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





Nikko Alpha 220 power-amp

Nikko Audio's Alpha 220 is a 120 watts per channel power amplifier having a DC servo-feedback loop, non-switching output circuitry, and a high slew rate The unit's input circuitr uses dual field effect transistors (FEDs) for lowest noise and distortion; the remaining stages employ wideband bipolar transistors. The amplifier has a slew rate of 100 volts per microsecond and a rise time of one microsecond. Low frequency signals are monitored and corrected by a DC servo-feedback loop.
The output stage is operated in a continuous non-switching mode, using circuitry that tracks transistor bias in synchonization with the music signal, to avoid excessive heat generation and resultant cost associated with traditional Class A designs while nonethless offering the exceptional degree of sonic clarity and openness of Class A operation. Additional features include; protection circuits to prevent speaker damage even if the preamp has a DC offest signal; front panel headphone jack and speaker selector switches; indicator lamps that monitor power-on and protection-circuit status.
Specifications:
Continuous Power Output per Channel:
More than 120 watts  - 20 -20,000 Hz at 8 Ω
More than 130 watts - 20 - 20,000 Hz at 4 Ω
More than 120 watts - 1000 Hz at 8 Ω
More than 130 watts - 1000 Hz at 4 Ω
Total Harmonic Distortion :
Continuous Power Output  at 8 Ω :   no more than 0,008%
Continuous Power Output  at 4 Ω :  no more than 0,02%
1 Watt power Output (8 ohms):  no more than 0,02%
Intermodulation Distortion :
Continuous Power Output  at 8 Ω :  no more than 0,01%
1 Watt Power Output :  no more than 0,02%
IHF Power Bandwidth (8 ohms):  5 - 70,000 Hz
Damping Factor at 1000 Hz (8 ohms):  more than 60
Frequency Response (Normal Input 8 Ω)
At 1 Watt Power Output :  10 - 100,000 Hz +0, -1 dB
Input Sensitivity for 120 watts Power Output
Main In :  1 V ±2 dB
Signal-to-Noise Ratio (IHF A network):
Main (Normal, Direct) :  better than 105 dB
Signal-to-Noise Ratio (DIN Filter):
Main IN (Normal, Direct) :  better than 90 dB
Channel Balance:  no more than 1 dB
Residual Hum and Noise, 8 Ω:  no more than 0,5 mV
Idling Current:  40 - 120 mA
Midpoint Voltage:  0 ±20 mV
Muting Delay Time:  3 - 7 seconds
Power Requirements:
W-type :  AC 120 V, 60 Hz
E-type :  AC 220 V, 50 Hz
B-type :  AC 240 V, 50 Hz
Power Consumption:  480 W (620 VA)
Dimensions (W x H x D):  482 x 138 x 344 mm (19" x 5-1/3" x 13-1/2")
Weight:  13,5 kg (29,7 lbs)

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