hifi engine

Manual Library / Sansui

Sansui QS-800A

4-Channel Decoder / 2 Channel Rear Amplifier (1973)

add a review (1 review)

Sansui QS-800A


The QS-800A is a combination of Sansui's new QS matrix system 4-channel decoder and a high performance 200 watt stereo amplifier to amplify the rear channel signals for 4-channel sound reproduction.

The decoder features the exclusive QS Vario-Matrix circuitry which provides optimum separation among the reproduced sounds.

When added to a present stereo system, this decoder and the rear channel amplifier will work together to (1) decode encoded 4-channel program sources back into 4-channel, and (2) transform (synthesize) conventional 2-channel sources into 4-channel.

The QS-800A as a whole also offers complete provisions for reproducing discrete 4-channel program sources and for reproducing 2-channel sources in 2-channel stereo if you so desire.

As such, it is the most complete, most authentic means of upgrading your stereo system to immediate 4-channel status.


Power output: 45W/ch into 8Ω (stereo)

Frequency response: 20Hz to 30kHz

Total harmonic distortion: 0.5%

Damping factor: 200

Input sensitivity: 150mV (line)

Signal to noise ratio: 80dB (line)

Output: 150mV (line), 30mV (DIN), 0.8V (Pre out)

Speaker load impedance: 4Ω to 16Ω

Semiconductors: 61 x transistors, 2 x FET, 39 x diodes, 1 x zener diode

Dimensions: 147 x 462 x 335mm

Weight: 15.5kg



 Login or register to post reviews

Reviewed Jan 07th, 2020 by

The most under rated Sansui misunderstood unit ever made by the leader In quadraphonic decoding. The 800 versus 800a are day and night apart with the A model having the holy grail decoder of the X001 models the various matrix decoder. This is the decoder that gives 20 dB and 30 dB seperation. This unit has so many settings like inverting phase shifting That actual moves sound. All the same settings as the X001 units and the outboard decoder QSD 2 another fantastic decoder. These are so misunderstood that they are inexpensive because people don’t understand how they work and that they actually have the most desired decoder in them that Sansui ever made. Take the pre outs from the tape loop from your main unit and connect to input of the 800A and you have a full quad unit with great seperation. Now the good the unit is very inexpensive But you will find the 500 and 800 model regularly but the 800A you probably have a better chance seeing Bigfoot than finding this unit in the field even on line they don’t show up much because they were made at the end of the quad era. A real quality vintage unit that is a sleeper when it comes to monetary value.



This website is not affiliated with or sponsored by Sansui. To purchase QS-800A spares or accessories, please contact the company via their website or visit an authorised retailer.