Kronos Sparta Turntable

A New Concept in Turntables

Equipment report
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Turntables
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Products:
Kronos Sparta
Kronos Sparta Turntable

The Soul of a New Machine
Unique to behold, the Sparta is essentially two complete turntables—each including a skeletal, metal-framed plinth fabricated of solid aluminum boards with phenolic inserts—one situated immediately above the other. Both hang freely from the same, patented, four-post, pillar suspension system. Occupying a space some 20 inches wide, 14 inches deep, and 11 inches tall, and weighing 70 pounds, the Sparta comes in at less than half the weight of my reference Redpoint Model D, yet with a similar overall footprint.

Like most suspended ’tables, each bearing set for the platters is positioned slightly left of the physical center of the plinth. The Sparta shares the same bearing system as the PRO. When Desjardins was designing and building these bearings, his object was to provide the quietest operation possible, yet still maximize service life. The in-depth design process included extensive research into the alloys and vapor-deposited coatings used in the aerospace industry. Settling on an inverted-bearing design to reduce contact in the rotational plane and to lessen torque-induced drag, he employed double hydraulic insulation to achieve the highest dampening possible. The bearings are hand-lapped and described as having tolerances to within one-thousandth of an inch. Kronos claims that the result of this design yields the lowest noise floor yet encountered in an audio turntable.

A pair of high-quality, Swiss-made Maxon DC motors, originally developed for the space program, are used to deliver quiet, smooth, linear power to the platters. The lower plinth has its brushless DC motor mounted to the right of the platter, while the upper plinth has it mounted at the equivalent location to the left. The choice to place the motors 180 degrees opposed was made to offset and “equalize” any oscillation that the torque they generate might produce.

Both plinths are suspended from four round corner towers that feature a central piston, attached via screws (accessible for setup) to a top cap fitted with elastic O rings. Each corner tower hangs freely from this cap, affording unrestricted motion in both the horizontal and vertical planes, and each pillar is terminated with an adjustable footer.

Thin round belts, approximately 1mm in diameter, go around each pulley atop the motors, and then around the outside perimeter of each respective platter, both of which are fabricated of multi-layered, multi-material composites, topped by a carbon-fiber mat.

The easily adjustable armboard attaches to the top plinth and, with the loosening or tightening of one large screw, may be freely adjusted forward or backward, then securely locked in place. The result is two completely independent, isolated turntables, mounted at a fixed distance from one another on the same suspension, with identical platters and motors, running in opposite direction, at the same speed.

Two control cables—each about three feet in length to facilitate convenient placement of the controller, with different pin configurations so they cannot be mistakenly interchanged—run from the back of the bottom plinth to the back of the 4-inch-wide, 4½-inch-deep, and 3¼-inch-tall controller/power supply. A third rear connection allows for an optical strobe cable for speed adjustment. The IEC socket is at the lower left corner of the back. By default, the Sparta also includes single-ended (RCA) connections, also accessed from the back of the lower plinth.

This controller/power supply provides DC voltage to the twin motors using a CPU-controlled, fully regulated Class A dual power supply. Rather than using pulse-width modulation, which can produce jerkiness, the CPU receives speed readings from the top platter via an optical sensor (the PRO uses four of them) and adjusts voltage to the motors in real time. The lower platter speed is not individually controlled, as it is with the PRO; it shares voltage with the top platter motor and is calibrated in the analog domain. As speed stability is dynamically monitored and addressed, Kronos claims greater stability and accuracy over the life of the turntable, regardless of environmental factors, belt-stretching, or mechanical wear.

The controller’s silver face, etched with the Kronos logo beneath the Sparta name, features an on/off rocker switch in the lower right, and three toggle switches across the top. From left to right, these silver toggles manage RPM selection, 33 (up) or 45 (down), speed adjust + (up) or – (down), and a memory switch, to allow storing the final speed selections. Speed control on the PRO is completely automated.

My Sparta was fitted with the 10.5-inch, tapered-tube, carbon-fiber Helena tonearm, which, along with the 12-inch Black Beauty ’arm, is the design of André Thériault of Montreal. Both ’arms are ball-in-cup, unipivot designs, featuring a twin-wall, tapered, carbon ’arm tube for maximum rigidity and minimum mass. The counterweight hangs well below the back of the ’arm, significantly lowering the center of gravity. Louis assisted in finalizing the tonearm design, primarily in making it more consumer friendly. And while the two tonearms are nearly identical save for their effective length, Louis feels that the 10.5-inch is a better fit for the smaller footprint of the Sparta, hence its inclusion for this review.