The Tandberg TCD 340 A is a stereo cassette deck designed for high-fidelity audio recording and playback. It features a sophisticated three-head, three-motor, and dual-capstan transport system, which is indicative of its professional-grade capabilities. The inclusion of a Dolby NR system (B-type) further enhances its performance by reducing tape hiss during recording and playback, ensuring a cleaner audio signal.
Function Description:
The TCD 340 A operates as a comprehensive stereo cassette deck, allowing users to record and play back audio on standard compact cassettes. Its three-head configuration (erase, record, and playback) enables real-time monitoring of the recorded signal, a feature typically found in higher-end decks. The dual-capstan drive system, a hallmark of Tandberg's design philosophy, ensures stable tape tension and speed, minimizing wow and flutter for accurate sound reproduction.
The deck offers both microphone and line-level inputs, providing flexibility for various recording sources. The front panel includes dedicated input level controls for both left and right channels, along with output level controls, allowing for precise adjustment of audio signals. A monitor switch enables users to listen to either the source input or the tape playback, facilitating accurate recording level setting and quality control.
Playback features include standard play, rewind, stop, and wind functions. The unit also incorporates a memory function, allowing users to quickly return to a specific point on the tape. An azimuth calibration oscillator is built-in, which is crucial for optimizing the alignment of the record head for different tapes, ensuring the best possible high-frequency response.
Important Technical Specifications:
While specific numerical specifications (e.g., frequency response, signal-to-noise ratio) are not explicitly detailed in the provided pages, the manual highlights several key technical aspects:
- Transport System: 3 Heads, 3 Motors, Dual Capstan. This configuration is designed for superior tape handling, reduced wear, and excellent speed stability. The dual capstan system, in particular, isolates the tape path from the cassette shell, leading to lower wow and flutter.
- Noise Reduction: Dolby B-type NR system. This is a standard and effective noise reduction technology for cassette decks, significantly improving the signal-to-noise ratio.
- Tape Compatibility: The deck supports different tape types, specifically Type I (Normal) and Type II (CrO2/High Bias). The manual outlines adjustment procedures for both tape types, indicating optimized performance for each.
- Oscillator Frequency: The internal oscillator operates between 80 and 100 kHz, with a voltage of 25-32 volts measured on the erase head. This ensures effective erasure of previous recordings.
- Input/Output Levels: Sensitivity adjustments are made to achieve 775 mV at the Dolby encoder output and 775 mV at the Dolby decoder output, indicating a robust internal signal path.
- Speed Check: The speed accuracy is specified at < ±0.5% (995 to 1005 Hz) when playing a 1000 Hz test cassette.
- Wow and Flutter: The wow and flutter specifications are impressive for a cassette deck: Weighted RMS < 0.09% and Weighted Peak DIN 45511 < 0.2%. For record/playback, the weighted RMS is < 0.12%. These figures demonstrate the effectiveness of the dual-capstan system.
- Distortion: Maximum record/playback distortion is specified at 3% at 0 dB deflection on the meters.
Usage Features:
The TCD 340 A offers several user-friendly features designed for precise control and high-quality audio:
- Input Level Meters: The front panel features clear output and input level meters for both left and right channels, allowing users to visually monitor signal levels and prevent clipping.
- Tape Type Selection: A dedicated "Tape" button allows selection between Type I and Type II tapes, ensuring proper equalization and bias settings for optimal recording and playback with different cassette formulations.
- Dolby NR Control: A "Dolby N.R." button enables or disables the Dolby noise reduction system, giving users control over noise reduction based on their preference or the recording.
- Monitor Function: The "Monitor" button allows switching between "Source" (listening to the input signal) and "Tape" (listening to the recorded signal), which is essential for real-time monitoring during recording.
- Memory Function: A "Memory" button likely allows the tape counter to stop at a preset point (e.g., "0000"), facilitating easy navigation to specific sections of a recording.
- Headphone Output: A headphone jack with a dedicated level control allows for private monitoring of audio.
- Counter and Reset: A digital tape counter with a reset button helps track tape position.
- Eject Button: A standard eject button for convenient cassette loading and unloading.
Maintenance Features:
The manual provides detailed instructions for electrical adjustments and general maintenance, emphasizing the importance of proper calibration for optimal performance:
- Pre-Adjustment Cleaning: Before any adjustments, the tape path must be cleaned and demagnetized. This is a critical step to ensure accurate measurements and prevent damage to tapes or heads.
- Ordered Adjustment Procedure: The adjustments must be carried out in a specific order as they affect each other. This systematic approach ensures that each parameter is correctly set relative to others.
- Accessibility: Removing the top panel, base panel, and right side panel provides access to the internal components for adjustments.
- Required Equipment: A list of necessary equipment, including voltmeters, audio signal generator, frequency counter, distortion meter, wow and flutter meter, and specific Tandberg test cassettes (No. 21, 22, 23, 24), is provided. This indicates the precision required for calibration.
- Bias Adjustment: Procedures for adjusting bias for both Type I and Type II tapes are detailed, using pots like C1502, C1602, and R1508. Correct bias setting is crucial for optimal frequency response and low distortion.
- Record Current Adjustment: Separate procedures for adjusting record current for Type I and Type II tapes (using R108, R208, R109, R209) ensure consistent recording levels across different tape types and monitor positions.
- Playback Level Adjustment: Playback level is calibrated using test cassette No. 24 and pots R119 and R219 to achieve 775 mV at the Dolby decoder output.
- Level Meter Adjustment: Both playback (R114, R214) and record (R113, R213) level meters can be adjusted to ensure accurate visual representation of audio levels.
- Azimuth and Height Adjustment: Detailed instructions for adjusting playback and record head azimuth and height are provided, including the use of test cassettes and the built-in azimuth calibration oscillator (10 kHz). This is vital for maximizing high-frequency response and channel separation.
- Frequency Response Check: The manual emphasizes checking the frequency response in both Source and Tape modes, with specific instructions for sweeping the audio generator and adjusting curve with C1502 and C1602 to achieve a flat response (± 3 dB, 30 to 18000 Hz).
- Erase Test: A procedure to test the erase head's effectiveness by recording and then erasing an overload signal.
Overall, the Tandberg TCD 340 A is a meticulously engineered stereo cassette deck, designed for enthusiasts and professionals who demand high performance and precise control over their audio recordings. Its robust construction, advanced transport system, and comprehensive calibration features underscore its commitment to audio fidelity.
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