Turntable speed accuracy


There is another thread (about the NVS table) which has a subordinate discussion about turntable speed accuracy and different methods of checking. Some suggest using the Timeline laser, others use a strobe disk.

I assume everyone agrees that speed accuracy is of utmost importance. What is the best way to verify results? What is the most speed-accurate drive method? And is speed accuracy really the most important consideration for proper turntable design or are there some compromises with certain drive types that make others still viable?
peterayer
Davide256: "the belt provides isolation in power transfer. But a platter mounted on same sub chassis as motor still sees vibration transfer through the chassis. Rega follows this model."

The Sota Cosmos (couple models higher than your Sapphire, which I owned and used before) does the same thing and you know why? Because Sota wants to solve the speed issue from previous models! As mentioned by Michael Fremer in Stereophile, on many suspended turntables the motors are "hard-mounted to their bases; when the subchassis was horizontally deflected, the platter-to-motor pulley distance would vary, causing speed irregularities."

I no longer own the old Sota Sapphire for a reason.

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Dear Unoear,

(why not Duoear ?) you are fully correct. It is not a big problem finding me if you are not restricted to the US as some people seem to be, like Audiofeil for instance. Nevertheless this guy knows all kind of ice cream tastes and National League players (of the US of course) - hmmm maybe interesting.

But back to the topic. Has anyone really opened the Timeline and do you know what this means? Did you count the screws Halcro?

Unoear is a nice acronym. Is Duoear still available :-)

best @ fun only
Dear Hiho, I am trying to understand your post on SOTA. Do you mean to say that the Cosmos is subject to M Fremer's critique (motor mounted to base/platter on spring suspension, which is also my criticism), or not? Most users seem to like the Cosmos and the Millennium, so I was not sure whether the current owners of SOTA had cured that problem (by re-design) or not. Surely it was a major issue with the Star Sapphire and that design flaw goes all the way back to the AR. (I have owned both for years at a time.) We forgave the AR for it, because the tt was so cheap and otherwise a good performer. I don't know how the Linn Sondek LP12 is built (never owned one), but the same issue is posed for any belt-drive/spring suspension.
That is one thing about the original Empire table that they got right- the platter and the motor mounts are not floating with respect to each other. Wow and flutter on even the first models had excellent specs. The motor on those machines are also quite powerful and have a lot of torque.

A powerful drive is really helpful to speed stability and is why the best vintage machines are still respected today.
Hi Unoear - so the Sirius is yours :^)
I have never seen one let alone heard one.
If I owned one I would never sell it - even if it meant my two 17 years olds had to pay for their own university.
FWIW - My earlier comment came from reading past posts here by members who have heard it and actually complained about some part of its sonics.
Sounds unbelievable to me. I can only assume the setup (most likely the arm?) must not have been optimal.
Cheers