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SME 20/3A Turntable with Series V Arm
SME 20/3A Turntable with Series V Arm


 


Product Code: SME0000003
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Description
 
This finely engineered precision turntable is built to the same exacting standard and incorporates many design features originated for the Model 20/12. Massive construction, extensional damping of major surfaces and lack of vibration from moving parts ensures exceptional detail, resolution and uncolored performance.

A turntable should address the problems of extraneous vibrations. These emanate from numerous sources including air and structural vibration from loudspeakers, groove modulation, stray electrical fields and mechanical imperfections in moving parts. In the Model 20/3, superb instrument quality machining is allied with fundamental physics. The higher the mass and stiffness of a body the less it will flex and vibrate; the duration of a vibration can be shortened by suitable damping.

Model 20/3 weighs approximately 63lb, significant in relation to its size because it is density that matters. For example, the same weight of metal spread over a large enough area would be aluminium foil! The sub-chassis measures only 17 5/16” by 13 3/4" but weighs 24lbs. Its thickness 5/8” resists flexing at low frequencies while high frequency resonance is attenuated by efficient extensional damping.

A large centrally placed fluid-damper disciplines sub-chassis movement with a pleasing sense of security when handling records on and off the platter, offering a resistive ground-path for acoustic signals.

In addition to a cartridge’s electrical output, mirror image acoustic signals reacted in the arm and record, will pass into the sub-chassis in the course of dissipation. However the usual closed loop design does not address the problem of their differing phase so in the Model 20/3 the structural interfaces concerned have received special attention to provide paths of the required impedance.

This control of vibration is fundamental to the design of the player and goes much of the way to explaining the stunning tonal and dynamic neutrality that it exhibits.
Platter

The platter weights a substantial 14lbs. The face is machined with a fine scroll found to interface better than a plain surface. A substantial reflex clamp ensures maximum contact with the platter even when severe record warp is present. The sub-chassis/arm mounting board interface is extensionally damped and the mounting board is reversible to allow mounting of nine inch pick-up arms when necessary.
Motor

The turntable is driven by a 3 phase, brushless outrunner motor with 8-pole Neodymium magnets and 3 integrated Hall effect sensors and is virtually vibrationless by reason of its 5.5lb weight as well as being isolated on urethane mounts that are adjustable for accurate belt positioning.
Speed Control

The electronic controller uses a high performance microprocessor, optimized for motor control. Closed loop speed control is implemented using a proportional plus integral (PI) algorithm. Fine pitch speed adjustment allows increments/decrements of +/-0.01% of selected speed. Speed ranges: 33.3, 45 & 78 rpm.
Dimensions and Weight

Dimensions: 12.4" x 10" x 5"
Net weight: 68lbs
Shipping weight: 100 lbs

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