Atmasphere wrote,
"When the base of the arm and the surface of the platter are not rigidly coupled, the result is that any motion in which both are not a party will be interpreted by the pickup as a coloration. One example could be a loss of bass.
In a turntable ideally there will be no slop in the bearing of the platter or the bearings of the arm so that this rigid coupling can occur. In that way if the platter has motion other than rotation, the arm is moving in the same plane and so cannot pick up whatever that motion (noise) is about. Quite simply, any turntable that breaks this rule for whatever reason will be incapable of state of the art performance."
Actually, Maplenoll turntables employed both air bearing platters AND air bearing tonearms. One assumes the $100K Walker turntable does as well since Lloyd bought out Maplenoll years ago. Thus the tonearm base and the surface of the platter cannot be rigidly connected. Yet Maplenoll TTs are some of the best sounding turntables of all time, and one would imagine Lloyd’s TT is as well, including bass performance. The warhorse Verdier TT employs a mag lev suspension for the heavy platter, obviously decoupling the platter from the tonearm base.
even in the case when the platter and tonearm base are rigidly coupled the whole TT is subject to bending forces produced by Seismic vibration, not to mention the tonearm and platter are excited by Sesimic vibration in the region of their resonant frequencies. So it’s no as if the situation is inert or competely rigid, anyway.
geoff kait
machina dynamica
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Ct0517 wrote,
@Atmasphere and Geoffkait - I find your use of the word Rigid misleading. Why don’t you use "Mechanically Connected" or something like that instead.
Rigid
- unable to bend or be forced out of shape; not flexible.
- not able to be changed or adapted.
That's how we're using the word rigid. With the caveate I'm using that seismic forces can bend anything even a foot thick aluminum bar. Thus, speaking for myself there can be no such thing as completely rigid in the sense that even when two objects are mechanically connected both objects can move when forced by seismic uh, forces.
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One can’t help wondering why the inventors of the mag lev turntable didn’t also employ mag lev for the tonearm, which appears to be an easier task than mag leving the platter. Then the new mag lev turntable would be analogous to the air bearing everything Maplenoll (that I used to own), the special edition one with the 50 lb platter. I’m also not sure why all the hoopla since vinyl records have been "flying in the air" for more than 30 years, you know, with Maplenoll, Verdier and Walker turntables. Looks like a clear case of stove piping.
cheers
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"You know, what doesn’t make a lot of sense to me at all with Audiophilia, is that we have some "well heeled" Audiophiles searching for that sound; spending thousands on gear. And as we are in the analog forum here, this means - multiple turntables, tonearms, even more cartridges. Yet, they do not take a small portion of that budget, and buy a good reel to reel with one days worth of 15 IPS master tape dubs to use as a reference point . Seems like an obvious way to start at Ground Zero with a good Analog Audio Reference .... and go from there. Let it guide your journey. What better way? Just makes sense to me.@
Nothing really compares to that analog sound you get from tape, whether it’s the master tape, reel to reel, or even the more humble cassette. With the major advantage at least in theory of CDs having been virtually wiped out by overly aggressive dynamic range compression over the past 20 years I am rapidly losing interest.
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"Geoffkait, How do you think this Mag lev table platter stays aligned ? I think it has to do with same pole repulsion for the main part of the platter and around the edges there is a circular opposite pole pattern. . What do I know. You are the NASA guy right ? What do you think ?"
I don't know. How much do you think the platter weighs?
geoff
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I also suspect the platter is light, perhaps very light, in order to minimize the magnetic field requirements. I also don’t think that some motion of the platter during play is necessarily a bad thing. The primary advantage of isolating the platter is the attenuation of structural vibrations in the frequency range that could excite the resonant frequency of the cartridge (and tonearm). Thus, low frequency motion of the platter, even visible motion, would be relatively innocuous as far as SQ goes since those very low frequencies are well below the 10-12 Hz resonant frequencies of the cartridge and tonearm. And they would be well below audio frequencies
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sarcher30
594 posts
11-27-2016 10:48am
Geoff, that is true but any extra motion is not ideal.
that's probably true but it might be a trade off between seismic vibration and any motion the platter provides, I.e., which is worse? On a related subject I'm not sure how accurately the spindle holes are centered in records generally. Maybe I shouldn't worry about it. 🙂
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"Geoff, vinyl has many flaws. If you do not want to sweat the details that is fine. I prefer not to add errors if I can help it personally."
geez, just when I was learning to put smiley faces after my posts
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"Hit the platter and it wobbles side to side while the arm remains static. How in the world is that suppose to track without distortion and possibly skipping. Now, if they levitated the arm on a beam connected to the same plain as the platter, e.g., Rega, and it could move in accordance to the same micro and macro vibrations I might consider it."
to which atmosphere replied,
"S'what I'm say'n!"
helpful hint: don't hit the platter whilst the record is playing.
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raymonda
What holds true for macro vibrations, hold true for micro.
actually that’s not true for isolation devices since the top plate, which in the case of the mag lev turntable is the platter, can only move at the mag lev ISO system resonant frequency, probably 3 or 4 Hz. Mico vibrations (of low amplitude) can be ignored since they cannot overcome the inertia of the platter. Micro or Macro vibrations of higher frequencies can be ignored as well due to isolation. That’s why a granite slab on a spring system won’t ring - because the granite slab is itself isolated from vibrations of the specific frequencies that would otherwise cause the granite to ring.
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"Hit the platter and it wobbles side to side while the arm remains static."
Any iso device worth it’s salt will move when struck or pushed. It’s the advantage of mass on spring iso devices (and mag lev devices) that they move EASILY in the direction of isolation. If an isolation device didn't move in the direction of the push it couldn't isolate in that direction. Obviously the Mag Lev turntable isolates in both vertical direction and all horizontal directions. If it couldn’t move easily it would NOT isolate. Hel-loo, Of course you wouldn’t want the Mag Lev platter to move due to the micro force of the stylus/cartridge.
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raymonda wrote,
"Geoffkait,
Looks like you really like the engineering of this"
Sure, why not? And with a half million dollars raised in the Mag Lev Kickstarter a lot of others like it too. Things that on the surface appear to be problems are actually advantages, that’s all.
All you need to do is put the whole shebang up on some high carbon cryo’d springs then you’d really be in business. You’d have two stages of isolation for the platter and one stage of isolation for the tonearm and cartridge. 😊
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Raymonda, are you planning to contribute to the Kickstarter campaign for the Mag Lev turntable?
Don’t let the sun catch you crying. 😥
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