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In Reply to: RE: Finally! Automatic Speed Control... posted by John Elison on January 12, 2017 at 21:03:21
During this warm up could you hear the speed changes as Wow and Flutter or were you merely following them on the read out?
I don't have the Math Gene...the change from 33.1 to 33.333 is .06 per cent? You can hear that?
Follow Ups:
It seems no body is looking at the numbers. John wrote .003 +/- . That is 33.330 to 33.336 rpm. Your number is .233 which is over 75 times higher. You can easily hear 33.1 vs 33.333. Can you hear 33.330 vs 33.333? Pitch I would question. Wow is anyone's guess.
Tom
Actually, the difference between 33.1 and 33.333 is 0.7%. I don't think I heard the difference because it didn't manifest itself as wow % flutter. It was a gradual drift over a long period of time. However, it annoyed the heck out of me and it was totally unacceptable for a ten-thousand dollar turntable. Also, the fact that Sota used a stepper motor as a turntable motor is very unusual if not truly a bad design choice. Stepper motors have the maximum amount of cogging of any motor. Of course, the massive platter combined with the elastic belt should have isolated the LP, but I truly believe I hear an improvement with my new 3-phase motor and controller.
Best regards,
John Elison
On my VPI Prime the addition of the Eagle/Roadrunner is audible. I tried to explain this before. Let me try again. The late Joe Morello, of the Dave Brubeck Quartet, was a hero of mine. He was several years older, but we both shared the same drum teacher. Joe played Ludwig drums in those days and his bass drum was 22"x14". I had to have the same set of drums of course. To this day I still own a set of Ludwigs with the same size bass drum. On the DBQ album, Time Further Out, the first track on the second side has a drum solo. Joe was never shy about hitting his drums with considerable energy. Anyway, he hits the bass drum in the beginning of that solo with enough force to make the unwary jump. With the Eagle/Roadrunner on my Prime it is possible to hear not only his hard felt beater hit the head, but the air moving through the vent hole right on the top of the bass drum. Without the Eagle/Roadrunner, the note is clear, but the air passing through the vent hole is not audible. I could cite other examples. There is no question at all that the Eagle/Roadrunner provided an audible, if subtle difference.
The road runner is showing 33.333 as perfect. So if I read this correcty John is seeing 33.330-33.336. Then the question arises how chose where all the albums made to that 33.333 number???
Enjoy the ride
Tom
I'm not sure why that question would arise, but its my impression that cutting lathes are direct-drive and exceedingly accurate. They are probably quartz locked direct-drive like my Technics SL-1200 turntable. I measured its average rotational speed to be accurate to 0.0008% at 33.333-rpm. This equates to an accuracy of 0.0003-rpm, which is one-tenth the error of my Sota Millennia turntable with its new motor.Best regards,
John Elison
Edits: 01/13/17
My point was 33.1 is a far cry from 33.330 and to think the music business was that concerned about .003 rpm to keep constant tabs on it would surprise me!!!
Regardless of all the quessing I bet that sota platter loves being hooked to a high quality 3 phase brushless DC motor.
Seeing you have direct drive table and the new sota combo maybe if Bill has a extra pick up you could throw one on the techniques and see if the road runner stays at 33.333. That would be interesting from the wow angle but still not answer can anyone hear a pitch difference of .003.
Enjoy the ride
Tom
The RoadRunner does not measure wow & flutter. Originally, it did seem to measure wow & flutter, but Bill rewrote the software to incorporate an averaging algorithm to eliminating wow & flutter from affecting its reading. Therefore, if I connected it to my Technics SL-1200, it would not drift at all. It might fluctuate slightly like it does on my Sota, but it would always remain centered on 33.333-rpm.
Best regards,
John Elison
Having bought an extra sensor and installed it on my SL1200MK2, I can attest that you are 100% correct. The Technics locks at 33.333 and stays there. I still have the sensor, but have not tried to install it on my SL1200G. The result would be expected to be the same, though.
Did it fluctuate at all or did it actually lock on to 33.333 and stay there?
No fluctuation on the SL1200MK2 for all practical purposes. My Prime fluctuates but not frequently (perhaps once every 10-15 seconds) and not by more than 0.001-0.003 all to the plus. This is not audible.
Unlikely. It will manifest as a change of tone more than anything. My Lenco does the same thing. Takes several hours for proper speed give the bearing fluid.
It might be. Too slow is more detrimental than a little fast.
-Wendell
'Too slow is more detrimental than a little fast.'
A matter of personal opinion/taste. The type of speed error, broad over time, is going to impact tone more than anything. Too fast and tone will be shoved up. Too slow and tone will be shoved down. I much prefer tonal balance changes that are down rather than up.
Timing, etc., and other factors will be impacted by improper speed but is shifts in tonal balance is what will be the most apparent.
Of course that is provided one is sensitive to minor shifts in tonal balance. Some me more bothered but the change in timing, etc.
Can only speak to my experience. I may not notice a little fast. I seem to always be aware of a little slow.
-Wendell
Agreed. Our own experience is what matters. I just did not agree that a little slow is bad.
I hear both fast or slow but I am very sensitive to minor tonal balance shifts.
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