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

B&O Beomaster 1900

 The Beomaster 1900 Receiver
The dramatic center of the Beosystem 1900 is the Beomaster 1900 receiver. Its operation borders on magical, its performance is without audible flaw,,its aesthetics are beyond reproach. It is a component which has truly domesticated high fidelity.
All major functions of the 1900 receiver are controlled by touch-sensitive electronic switches: the sculpted depressions aligned along the top panel. They are volume, input selection, selection of up to five user pre-set FM stations, and standby. These controls function electronically, completely eliminating mechanical linkages which can wear out or become misaligned (estimated to cause approximately 80% of service problems).
 When any of the electronic controls are touched, a lighted indicator immediately appears directly above. You always know the operational status of the 1900, even from across the room.
 The 1900 also allows you to pre-set up to five FM stations for instant, electronically accurate recall. Four separate tuning indicators and the main random tuning dial are located under the aluminum lid. By tuning the four indicators to those stations you listen to most frequently, they may be recalled by simply touching their respective control on the front panel. The main tuning dial can also be set at a preferred station and this station immediately recalled by a control on the front panel. Random tuning is accomplished by a flush-set tuning control moved effortlessly by a single finger. Also, positioned under the aluminum cover is the AFC which, when in effect, eliminates drift from the stations you select.
Also found under the aluminum lid are the controls for adjusting bass, treble, and balance between your speakers. These controls are smooth sliding potentiometers. Easily viewed, illuminated indicators are used to show visually the extent to which the controls have been moved from their neutral position.
 The Beomaster 1900 receiver has a split power supply which provides optimum performance throughout the frequency range. All output transistors are usd conservatively and an electronic protection circuit automatically respondes to any overload, breaking the circuit and preventing any damage from occuring to receiver or speakers. The tuner section of the 1900 utilizes FETs for high sensitivity and selectivity,PLL circuitry is used to guarantee excellent channel separation and greater long term circuit stability. Ceramic filters and integrated circuits in the IF amplifier and stereo decoder provide excellent separation and low harmonic distortion.

Amplifier Section
Power Output (1000 Hz RMS):  2 x 30 W at 4 Ω; 2 x 20 W at 8 Ω
Music Power :  2 x 50 W at 4 Ω ; 2 x 30 W at 8 Ω
Speaker Impedance:  4 Ω
Harmonic Distortion:
1000 Hz, 50  mW :  less than 0,07%
DIN 45 500, 40 - 12,500 Hz :  less than 0,13%
Intermodulation DIN 45 500 :  less than 0,15%
Frequency Range (±1,5 dB DIN 45 500):  20 - 40,000 Hz
Power Bandwidth (1% distortion):  10 - 40,000 Hz
Damping Factor (1000 Hz):  better than 70
Input Sensitivity/Impedance:
Pick-up:  3 mV/47 k Ω
Tape:  220 mV/ 470 k Ω
Signal-to-Noise Ratio (DIN 45 500):
Pick-up (50 mW) :  better than 60 dB
Tape recorder (50 mW):  better than 65 dB
Channel Separation
1000 Hz (DIN 45 500):  better than 56 dB
250 - 10,000 Hz :  better than 38 dB
Output Level:
Tape Recorder (1000 Hz DIN 45 500):  100 mV/100 k Ω
Headphones :  max, 6 V/200 Ω
Bass Control at 40 Hz :  ±18 dB
Treble Control at 12,500 Hz :  ±15 dB
Tuner Section
FM Range:  87,5 - 108 MHz
Sensitivty [stereo 46 dB]:  less than 30 µV/75 Ω
Signal-to-Noise Ratio  [stereo, weighted]:  better than 60 dB
Frequency Range (DIN 45 500, ±1,5 dB):  20 - 15,000 Hz
Harmonic Distortion (DIN 45 500):  less than 0,4%
Stereo Channel Separation (1000 Hz):  better than 35 dB
Pilot Suppresion
At 19 kHz:  better than 45 dB
At 38 kHz :  better than 50 dB
General Section
Power Supply:  110 - 130 - 220 - 240 V; 50/60 Hz
Power Consumption:  25 - 185 W
Dimensions (W x H x D):  620 x 60 x 250 mm
Weight:  7,6 kg

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