A turntable must address and resolve all of the issues that affect ultimate performance, if it is to achieve the goal of bringing you closest to the musical experience. The basic goal of achieving maximum information retrieval in turntable performance is one of controlling microscopic vibrations - a task that requires the utmost in engineering precision and comprehensive design.
The design objectives of Dynamic Stability (the control of forces present in a dynamic system), Environmental Isolation (the control of forces from "outside" the turntable’s world), Easy Set-up (guaranteed results in all situations), Control Over Vinyl Resonance and Variations, (which would otherwise undermine the performance of even the best turntables) and Control Over Power Line Impurities (which are present in all installations and result in sonic anomalies if not controlled), are all addressed in the design of the SOTA line of precision turntables.
THE SOTA PLATTER
All SOTA models use the same basic platter design. It is a very sophisticated, unified record suspension system utilizing SOTA’s "Constrained-Mode" design theory. This theory integrates alternate layers of hard and soft materials to make internally damped sandwiches that cause the transmission of unwanted vibrations away from the stylus/record/platter interface. The top layer of the platter is an acrylic material, impedance-matched to the vinyl record. A special damping material isolates the mat from the platter, a one-piece cast aluminum frame integrated with a variety of special damping materials. To achieve maximum flywheel effect (for speed consistency), 60% of the platter’s mass is concentrated on the outside edge. To further enhance the flywheel effect, the platter is driven off its outside edge by its high-tech, precision cast, low-tension belt. And finally, each platter is individually precision-balanced at the factory while fitted to its bearing.
Unlike virtually every other turntable in the world, the SOTA platter’s pivot point turns at its center of gravity, thanks to the unique Inverted Bearing Design. This design ensures stability, balance and extreme consistency over time, as well as totally eliminating the forces that cause the wobble and wear that come with age on other turntables. Located at the very center of gravity on the SOTA platter is the synthetic Sapphire crystal thrust plate (ground to one wavelength of light accuracy), which balances the platter and rotates on a chrome steel ball bearing. Sapphire, second only in hardness to diamond, keeps friction to an absolute minimum. It doesn’t deform, it keeps the contact area extremely low, and has MUCH better wear characteristics than steel. (On the SOTA NOVA, COSMOS and MILLENNIA turntable, the Zirconium ball bearing is used. Zirconium is a super-high-strength space age ceramic, manufactured using an iso-static pressure process, creating a fracture-resistant and wear resistant material.) Thus, the SOTA platter achieves the design goal of Dynamic Stability, as well as long-term, maintenance-free dependability.
THE SOTA FLOATING SEISMIC PLATFORM
The lofty goal of Environmental Isolation resulted in the development of SOTA’s unique sub-chassis system, the Seismic Platform. Environmental Isolation means isolating the moving platter from all the physical and mechanical threats (footfalls, room resonance, air-borne waves, etc.) that will ultimately disrupt the retrieval of the information contained in the record grooves.
Key to the SOTA floating seismic platform is the theory of basic mechanics that tells us that the motion of a moving mass will be most constant when supported by the inertia of a greater mass. In the SOTA turntables, the 12 pound platter is successfully isolated from the environment because of the enormous mass of the 22-pound sub-assembly. To further enhance isolation, the sub-chassis is constructed of self-damping materials (again, constrained-mode construction techniques), with lead providing mass and energy sinking. Each sub-chassis is individually balanced at the factory, complete with its matching platter attached.
The unique SOTA turntable sub-chassis is then hung from a four-point spring suspension (spring utilized on the Sapphire, Star, Nova and Cosmos), giving it all the stability of four pendulums at rest. The four springs are damped to absorb high frequencies and decoupled from the sub-chassis to minimize energy transfer, fixing the suspension frequency at 2.5 Hz. By "hanging" the sub-chassis on springs, gravity stabilizes all external energies due to the centering tendency of the pendulum motion, rather than pulling the mass off center as is the case in the typical "compressed" spring suspension. With a four point suspension (made of four springs placed equi-distant from the center of gravity) and four equal masses (one of which is the adjusted mass* of the tonearm), the SOTA turntables offer a level of stability that can only be achieved with a constantly-balanced- mass system. No matter the tonearm, mass is constant, motion is predictable, and the end result is once again a system that achieves our goal of Dynamic Stability.
