QL-G901J

RACKMOUNT FRONT-LOADING TURNTABLE

MSRP: $485.00

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The QL-G901 represents a bold new aproach to studio production:
we've put the turntable into a rugged enclosure, made it front
loading, rack mountable, and placed all controls on the front.
Now you can stack a turntable in a rack just like other studio
components.  Yet this is just the first innovative feature of the
QL-G901:  inside you'll find a fine selection of JVC turntable
technologies--a linear tracking tonearm, a coreless motor with
Double--Servo Quartz control, a microcomputer that permits random
access play of 8 cuts, index play and skip.
 
JVC Quartz is the most accurate means to maintain exact platter
rotation speed.  JVC introduced the world's first Quartz turntable
back in 1974.  Since then we've continually upgraded our
technologh.  Today our Double-Servo Quartz turntables--first
introduced in 1978--are thrity times more accurate than
conventional Quartz designs.  To be specific, they offer the
following advantages:
 
1)  100 times better speed accuracy than conventional direc-drive
turntables.
 
2)  100 times better resistance to temperature and voltage caused
speed fluctuations than conventional direct-drive turntables.
 
3)  100 times better speed stabilility than conventional
direct-drive turntables in terms of resistance to drag such as
caused by heavily modulated grooves.
 
Our coreless Super FG Servo DC motor:  Accurate and cog-free.
In the JVC Quartz turntable, a coreless DC motor is assisted by a
Dougle-Servo Quartz control system for accurate rotation and speed
detection.  The coreless design eliminates cogging, yet retains
high torque.  The Double-Servo Quartz control system employs phase
comparison and output integration for absolute accuracy.  Little
wonder, then the JVC Quartz turntable wow and flutter of 0.025% or
less (WRMS), and a signal-to-noise ratio approaching 80dB (DIN-B).
 
 
LINEAR TRACKING TONEARM

Linear Tracking - With the Relative Movement of the Stylus and the Record the Same as in Cutting, Playback Is More Accurate The basic requirements of a tonearm are: (1) It should move smoothly and have very high sensitivity. (2) It should be structurally strong and free from mechanical deformation. (3) It should be such that the reproduced sound is free from the influence of low-frequency resonance. Looking at the record cutting process, the groove is cut by the cutting stylus which moves in the direction perpendicular to the groove; in playback, the stylus of a conventional tonearm moves through the arc of a circle, the center of which is the pivot, so that its contact with the groove changes as the record is played. Because of this, the stylus does not have the ideal contact with the walls being slightly ahead of its point of contact with the other wall. This causes distortion which is called tracking error. The linear tracking tonearm used in the QL-G901 is designed to eliminate tracking error. Advantages of the Linear Tracking Tonearm Used in the QL-G901 The linear tracking tonearm moves perpendiculary to the groove so that it always makes the same optimum contact with both walls of the record groove. It has the following advantages. (1) Because tracking error is almost entirely eliminated, harmonice distortion is greatly reduced. (2) In theory, at least, centripetal force (i.e. the skating force toward the center of the record) is eliminated, which improves channel separation and reduces intermodulation distortion so that sound with superb localization can be reproduced. (3) The length of the tonearm can be minimized so that its mass is lower than ever; this reduces the possibilities of record warp, etc. causing low frequency resonance so that intermodulation distortion is reduced. Low-mass straight tonearm: for better tracking. The combination of a high-compliance cartridge and a massive tonearm creates a resonance frequency that falls within the same low-frequency range as frequencies generated by record warps and eccentricities. When the cartridge is called on to reproduce these subsonic frequencies, mistracking occurs. This mistracking causes audible dropouts and intermodulation distortion. A low-mass tonearm, in the other hand, has a higher resonance frequency that is not reinforced by frequencies generated by warps and eccentricities, therefore mistracking rarely occurs. And because the arm is straight, it also has greater mechanical strength and higher precision. Plug-in connector for simple and sure cartridge connection.

The tonearm of our turntable, equipped with plug-in cartridge connectors. The plug-in design makes mounting cartridges easier, eliminating the chance for wiring error. Since the cartridge firmly locks onto the tonearm, mechanical strength and rigidity are improved too. Linear tracking prevents tracking error.

A pivoted tonearm has unavoidable designed-in "tracking error"

tonearm traces an arc across a record's surface. This is because grooves of a modern record are cut by a linear-tracing master cutting machine. It's true that tracking erros is usually reduced to negligible proportions by optimizing geometry, but it can never be eliminated entirely. Even a slight amount of tracking error can cause distortion. A linear-tracking tonearm, by definition, suffers no tracking error. Therefore, harmonic distortion is much lower. No skating force compensation is required either, so channel separation is improved and intermodulation distortion is reduced. A linear-tracking tonearm can be shorter and lower in effective mass to prevent resonance problems. Optical systems maintain arm tangency and determine record size and speed. The linear-tracking turntable utilizes two sophisticated optical systems to assure accurate tracking and make possible automatic convenience. The first employs a photointerruption device to monitor tonearm tangency and correct tracking error by means of a responsive servo system. The other, consisting of a lamp and phototransistors, and supervised by a microcomputer, checks for the presence of a record on the platter, then determines the record's size (LP or single) and its speed (33rpm or 45rpm).


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