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

Acoustic Research Receiver

 The earliest high-fidelity components were designed during the vacuum-tube era, and generally followed broadcasting practice in separating tuner, power amplifier, preamplifier and power supply, each circuit section on its own chassis.
The characteristics of transistors, primarily their small size, cool operation and indefinitive service life, permit the consoloidation of all of the electronic circuitry needed in a high-fidelity system into one component, the receiver.
The AR silicon solid state FM receiver is an integrated stereo FM tuner, stereo preamplifier and power amplifier, mounted on one chassis.  FET front end with 4-section capacitor, multisection crystal IF filter, IC IF amplifiers, and 2µV sensitivity insure superb FM reception.
 The AR receiver was under development for some time. When the amplifier section was completed, several years ago, it was offered to the public as a separate component.  High Fidelity, citing test reports from CBS laboratories, stated, "It is, in our view, an unqualified success, a truly excellent and unimpeachable amplifier … (at 20% more than its rated power) it either met or exceeded it specifications … the IM distortion characterisctics must be counted as the best we've ever seen …" Stereo Review called the amplifier's power "staggering", and added, "it ranks among the very best available."
 Circuit Characteristics
(FM) FET front end with 4-section variable capacitor;
Multisection crystal IF filter;
IC (integrated circuit) IF amplifiers;
Automatic interstation noise suppression with defeat switch for very weak stations;
Automatic mono/stereo FM switching with stereo indicator light;
Low-distortion shunt multiplex detector;
Tuning meter.
(Amplifier) DC driver clamping for clean overload recovery;
Idling power supply eliminates turn-on transient noises;
Bass and treble separately controlled for each channel;
Differential loudness compensation curves in bass control circuit;
Special null circuit permits exact balancing of stereo source material;
Stable under short-circuit of output terminals;
Line fuse, speaker fuse and self-resetting circuit breakers for full protection.
The AR receiver is guaranteed for 2 years from date of purchase.
 The receiver has now been completed by the addition of the circuitry required for stereo FM broadcast reception which is in every respect the counterpart of the performance of the amplifier. The receiver circuit is all-silicon solid state; the most rigorous manufacturing and inspection techniques we know are used in its assembly. The receiver is guaranteed for 2 years
While no compromise is made with optimum performance, the AR receiver is lower inprice than might be expected. This is because of the rational approach taken in its design. The AR Receiver is as sensitive, precise and powerful a unit as is ever likely to be needed in the home. In addition, it is one of the simplest to operate; as in the best of professional equipment, control functions have been limited to those which are actually needed.

Applicable IHF test standards are used for the following guaranteed performance specifications.
Switched Input Circuits:  magnetic Phono; Tape Playback;  Extra high-level input pair ("Special")
Outputs:  tape record;  4 - 16 Ω speakers;  headphone jack on front panel;  output to amplifier for center-channel or mono extension speakers.
FM Section
Sensitivity:  2,0 microvolts or better (hush control "off").
Signal-to-Noise Ratio:  65 dB ASA "C" weighting (flat)
Harmonic and IM Distortion (Mono or stereo):  less than 0,5%
Frequency Response:  20 to 15,000 Hz  ±1 dB (mono or stereo)
Capture ratio:  2 dB or less
Separation:  35 dB minimum at 50 Hz; 40 dB minimum at 400 Hz; 30 dB minimum at 10,000 Hz
Control Amplifier Section
Power Output (measured with both channels driven):
60 watts per channel RMS at 4 Ω
50 watts per channel RMS at 8 Ω
30 watts per channel RMS at 16 Ω
Distortion (at any level up to and including full rated power)
IM Distortion (60 and 7,000 Hz, 4:1):  less than 0,25%
Harmonic Distortion:  less than 0,5% from 20 to 20,000 Hz
Power Supply:  110 - 220 V  50/60 Hz
Dimensions (W x H x D):  16-5/8" x 5-11/16 x 11-1/8"(without cover)
With Optional wood cover:  17-1/4" x 6" x 11-1/8"

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