Reverberation Amplifier RA-900

Predecessor of the RA-990. Sansui said:

The addition of reverberation (or echo effects) to your stereo sources makes all musical reproduction seem much closer to the authentic realism of the original performance - concert hall realism, disco realism, much more. Now with the Sansui RA-900 the listening pleasure of your current Hi-Fi system is sure to be enhanced. This efficient unit has a special circuit with which to mix a tape, FM or record sound with another source - say, a microphone or guitar sound. It also accepts two stereo tape decks, cassette or open-reel, and permits dubbing in either direction. When you add up all these capabilities you quickly arrive at the fact that it's the most versatile and easy to use reverb amp available. Noise and distortion? Not with the RA-900. We've built it with select parts and advanced circuitry. Of the double pickup type, the RA-900 boasts no more than 0.05% total harmonic distortion and better than 96 dB signal to noise ratio.
Designed for instant 19-inch rack mounting.

Specifications:
Frequency response: 20 to 20,000 Hz
Input sensitivity: 1 mV (mic), 20 mV (guitar), 150 mV (source/tape)
Total harmonic distortion: 0.05%
Signal to noise ratio: 68 dB (mic/guitar), 96 dB (source)
Rated output: 150 mV (output/tape)
Reverberation time: 0 to 3 s
Semiconductors: 8 x transistors, 6 x diodes, 3 x IC
There is also mixing possible by adding voice or guitar sound. Input for Mic./Guitar and mixer at the front.

Here you find 435 models, 421 with images and 133 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from Sansui Electric Co., Ltd.; Tokyo