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





Hitachi D-E55 cassette deck


Hitachi D-E55
Microcomputer-Controlled Cassette Deck with Metal-tape Compatibility, Feather- Touch Controls, Auto Rec Mute Function, and Dual 12-LED peak Meters.
The first thing that will impress you about the D-E55 is that it has the look and feel of a precision instrument. The handsome styling and the incredibly smooth operation provided by the built-in microprocessor and power-assisted feather-touch controls are unexpectedly luxurious considering the D-E55's accessible price tag. A large number of computer-controlled automatic functions have been incorporated, too - for exceptional flexibility and convenience. You get Auto Rec Mute, Auto Rewind Play/Stop, Computerized memory Rewind, Timer Play/Record, and provision for optional remote control.
Naturally, the D-E55 also gives you the greatsound Hitachi is famous for.. It's metal-tape compatible, and there's a 4-position tape selector switch to get excellent performance with any find of tape. Dual 12-LED peak level indicators permit accurate setting of recording levels.

Microcomputer Control
Conventional tape decks use mechanical linkages to engage the mechanism when you push the transport controls. These can eventually cause alignment problems, particularly if too much force is used. Also, a mistake in operation such as pushing fast forward instead of stop when  the tape is rewinding is liable to stretch the tape or damage the transport. The D-E55's microcomputer control ends thaes problems by intelligently managing all functions, gliding the transport into position at the proper time with just the right amount of force. What's more, all controls are feather-touch and can be switched directly from mode to mode without the need to push the stop button. The microprocessor also controls a variety of automatic functions.

Computerized Memory Rewind
Unlike ordinary memory rewind systems which rely on the tape counter to specify the desired stopping point on the tape, the D-E55 system uses the microcomputer to memorize the position of the tape when the Play button is pressed, allowing to rewind to the that point at any time. When the Memory rewind Play mode is selected, the tape begins to play after being rewound, very convenient for listening to a particular selection a number of times. Memory rewind is also a big help when recording; to re-recorded after having made a mistake, use memory rewind stop to return to the exact position you started at.

Auto Rewind Play/Stop
This handly feature adds a lot to operating convenience. In the Stop mode, the tape is automatically rewound when the end is reached and the transport is shut off- no need to waste time rewinding it later. In the play mode, the tape is automatically rewound at the end, the Play function is re-initiated so you hear the same side again until you stop it manually - ideal for continuous background music.

Auto Rec Mute
Still another feature made possible by the microcomputer, Auto Rec Mute makes taping easier and gives better results. One touch of the Rec Mute button and a 4-second section of blank tape is automatically made, the ideal waay to place intervals of silence between the selections on your tape. Intervals other than 4 seconds may also be made by using the pause button in combination qith the Rec Mute button. The pause indicator flashes once a second to help measure the exact time desired.

LED peak Meters
Instead of the usual machanical VU or peak meters, the D-E55 offers dual 12-LED peak indicators driven by advanced digital circuitry. Since there are no moving parts,, these meters do not suffer from delay or overshoot like their mechanical counterparts, and therefore provide accurate, instantaneous visual monitoring of signal levels.
You'll really appreciate how easy these meters make it to set precise record levels for top-quality recordings.

4-position Tape Selector Switch
A large variety of  recording tapeare available on the market, with widely varying characteristics. It is essential that the deck be matched to the particular type of tape in use ifideal results are to be obtained. The D-E55 has switch settings for metal, CrO₂, Normal, and FeCr tapes, giving you optimum results whatever tape type you use.

Specifications
Motor:  Electronically controlled DC motor
Heads:  metal Sl record/playback head double-gap ferrite Erase head
Semiconductors:
41 Transistors ; 27 Diodes; 2 varistors; 5 LEDs; 6 ics
Track System:  4 track, 2 channel stereo
Tape:  cassette Tape C-30. C-60, C-90
Tape Speed:  4,75 cm/s
Recording System and Bias Frequncy:  AC bias, 85 Hz
Erasing System:  AC erase
Erase Ratio:  65 dB or more (at 1 kHz)
Frequency Response:
Normal :  20 Hz - 17 kHz
Cro2 :  20 Hz - 18 kHz
Metal :  20 Hz - 18 kHz
FeCr :  20 Hz - 17 kHz
Signal-to-Noise Ratio
Dolby NR Off :  59 dB (weighted A, reference 3% THD.  Metal tape)
Dolby NR On :  67 dB (weighted A, reference 3% THD. Metal Tape)
Wow and Flutter:  0,04% WRMS (0,13% DIN)
Input Sensitivity/ Impedance:
Microphone :  0,3 mV/  300 Ω - 5 kΩ
Line In :  50 mV/ 50 k Ω or more
DIN  (Rec/Pb) :  0,3 mV/3,3 k Ω
Output Level:  500 mV
Output Load Impedance:
Line Out :  50 k Ω or more
DIN (Rec/Pb):  50 k Ω or more
Headphones :  8 Ω - 2 k Ω
Distortion:  1,0% (1 kHz , -3 dB)
Crosstalk:  60 dB or more (at 1 kHz)
Channel Separation:  30 dB or more (at 1 kHz)
Power Supply:  AC 120V, 100-110 V, 115-127 V, 220-220 V, 230-240 V, 50/60 Hz
Power Consumption:  21 W
Dimensions (W x H x D):  435 x 110 x 266 mm
Weight:  4,6 kg


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