I looks like Kuzma uses a commercial air bearing, they are expensive, i understand why not many use this solution. Kind of overkill for a simple 33,33/45 rpm low weight application.
American Sound, "The Absolute Nothing"
- Thread starter PeterA
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While a full air bearing or a platter floating entirely in the air without any contact might be seen as the ultimate goal, I don’t believe it’s necessarily the best solution.
Focusing on the vertical plane, where the platter is suspended by an air cushion, the issue is that the air cushion behaves like a spongy material, acting as a damper and reducing dynamics. More critically, minor fluctuations in air pressure or other factors can cause the platter to bounce at a microscopic level. The same issues apply to magnetic levitation systems.
To address these problems, it’s more effective to lift most—but not all—of the platter’s weight with air or magnets. For instance, lifting 28 kg of a 30 kg platter would leave the bearing to support only 2 kg (about 19.62 N in weight). This approach retains the benefits of high mass, such as the full flywheel effect, which is crucial for motor performance, while eliminating issues like platter bounce, as it behaves like a much lighter 2 kg platter.
This might explain why most magnetically levitated turntables adopt this partial lift approach. Maybe same goes for air bearing turntables too but I don’t know.
Focusing on the vertical plane, where the platter is suspended by an air cushion, the issue is that the air cushion behaves like a spongy material, acting as a damper and reducing dynamics. More critically, minor fluctuations in air pressure or other factors can cause the platter to bounce at a microscopic level. The same issues apply to magnetic levitation systems.
To address these problems, it’s more effective to lift most—but not all—of the platter’s weight with air or magnets. For instance, lifting 28 kg of a 30 kg platter would leave the bearing to support only 2 kg (about 19.62 N in weight). This approach retains the benefits of high mass, such as the full flywheel effect, which is crucial for motor performance, while eliminating issues like platter bounce, as it behaves like a much lighter 2 kg platter.
This might explain why most magnetically levitated turntables adopt this partial lift approach. Maybe same goes for air bearing turntables too but I don’t know.
The B 62 probably relies on frequency of the main power for speed stability, the later A 80 have a feedback system that constantly adjust capstan motor speed with voltage variations. I am sure they sound different in regards to rhythm/timing.Now this is what i call a spindle / bearing .
This is what i usually installthe bearing is over 100 K euros , 1500 mm OD
On topic , you can talk all you want about bearings / speed regulation but its the outcome that counts and i have not heard better then my Studer B62 / Telefunken M15A regarding natural rhythm/ timing .
I dont know what they use but i doubt its that sophisticated / accurate as what they use in modern TT s.
I think the magic lays elsewhere in the TT design
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Yes they do , the tech who serviced them both thought the same .
The A80 RC Mk2 sounded more laid back .
The B62 more Dynamic
This is from an old review when Jonathan Valin visited Audio Tekne. So, I don’t believe this is as delicate as you think. I have not tried this!
“As an added bonus, I also got to hear my LPs played back on Mr. Imai’s record-playing system, the ACP-8801 with air-bearing turntable, pivoted arm, and Audio Tekne MC-6310 phono cartridge (third picture to the left below)—a device so immune to vibration that I actually watched, in some horror (since it was one of my discs on the platter), Mr. Imai slam a heavy rubber-coated mallet onto the tonearm standard, the plinth, and—with my heart in my throat!—the record clamp while the record was playing! I heard nothing through the speakers (and these were, as you will soon find out, horn loudspeakers), save for a very-low-level “thunk.” The tonearm never skipped a beat!”
Of course, any engineering solution is a series of compromises and trade-offs. Many excellent minds have attacked the bearing solution from many different angles. What is more noticeable to the sound, bearing rumble (inescapable) or nano-scale bounce or eccentricity of a floating platter? Eccentricity of the record itself far, far greater than any ‘wobble’ of the platter. And for vertical lift the air cushion is typically only a few microns so not a lot of room to bounce. Granted, on a micro-level these deviations must exist, but the designer/engineer is convinced the solution has less audible impact than bearing rumble and drag.
Sadly, for most of us, it will never happen multiple spanky tables in our own systems at the same time to decide which we like better. MikeL is fortunate to have a few side-by-side and each excellent approach brings differences in sonic character more so I imagine than highlight any deficiencies.
Like fine wine it comes down to matters of taste and what appeals to you. I have no problem having two glasses in front of me to sample from and compare and contrast. Pockets not quite deep enough to do the same with turntables.
Sadly, for most of us, it will never happen multiple spanky tables in our own systems at the same time to decide which we like better. MikeL is fortunate to have a few side-by-side and each excellent approach brings differences in sonic character more so I imagine than highlight any deficiencies.
Like fine wine it comes down to matters of taste and what appeals to you. I have no problem having two glasses in front of me to sample from and compare and contrast. Pockets not quite deep enough to do the same with turntables.
On the contrary, this actually reinforces my point about the significant damping in that particular design. It’s still surprising to see how many people misunderstand the concept by tapping the plinth. But tapping the armboard and clamp takes it to another level of confusion. The proper way to test a turntable’s isolation is by tapping the platform it sits on, not the plinth or the clamp.
Then you have a stable vertical and horizontal contactless movement no other way is possible my opion. Three air bearings with high pressure up to 150000 rpm/min.
It’s not just about the microscopic bouncing of the platter; the real issue is how it negatively impacts the dynamics, diminishing the overall sound quality.
The air bearing design you mentioned relies on high rotational speeds and air film formed because of that. IMHO it is not applicable to turntables since 33.3rpm is just a fraction of those high (150.000) rotational speeds. Turntable air bearings rely on pressurized air.
I see, the Audio Tekne has nothing like that. See the picture I posted on previous page.
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