Turntable speed accuracy

Hi Peter,
Sorry for the confusion this morning. I was rushing because we were preparing to go to a wedding. I was excited to see your post and wanted to reply before we left and my wife was bugging me to get off the computer and get ready to go.

The drift is 0.4 degrees/minute or 0.001133 revs/min. So after 5.2 minutes, the total error was 0.00589 revolutions out of 173.33 total revolutions. That is a speed error of just 0.003%. It may not be 0 as some DD turntables claim to be; but it is pretty close.

Your turntable is absolutely perfect. Its speed control is on the order of any type of drive system, ie. direct drive, rim drive, etc. in terms of accuracy. The only other check would be with a scope to see the constancy of speed over a single revolution (Wow and Flutter); but I'm sure it is laboratory grade as well. I wonder why the Timeline device does not flash more often. If it did, it would give some indication of speed variation during one revolution.

Thanks for sharing.

Hi Tony,

The TimeLine device that I borrowed from Albert Porter is the older model. The new/current one has, I think, six strobe lights/flashes spread equidistant around its perimeter. I know it is different in some meaningful way.

It would also be interesting if the duration of the strobe itself would be quicker on and off. Then the strobe slash or line on the wall would be of shorter length. As it is now, because the device is rotating on the platter, the length of time that the light is on smears what would be a dot into what appears to be a line. This is consistent with my observation that the further away the wall is from the spindle, the longer is the strobe line/slash.

It is an incredibly interesting device and I think one could study what happens to the line with a slow speed camera and thus detect different behavior between belt drive and DD tables during the moment of flash, i.e. during very short durations, and perhaps detect visually deviations of speed consistency. Some listeners claim to hear this earlier in this thread.

If you look closely at Halcro's video, the strobe line looks different than it does on my video and the quality of my line changes slightly during the course of my video. So something else is going on.

As was mentioned earlier in this thread, there is also a distinction to be made between speed accuracy and speed consistency. I agree with those who think the latter is more easily heard.

Peter,
Having extra flashes would not necessarily be more accurate or enable small period variations to be seen. That would depend on the indexing accuracy of the machine used to make the multi flash Timeline. A typical Rotary Head might be a factor of 10 less accurate than the performance of your deck in percentage terms as shown above, and certainly less than the clock in the Timeline.

John
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I am hoping to establish a video database of various turntable speed test results. The thread is over on WhatsBestForum. Here is a link:

http://www.whatsbestforum.com/showthread.php?13137-Turntable-Speed-What-matters&p=239164#post239164

So far, I've only posted Halcro's excellent Victor T101 video and my own video of the SME 30/12. Perhaps in time, there will be more turntables added. If anyone wants to upload such videos to YouTube, I will gladly add those links to the WBF thread in a list in post #1.

I really enjoy reading about this topic!. as most of us have been through many different TT combinations etc.. think its possible to come up with a workable compromise..

I did post up a video but some people had a laugh at it as i have no idea why but it clearly showed with a hi quality strobe that groove modulations and my finger did not pose a problem for this fantastic turntable...let me tell you i put a fair amount of pressure much more then 20 tonearms!

The table is the Pioneer pl L1000A.... quiet as its kept, it has some of the best electronics for controlling the hung rotor motor! If i had a timeline or equivalent i would post up a video but i do not ...anyone want to borrow one?

Lawrence
Fidelity_Forward