Teac W-470 - User Manual

This document describes the TEAC W-470 Stereo Double Cassette Deck, a device designed for high-quality audio recording and playback using cassette tapes. The W-470 features a dual cassette mechanism, allowing for various functions such as continuous playback, high-speed dubbing, and simultaneous recording on two decks.

Function Description

The TEAC W-470 is a stereo double cassette deck, meaning it incorporates two independent cassette mechanisms, typically labeled Deck I (Play I) and Deck II (Rec/Play II). This dual-deck configuration enables a range of functionalities beyond what a single deck can offer.

Playback: The device supports playback from both Deck I and Deck II. Deck I is primarily a playback-only deck, while Deck II is a record/playback deck. This allows for continuous playback from one tape to another, or for listening to a tape while preparing another for recording. The W-470 is designed to handle standard cassette tapes (C-60 and C-90 Philips type).

Recording: Recording is performed on Deck II. The W-470 supports recording from external sources connected via the LINE IN input. It also features a microphone input for direct voice or instrument recording. The device includes equalization settings for different tape types: METAL, CrO2, and NORMAL, ensuring optimal recording quality for each.

Dubbing (Tape-to-Tape Copying): One of the key features of a double cassette deck like the W-470 is its dubbing capability. Users can copy content from a tape in Deck I to a tape in Deck II. The W-470 offers a "Hi-speed Dubbing" function, which significantly reduces the time required to copy a tape, making it convenient for users who need to duplicate cassettes quickly.

Noise Reduction: The W-470 incorporates Dolby noise reduction technology. This feature is crucial for improving the signal-to-noise ratio of cassette recordings, reducing tape hiss and enhancing the overall audio clarity during both recording and playback. The "DOLBY" trademark and the double-D symbol indicate its licensed use of this technology.

Head Configuration: The device is equipped with specialized heads for optimal performance. Deck I features a playback head, while Deck II includes a 1/2-track, 1-channel erase head and a 1/4-track, 2-channel record/playback head. This configuration ensures efficient erasing before recording and accurate stereo recording and playback.

Motor System: The W-470 utilizes DC servo motors for both Deck I (playback) and Deck II (record/playback). Servo motors provide stable tape speed, which is critical for minimizing wow and flutter and ensuring consistent audio quality.

Usage Features

The W-470 is designed for user-friendly operation with a clear layout of controls and indicators.

Front Panel Controls: The front panel typically includes controls for basic cassette operations such as Play, Record, Fast Forward, Rewind, Stop, and Pause for both decks. There are also dedicated buttons for functions like "Hi-speed Dubbing" and "Dolby NR" activation. Input level controls (RECORDING LEVEL) and a balance control are provided for precise audio adjustment during recording. A headphone jack with its own output level control allows for private monitoring.

Input/Output Connections: The rear panel provides LINE IN and LINE OUT RCA connectors for connecting to other audio components like amplifiers, receivers, or other recording devices. This allows for seamless integration into a home audio system.

Tape Type Selection: The W-470 features an automatic tape selector. This means the deck can automatically detect the type of cassette tape (NORMAL, CrO2, or METAL) inserted, and adjust the equalization and bias settings accordingly for optimal recording and playback performance. This simplifies operation as users do not need to manually select the tape type.

Monitoring: The device includes a meter display to monitor audio levels during recording and playback, helping users prevent clipping and ensure proper signal strength. The headphone output allows for direct monitoring of the audio signal.

Timer Function: The W-470 includes a timer knob, suggesting compatibility with external timers for unattended recording or playback. This can be useful for recording radio programs or for waking up to music.

Operation Position: The device is designed for horizontal operation, ensuring proper functioning of its mechanical components.

Maintenance Features

Regular maintenance is essential to ensure the longevity and optimal performance of the W-470. The service manual provides detailed instructions for various adjustments and checks.

Cleaning and Demagnetization: Before performing any adjustments or checks, it is crucial to clean and demagnetize the entire tape path. This includes the heads, pinch rollers, and capstans, as residue buildup and magnetization can degrade audio quality.

Mechanical Adjustments:

Wow and Flutter Check: This measurement assesses the stability of tape speed. The manual outlines a procedure using a TEAC MTT-111 test tape and a wow-and-flutter meter to ensure the reading is within specified limits.
Tape Speed Adjustment: The tape speed can be precisely adjusted using variable resistors (R31, R32, R33, R34) for both high and low speeds on both decks. This involves using a frequency counter and a 3,000 Hz test tone tape.
Reel Torque Check: The torque of the take-up, supply, fast forward, and rewind reels is measured using a cassette torque meter to ensure it falls within the specified ranges. This is important for proper tape handling and preventing tape damage.
Lubrication: The manual specifies the type of oil (TEAC spindle oil, Mobil D.T.E. Oil Light, or equivalent) and the points of application, such as the capstan shaft, when parts are replaced. Proper lubrication reduces friction and wear on moving parts.

Electrical Adjustments and Checks:

Playback Performance: This section covers checks for head azimuth, specified output level, frequency response, and signal-to-noise ratio during playback. Test tapes like MIT-150C, MIT-256, MIT-356, and MIT-5511 are used for these procedures.
Monitor Performance: This involves checking minimum input level, specified LINE input level, and headphone output level.
Recording Performance: This includes adjustments and checks for BIAS oscillation, record bias, record level, frequency response, and signal-to-noise ratio during recording. Various TEAC recording test tapes (MIT-5571 for METAL, MIT-5561 for CrO2, MIT-5511 for NORMAL) are used.
Azimuth Check: This critical adjustment ensures the recording/playback head is perfectly aligned with the tape path. It involves using an oscilloscope and an azimuth adjusting screw to achieve maximum output and correct phase relationship.
Voltage Conversion: For general export models, the manual provides instructions for adjusting the voltage selector on the rear panel to match the local power requirements (120V, 220V, 240V, 100V AC).
Safety Critical Components: The manual highlights parts marked with a special sign as "safety critical components." These parts must always be replaced with identical components to ensure the device's safe operation and compliance with safety standards.

The W-470 is a comprehensive cassette deck designed for enthusiasts who appreciate the versatility of a dual-deck system, offering both advanced recording capabilities and convenient tape duplication features, all while emphasizing precise adjustments for optimal audio fidelity.

Teac W-470 Specifications

General

Track System	4-track, 2-channel stereo
Motor	DC servo motor
Frequency Response (Normal Tape)	30 Hz - 14 kHz
Wow and Flutter	0.08% WRMS
Output	0.5 V (line out)
Outputs (Line Out)	500mV (line)
Power Supply	AC 120V, 60Hz