About the Turntable

ONEDOF ™ or ONE DEGREE OF FREEDOM TURNTABLE

Proudly manufactured in the USA by ONEDOF LLC, Denver, Colorado

The USA market retail price is $150 Thousand directly from the manufacturer. 

ONEDOF™ is a revolutionary belt driven turntable designed by NASA-award winning aerospace engineer Aleks Bakman.  The result is pristine, unspoiled sound.  The turntable features:

·         The first turntable in history with self-centering platter bearing in a non-resonant liquid suspension.  The platter spindle instability, a never before addressed cause of acoustic distortion, is eliminated.

·         A noise canceling drive with on-the-fly motor position adjustment.  This adjustment eliminates distortions related to the vertical drive belt position.  The drive is based on a Texas Instruments’ microprocessor; it is a product of the most advanced Swiss craftsmanship and innovative American engineering.

·         Synchronous motor with coreless skewed winding that eliminates cogging and provides torque ripple free operation.

·         50 lb aluminum high quality alloy platter with internal liquid damping. The mass of the entire turntable is 110 lb. 

·         Tonearm tower with continuous, smooth yet solid on-the-fly Vertical Tracking Angle adjustment of over three inches.

·         Enough space to accommodate three tonearm towers.

·         24 carat gold plating.

Bearing

A first in the history of the audio turntables the self-centering One Degree of Freedom or Onedof™ bearing eliminates the source of acoustic distortions associated with microscopic movements of all existing cylindrical shafts. With its unique precision the Onedof™ bearing is holding the massive spinning platter steadily. The bearing only permits the platter steady rotation about the vertical axis, passing through the center of the planet Earth.  It is the only degree of freedom that the bearing leaves to the platter. 

The microscopic shifting and wobbling inside all existing cylindrical bearings and the consequent blurriness of the sound is not due to the manufacturing imperfections. These unwanted movements are happening by design, because there should be a small gap between the shaft and the bearing in order for the shaft to rotate inside the bearing. Follow these links to see the illustrations of this problem:  Microscopic movements in the cylindrical bearing that leads to macroscopic wobbling of the platter.   For the first time in history of the phonograph this problem is solved and eliminated by the Onedof™ platter bearing.  The innovative design of self-centering in all directions Onedof™ platter bearing avoids any wobbling and shifting. Because of its design this bearing is much more precise than any of its parts.  It is so precise that its precision cannot be measured directly because the manufacturing tolerances of the parts are always in the way.  The only reasonable method of evaluating the precision of this bearing is by subtraction.  All parts of the bearing are manufactured on the super-precise metalworking lathe. The total runout, measured at the edge of the freshly manufactured platter when it is spinning on the metalworking lathe is 0.0002 in. (5 micrometers) or 1/10 of the human hair thickness. The total runout of the platter spinning on the Onedof™ bearing is also .0002 in. Subtracting one small number from the equal small number, we are receiving ZERO total runout of the platter bearing in radial or axial direction. Because of the self-centering capability, the platter bearing is even more precise than the lathe on which the parts of the bearing were manufactured.

Suspension and Damping

Another first in the history of turntables feature is a resonance free liquid suspension with non-linear stiffness.  The suspension provides sound isolation of the spinning journal (shaft) and platter from the environment.  It cancels external excitation.  Most importantly, it does not resonate.  It does not have resonant frequencies.  The liquid suspension is an integral part of the Onedof™ bearing.  A thick film of oil, created by the rotation of the platter suspends the rotating mass.  Oil supports spindle at the bottom, at the top, and around circumference of the journal.  Suspension works only when it is needed, when the spindle spins and the platter receives external acoustic excitation.  The condition for the resonance is always the permanent or linear stiffness of the spring element in suspension.  In the Onedof ™ bearing this spring is replaced by the film of oil.  The stiffness of this film is changing non-linearly (exponentially) with the microscopic up, down, left, right, back and forth movements of the platter/journal.  Because of this non-linear and perpetual change of stiffness the condition for the resonance is eliminated, resonances do not occur.  Because of the fast exponential rise of the suspension stiffness the unwanted movements do not develope, which is why the bearing is so dead steady and precise.  There are no rolling elements like balls and rollers.  There is no stiff solid load path from the platter to the supporting stand.  The thick film of liquid lubricant dynamically centers the rotating journal in the three orthogonal planes.  The viscous oil provides ideal damping in all directions.

Six large chambers inside the 3 in. thick aluminum platter are filled with a mix of viscous oil and solid particles to damp out the resonances of the platter.  Around perimeter of the platter precious vinyl record is pressed down by a massive ring, also damped and centered by two parallel o-rings.  The rotating mass of platter/journal assembly is 50 Lb (23kg)

The Drive

The permanent magnet brush-less motor creates no cogging, no torque ripple, and no speed ripple due to the skewed winding and the core-less stator.  A very small distortion unavoidably produced by the bearings of the motor is absorbed by the drive belt and platter suspension.  The resonances of the belt itself are cancelled by the drive.  The motor design and phase locked computer controls reduce the velocity error to less than .0000001 (one ten-millionth) or .00001% of velocity value per revolution.  This level of precision would not be possible to achieve without the extraordinarily precise Onedof™ platter bearing, which provides complete absence of precession (whirl).  The motor rotates the platter by means of three precisely manufactured o-rings.  Tension of the o-rings is controlled by the damped standoff between the housing of the drive and the bearing housing.  The vertical position of the motor can be adjusted on the fly with micro-inch resolution in order to tune out possible resonances in the drive belts, to farther eliminate excitation of the platter and refine the sound.

Noise canceling feature of the drive utilizes the same principle as high quality noise canceling earphones. Electric motors are never all the way quiet.  However, it is possible to decompose any noise into harmonic cyclic components and kill it by applying the same, but with a minus sign to the motor's driving current.  Using feedback instrumentation, the drive monitors rotational velocity of the motor and reverse current electromagnetically induced in the winding of the motor.  If the mechanical system (motor’s rotor, belt, and platter) develops resonance at one or several resonant frequencies it causes distortions of velocity.  The microprocessor receives a signal about it in the shape of the cyclic component of the back current.  The microprocessor replies to this signal with the cyclic direct current of equal amplitude, but in an exact counterphase to the current generated by the distortions.  Noise canceling drive action, heavy platter and powerful enough motor unite in canceling distortions in real time and keeping the velocity of the platter constant.

The Tonearm Tower

The tonearm tower, featuring continuous and smooth on-the-fly VTA adjustment over 3 in., works with any tonearm and cartridge combination. Tonearm has massive support, to prevent high frequency resonances. The Onedof ™ turntable can work with three tonearms simultaneously.