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, With all due respect, you are wrong. Linn is OK right after the suspension is tuned and for the next week thereafter. AR and SOTA, up to and perhaps not including their very latest TOTL models, are seriously flawed as regards speed stability. My SOTA Star Sapphire III was a distortion generator on piano music. Have you ever heard a real piano? Do you really like stretch-y belts and belt creep that much? And AR? A classic, yes. A bargain in its day, yes. But an example of how to build a speed-stable tt? Puh-leeeeeze.

Also and parenthetically, you don't understand the mechanism of a direct-drive turntable. I think I mentioned this to you somewhere above this last post. Do some reading on this subject. The issue in direct-drive is not noise but designing a motor that is free of cogging at slow speed. (The DD motor has to turn at 33 rpm, whereas belt drive and idler drive motors turn much faster. This tends to make them noisier than DD, not quieter, but a little easier to mask the cogging effect.}

But the syntax of your post actually suggests you like direct-drive better than belt drive. (You start with your criticism of direct drive and then begin your discussion of belt drive with the phrase "next best", implying dd is better, which it actually is when done right, IMO.)
Hi Thuchan,

I do understand that your system stands in Bavaria and it is located on-speed outside of Munich :-)

Also, I like following this attitude of "but sometimes fast driving"...out on the road! :-)

Always happy listening!
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.

_______
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.