New Turntable Advice

@richardkrebs 

A plain bearing should not have a highly polished shaft. It needs a tiny amount of roughness to ensure an even oil film

My favourite example of the metallurgist’s art is Babbitt Metal for industrial bearings, first invented in 1839.  The concept is that very hard, smooth cubes are embedded in a soft metal matrix.  In use, the soft matrix allows the cubes to align with the shaft surface.

The matrix is mainly tin or lead, to which copper and antimony are added.  On cooling, hard cubic crystals precipitate first, then the white metal matrix solidifies.

But wait, there’s more!  The cubes are lighter than the matrix, and tend to float to the top.  To make sure they are evenly distributed throughout the matrix, extra alloying elements can be added which precipitate before the cubes, and form long filaments which stop the cubes floating.

That’s before we get to powder metallurgy used for sintered, oil-impregnated bearings, or additive manufacturing like 3D printing.  Wilson Benesch use laser technology to form tonearm parts by fusing powdered titanium into intricate 3D shapes, some with an internal structure like lightweight bird bones.  They even encase titanium powder in a fused titanium shell - the powder is great for damping vibrations.

@badbruno 

All of which makes me think that your quest for low wow and flutter may not uncover the most cost effective improvements.  After all, the purpose of a turntable is to allow a stylus to accurately track a microgroove, let's say down to a micron or so.

To me, you may find it more productive to examine the tone-arm end.

It is a bit like Formula 1 racing.  You can improve engine power, braking performance and / or cornering ability.  After almost 100 years of focusing on power, computer simulations showed that the same percentage improvements in cornering force could dramatically improve track lap times.  The simplest way is to increase downforce, even if doing so 'wastes' some power.

Being Formula 1, anything that was too effective got banned.  We no longer see huge wings pressing down directly on the rear axle, nor side skirts which skid on the tarmac to create a partial vacuum, nor fans to suck the car to the track.  But we do have aerodynamics which theoretically would allow a race car to fly upside down at 100-mph.  At high speed, downforce can be triple or more the car's mass.

So I think trackability is nowadays more important than speed stability.  In particular, how are unwanted vibrations channeled away from the stylus / record interface?

@richardbrand. 

Here in New Zealand, we use 3D printing of titanium to build rocket engines . but I digress.

Yes there is a lot of cool tech out there, some dating from way back. The trick is to use this technology to further the state of the art in audio reproduction. A healthy eye on the past along with innovative use of tech advances, rather than slavishly adhering to the current fashion.  

All audio equipment design is fundamentally an engineering problem. My passion being TTs which I see as an impossible engineering problem. One can only get as close as possible to the ideal, not actually reach it.  

To describe what a TT/TA needs to do is easy. " As viewed by the cartridge rotate the record at a constant speed under dynamic conditions" 

To unpick this statement. W & F figures are meaningless if measured by a steady state tone. This is not stressing the system dynamically and the TA will have an impact on the end numbers. Any movement in the platter other than its plane of rotation is  viewed by the cartridge as a change in speed. Any play in the main bearing is viewed by the cartridge as a change in speed. Any flexing of the main bearing housing changes the speed. Any resonance or flexing of the chassis (plinth) will be viewed as a change of speed. Outboard, standalone, arm boards need not apply. Any bending, resonance in the arm wand changes the apparent speed, Arm bearing play.....   etc etc. The list of speed deviation possibilities is extensive 

So when designing a TT we need to consider the perspective of the cartridge and work backwards with this knowledge to reduce these speed change impacts. If we turn this approach on its head and say that absolutely constant speed as viewed by the cartridge is the goal and that any deviation from this is movement, then the TT/TA  pair need to be "still"  And yeah, there is also the cartridge body in the mix. 

Cheers.

I was able to locate a beautiful bespoke refurbished Sony PS-X9 today here in The USA. In fact the person who refurbished my Sony PS-X700 has both a Nakamichi Dragon CT and the Sony PS-X9. It’s been his reference TT since 2020.
 

The unit has been carefully reworked caps, transistors and some special devices also with cleaning and re-lube all the actuators and mechanicanisms. So I’m very excited to be able to see the unit and take a listen. He has been a great trusted source for me in the past. No need to ship it within driving distance!

Richard we 3D printed large propellant tanks for our Satellites. We designed a built a manufacturing cell with four robotic stations 90 deg apart. Two stations which were 180 apart from each other were additive manufacturing and the two stations were machining centers. And all four stations included optical inspection. These tanks were ~ 40-50" in diameter and ~ 6-7' tall. 
technology !