortion: 0.8% Type II

Fast rewind: Within 70 seconds with LC-60 tape

Inputs: Microphone and line, with independent level controls

Outputs: Line and headphone

Noise reduction: Dolby B, with external dbx capability

Power consumption: 37 W

Dimensions: 440 × 230 × 310 mm

Weight: 18 kg

Original sale price in Germany: 2.900 DM (dbx unit: 1.200 DM)

The Elcaset Concept

Elcaset was designed to bring open-reel performance to a cassette. The format was jointly developed by Sony, TEAC, and Technics and used 6.3 mm-wide tape—the same width used by open-reel machines—inside a much larger A-6-sized cassette. With a tape speed of 9.5 cm/s, the format offered considerably more tape area for recording than a conventional cassette. The result was an ambitious attempt to combine the convenience of a cassette with the sound quality associated with open-reel tape. A major difference was the outer tape guidance system. Instead of relying entirely on the precision of the cassette shell, the AL-700 pulled the tape out of the cassette and controlled it with the deck's own transport mechanism. This approach allowed TEAC to use sophisticated mechanisms such as a dual-capstan transport and three-head arrangement. TEAC's Open-Reel Technology in an Elcaset. Its three-motor drive system used an FG servo DC motor for the capstan and two coreless DC reel motors, directly reflecting TEAC's experience with three-motor open-reel machines. Twin-Belt Closed-Loop Dual Capstan. The twin-belt system was one of the AL-700's most distinctive mechanical features. Its closed-loop dual-capstan transport used two sets of capstans and pinch rollers to grip the tape and maintain controlled tension. The slight difference in capstan speed helped suppress tape movement and flutter caused by external disturbances. However, excessive speed differences could produce excessive tension, which was particularly undesirable with relatively thin Elcaset tape. TEAC therefore added a wide auxiliary belt directly to the outer flywheel. This belt acted almost like a mechanical servo, helping maintain soft and consistent tape tension while also reducing stress on the main drive belt and flywheel. High-Precision Fixed Head. TEAC also paid unusual attention to head mounting accuracy. The AL-700 used a fixed-head system derived from TEAC's in-vehicle data recorder technology. A precision die-cast structure and central locating pin determined the head's height, tangency, and tilt. Azimuth could then be adjusted with a single screw, allowing the head to pivot around the central reference point without changing its height. The result was a considerably more precise head-mounting system than the conventional three-point adjustment arrangement. Automatic Self-Aligning Pinch Roller. The pinch roller was another example of TEAC's data-recorder engineering. Several metal balls surrounding the roller shaft allowed considerably more movement than a conventional pinch roller. This gave the roller the ability to compensate for a tilted shaft or uneven rubber wear while maintaining even pressure against the capstan. Magnefloat Capstan. TEAC's Magnefloat system addressed unwanted capstan shaft movement. Magnets positioned near the flywheel and bearing used magnetic repulsion to keep the capstan shaft pressed against a defined point. Unlike a spring-loaded mechanical arrangement, the system produced very little mechanical noise and friction. It also avoided changes in clamping force caused by temperature variations and was designed for long-term durability. Three-Head Recording and Dolby Noise Reduction. The AL-700 used a true three-head configuration, with separate erase, record, and playback heads. The record and playback heads were made from high-hardness permalloy, while the erase head used ferrite. The deck supported Type I, Type II, and Type III Elcaset tapes, with automatic bias and equalization selection through detection holes in the cassette shell. Dolby noise reduction could also be selected automatically through the cassette's detection tab. The deck additionally incorporated an MPX filter to prevent problems caused by the 19 kHz FM stereo pilot signal during radio recording. For users wanting even greater noise reduction, TEAC provided a dedicated connection for the separately sold dbx RX-10 unit. Recording and Control Features. The AL-700 was far more sophisticated than a simple playback deck. Its microphone and line inputs had independent level controls, allowing microphone mixing during recording. A centrally positioned REC MUTE button made it possible to create silent sections while recording, while the large VU meters displayed average input level and independent peak indicators helped monitor momentary overloads. The transport was operated through soft-touch microswitches and logic circuitry. Additional functions included timer operation, memory auto-stop/auto-play, output volume control, mono/stereo switching linked to the microphone input, and a Dolby copy function. The Elcaset format itself provided automatic detection for tape type and Dolby selection, allowing the AL-700 to configure important recording and playback parameters without manual intervention.

External Accessories

The AL-700 could be expanded with dedicated accessories. TEAC offered the RX-10 dbx unit and RC-90 remote control as separately sold options. TEAC RX-10 dbx unit: ¥78,000 | TEAC RC-90 remote control: ¥10,500

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