SME
Precision Turntable
Model 20/12
(without Model 312S tonearm)

$ 137,800
Quantity:
+
Description

Model 20/12 Turntable
A larger and more massive version of our well known Model 20/2. It will accept nine, ten and twelve-inch arms but is especially directed at the exciting Model 312S. This offers a performance some 27% better than a nine-inch arm in respect of angular error distortion. The wand and headshell are pressure die-cast in magnesium and are 27g lighter than they would be in aluminium.

Probably the stiffest and lightest twelve-inch arms ever made these dual problems are at last addressed and on listening, the benefits of minimal tracking error and harmonic distortion are clearly revealed. 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.

Model 20/12 Turntable
Graph compares angular error distortion of typical nine-inch and twelve-inch arms, with null points selected to equalize distortion at maximum and minimum recorded diameters. Stable four point suspension. Sub-chasis suspended on eighty strands of rubber in the form of forty purpose moulded ‘O’-rings. Trimming screws for suspension adjustment. Central fluid damper controls sub-chassis motion and offers resistive ground-path for acoustic signals. For transport lock down screws secure the sub-chassis and seal the damper. 19mm diameter main spindle machined from high-chrome steel hardened, ground and super finished. Runs in a sealed oil bath. Reflex clamping system minimises record resonance. 6.5Kg (14.3lb) machined platter with unique Isodamp face. Generous use of extensional damping and resistive loop construction ensure sonic neutrality. Adjustable ball feet with optional compliant inserts. Four jacking screws built into the sub-platter allow the thrust bearing to be off loaded for transit. Driven by a 3-phase, 6 pulse, inductance motor, with 8 pole Neodymium magnets and 3 integrated Hall position sensors. The power supply houses an electronic controller using a high performance microcomputer, optimised for motor control. Closed loop speed control is implemented using a pseudo sine wave commutation sequence and a proportional-plus-integral (PI) algorithm. New design incorporates a 4 layer surface mount technology pcb with on-board user adjustable speed variation control. Large diameter strobe disc supplied allows precise adjustment of standard speeds. Speeds ranges: 33.3, 45 and 78 rpm.
Dimensions
520 x 375 x 173.5mm
Packing
Substantial case.
Net weight with power supply
35.5kg (78lb).
Shipping weight approximately
45.5kg (100lb).