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Stroboscopic disk sets wrong speed for turntable?

Hi all! I am new here.

I have just set up my Clearaudio concept turntable. Unfortunately, the speed of the turntable was wrong so I had to reset it. In order to do this I have used two methods: an iPhone app called RPM; the stroboscopic disk + the iPhone app StrobeLight.
The problem is that when everything is correct at 33 1/3 (both verified with the RPM app and the stroboscopic disk), the songs are playing one semitone lower than what they should. In order to make them play at the correct note, I have to set the speed at around 34 RMP as shown by the RPM app. Also the stroboscopic disk shows that now I am going faster than the 33 1/3, being consistent with the RMP app. How is this possible? Am I doing something wrong or even the stroboscopic disk is not accurate enough? Could it be the StrobeLight app not being an accurate enough light source for the stroboscopic disk? It is just peculiar that both the RMP app and the stroboscopic disk are consistent in saying that I am going too fast. 

Any help is much appreciated. Thanks!
agforte
fsonicsmith's avatar
fsonicsmith
334 posts
 
Thank you Peter! I thought it was PBN and not Sota that was coming to market with a similar product. Is it Sota that bought the rights to the Phoenix design but just for Sota tables?
Could you expound on why your product won't display actual speed? Is it so as to not infringe on the Phoenix design? Is the Phoenix design patented or otherwise protected from copying? Certainly the more intuitive the better and I don't see how anything could be more intuitive than displaying speed in rpm to two digits rather than what amounts to a revolution count without being per-minute. 
oldears
208 posts
 
I presume you are counting on having perfect pitch to determine if the speed is correct. This is a wonderful gift!In any case, with  the strobe disc, be sure to use an incandescent lamp as mentioned before. As a cross check, use a test lp such as the The ultimate Analogue test LP from Analogue Productions and the hz function on your Fluke DVM. This is more precise than the strobe method and negates any presumption that stylus drag could cause a difference.
millercarbon's avatar
millercarbon
324 posts
 
Wow you guys are good. Can you figure out my copy of Kind of Blue? Side 1 seems a little off....
https://forums.stevehoffman.tv/threads/miles-davis-kind-of-blue-mono-speed-issues.232772/
oldears
208 posts
 
It is for the first 3 tunes where one of the tape machines ran slow. As the playback for mastering was on a different machine, these tunes are sharp on the early lps.
This was corrected later and is explained on the columbia legacy jazz cd that I have,
bgpowell
67 posts
 
I read sometime last year that the regulatory agency for the utility companies relaxed the standard for 60 Hz, because it was too expensive and time consuming for the utilities.  So some type of device/app is now needed, that is not dependent on power company frequency.
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