Ultimate turntable design: modern technology to remediate root cause issues

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#81
Do you think that the bearing could support almost twice the weight of the plate?
It is not a concern, I insist, I would like to know how is the construction of the bearing in general in these small size DD engines.
I think that it should not be something so special, although there may be differences in the electromechanical part between different manufacturers.
Should I imagine a ball bathed in heavy oil like an old Lenco?
 
#82
12russel3456 said:
Hi Dreamth,

I instead believe that 2 motors and a Fly Wheel to drive the platter are an improvement ( VPI and others have developed it ). A heavy Fly Wheel with similar weigh as the platter such as around 5 Kg ) needs 2 motors for torque reason.

I have also tried an attempt to make it, unfortunately the fly wheel made by the lathe guy did not have the necessary precision and was not well balanced so gave some short coming, but regarding the speed stability and dynamic of the sound was an improvement VS the single motor.

Allow me to add that type of belt and length is also important so the system need e total matching and not just a simple single or double motor....

Regarding the type of motors and controllers, well..........it is a jungle, almost an endless debate.

Rgds

Adelmo
Click to expand...
i have no idea what turntables you're using...Both my duals have 12inch 3.1 kg platters and i consider them heavy enough as flywheels. I bought a dual 1219 which is an idler especially for experiments and my first try on it was to supply the motor from a sine VFD with constant V/F=1.The speed became indeed very stable, but i wasn't able to hear any clear sonic improvement.Then i used a hard drive magnet to slow the platter simply by bringing it close to the platter and the eddy currents would visibly change the platter speed as there's was no feedback system, but yet again nothing sonically could be perceived as an improvement by adding lateral controlled drag, probably because the delivered power vs drag forces were already well thought by Dual engineers .I simply think that when we have great expectations from out work we start "hearing" improvements, unless the initial design is flawed right from the start...but if we strive being objective we can't really improve a good design in such a manner that we could clearly convince others too by the improvement .
 
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#83
One Method to discover if your Platter/Spindle Bearing Assembly is deemed able to take extra weight without a raised concern, is to see if there are alternative Platters available for the Model of TT or other Models of TT from the same range that has a Platter Produced in Gun Metal or Stainless Steel.
Either of these will have more weight than a Pucks weight that is being questioned.

There are Alternative Platters being used, by both Manufacturer and Third Party Producers, on DD TT's, that in some cases of usage, are also using Periphery Rings and possibly a Puck combined.

I am not aware of any raised concerns about the effects on the Mechanical Interfaces,
there might be the odd question raised about the Electronics Interface, but again I am not aware of any supplied information suggesting the Additional Weight is detrimental to the TT's performance.
In my mind but not proven, a Thrust Pad is a Sacrificial Part, in some cases the added weight might put the Thrust Pad in need of a exchange earlier if extra weight is being managed.
In the case of Lenco's a Harder Wearing Thrust Pad Material (PEEK in place of POM) is suggested when the Added Weight (Stacked Platter Method) is applied to the Spindle.
 
#85
academia50 said:
Do you think that the bearing could support almost twice the weight of the plate?
It is not a concern, I insist, I would like to know how is the construction of the bearing in general in these small size DD engines.
I think that it should not be something so special, although there may be differences in the electromechanical part between different manufacturers.
Should I imagine a ball bathed in heavy oil like an old Lenco?
Click to expand...

HI,

I have the following experience :

My platter weigh is 4.5 Kg, I have a puc 500grams adding and my bearing have a shaft of 13mm, a thrust pad and a ball 5 mm. All in oil bath . Rumble cannot hear while play records, between songs of the record is very silent. I have recently overhauled it and after 14 years of use was like:

Thrust pad had a wear of about 2 mm so I replaced , same bronze material.
I did not detect any noticeable wear on the bushes, once I in let the oil takes very long time to the platter to go down, I need to spin it with the motor for few hours. Allowance are pretty precise still.

The platter reach the 33.33 Rpm immediately.

To hilight:

Shaft is not big but not small either, most of TT have it around 9 to 10 mm while mine is 13mm

I did not use sintered olive bushes but bronze bushes. About it there is a long debate which one is better, I am satisfied of mine.

