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





Akai GX-F90 cassette deck

Stereo Cassette Tape Deck

Super Slim Up to The Minute Design with Feather Touch Control

 

Super GX Heads Usher in The Age of Metal Tape

Superficial modifications would have been totally inadequate to bring about the greatly improved performance achieved in the GX-F90. for this, Akai's engineers went to the heart of the matter - the heads. The Super GX Head follows in the tradition of the immensely successful GX and new GX heads. It employs improved crystal ferrite as the core material, a super-hard substance which provides longer head and tape life. The heads of the 3-head system maintain optimum individual gap widths for better recording and playback characteristics with virtually no azimuth loss. Another advantage is that it enables direct tape monitoring. All this makes the Super GX Head ideal for metal tapes, with their greater dynamic range and improved Signal-to-Noise Ratio. Greater performance is obtained from conventional tapes, too.

 


Two-Motor System for maximum Stability.

High torque and minimal ripple, resulting in Wow and Flutter of less than 0,08 (DIN) are the major advantages of the GX-F90's transport mechanism. The Direct Capstan Drive system employs a coreless/FG Servo DC motor incorporating a Sample-and-Hold circuit for the capstan and a coreless DC servo-controlled motor for the reel drive.

 

FL Display BAR Meters

Reflecting the latest trend in electronics, the conventional needle-type level meter has been replaced in the GX-F90 by a 48-segment fluorescent meter. Using 2 colours to indicate levels below and above 0 dB, it shows either the peak level or VU reading at the press of a button. The advanced digital circuitry provides level readings of much higher accuracy than the mechanical type.

 

Playback - It's All Automatic

Let the instant Programme Locating System find the song you want to play. The system detects the beginning of the song by the volume level and the time constant and then commences playback automatically. The song can also be played repeatedly by setting the index counter to "000" and pressing the Repeat and Memory buttons. For continuous playback, press the Repeat button and at the end of the tape it will rewind to the beginning and resume playback.

 

Illuminated IC Logic Control Buttons

The feather-touch logic controls light up when touched. And with the Pause button on, when you press a mode button, the button will flash, to indicate the next mode. What's more, you can switch directly from one mode to another without having to press the Stop button. Operating the deck is thus exceptionally fast and simple

 

Calibration Tone Switch and Adjusters

A Cal Tone button is provided which activates a built-in oscillator to supply a 400 Hz recording signal for recording calibration adjustment. Use this reference signal when performing re-calibration with the two Rec Cal adjusters to match the characteristics of the tape being used. An especially useful feature when making Dolby NR recordings.

 

Dolby NR System and MPX Filter

Much has been written about the unique Dolby NR system, and how it greatly improves the sound of cassette tapes. It is exemplified by the GX-F90's Dolby NR system which works by raising low level signals prior to recording and then lowering them proportionately on playback. This results in sharply reduced tape hiss and an improved Signal-to-Noise Ratio of up to 10 dB above 5 kHz. The Dolby effect can be monitored during recording to cut the disturbance caused by the 19 kHz pilot signal during FM stereo broadcast recording with Dolby NR system, this deck ha an MPX Filter Switch. The ability to turn off the filter at all other times ensures full wide range frequency response.

 

The Akai A.D.R. System

This system designed by Akai automatically adjusts recording equalization at high frequencies while at the same time suppressing intermodulation distortion Sound that is crystal clear over the entire frequency band is obtained.

 


Specifications

Track System:  4-track, 2-channel stereo system

Tape:  Compact Cassette type

Tape Speed:  4,76 cm/s (1-7/8 ips) ±0,5%

Wow and Flutter:  less than 0,03% (WRMS); 0,08% (DIN 45500)

Frequency Response

LN Tape :  25 to 15,000 Hz ±3 dB (-20 VU)

LH Tape :  25 to 17,000 Hz ±3 dB (-20 VU)

CrO₂ Tape :  25 to 15,000 Hz ±3 dB (-20 VU)

CrO₂ Tape :  25 to 9,000 Hz ±3 dB (0 VU)

Metal Tape :  25 to 21,000 Hz ±3 dB (-20 VU)

Metal Tape :  25 to 13,000 Hz ±3 dB (0 VU)

Total Harmonic Distortion (1,000 Hz "0" VU):

LN Tape :  less than 0,8%

LH Tape :  less than 0,8%

CrO₂ Tape :  less than 0,7%

Metal Tape :  less than 0,6%

Signal-to-Noise Ratio :

LN Tape :  better than 58 dB

LH Tape :  better than 60 dB

CrO₂ Tape :  better than 61 dB

Metal Tape :  better than 62 dB

Erase Ratio:  better than 70 dB

Bias Frequency:  100 kHz

Heads:  Super GX recording head Super GX playback head and erase head (3 head System)

Motors:

Capstan Drive :  One FG servo DC motor (Direct Drive)

Reel Drive :  one DC motors

FF and Rewind Time:  60 sec. Using a C-60 cassette tape

Output (Jacks)

Line :  410 mV (0 VU). Required load impedance :  more than 20 k

Phone :  100 mV/8

Input (Jacks)

Microphone :  0,25 mV (Input impedance 4,7 k ). Required microphone impedance :  600

Line :  70 mV (Input Impedance 100 k )

DIN Jack:

Input :  2 mV (Input Impedance 10 k )

Output :  0,3 V Required load impedance: more than 20 k

Power Requirements:  100 V, 110/120/220/240 V switchable, 50/60 Hz

Power Consumption:  38 W (JPN, CSA, AAL) 

Dimensions (W x H x D):  440 x 105 x 370 mm (17,3" x 4,1" x 14,6")

Weight:  9,8 kg (21,6 lbs)

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