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





Marantz Model 15 (Fifteen)

 The Marantz Model 15 Solid State Stereo Power Amplifier is an instrument without precedend in performance and rugged reliability. As renowned audio authority Julian Hirsch exclaimed, "if any amplifier can be termed ''indestructible''. This is the one." two independant and identical monophonic amplifiers, each with its own power supply, are bracked together and mounted to a handsome gold anodized front panel that matches both the Model 7T preamplifier and Model 10B tuner. Because the channels are completely isolated, you suffer no power loss, "cross-talk', or other interactions that oftentimes occur from simultaneous operation of both channels with only one power supply. The amplifiers are direct-coupled, providing instantaneous recovery from overload and full rated power throughout the full frequency range. At any audio frequency, and on any output impedance from 4 to 16 ohms, the Model 15 is lower than on any other currently available power amplifier. You can use the Model 15 with any loudspeaker on the market, from  a 4 Ω acoustic suspension system to the 16 Ω electrostatic. And, a built-in fool-proof protection circuit gives instantaneous and unobtrusive protection without causing annoying program interruptions.
 All of these features combine to bring you completely reliable operation - year in and year out. The performance of the marantz Model 15 establishes wholly new standards of technical excellence for amplifiers of all types.
 Safety Circuit - A new, current-limiting circuit developed by Marantz protects both output and driver transistors from output short circuits, open circuits, capacitive loads or any type of complex reactive loudspeaker loading. Accidental open - or short-circuiting, even with full-power, 20,000 Hz output is completely safe. Short circuits during operation activate a visual indicator. This unique safety circuit gives instantaneous and unobtrusive protection without causing annoying program interruptions.

Overload Recovery - Instantanous. Clean performance at high peak-clipping levels.

Time Delay Circuit - Loudspeakers are protected agains damage from turn-on "pops" and surges.

 Separate Power Supplies - Channels are completely isolated. No power loss or other interactions from simultaneous operation of both channels.

Crossover Notch - These sharp switching discontinuities have been virtually eliminated in the Maantz Circuit, even at 20,000 Hz. This results in noticeably cleaner performance, especially apparent at normal listening levels.

Front Panel - Matches those of Marantz Model 7T Solid-State Stereo preamplifier Console and Model 10B Stereo FM Tuner in both size and type of finish.
Cabinet or rack mouting available at extra cost

Electronic Time Delay Circuit -  This mutes the signalto the loudspeaker for about five seconds after the unit is turned on, thus elminating the irksome popping noise normally produced at that time by high power supply transistorized units.
Specifications
Power Output Each Channel (Will operate continually at full rated power from 20 to 20,000 Hz with complete safety):
70 Watts at 4 ohms
60 watts at 8 ohms
40 watts at 16 ohms
Frequency Response:    10 to 60,000 Hz (within 1 dB)
Damping Factor:  Greater than 30 with 8 Ω load.
Total Harmonic Distortion:  less than 0,1% at and below rated power, 20 to 20,000 Hz
Typical Harmonic Distortion:  0,03% with 8 Ω or higher load - at full rated output,any frequency from 20 to20,000 Hz. Distortion decreases as output level is lowered.
Total Noise:  better than 90 dB below 60 watts into 8 Ω
Optional Accessories: Oiled walnut cabinet and rack Mount panel
Power Requirenets:  105 - 130 V AC, for 50-60 Hz. Easily covertible form 110 volt to 220 volt operations.
Dimensions (W x H x D):  376 x 150 x 216 mm (14,8" x 5,9" x 8,5")

Weight:  13,6 kg (29,9 lb )

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