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Visual feedback for reverberation time. The two rainbows draw apart as time shortens.
Adjusts reverberation time by turning clockwise to lengthen or counterclockwise to shorten.
Operation of the power button and its indicator light.
Function of ON, OFF, and RECORD buttons for reverberation.
Options for selecting tape deck operational modes (REC/PLAY, DUBBING).
Instructions for proper grounding of the unit for optimal SN ratio.
Diagrams showing connections to receiver, control amplifier, and tape decks.
Guides on reverberating program sources, tape playback, recording, dubbing, and monitoring.
Tips on shielded cables, connections, noise reduction, and AC outlet capacity.
Information on identifying and replacing the power fuse with correct specifications.
How to adjust voltage selector and recommendations for unit placement.
Detailed technical data including output voltage, distortion, frequency response, and dimensions.
Visual representation of the unit's internal signal flow and components.
The Sansui RA-700 is a solid-state reverberation amplifier designed to enhance the stereo listening experience by adding reverberation effects to various audio sources. This unique component integrates seamlessly into an existing stereo control amplifier setup, offering a new dimension of sound for records, radio broadcasts, tapes, and even live recordings.
The primary function of the RA-700 is to introduce a controllable reverberation effect into an audio signal. Reverberation simulates the natural echo and decay of sound in a large space, making the audio sound richer and more expansive. The RA-700 can apply this effect to any program source connected to your stereo control amplifier, including playback from a tape deck, recording onto a tape deck, and even dubbing between two tape decks.
At its core, the RA-700 processes the incoming audio signal, adding a delayed and decaying replica of the original sound to create the reverberation. This processed signal is then mixed back with the original audio, outputting a more spacious and immersive sound. The device features a continuously controllable reverberation time, allowing users to fine-tune the duration of the effect to suit different types of music or personal preferences.
The RA-700 is designed for intuitive operation, offering several features that make it versatile and user-friendly:
Reverberation Mode Selection: The amplifier provides three main reverberation modes via pushbuttons:
Reverberation Time Control: A dedicated knob allows for continuous adjustment of the reverberation time. Turning the knob clockwise lengthens the reverberation time, making the sound decay more slowly, while turning it counter-clockwise shortens it. This control is crucial for tailoring the effect to different audio content, from subtle ambiance to dramatic echoes.
Reverberation Indicator: A distinctive multicolored indicator provides visual feedback on the reverberation effect. When the "Reverberation On" or "Record" button is pressed, the indicator illuminates. As the reverberation time is shortened, two rainbow-like patterns, one inverted, draw sharply and distinctly apart, offering a clear visual representation of the effect's intensity.
Tape Mode Selector: This selector is a key feature for integrating the RA-700 with tape decks, offering multiple positions for various tape operations:
Power Switch and Indicator: A simple push-button power switch turns the unit on and off. A corresponding power indicator light illuminates when the unit is on, providing clear status feedback.
Versatile Connection Options: The RA-700 is designed to connect to a receiver or control amplifier and up to two tape decks (Tape Deck A and Tape Deck B). This allows for a wide range of configurations, including adding reverberation to record players, tuners, microphones, and, of course, tape decks.
Dubbing with Reverberation: The RA-700 facilitates dubbing between two tape decks (A to B or B to A) with or without reverberation. By depressing the "Reverberation Record" button during dubbing, the reverberation effect can be incorporated into the copied tape. Alternatively, depressing the "Reverberation Off" button ensures the original tape is copied without any added effect.
Monitoring Capability: For tape decks equipped with their own preamplifier and separate recording/playback heads, the RA-700 allows for instant monitoring of the tape after recording, or even while recording is in progress. This is a valuable feature for ensuring the desired reverberation effect is being captured correctly.
The RA-700 incorporates several design elements and instructions to ensure its longevity and proper functioning:
Shielded Cable Requirement: The manual strongly emphasizes the use of shielded cables (four connecting cords are supplied with the unit) for connecting the control amplifier and tape decks to the RA-700. This is crucial for preventing hum or noise interference, which can degrade audio quality. It also warns against loose connections, which can lead to abnormal performance and potential damage over time.
AC Outlets: The rear panel includes two unswitched AC outlets with a maximum total capacity of 300VA. These are provided for convenience, primarily for plugging in tape decks. Users are cautioned not to exceed the rated capacity to prevent overloading.
Power Fuse: The unit is protected by a power fuse. If the unit fails to power on, the manual guides the user to check and replace the fuse with an identical glass-tubed fuse (0.5A for 100-117V operation, 0.3A for 220-240V operation). This is a standard safety and maintenance feature, preventing damage from electrical surges. The manual explicitly warns against using wire or a fuse of a different capacity as a substitute.
Grounding Terminal: A GND terminal is provided on the rear panel for grounding the unit. Connecting this terminal to an earth ground (e.g., a copper plate buried underground) is recommended to achieve a better signal-to-noise (SN) ratio, reducing unwanted noise and improving sound clarity. For an entire audio system, connecting the grounding wire of each component to this terminal is advised.
Voltage Adjustment: The RA-700 features a voltage selector, accessible by removing two screws from the nameplate on the rear panel. This allows the unit to be adapted for operation at different AC line voltages (100V, 117V, 220V, or 240V). Users are instructed to adjust this selector to the required voltage and to change the power fuse accordingly when altering the voltage setting. This feature ensures compatibility with various power grids worldwide and can also be used to mitigate issues caused by significant voltage fluctuations by setting it to the peak voltage.
Placement Recommendations: While the RA-700 can be placed in any convenient position, the manual recommends placing it away from speakers. This is to prevent "unnatural reverberation or booming noise" that could occur if the unit is too close to the sound source, ensuring the generated reverberation is purely electronic and controlled.
In summary, the Sansui RA-700 is a sophisticated yet accessible reverberation amplifier designed to enrich the audio experience. Its robust feature set, including flexible reverberation control, comprehensive tape deck integration, and thoughtful maintenance guidelines, makes it a valuable addition to any stereo system seeking to add depth and spaciousness to its sound.
General| Type | Reverberation Amplifier |
|---|---|
| Total Harmonic Distortion (THD) | 0.5% |
| Frequency Response | 20Hz to 20kHz |
| Input Sensitivity | 150mV (line) |
| Signal to noise ratio | 70dB (line) |
| Dimensions | 420 x 150 x 300 mm |
| Weight | 6.5 kg |
| Total harmonic distortion | 0.5% |
| Signal-to-Noise Ratio | 75dB |
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