What is stereo?

There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.

H.H. Scott '59

Sansui 771

FM/AM Stereo Receiver
You enjoy greater stereo power and superior stereo performance at much less cost with Sansui's newest medium-priced FM/AM stereo receiver, the 771. thanks to its refined CBM (Circuit Board Module) construction, the 771 outperforms many higher-priced receivers in the field. Here's how.

Thanks to CBM, which simplifies construction, reduces costs and increasas electronic capabilities, the moderately-priced 771 is able to offer a very superior power amplifier - an all-stage direct-coupled OCL powerhouse delivering a continuous RMS 40W/40W (total music power of 140 watts) to drive up to two stereo pairs of speakers at a time with less than 0,5% THD and a urprisingly wide power bandwidth of 15 to 40,000 Hz. Its FM/AM tuner features an MOS FET equipped FM section with sensitivity of 2,0 µV (IHF) to pull in the fuzziest of stereo signals with surprising clarity. And its preamplifier and control sections are equally outstanding providing inputs and controls for two stereo tape decks, two Aux, a microphone circuit, a superior 2-stage direct-coupled phono equalizer, distortion-free tone controls with FETs, audio muting, low/high filters and loudness, and a unique stereo/mono switch which bypasses the FM multiplex circuit when it is turned to mono position.
 Exclusive Sansui CBM design improves performance while reducing costs.
Sansui developed the unoque CBM technique specifically for its finest 2- and 4-channel studio and consumer products. This new design concept increases electronic capability and dependability, reduces wiring and size, and greatly lowers the expense of construction and chassis assembly. The 771 incorporates four such CBM units, one each for its tuner, preamplifier, power amplifier and power supply sections. Ordinary receivers with considerably higher price tags require up to a dozen complicated and potentially troublesome circuit boards to produce the same results.
 Sensitive FM tuner with integrated circuits and MOS FETs
The RF amplifier in the 771's newly-designed FM frontend uses a dual-gated low-noise MOS FET and a 4-gang tuning capacitor to pull in distant or weak signals with high resolution while rejecting undesired interference from stronger adjacent stations. The F amplifier and FM mixer stages are coupled through a double tuning circuit to achieve excellent selectivity, intermodulation and image characteristics. Outstanding FM sensitivity is 2,0 µV (IHF). The FM IF section incorporates three bi-resonator ceramic filters, a sharply-limiting 2-stage 2-IC differential amplifier and a phase-compensation circuit for greater phase linearity. The sum effect of these devices is reflected in the receiver's excellent FM capture. AM suppression and S/N ratios and its low THD performance.

Newly-developed IC-equipped FM Multiplex demodulator.
The 771's new FM multiplex demodulator features a high-density IC for improved stability. Stereo separation is better than 35 dB and THD in stereo FM reception is less than 0,6%. An FM de-emphasis switch inside the chassis allows the 771 to be easily converted for ideal reception of FM signals anywhere in the world.
Wide-Range, whine-free AM tuner.
Like the FM section, the circuitry of the 771's superior Am tuner is designed for the sharp, clean reception and reproduction of both local and distant signals. It features a 2-gang tuning capacitor, and a bi-resonator Jaumann type ceramic filter to eliminate AM whine and other annoying noise. The built-in AM ferrite bar antenna is space wound and highly sensitive.
 Dependable, independent amplification power.
An all-stage direct-coupled OCL semi-complementary power amplifier is employed in the 771 to provide dependable and extemely clean stereo power to drive even the largest of stereo speaker systems with ease. Thanks to a differential amplifier in its initial stage and its dual plus/minus power supply, independent from the supply stages in other parts of the receiver, you have at your command a full 40 watts of continuous RMS power per channel (into 8 ohms at 1 kHz, both channels driven). Its power bandwidth is especially wide - from 15 to 40,000 Hz -  while THD and IM Distortion figures are both held to a low, 0,5% or below at any power level up to the rated power output. This means that you can enjoy clear-cut high-fidelity reproduction of a broad audio spectrum from the rich and mellow bass tones to tingling and transparent highs.

