New Turntable Advice

The TT Brand which has a sought after model produced in the 80's off which I own Three, where all have Bearing Housing Spindle Rattle and a Platter that  Rocks when seated on its Spindle Mount.

Which has been seen fot £8Kish is a Sony Model.

I have one as a Hospital Job Overhaul, where the Bearing Housing Spindle / Bush - Spindle / Thrust Pad - Bearing Housing Sump Seal is a complete redesign.

There is a plan to produce a perfect fit part to insert into the Platter to create a rigid coupling for the Platter. 

These models are not able to be produced as  Kaneta variant so has been a rested work on more than one occasion. 

I am not the first to have the bearing overhaul. The owner of 2 x Same Model Sony's as my own, who has done A/B comparisons with their TT's in Panzerholz Plinths can't help but inform the OEM TT that was so impressive, is now totally unwanted when the modified version is the other option.

My own design being produced has added knowledge and design tolerances incorporated, which will tidy the mechanical interfaces further and enhance the End Sound further, especially with the Platter addressed as well. 

Caveat Emptor is always ones best friend when considering Sony. DD TT's.

I always wondered with the Sony knowledge of CD being launched, did Sony  reduce analogue investment much earlier than other Brands, as the concern shown for mechanical interfaces is extremely poor. 

Slam = drive/propulsion.

Maybe you should say what specific models of vintage Sony TTs you have examined so intimately, because they made products for every price point. I think the psx series are their best with PSX9 being top of the heap. Some of their lower end stuff may indeed not be so good by today’s standards.

I wanted to make an additional point about the use of a servo mechanism to maintain constant speed in DD TTs. It used to be common complaint of belt drivers that they could hear the speed corrections in DD as distortion. These days nearly all high end belt drive TTs employ some sort of speed regulation even if it’s as simple as a motor controller or a 3 phase self correcting motor, right up to reading the speed and feeding back to the motor, as in the SOTA Eclipse system. One never sees such a complaint with reference to the Eclipse. So it’s harder to justify criticism of DD servos. I think what some may hear in DD TTs could be EMI emitted by the motor and picked up by the cartridge. So the platter has to function as an EMI shield among many other things.

Thanks the only experience I have with Sony is the PS-X700 which I've had since it was released. I enjoyed the simplicity of it. But then I got convinced by a friend that I needed that VPI...

I have no problems with DD and servos working properly with the correct windings for the job! 
 

So to your question I don't have any other experiences but thru reading the discussions on the Nak an owner said he much preferred his Sony PS-X8 over the Nak.

@lewm 

effect of AC voltage on torque of an induction motor

Thanks Lew

I’ve done some reading as you suggested and have a better understanding of how the Garrad 301 motor works.  I also know more about why Festool generates 3-phase AC in their hand-held battery-operated drills!

The issue when the motor is rotating a turntable is surely the effect of varying AC voltage on the speed of the motor.  Torque is of no direct interest provided there is enough to maintain the required speed.

The stonking big motor in the Garrard 301, as you correctly point out, does not generate much torque for its size.  That is because it is an asynchronous, single phase, shaded pole design.  These rotate slightly slower than a synchronous motor would, with a slip somewhere between 0.5% and 5%.

The greater the slip, the higher the torque produced.  Indeed, if the slip were 0% no torque would be produced at all.  So they self regulate to a near constant speed which is related to mains frequency but not to voltage.  The same motor is used for dual voltage ranges (200- to 250-Volts and 100- to 130-Volts) via two different connection points.  Two different pulley diameters are used for 50-Hz and 60-Hz.

I am connected near the middle of the world’s longest power grid and frequency stability has never been an issue!