* Mass of tonearm plus added lead shot
THE SOTA DRIVE SYSTEM
All SOTA turntables employ a super-accurate, double-regulated synthesized sine-wave drive system to run an ultra-high efficiency, high-torque AC synchronous motor. The result is sufficient torque to start the heavy platter, plus exceptional speed stability regardless of the power company’s voltage or frequency fluctuations. The ultra-low loss motor insures long life and cool operation, and is run at low power to minimize invasive energy. The use of the synthesized sine-wave drive also allows the SOTA turntables to include adjustable pitch control, and to switch from 33 RPM to 45 RPM with the push of a button.
Finally, each precision, hand-assembled drive system is topped with a polished, low profile pulley, each individually balanced at the factory, driving a precision cast, long-life, low-tension belt.
SOTA SET-UP: VERSATILITY = GUARANTEED RESULTS
Unlike most every turntable design which adjusts Spring Tension to adjust for various tonearm-assembly weights, the SOTA turntables adjust mass, a far simpler and vastly more predictable method of set-up. The SOTA turntable set-up allows you to vary the mass of the system to compensate for the mass of the arm (much like balancing a tire for your car). By maintaining a constant mass, the unknown variable of tonearm mass has now become a predictable constant. And since the entire system’s mass remains constant, damping and isolation are controlled and predictable. The SOTA suspension follows the physics principle that mass at a stable rest will tend towards stability after excited or moved.
Because the mass on each spring is constant, the turntable’s setup will not vary with time, and all springs will age at a constant rate. By having the suspension factory-fixed and the mass adjusted to accommodate a wide range of tonearms, the end user is assured that his/her SOTA can be set-up quickly and easily, and will
replicate the performance levels achieved in lab and reviewer tests.
RESOLVING THE UNKNOWN OF THE VINYL DISC
SOTA turntables seek ultimate control over vinyl resonance and variations – with a goal of making the stylus "think" that it is tracking a record far thicker and with virtually infinite damping. Functionally, the LP should "merge" with the platter. This goal requires both an ultimate mat and an ultimate clamping system.
The SOTA acrylic Supermat™ utilized on the JEWEL, SAPPHIRE and STAR platters, provides the rigid, flat surface necessary to flatten vinyl warps and damp spurious energy. The mat also provides an excellent impedance match to the vinyl LP, allowing the record to effectively merge with the platter system. To fully realize this effect, a clamping system is required to assure intimate contact between the record and the mat over its entire surface. The precision SOTA I-Clamp™ or Reflex Clamp™ are available accessories for all SOTA turntables and represent the ultimate mechanical clamping systems.
The SOTA NOVA, COSMOS and MILLENNIA turntable improves upon the Supermat’s goals by utilizing the Vinyl-Format Mat™ . Slightly softer than the acrylic Supermat, this one-piece, massive "vinyl-mimic" mat is a near perfect interface and impedance match to the LP. Internally damped during an elaborate and expensive manufacturing process, this multi-layer, precision-molded mat provides un-matched record coupling and record and platter damping.
To carry this theory to its logical conclusion, the SOTA STAR, NOVA, COSMOS and MILLENNIA turntables employ the ultimate clamping system: Vacuum Hold-down. Utilizing the same principles of record hold-down used for the creation of LP masters, the SOTA vacuum system is a marvel of engineering excellence. Employing a proprietary system, the SOTA vacuum hold-down system is a self-sensing, low-pressure vacuum system, utilizing state-of-the-art electronic sensing devices to allow only the amount of vacuum pressure necessary to hold and maintain the record securely to the platter. With the SOTA vacuum hold-down system, the turntable acts as if it is playing a record of virtually infinite mass and damping, totally free of the vinyl resonance that undermine the performance of other high-quality turntables.
DEALING WITH POWER LINE VARIATIONS
SOTA discovered back in the mid-80’s that turntable motors are incredibly sensitive to disturbance in the AC power. Typical AC power problems include RFI noise and spikes on the line, as well as voltage and frequency instability. The SOTA Electronic Flywheel™ with its unique filter circuits (included in the power supply of the STAR, NOVA, COSMOS and MILLENNIA turntables), acts as a buffer to all these outside noises and fluctuations. Due to the low current application, the Electronic Flywheel’s super-fast and dynamic regulator circuits are able to deliver only pure DC voltage to the motor system. And the Electronic Flywheel circuits are always on, to insure that the drive system is warm and fully charged the moment the turntable is turned on.