Speed Stability

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Sterling1
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Speed Stability

Post by Sterling1 » 19 Nov 2019 13:27

At this moment I am enjoying Diana Krall's "You Go To My Head" from her Best of Diana Krall album. I am listening to the tune via my Technics SL-1210GR. The tune has some sustained notes which puts a demand on speed stability and the Technics comes through on those notes. I also have a 44 year old Sony DD PS-4750, which has no speed/pitch lock and this TT does not play the aforementioned tune so well. I bring this to attention here for anyone who wants to better understand the importance of speed stability, as the Diana Krall piece is the perfect tune to get a feel for it all. Just play the tune on TT and compare to downloaded version.

Bob Dillon
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Re: Speed Stability

Post by Bob Dillon » 19 Nov 2019 17:51

Make sure it's a perfectly centered pressing.

georgesgiralt
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Re: Speed Stability

Post by georgesgiralt » 20 Nov 2019 15:09

Hello,
If the designation is correct, the Sony is a direct drive. So it uses a regulator to set and stabilise the motor. Even forty years ago a decent electronic engineer was able to design a very precise regulator up to the task. I would have been able too but I did not practice for the last 40 years so won't remember the theory nor the practicalities ...
I bet this regulator can be vastly improved by checking/replacing 40 years old electrolytic capacitors and cleaning the adjusting resistors which should be present.
IMHO, all DD turntables are eager to spin sufficiently regularly to play Diana Krall sustained notes without any glitches or problems... Even Sony made !
P.S. : on modern hard disks, the regulator is able to spin a DD motor at 7200 RPM and so precisely that the heads can read data on the platters. I can't remember the tolerance right now but is is faaaaarrrrr better than we use in a turntable.

Pauw
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Re: Speed Stability

Post by Pauw » 20 Nov 2019 15:40

My SL D303 is a non quartz but it is as steady as a rock after careful cleaning and adjustment and that is not the best Technics direct drive motor......so if you can hear a speed variation you need to service your drive. :D

rewfew
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Re: Speed Stability

Post by rewfew » 20 Nov 2019 15:45

Maybe also the technical superiority of quartz vs servo drive. Speed stability was one of my personal foremost reasons leading me to direct drive. And ever since have never been plagued by sustained note instability.

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