Technics RS-610US / RS-610USD Dolby System Hi-Fi Cassette Deck
The Technics RS-610US and RS-610USD are high-fidelity cassette decks featuring the Dolby System for noise reduction, an HPF (High Performance Frequency) head, and an auto-stop mechanism. These models are designed to provide quality audio recording and playback for stereo cassette tapes.
Function Description
The core function of this device is to record and play back audio on standard cassette tapes. It supports both recording and playback operations, with features aimed at enhancing audio quality and user convenience. The Dolby System is integrated to reduce tape hiss during recording and playback, resulting in a cleaner audio signal. The HPF head is likely designed for improved frequency response and durability. An auto-stop mechanism protects the tape and the deck by automatically stopping the tape transport at the end of a side or in case of a tape jam.
The front panel provides essential controls and indicators for operation:
- Eject button: Releases the cassette compartment.
- Record button: Initiates the recording process.
- Rewind button: Rewinds the tape.
- Fast forward button: Fast forwards the tape.
- Playback button: Starts tape playback.
- Stop button: Stops tape transport.
- Pause button: Temporarily pauses tape transport during recording or playback.
- Head cover: Protects the tape heads.
- Tape counter and reset button: Displays tape position and allows resetting the counter.
- Cassette cover: Encloses the cassette tape.
- Level meters: Visually indicate audio input/output levels, crucial for setting optimal recording levels.
- Power switch: Turns the unit on/off.
- Record indicator: Illuminates when the unit is in record mode.
- Balance control: Adjusts the left/right channel balance.
- Record level control: Adjusts the overall recording input level.
- Tape selector: Optimizes the deck's performance for different tape types (e.g., normal, CrO2).
- Dolby NR switch: Engages or disengages the Dolby Noise Reduction system.
- Microphone jacks: Inputs for connecting external microphones.
- Headphone jack: Output for private listening.
The rear panel includes connectivity options:
- Earth terminal: For grounding the unit to reduce hum and noise.
- LINE OUT jacks: Audio outputs for connecting to an amplifier or receiver.
- Record/playback connection socket (DIN): A multi-pin connector for integrated record/playback connections with compatible DIN equipment.
- LINE IN jacks: Audio inputs for connecting external audio sources (e.g., tuner, turntable with pre-amp).
- AC power cord: Connects the unit to mains electricity.
- AC voltage selector switch (RS-610US only): Allows selection of different AC input voltages to suit various regions.
Important Technical Specifications
Power Source:
- RS-610US: AC: 90~109, 110~125, 200~219, 220~250 volts, 50/60 Hz (selectable via AC voltage selector switch).
- RS-610USD: AC: 220 volts, 50/60 Hz (fixed).
Power Consumption: Approx. 8 W
Motor: Electronic speed control motor, ensuring stable tape speed.
Transistors: A variety of transistors including 2SC1327 (4), 2SC644 (2), 2SC828 (14), 2SA564 (2), 2SC1347 (3), 2SK37 (2).
Diodes & Rectifiers: OA90Z (6), 1S1211 (6), EQA0108 (1), SIB0102 (2).
Recording System: AC bias, 85 kHz. This high-frequency bias helps to linearize the recording process and reduce distortion.
Erase System: AC erase.
Tape Speed: 4.8 cm/s (1-7/8 ips.), the standard speed for compact cassettes.
Track System: 4-track, 2-channel stereo, allowing for stereo recording and playback.
Frequency Response:
- 20~14,000 Hz (with normal tape)
- 20~16,000 Hz (with CrO2 tape)
Signal to Noise Ratio:
- Dolby NR OUT: 49 dB
- Dolby NR IN: 59 dB at 10 KHz (This indicates a significant improvement in noise reduction when Dolby is active).
Wow & Flutter: 0.12% (WRMS), ±0.25% (DIN45507). These low figures indicate stable tape movement and minimal pitch variations.
Inputs:
- 2-MIC: 0.3 mV (applicable), MIC impedance 200~600Ω.
- 1-DIN: 0.3 mV/2 KΩ.
- 2-LINE: 60 mV/470 KΩ.
Outputs:
- 1-DIN: 420 mV/3 KΩ.
