Direct drive vs belt vs rim vs idler arm

I see variation about the setpoint which is normal. That is the speed control system working. The DD table has a funny pattern to it. Notice the two bumps and then a flat line in the speed plot? The DD table speed control seems to do a correction over about 10 seconds and then rest. Then the cycle repeats. The Raven on the other hand has a pretty constant cycle about the speed setpoint which is very similar to my table. Note that these corrections are within 0.01% to 0.02% of speed. Very fine control.
Also note that even if your speed is off by 0.1Hz, it will take 945 minutes of running time for your platter to gain/lose one rotation. Nothing against the timeline, just that your turntable would have to run for almost a day with the timeline to see how accurate it is. These plots show you results in a matter of seconds.

Note the almost perfect Mean Frequency Response against the recorded 3150Hz and the impressive .01% speed deviation.

It makes you wonder if you're measuring the speed stability of your turntable, the lathe that cut the test record, or both. Perhaps this is a benefit of the Timeline. Your measurements are not hindered by lathe inaccuracy. There has to be some lathe inaccuracy. If there wasn't, wouldn't we all be listening to records on lathes or turntable with record lathe type drives?

If your Timeline was 31" from a wall, a speed error of .01% would appear as a 0.02" (0.5mm) laser deviation per revolution.

Also note that even if your speed is off by 0.1Hz, it will take 945 minutes of running time for your platter to gain/lose one rotation. Nothing against the timeline, just that your turntable would have to run for almost a day with the timeline to see how accurate it is. These plots show you results in a matter of seconds.

It's not quite that bad. If your TT is 3' from the wall and your laser deviation is 1.5mm per revolution, your speed is off by 0.1Hz. 1.5 mm may be hard to see, but if you let it run for 10 revolutions and divide your total deviation by 10 you should be able to determine a 0.1Hz error pretty easily (if you have my Timeline Calculator Excel file that I posted about in this thread):

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1327029459

The phone app sounds pretty cool, though. It is actually not just an iPhone app. I just discovered that you can get it for Android devices, too. I may have to try it out.

Hi Tonywinsc/Henry et al.

Thanks for publishing that excellent information Henry !

From Dr. Feickerts website.
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The optimal Azimuth can be found reliably using a systematic analysis of the values of level and phase angle of the crosstalk signal against different azimuth settings.
But this is not the complete functionality you get. You can also measure dynamically using Pink Noise to see how your cartridge reacts under complex signals. Additionally you can measure the frequency response of your cartridge/phono-stage with Pink Noise (dynamic) or with a sine-wave sweep (static). In both cases also in left or right channel only mode.

Setting up turntable speed now is an easy task as you don’t need to use inaccurate strobe discs. Simply use Adjust+ and enjoy additional benefit from the built-in wow&flutter analyzer – now even evaluating according to DIN IEC 386 (formerly DIN 45507)! Now you can test how good your turntable spins your discs….

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To All.

Would I be correct in assuming that if we wanted a real apples to apples comparison of the data, turntable to turntable – then Halcro (Henry) needs to use the same tonearm/cartridge on each table ?

Did u use different tonearms and cartridges on the two turntables Henry ?

From Dr Feicket’s website again. Btw - I am not affiliated with Dr. Feickert.

Another feature is the fres task. You can measure the resonance frequency of your cartridge/tonearm combination, something very, very rarely found nowadays. Adjust+ helps you to see if your chosen combination works in the recommended range of 8-12 Hertz. Well, and if you are not sure if you have additional resonances in your tonearm resulting from tracking you can measure in the range from 30 to 500 Hertz and see…..

Back in the 70- 80’s when vinyl was at its peak, Bruce Thigpen did a number of wow and flutter tests, without an Android or I phone :^) ........ on various tonearms using the same table.

But this a turntable thread...

Cheers

wow and flutter defined

Halcro, thanks for your interesting post. I wonder if you would get different test results on your Raven if you used one motor? Any thoughts?