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





Revox A 76


A76 Revox Builds the tuner of the future.
The conventional design concepts for tuners are not satisfactory any more if one wants to reach the optimum in freedom from distortion and signal interference. Therefore, Revox have tossed overboard traditional ideas and by designing the "third generation tuner" they have  a whole leap forward.
The approach  has been thoroughly professional and without compromise. The input section features "dual gate" field effect transistors and quadruple variable capacitor tuning, while the IF-strip consists of a passive Gauss Filter, followed by an amplifier which is made up entirely of integrated Circuits (bandwidth 5 MHz). delay-lines are employed for demodulation without deteriorating the five megahertz bandwidth. A76 khz oscillator runs phase-locked to the subcarrier and supplies  after binary scaling the switching frequency to the stereo demodulator. Supplementary circuits permit silent tuning and effect automatic stereo changeover, they triogger a visual signal in th ecase of multipath reception and provide for th eindication of signal strength, centre tuning and the presence of a Stereo modulated carrier. To describe the distortion and noise free performance of  this tuner is virtually impossible.

Special Features:
Antenna Inputs:  60 ohms unbalanced (BNC); 240 ohms balanced (DIN)
RF-Input circuit with 2 MOS-FET and 4-section variable air - capacitor
Passiv gauss IF - Filter
Wideband IF - amplifier with 5 integrated circuits
Delay-line demodulator
Subcarrier regeneration with "phase locked loop" oscillator
Separate subcarrier demodulation with subsequent matrixing
Automatic stereo-mono selection
Silent tuning
Meters for Fieldstrength and Centre tuning indication
Stereo indicator light
Multipath warning light

Specifications
Tuning Range:  87,5 - 108 MHz
Sensitivity (60 Ω, 30 dB S/N, deviation 15 kHz):  1 µV
Static Selectivity 9at 300 kHz separation):  60 dB
Operational Selectivity (for two signals 100 µV and 1 mV, 40 kHz dev.at 1 kHz, 300 kHz separation):  80 dB
Spurious Response:  90 dB
Image Response:  70 dB
Bandwidth:
 IF Filter:  130 kHz
IF Ampl. And Demodulator :  5 MHz
Capture ratio:  1 dB
Pulse Noise Rejection (signal 100 µV and 1 mV peak per 100 kHz pulse noise, 75 kHz deviation):  40 dB
Distortion (40 kHz deviation at 1 kHz):  0,2%
Signal-to-Noise Ratio (unweighted, 75 kHz deviation):  70 dB
Stereo Separation:  40 dB 91 kHz)
Pilot Signal and Subcarrier Suppression: 40 dB
Audio Output (75 kHz deviation; adjustable, low internal impedance):  1 V
Frequency Response:  30 Hz - 15 kHz, -1 dB
Deemphasis:  50 µs
Semiconductor Complement:
Dual Insulated-gate FET :  2
Intergated Circuits :  6
Silicon Transistors :  41
Diodes :  27
Silicon Rectifiers :  2
Power Supply:  110, 130, 150, 220, 240, 250 V, 50/60 Hz
Power Consumption:  20 W
Dimensions (W x H x D):  415 x 160 x 245 mm
Weight:  7,8 kg (17,5 lbs)

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