- 2-LIN: 420 mV/50 KΩ.
- 1-HEADPHONE: 8Ω.
Fast Forward and Rewind Time: Approx. 90 seconds with C-60 cassette tape.
Dimensions: 336mm (W) × 116mm (H) × 290mm (D) [13-1/4" (W) x 4-1/8" (H) x 11-1/2" (D)].
Weight: Approx. 6 kg (13-1/4 lbs.).
Usage Features
The Technics RS-610US/USD is designed for straightforward use, offering features that enhance the recording and playback experience:
- Dolby System: A key feature for improving audio fidelity by reducing tape noise, especially noticeable in quieter passages.
- Tape Selector: Allows the user to optimize the deck's equalization and bias settings for different tape formulations (e.g., Normal, CrO2), ensuring the best possible frequency response and lowest distortion for each tape type.
- Level Meters and Record Level Control: Provide visual feedback and manual adjustment for recording levels, essential for preventing distortion (over-recording) and ensuring a strong signal-to-noise ratio (under-recording).
- Microphone Inputs: Enable direct recording from microphones, making it suitable for live recording or voiceovers.
- Headphone Output: Allows for monitoring recordings and playback without disturbing others.
- Auto Stop: A protective feature that automatically stops the tape at the end of a side or if the tape jams, preventing damage to the tape and the deck's mechanism.
- Electronic Speed Control Motor: Contributes to stable tape speed, which is crucial for accurate pitch and low wow and flutter.
Maintenance Features
The manual provides detailed instructions for mechanical and electrical adjustments, indicating that the device is designed for serviceability.
Disassembly Instructions:
- Top Cover and Bottom Plate Removal: Involves removing specific screws (4 for top cover, 6 for bottom plate) to access internal components.
- Back Board Removal: Requires removing 12 screws.
- Front Panel Removal: Involves removing knobs, front panel holding screws, and level meter holding screws.
- Cassette Case Assembly Removal: Requires removing 2 screws.
Mechanical Adjustments:
- Pressure Roller Adjustment: Ensures proper tape contact with the capstan for stable transport. Measured with a spring gauge (400±50 gr) and adjusted by bending the pressure roller spring.
- Takeup Tension Measurement & Adjustment: Critical for stable tape winding and preventing tape spills. Measured with a cassette torque meter (55±15 gr-cm) and adjusted by turning the plate spring.
- Tape Speed Deviation: Checked with a 3 kHz test tape (C-WAN) and a digital frequency counter (±3% or less). Adjusted via a VR (variable resistor) inside the motor.
- Wow & Flutter: Measured with a 3 kHz test tape (C-WAN) and a wow meter (0.12% WRMS, ±0.25% DIN45507).
- Detecting Piece Tension: Ensures the auto-stop mechanism functions correctly. Measured with a spring gauge (50±10 gr) and adjusted by bending the detecting piece spring.
Electrical Adjustments:
- Head Azimuth Adjustment: Crucial for optimal high-frequency response and channel separation. Involves playing an azimuth test tape (C-AAN 6.3 kHz) and adjusting the R/P head angle screw (A) for maximum output at the LINE OUT jack, monitored with a VTVM or oscilloscope.
- Amplifier Adjustments: A comprehensive set of adjustments for various amplifier stages, including:
- Playback frequency response and gain.
- Bias oscillation frequency and erase current.
- Recording bias current and bias trap coil adjustment.
- Standard recording level and level meter adjustment.
- Overall frequency response.
- Overall Frequency Response Adjustment: Involves recording and playing back signals across a range of frequencies (40 Hz to 12 kHz) and adjusting coils (L5, L6) to ensure the response falls within specified limits.
- Dolby NR Circuit Adjustment: Ensures the Dolby noise reduction system operates correctly, involving setting specific input levels and adjusting VRs (VR9, VR10, VR11, VR12) to achieve specified output levels at test points (TP3, TP4).
These detailed adjustment procedures highlight the professional-grade design and the ability to maintain the deck's performance over time. The inclusion of part numbers for all components, categorized by mechanical, electrical, and cabinet parts, further supports comprehensive maintenance and repair.
To Next Page
Need help?
General