Other Features:
Easy-to-read linear tuning scale and smooth-tune mechanism.
Direct-coupled low-noise phon equalizer.
Microphone circuit for extra convenience.
NF type tone control amplifier with FETs.
Two tape record/playback circuits and two stereo Auxiliary inputs.
Power protection a plenty.
Attractive champaigne-gold front panel with user-oriented control display.
All-wood cabinet with cushioned no-mar feet.
Audio Section
Power Output (at rated distortion)
Music Power (IHF) : 140 W (4Ω, 1kHz);  110 W (8Ω, 1kHz)
Continuous Power
Each Channel Driven : 55/55 W (4Ω, 1kHz);  45/45 W (8Ω, 1kHz)
Both Channels Driven : 40 + 40 W (8Ω, 1kHz);  32 + 32 W (8Ω, 20-20,000Hz)
Total Harmonic Distortion (at rated power output):
Overall (fromAUX) : less than 0,5%
Intermodulation Distortion (at rated power output, 70Hz : 7,000Hz = 4 : 1 SMPTE method)
Overall (from AUX) : less than 0,5%
Power Bandwidth (IHF):  15 to 40,000 Hz
Frequency Response (at 1 Watt power output)
Overall (from AUX) : 15 to 30,000 Hz,  +1  -2 dB
Equalization (at tape Rec output):  RIAA Curve (30 to 15,000 Hz ±1 dB)
Load Impedance:  4 to 16 Ω
Damping Factor:  60 (8Ω)
Channel Separation (1kHz at rated power output)
Phono : better than 45 dB
Aux 1, 2 : better than 45 dB
Hum and Noise (IHF)
Phono : better than 70 dB
Aux 1, 2 : better than 80 dB
Input Sensitivity and Impedance (1kHz for rated poer output)
Phono : 2,5 mV/ 50 kΩ (Max. Input capability 200 mV at rated distortion)
Mic (monophonic) :  2,5 mV/50 k Ω
Aux 1, 2 : 100mV/50 kΩ
Play Pin Jacks : 100 mV/50 kΩ
Rec/Play DIN Socket : 100 mV/50 kΩ
Tape-2 (4-ch adaptor)
Play Pin jacks : 100 mV/50 kΩ
Recording Output
Rec Pin Jacks : 100 mV
Rec/Play DIN Socket : 30 mV
Tape-2 (4-ch adaptor)
Rec Pin Jacks : 100 mV
Switches and Controls
Bass : +12 dB, -12 dB at 50 Hz
Treble : +12 dB, -12 dB at 10,000 Hz
Loudness : +10 dB at 50 Hz;  +8 dB at 10,000 Hz
High Filter : -10 dB at 10,000 Hz (6 dB/oct)
Low Filter :  -10 dB at 50 Hz (6 dB/oct)
Tuner Section
FM Mode
Tuning Range:  88 to 108 MHz
Sensitivity (IHF):  2,0µV
Total Harmonic Distortion
Mono : 0,4%
Stereo : 0,6%
Signal-to-Noise Ratio:  better than 60 dB
Selectivity:  better than 60 dB
Capture Ratio:  2,0 dB
Image Rejection:  better than 70 dB at 98 MHz
IF Rejection:  better than 90 dB at 98 MHz
Supurous Response Rejection:  better than 80 dB at 98 MHz
Spurious Radiation:  les than 34 dB
Stereo Separation:  better than 35 dB at 400 Hz
Frequency Response:  30 to 12,000 Hz;  +1 -3 dN
Antenna Input Impedance:  300Ω balanced (75Ω unbalanced)
AM Mode
Tuning Range:  535 to 1,605 kHz
Sensitivity (Bar Antenna):  50 dB/m at 1kHz
Selectivity:  better than 28 dB at 1MHz
Image Frequency Rejection:  better than 80 dB/m at 1Mhz
IF rejection:  better than 80 dB/m at 1MHz
Semiconductors:  49 Transistors;  25 Diodes;  3 FETs;  3 ICs;  4 Zener Diodes
Power Requirements
Voltage : 100,117, 220, 240 V  50/60 Hz
Consumption : 100 W (rated), 310 VA (max.)
Dimensions (W x H x D):  480 x 135 x 300 mm (18-7/8" x 5-3/8" x 11-13/16")

Weight:  12 kg (26,4 lbs ) Net;  14,6 kg (32,7 lbs) Packed

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