AURA turntable tear-down

In 1990, Stereophile’s Dick Olsher declared that the AURA turntable offered:

…..borderline Class A performance….. I’m not letting the Aura out of my grasp.  It’s one hell of a ‘table and one that I’d be perfectly happy with until the end of time.

In 2008, Dave Whittaker made his last AURA.  Incorporating many improvements over 20+ years, his later AURAs looked similar to this:

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(My own AURA – built in 1998, the Intermediate Flywheel was added in 2004.)

The motor belt is flat rubber, the platter drive belts are Pyrathane 2mm round polyurethane. (Mylar tape, eg. 6mm cassette tape, is also a suitable option.)

This is what the AURA looked like back in 1990:

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Cross-Section drawing of the AURA turntable from 2006:

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Platter and tonearms removed:

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The Main bearing pillar (stainless steel) is fixed onto a steel base-plate stiffener. Up to 3 tonearm pillars can be attached.

The concept of the heat-treated, cast alloy Platter was to be relatively lightweight (to minimise energy storage), but filled with Constrained Layer Damping.

Additional Platter Flyweights provide high Rotational Inertia and low Platter Centre of Gravity in relation to the bearing support point.

The Sub-base contains a combination of Sorbothane pucks (or hemispheres) and springs for isolation and 3 adjustable point feet underneath.

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Platter spindle:

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Removed to reveal the super-hard  tungsten carbide main bearing uni-pivot point, located high under the platter top.

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Main bearing pillar with Bearing Thrust Pad on top:

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An oil bath at the bottom, lubricates the platter lower sleeve (Teflon).

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An acrylic V-insert forms a small oil well and guides the bearing point down to the hardened thrust pad.

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Bottom sleeve oil bath

The one-piece platter & bearing sleeve has been designed to drop over the main bearing pillar into the bottom oil bath.

A Teflon ring, with grub-screws (3) for clearance adjustment, is inside the bottom of the sleeve/tube.

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Platter sleeve

The Platter Flyweights significantly increase the Rotational Mass/Inertia of the platter, but are ‘decoupled’ from the main Platter, supported simply on a plastic ring.

Motor Unit:

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Removing the motor and controller circuit housing.

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Coarse and Fine Speed adjustments provided.

The Intermediate Flywheel further increases Rotational Inertia (high mass + high rotational speed) and further isolates the motor.

In this case, for Platter speed 33.3 rpm, Flywheel speed is 270 rpm and motor speed 2,230 rpm.

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mtr-out

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Underside of motor housing.

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Later motors are fitted with a brass mini-flywheel pulley.

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Motor Flywheel removal using a DIY puller.

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(The pulley is normally held onto the motor shaft by a drop of Super Glue.)

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Matsushita DC motors have been upgraded with a brass bush bearing & end-float thrust block.

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Detail of AURA Record Clamp

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See also: Skipper Wise’s Aura Turntable.

 

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