Turntable speed stabilty

[JP]

Interesting. On the polar for the MK3 there's a speed variation at 45 and 315 deg that corresponds with a noise I can barely hear at the motor - I suspect a bearing issue. I've four other MK3 I can measure so we can increase the sample pool there. Still, the R looks remarkably good.

 

[volken]

Thanks Volken. Always wanted to see measurements of Classic Vintage Turntable. How to interpret the graphs ? I presume the test track was 3K and narrower the band the more stable the speed. Right ? Original Thorens had wow and flutter measurements was 0.05%. It would be wonderfull to see Garrrads and Lencos measurements.
Regards.

Yes A 3khz testrecord with FM sidebands first tonearm/cart freq. second motor rotational speed , then belt flutter and the cursor at 100hz motor vibration.The sharp peak is a indication for speed stability very low wow fig.

 

[Dave Cawley]

When I attended the press briefing, they went on endlessly about noise floor and bearings. I wasn't convinced entirley but coupled with the review by HiFi News at http://www.soundhifi.com/images/HiFi News SL-1000R review.pdf maybe the were dead right ?

 

[Hiten]

Yes A 3khz testrecord with FM sidebands first tonearm/cart freq. second motor rotational speed , then belt flutter and the cursor at 100hz motor vibration.The sharp peak is a indication for speed stability very low wow fig.

Thanks and regards.

 

[JP]

Here's a different MK3:

Dropbox - sp10mk3-2-wf-sa7.wav

 

[IgorSPb]

Thanks Ray.


I guess heavy platter with some constant load heavier than other tonearm+cartridge criteria which affects speed stability (like spool tapes having felt disc ) can somewhat stabilize the speed. Isn't it ?
An example...

Regards

YES, it work!
There is a simple, but ingenious solution without any friction - this is an Eddie current-based brake based on a magnetic field. This is done in Sony TTS-2250/TTS-4000 direct drive turntables, permanent magnets are installed under the outer diameter of the aluminum platter. I do not know what the Sony's task was paramount, just to slow down (TTS-2250 does not have an electronic brake) or to increase the torque of the motor or all together. I tried to remove the magnetic brake, adjusted the rotation speed and the plate began to react more to the friction force, i.e. motor lost some torque.

There is some fotos of it
EngineerNate's Sony TTS-4000 Build | Audiokarma Home Audio Stereo Discussion Forums

And video
YouTube

 

[carlmart]

Before I read each and every one page of this thread, can anyone tell me if there's regulated supply anywhere that I can use on my Thorens TD160?

 

[IgorSPb]

Before I read each and every one page of this thread, can anyone tell me if there's regulated supply anywhere that I can use on my Thorens TD160?

Maybe this will help you find the power supply?
YouTube

 

[carlmart]

Absolutely too expensive. Also the Thorens is a belt driven system, not an idler wheel like the Lenco.

 

[Hearinspace]

Poking around, I ran across this sales video. The interesting part is the diy fix in the comment from F. B. below the vid. Wonder if it works.

There are also kits out there and diy solutions on the web. A couple on the AudioXpress site.

 

[ThomasA]

Bumping this thread again for a short question. Was there a program developed that can be shared free, used for polar plots? I have not read the whole thread, just to know if someone knows. Lucky, Billshurv?

 

[Hans Polak]

Bumping this thread again for a short question. Was there a program developed that can be shared free, used for polar plots? I have not read the whole thread, just to know if someone knows. Lucky, Billshurv?

Scott Wurcer made a program for this purpose.
Was meant to be supplied for free when I’m correct.

Hans

 

[billshurv]

Hi Thomas,


Good timing as I have promised to find that out for someone else. I am sure scott posted the link somewhere in the last 1000 posts here. I just have to find it.

 

[Hans Polak]

Hi Thomas,


Good timing as I have promised to find that out for someone else. I am sure scott posted the link somewhere in the last 1000 posts here. I just have to find it.

I’m not sure whether it was ever posted.

Hans

 

[lcsaszar]

It was some Python script, IIRC.

 

[fasterbyelan]

It was some Python script, IIRC.

Yes, it was, I have used it.

Unfortunately, I have changed computer since I uploaded the code so don't have a copy available. IIRC I used Anaconda/PyCharm to run it. Works OK and quick to get results.

 

[fasterbyelan]

Found it, it was part of the TT Speed Stability thread - see here This is issue 3 of the code Scott (Wurcer) wrote.

 

[Hans Polak]

Found it, it was part of the TT Speed Stability thread - see here This is issue 3 of the code Scott (Wurcer) wrote.

But this wasn’t the final version, was it ?

Hans

 

[fasterbyelan]

But this wasn’t the final version, was it ?

Hans

AFAIK, I downloaded no later one (just checked the disc drive from the old computer). Scott is the person to ask.

The third issue is attached.

View attachment polarplotrev3 .txt

 

[ThomasA]

Thanks,

this is Python? I have OSX so any chance to get the script to work?

Thomas