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


 If you can do without a computer but insist on recording/playback performance quality as high as that in our top-of-the-line KD-A8, you want JVC's KD-A77. it has three-head monitor capability and is ready to play back, record and erase the new metal tapes thanks to our SA Heads. Full-Logic 2-Motor transport means operational ease. The slim and trim profile makes it an ideal match for your sophisticated hi-fi setup.
You can hear the sound you've just recorded as you record with this 3-head deck.
Now you can hear your tapes as you record them. You can compare the original with the recorded signals instantly; with no chance of mistake, you can be sure you're getting the most out of your tape and deck. The  three heads in the KD-A77 are contained in two housing, one for the 2-Gap SA Erase head, the other holding the combination Record and Playback heads of the SA type. Ideal gap widths for for the latter two mean better recording and better response.
 Special Features:
Three Sen-Alloy heads; combined SA record/play (X-cut type) heads make possible record monitoring. The erase head is a 2-gap head also made from SA.
Two motor ID mechanism; this mechanism incorporates a newly developed back Tension system which gives improved tape contact with the head.
Self-illuminated buttons for full logic mechanical operation (excluding Stop or Rec-Mute modes.)
Three position Metal-Tape-Compatible tape select switch. (automatic switching between SA/Chrome and Normal)
The Rec Mute button is at the right side of the mechanical operation buttons.
Super  Automatic Noise Reduction System (ANRS), which reduces tape hiss to an inaudible level  and Super ANRS which improves linearity at high frequencies are incorporated.
2-stepped Gear/Oil Damped Cassette Lid
New Metal-Tape-Compatible multi-peak level indicators (+9, +6, +3, -2, -7 dB), together with back-lit VU meters with the expanded coverage from +7 VU to -20 VU, meke level observation easier.
Memory Stop/Play and Timer Standby (Rec and Play)
Output Volume Control, for Line and headphones use

1 - SA Recording Head   
2 - 4 µm gaps   
3 - 1 µm gaps   
4 - X-cut SA Playback Head   
5 - SA chips   
6 - Shield plate   
7 - Zinc die-casting head base
Combination SA heads for recording and playback.
Due to its high recording density, Metal Tape requires recording and playback heads that are made of materials having a greater maximum magnetic flux density than conventional ferrite or permalloy. The combined record/playback heads, newly developed for the KD-A77, both employ SA to ensure high performance.
The SA head has advantages over conventional heads in various fields such as fewer core loss, greater gap accuracy, better wear and corrosion resistance. However, its biggest feature is its high maximum magnetic flux density. Because of this, the SA head can bring the most out of the superior performance of metal Tape. This is especially true for its extended frequency response at high frequencies; something that has never been possible to realize with usual cassette tapes.
The playback head incorporates a unique X-cut core structure to improve the characteristics of the low frequency range. With ordinary core configurations, playback output is subject to peaks and dips in the low frequency range. This is called the "contur effect"; this effect is caused by interference between the length of the tape-to-head contact area and the wavelength of the recording frequency. With the X-cut design the core is cut diagonally to enable the tape to leave the head, not abruptly, but with a gradually lessening contact area.
Specifications KD-A77

Type: Stereo Cassette Deck
Track system:  4-track, 2-channel
Tape Speed:  4,8 cm/sec. (1-7/8 inch/sec)
Motors:  FG Type DC Servo Motor for Capstan; DC Motor for Reel
Heads:  3 Sen-Alloy heads
SA head for recording
X-cut head for playback
2-Gap head for erasing
Frequency Response
At -20 VU Recording:
Metal Tape :  15 - 20,000 Hz [25 - 18,000 Hz (±3 dB)]
SA/Chrome Tape :  15 - 20,000 Hz [25 - 18,000 (±3 dB)]
SF/Normal Tape :  15 - 19,000 Hz [25 - 17,000 Hz (±3 dB)]
At 0 VU Recording:
Metal Tape :  25 - 12,500 Hz (±3 dB)
SA/Chrome Tape :  25 - 8,000 Hz (±3 dB)
Signal-to-Noise Ratio:
ANRS - OFF :  60 dB (weighted, 1 kHz, 3% THD, Metal tape)
ANRS- ON :  Improved by 5 dB at 1 kHz and 10 dB above 5 kHz
Effects of Super ANRS (Normal Tape)
Improvement of S/N Ratio :  The same as with ANRS
Improvement of Frequency Response [0 VU / +5 VU Recording]:  6 dB at 10 kHz / 12 dB at 10 kHz
Improvement of Distortion [0 VU / +5 VU Recording]:  3% or less at 10 kHz / 3% or less at 10 kHz
Wow and Flutter:  0,04% (WRMS);  0,14% (DIN 45 500)
Harmonic Distortion:  K3 : 0,4%;  THD : 1,0% (Metal tape , 1 kHz)
Fast Forward Time:  85 sec. Or less (with C-60 cassette)
Rewind Time:  85 sec. Or less (with C-60 cassette)
Bias Frequency:  85 kHz (AC bias)
Erasure:  85 kHz (AC  erasure)
Input  Terminals:
Microphone Jack x 2
Max Sensitivity/ Matching Impedance :  0,2 mV (-72 dBs)/600 Ω - 10 k Ω
Line In Jack x 2
Min. Input level/ Impedance :  80 mV (-20 dBs)/100 k Ω
Output  Terminals
Line Out Jack x 2
Output level/Impedance :  0 - 300 mV/6 k Ω
Matching Impedance :  50 k Ω or more
Phones Jack x 1
Output Level/Impedance :  0 - 0,5 mW/8 Ω - 1 k Ω
Semiconductors:  49 Transistors;  18 ICs;  14 LEDs; 59 Diodes
Power Requirement:  AC 100/120/220/240 V, 50/60 Hz
Power Consumption:  36 W
Dimensions (W x H x D):  450 x 120 x 160 mm (17-3/4 x 4-3/4 x 12-7/16 inches)

Weight:  8,3 kg (18,3 lbs)

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