New Turntable Advice

@richardbrand 

Yes, and if you want to advance the state of the art, dissect the older designs and take their learnings. Then apply them to the materials, manufacturing and tech capabilities we have today.

One example. A plain bearing should not have a highly polished shaft. It needs a tiny amount of roughness to ensure an even oil film. This is common in my industry, hydraulics, but is rare in the audio TT world. EMT knew this and when you look at the shafts of their classic TTs they appear dull...by design. This is engineering done properly. 

cheers.

Porter - Dobbin - Galibrier all recognised for their Plinths and adopted methods for improving mechanical interfaces. All potentially got their early information from Lenco Heaven. From their starting out designs changed and in some cases, TT Models worked with have been expanded on.

There is very little that these Bespoke Services do that can’t be found on Lenco Heaven. 

More than enough info is Public and enabling for another to use to produce their version with a successful  finish. 

Even High End TT manufacturers have adopted the materials discussed on LH that have been used to great effect when ovrrhauling a Lenco TT’s Bearing Assembly. 

Rigidly coupling a Bearing Housing on a Lenco TT has been seen carried out as a design for numerous years. 

My own endeavours commenced before LH was a Forum, but the detailing of the used designs that are shown on LH are a fast track to intensive learning and successes with one’s own adaptations being realised. 

I can easily add an ID TT for the OP, I’m sure they would really enjoy the experience, I myself have a long period behind me of enjoying the experience. 

The OP should be let know that their concerns about Speed Fluctuation, when considering a ID or BD TT is usually best improved by a Off Board Purpose Produced Device. 

Certain devices that are recommended can comfortably be costing more than a JVDD TT, that if functioning without issues, is far more reliable for Speed Control. 

When this Costing for Speed Control becomes known, the JVDD TT, does become an attraction. 

Commonly available Vintage ID TT’s can easily cost $3Kish+, versions with a modernisation, can be double the cost.   

and Vintage BD TT’s can easily match and surpass the costs for ID TT’s. 

Each of the above will be likely to need a Off Board Speed Controller to give their optimised control of speed. Such Off Board Devices can easily cost $1.5K and ascending in cost. 

A JVDD TT Model - Aurex SR 510, is able to be everything the above drives can be for 40 - 50 x less as the purchase price. For 30 x less cost other JVDD TT’s can be a slight betterment for Speed Control over the 510.

Note: Much of what is discovered on Lenco Heaven to improve mechanical interfaces, is totally transferreble to the DD TT.

Add to this the use of a Resin Impregnated Densified Wood Board as the Plinth Material, and this will surpass any historical Plinths used and be a competitor in it’s performance  for any Plinths produced by so called Plinth Guru’s offerings where $2K get one on a waiting list, and enabled to dicuss the final asking price. 

@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.