SANSUI QSC-9050

Commentary

A 4-channel preamplifier that uses SANSUI's original QS Barrio matrix circuit.

The decoder circuit uses SANSUI QS regular matrix method.
The QS Regular Matrix system consists of 90 degree phase shifters based on a square matrix. The QS Barrio Matrix, a state-of-the-art proprietary technology, is used to reproduce the signals, providing optimal separation for audibility and improving musical performance.
Moreover, the newly developed 2-4 conversion encoder circuit can change the conventional 2-channel source to 4-channel one.

In the conventional matrix 4-channel system, there was a tendency for the phase relationship between the two rear speakers to be reversed. In order to solve this problem, a 90-degree phase shifter is installed. The phase is shifted by -90 degrees to the left rear and by + 90 degrees to the right rear (opposite to the encoder) and returned to the positive phase, thereby realizing accurate sound localization.

The QS Barrio matrix circuit is an application of an acoustic phenomenon called directional masking. It uses a phenomenon in which when two sounds of different sizes and directions reach the ears simultaneously, the human ears are distracted by the direction of the strong sound and the direction of the weak sound is masked.
In the QS Barrio matrix circuit, the matrix coefficient is changed instantaneously to control the directivity of the main signal (strong sound) so as to improve the separation between each channel.
A special phase discriminator is used for control, and a control signal obtained by detecting the phase of the input signal is used. Unlike gain control technology, the amount of signal energy during playback is not different from that of the input signal. In theory, the Barrio matrix circuit can obtain infinite channel separation by selecting the control level of the matrix coefficient. However, in view of music playback, Sansui sets the value to the most appropriate value for listening.

The QS Regular Matrix Method incorporates a newly developed 2-4 conversion encoder circuit that further improves the original SANSUI synthesizer function. When a normal 2-channel source is played back, the signal is subjected to special processing and then effectively converted into four channels by the QS Barrio matrix circuit that follows.

Equipped with 4-2 conversion encoder and 2-4 restoration decoder.
When the encoder is used on the recording side, all four channel sources are changed to the conventional two channel signal form. Therefore, record cutting technology and equipment can be used as they are, and four channel broadcasting is possible without changing the equipment of FM broadcasting station.
You can use the decoder function for effective playback of regular matrix 4-channel records such as QS or FM4-channel broadcasts.

It is equipped with a phase matrix function by adding a slight additional circuit to the QS Barrio matrix circuit, and it consists of a front / back logic circuit unique to SANSUI.
This makes it possible to play back four channel sources created by the SQ method with sufficient separation.

Equipped with a discrete 4-channel playback function, you can play 4-channel discrete sources by connecting a playback device such as a 4-channel tape deck or CD-4.

Equipped with a function function, you can control the optimum sound field from among 7 positions depending on the recording method of the source, songs, composition, etc.
The QS Synthesizer-Surround uses a QS Barrio matrix circuit and a newly developed 2-4 conversion encoder circuit to convert ordinary stereo records, tapes and FM stereo broadcast transmission into four surround channels, while the QS Synthesizer-Hall uses a QS Barrio matrix circuit and a newly developed 2-4 conversion encoder circuit to reproduce live performances of ordinary stereo records, tapes and FM stereo broadcast transmission with a hall effect.
QS Regular Regular Matrix-Surround, you can play four surround channels of four channel regular matrix sources, such as the QS method, through a QS Barrio matrix circuit. With QS Regular Matrix-Hall, you can play live four channel regular matrix sources, such as the QS method, through a QS Barrio matrix circuit.
Phase Matrix allows you to play 4-channel records, tapes, and FM stereo broadcast transmission created using the SQ method.
4-channel playback is possible with Discrete by connecting a 4-channel tape deck or CD-4 player.
2 ch is used to listen to the program source of 2 channels.

A 3-stage PNP-NPN-PNP direct connection circuit is used for the equalizer circuit.
The 3-stage direct-coupled equalizer circuit combines three transistors to supply a high voltage of 44 v from a constant-voltage power supply, and uses carefully selected feedback elements such as resistors and capacitors with little error.

The tone control amplifier uses a 2-stage direct connection circuit of PNP-NPN in the front stage, and a wide dynamic range and stability are secured even with the tone control booth.
In addition, the 4-channel volume is installed in the latter stage, and the S/N is improved because the volume can be used where the signal is large.

An emitter-follower circuit is used in the output stage, and the output impedance is designed to be low.
In addition, the pop noise generated when the power is turned on / off is eliminated by a transient canceler.

A constant voltage power supply circuit is adopted to enable stable operation.

Model Rating

Type	4-channel preamp
Input Sensitivity / Impedance (1 kHz)	Phono1, 2 : 2.5mV/50k Ω 4 ch Tuner, 4 ch Aux1, 2, 4 ch Tape mon1, 2 : 100mV/50k Ω Tape mon (PIN), Tape mon (DIN) : 100mV/50k Ω
Output Voltage / Impedance (1 kHz)	2 ch Tape rec (PIN) : 100mV/2k Ω 2 ch Tape rec (DIN) : 30mV/65k Ω 4 ch Tape rec1, 2 (PIN) : 100 mv 4 ch Pre out1, 2 : 800mV/600 Ω 6.5 V (Maximum Output, THD 0.5% or Less)
Total harmonic distortion factor	0.05% or Less (Rated Output)
Cross modulation distortion factor	0.05% or Less (Rated Output, 70 hz : 7 khz = 4 : 1 SMPTE)
Frequency Characteristics (Rated Output)	Tuner, Aux1, 2, 4ch/2ch Tape mon : 10 Hz to 90 kHz ± 1.0 db
Crosstalk (rated output, 1 kHz)	Phono1 and 2 : 45 dB or more 4 ch Tuner, Aux1, 2 : 50 dB or more 4 ch Deck1, 2 : 50 dB or more 2 ch Deck : 50 dB or more
Hum and noise (IHF)	Phono1, 2 : 70 dB or more 4 ch Tuner, Aux1, 2 : 80 dB or more 4 ch Deck1, 2 : 80 dB or more 2 ch Deck : 80 dB or more
Tone control	Bass : ± 15 dB (50 Hz) Treble : ± 15 dB (15 kHz)
Loudness (Volume-30dB)	+ 8 dB at 50 Hz, + 3 dB at 10 kHz
Synthesizer / decoder	Sansui QS Regular Matrix Method (built-in QS Barrio matrix circuit)
Semiconductor used	Transistor : 66 FET : 2 Diode : 45 pcs
Rated power consumption	15W (16.5 VA max)
External dimensions	Width 440x Height 140x Depth 322 mm
Weight	9kg