Turntables   On this Page :   Rota turntables    Bearings used in the Rotas   "The whole is greater than the sum of the parts"

The reson rota 2 turntable on the reson domo PS stand This quotation describes what can be achieved when things are done with care. The turntable problem cannot be resolved only by the use of high quality components and best engineering practice. It requires the systemic integration of all the parts to extract every last ounce out of each and produce an exceptional working unit such as the reson Rota turntable. Clearly the laws of physics impose limitations in design solutions. However, the tendency to question 'current thinking' has not only provided innovative solutions to existing engineering problems, but has shed new light on areas that have previously been overlooked. The motor has been confirmed as the primary source of vibration and movement in the whole turntable structure. The widely accepted closed loop relationship between arm, cartridge and motor unit has been misinterpreted and is something of a red herring.

While a relationship does exist between these components, it cannot be defined in a closed loop sense at audio frequencies. Freedom from this assumed constraint has allowed more latitude in design areas involving the arm to plinth interface.    The specially produced low vibration Swiss motor. The circuit board is part of the assembly, reducing the need for additional power supply cable routing   The problems of controlling movement created by motor energy can be divided into two parts. One concerns the compliance of the suspension bushes relative to the plinth. The other concerns the distribution of masses in the 'system'. The custom built low vibration motor used in the Rota is the first line of defence against unwanted movement. The motor coupling to the chassis and decoupling from the platter are critical. The Rota uses bushes with selected compliance for the motor mounting. The mechanical vibrational source impedance of the motor is matched to the mountings, pulley and load. A highly compliant round section belt takes the drive to the subplatter. This in turn is decoupled from the main platter by a three point mounting system employing '0' rings. This system further isolates motor vibration from the record and virtually eliminates the effect of belt side pull on the platter main bearing. Bearing system The unique bearing system employed by the Rota contributes greatly to a reduction in unwanted stylus deflection. The sub-platter uses a PTFE lined thrust bearing, designed to minimise the extra friction caused by belt tension. The reson Rota main platter bearing   The main platter is supported by a tight tolerance specially coated roller bearing, positioned slightly above the plane of the record playing surface. This overhead arrangement gives inherent stability as it couples to a ruby bearing in the pinnacle of the spindle. The small diameter of the roller bearing and the ruby interface results in a very low noise contact area. Bearing lubrication is an important factor when using an overhead bearing. A special oil was developed by the Swiss Institute of Clockmakers specifically to be used with the Rota's special bearing design. The oil is chemically compatible with all the bearing materials and is repelled by a coating applied to the bearing surface. Parts that actually touch break through the coating and the lubricant is drawn to that place - where it is most needed. Avoiding unwanted movement The arm board, its mounting method, material structure and interface with the plinth and motor assemblies, required considerable research. The compliance of the mounting bushes and their positioning, proved critical. Movement of the arm board in any plane causes stylus deflection, creating unwanted signal in the form of distortion. The laws of physics dictate that it is impossible to eliminate such motion. The motor is positioned where the effects of its torque will be reduced greatly. The mass of the acrylic platter provides excellent speed stability   The solution chosen to minimise it was movement control. Bush mounting positions and compliance, relative to the arm board, coupled with placing counterbalance weights directly under the platter and arm, ensure that any movement which does occur is smaller and linear in nature. Consequently it will dissipate more quickly, dramatically reducing stylus deflection. Materials The choice of construction materials for the Rota was carefully examined and the whole structure is predominantly non-metallic. The sand-blasted acrylic platter eliminates the possibility of induced eddy currents forming under the sensitive moving coil assembly. The plinth is machined in clear acrylic. Its light weight proves that 'mass management' negates the need for a heavy 'sink' type structure to absorb vibration and movement. Finally, a new record support was developed for the Rota. The Rota Ringmat supports the record in a way that minimises vertical stylus deflection caused by reflected resonances on the playing surface. Distortion and surface noise are greatly reduced. Clarity and information retrieval are improved. Tonearms and Supports Development of the total concept turntable continued with the Reson Greta tonearm. Its high quality Swiss bearing and solid core internal wiring match the Rota turntable unit and Reson cartridges. The Greta tonearm featured on the Rota 2 is 'loose coupled' to the arm board, with compliance provided by a rubber '0' ring. At the early research stage, DNM realised the futility of rigid coupling against movements that are comparable to the wavelength of light! A greater understanding of energy transmission in a turntable has allowed the elimination of the severe resonance problems associated with high mass, rigidly coupled designs. The top Reson turntable, the Reson Rota 2 is sold with the Reson Greta tonearm and the Reson Lexe cartridge. The Reson Rota 1 is supplied with the Reson Reta tonearm and the Reson Etile cartidge. Both Rota 1 and 2 are supplied with the Reson domo wall or floor stand as part of two total concept packages. These lightweight pre-tensioned stands perfectly complement the design philosophy of the turntables. The sound quality of both Rota turntables is uniquely satisfying. Fast, dynamic, detailed, transparent, obviously wide-band, with a lucid, almost tangible mid-band.

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