JVC QL-A7 turntable

JVC Super Servo Frequency Generator, Photokinetic End-of-Play Mechanism

 

We've used the JVC Quartz Turntable technology to great advantage in the QL-A7, then have added a unique arm operation mechanism to increase operating convenience. This model has our Photokinetic End-of-Play, device so that when the stylus reaches the lead-out groove on the record, the arm is lifted free without a moment's hesitation, and then the platter is stopped. One advantage is that the JVC design does not link the arm with the platter in any mechanical way thus the high performance standards of each are never threatened.

 

JVC Quartz for the Musical Truth

Accurate platter rotation is maintained in the QL-A7 with the JVC Quartz servomotor that's virtually impervious to influence from the environment. Changes in temperature or humidity, voltage fluctuations and even circuit warm-up changes never bother it. Thermal drift is less than 0,00005%/C and stability against voltage rises/drops as wide as 10V is complete.

Since the QL-A7 has JVC's DC servo-motor, precision Quartz oscillator, no-error JVC Super Servo Frequency Generator and a proven direct0drive mechanism designed and produced by our own engineers and craftsmen, its superb original performance is retained over the years.

 

Heavy Platter and JVC's DC Servomotor

The best Quartz servosystem in the world deserves only the most precise of motors. Since we were the ones to original Quartz servo control for turntables, it was only right that we should make a precision DC servomotor to go along with it in the JVC QL-A7. it features powerful torque of more than 1 kg.cm and is assisted for smooth rotation characteristics by its built-in JVC Super Servo FG. A JVC exclusive "super-finish" technique ensures mechanical precision and long-term durability and includes, in part, the amazing 0,6 µ roundness in the vital motor shaft. The platter of the QL-A7 weighs a heavy 2,2 kg (4,8 lb) with its thick rubber mat and has a large 350 kg-cm moment of inertia. These figures translate, of course, into superb musical performance by reducing flutter and keeping the speed constant even in the face of suddenly increased loads. Particular care has been taken to ensure that motor-caused resonance never occurs to spoil your music.

 

JVC's Photokinetic End-of-Play mechanism

Yes, the QL-A7 is a full-fledged manual turntable. But it also includes a feature that automatically lifts the tonearm and stops the platter the moment the stylus enters the innermost lead-out groove of your record. Our unique Photokinetic End-of-Play device works independently of the platter system, it is formed of a photosensor and a sophisticated mechanism including a plunger for no-contact, error-free operation. Benefits you'll enjoy include reduced tonearm mass for improved arm sensitivity, compared with a conventional tonearm auto mechanism. For convenience there are a Cue Lever and a record Size Selector Knob up front.

 

Touch Sensors for Speed Change

Stopping the platter or changing speeds from 33-⅓ to 45 rpm is a breeze. Simply touch the appropriate Touch Sensor button - the lightest of touches will do - and you get immediate results. The built in mechanical brake with an electromagnetic plunger stops the platter in less than 1,6 seconds with no wobbles, and speed-up changes are so fast you can hardly see them happen.

 

One-Row Strobe

Only one row? No more are needed since the neon strobe lamp is synchronized with the built-in Quartz oscillator. Unlike strobes which are synchronized with power-line AC frequency, this system avoids any chance of fluctuation. You select the speed and the one row of strobe dots is all you need to visually confirm its accuracy.

 

New Gimbal Support

The tonearm support system on the QL-A7 is our New Gimbal Support offering improved sensitivity, much lower mechanical error and higher rigidity than conventional types. Rare on automatic turntables, it includes an Arm Height Adjustor with an adjustment range of from 42,5 to 50 mm so that you may use any cartridge whatever its height, and Oil-Damped Cueing.

 

Solid Construction to End How.

Since the motor and tonearm of the QL-A7 are firmly mounted in the solid, "howl-free" cabinet neither the sonic bombardment coming from your speakers non the vibrations of footsteps on the floor can reach the stylus to cause musical degradation. One further JVC touch is the suspension system which effectively soaks up all vibrations - vertical and horizontal alike  -thanks to a rubber foot design to effectively prevent muddy or boomy bass reproduction. The insulators are height adjustable to help you keep your JVC Quartz QL-A7 strictly on the level.

 

Specifications

Drive System:  Direct-drive

Motor:  12-pole. 24-slot, DC type FG servomotor

Speeds:  33-⅓ and 45 rpm

Wow and Flutter:  less than 0,025% (WRMS)

Signal-to-Noise Ratio :  more than 63 dB (IEC-B);  73 dB (DIN-B)

Speed Detections:  Integrated frequency generator

Starting Torque:  1 kg-cm

Speed Deviation:  within 0,002%

Load Characteristics:  0% (with 120 g total tracking force)

Drift per Hour:  0,0001% /H

Power Characteristics:  0% (±10  V)

Temperature Characteristics:  0,00005% /°C

Platter:  313 mm diameter

Quick Stop Time:  within 1,6 sec.

Tonearm Type:  Tracking-Hold system, static balance, new gimbal support

Effective Length:  245 mm

Tracking Error:  +1°48' - 1°31'

Overhang:  15 mm

Tracking Force Range:  0 - 3g (0,25 g division, direct reading)

Weight Range (incl. Headshell:  14,5 - 23,5 g (12,5 g headshell )

Cartridge Type:  Moving magnet (cartridge body MD-1025)

Stylus:  0,3 x 0,7 mil. Diamond (DT-Z1TE)

Optimum Tracking Force:  2 gramm

Output:  3 mV (1 kHz)

Frequency Response:  10 - 25,000 Hz

Separation:  more than 25 dB (1 kHz) with test record TRS-1

Load Resistance:  47 k Ω  - 100 k Ω

Compliance

Dynamic :  10 x 10¯⁶ cm/dyne

Static :  25 x 10¯⁶ cm/dyne

General Specifications

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

Power Consumption:  15 watts

Dimensions (W x H x D):  481 x 165 x 403 mm [18-15/16" x 6-1/2" x 15-7/8"] (with cover closed)

Weight:  12 kg (26,4 lbs)