The house of the bushes is made of the same bronze material, actually it is made from one solid piece of bronze.

The gap between the bushes and the house is bigger than the conventional 2 mm of standard bushes, more oil there that I think benefit to control the frequency while spinning.

Increasing the weigh on the spindle shall increase the wear of the thrust pad definitely especially if your bearing have the small ball pressing on it.

Lately is fashion to use POM or peek material as thrust pad, these material is said to bring benefit to the rumble figure and sound better. I think they also last less than other materials. regarding the sound or rumble I did not compare so no comment.


Rgds

Adelmo
 
#93
These esoteric and "magical" bearings may work as intended, but IMO a bit obsessive and overkill.
When my lowly older DD Kenwood's main platter bearing is so precisely manufactured that it produces no detectable rumble or noise that's transmitted to the stylus.
In fact, the noise floor of a good vinyl record is above any possible bearing noise.
 
#94
There was an inquiry within this Thread about Added Weight being Loaded onto the Spindle, the thoughts were about the Vertical Loading onto the Thrust Pad Interface on a Common Bearing.

The few replies were polite and offering an answer to an inquiry.

The Answers offered by myself were for the Individual asking for information, they were not a suggestions of a method to produce a Superior Platter Spindle Bearing Assembly.
 
#95
banpuku said:
Keep in mind, I would not build a mechanical contact thrust bearing. I would go with either magnetic or air.
Click to expand...

That is contrary to some of the best TT's, Continuum, Dohmann and SAT all use contact bearings. I know Dohmann designed the Continuum Caliburn and Helix both of which use thrust bearings, with the engineering capability Dohmann had at his disposal for the design if no contact was superior it would have been used in the Helix 1. The Helix uses a magnet between the platter and bearing to reduce load on the ball/thrust pad.

Using a contact point gives energy imparted into the platter spindle a path to exit the spindle. If you have no contact then ALL of the vibration energy will be reflected straight back to the LP/stylus. If you use a non-contact bearing then you will need to deal with this vibration energy in the platter or it will smear the sound.
 
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#96
JohnnoG said:
There was an inquiry within this Thread about Added Weight being Loaded onto the Spindle, the thoughts were about the Vertical Loading onto the Thrust Pad Interface on a Common Bearing.

The few replies were polite and offering an answer to an inquiry.

The Answers offered by myself were for the Individual asking for information, they were not a suggestions of a method to produce a Superior Platter Spindle Bearing Assembly.
Click to expand...


I know, thank you!
 
#97
warrjon said:
............ If you use a non-contact bearing then you will need to deal with this vibration energy in the platter or it will smear the sound.
..............
Click to expand...

But a DD motor that rotates at 33 1/3 revolutions does not generate as much vibration as a 2500 RPM motor in a belt system, that is the eternal discussion, the belt together with a high mass of the plate, absorbs that vibration in its entirety ? Exceeds DD?
 
#99
academia50 said:
But a DD motor that rotates at 33 1/3 revolutions does not generate as much vibration as a 2500 RPM motor in a belt system, that is the eternal discussion, the belt together with a high mass of the plate, absorbs that vibration in its entirety ? Exceeds DD?
Click to expand...

Regardless of drive system, ALL platters sit on a bearing and all platter bearings rotate at 33rpm. And that bearing noise has to go somewhere and if there is no path to drain that energy it will travel back to the stylus. I agree with Warren's idea of mechanical grounding.
 
#100
No matter what you do, you can never get better replay of a vinil recorded on a machine driven by this:
Disc-cutting lathes
Neumann VMS spindle bearing - The Secret Society of Lathe Trolls
How to service and refurbish Lyrec SM motors used in disc cutting lathes (Neumann, Lyrec) - YouTube
I couldn't find photos of the Neumann spindle bearing, but a high performance CNC lathe that's aimed at making micron size cuts in hard steel has to be as low noise as can possibly be because noise tranlates into micron length vibrations that can damage the finest work you need to be done on a CNC Lathe and imagine you need to make the platter center hole on such a lathe and it obviously won't be higher precision than the machine doing it..
Lathe Rebuild CNC Spindle Bearings ???? - YouTube
 

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