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Do you use variable speed on your turntable?

My turntables JVC TT101 and TT81 both have elaborate speed controls which allow quartz controlled accuracy when the speed is changed in small controlled increments, faster or slower than the selected 33 1/3, or 45 rpm speed.

Many turntables allow this controlled speed variance but besides dj's looking to match beats, who ever uses this very expensive feature? When my tables were made no one was beat matching as far as I know so dj's needs didn't drive this design. I can understand this on 78's because of inaccurate recording technology, but there isn't a 78 speed on these turntables and modern records are probably 99.9% accurate so that wasn't the consideration either.

So what is the point?
aigenga
hifihvn
943 posts
 
Pardon the grammar.
lewm
12,845 posts
 
Ummm... Boys.... How is one to tune one's turntable to A440 or some variant thereof without an LP that bears a recorded A440 tone? A tone generator is only half of what one needs. I know of no test LP that has such a band on it, but possibly one exists. And even if one has both the necessary pieces of equipment, one is still dependent on a good sense of pitch. It might be better to run the tonearm cable directly into a calibrated oscilloscope, assuming you have the needed test LP. That would eliminate subjective judgement of pitch. (I ain't doin' any of this; I'm just sayin')

The beauty of the KAB strobe is that it runs on batteries and so gives a constant frequency regardless of what's coming out of your wall socket. It's very accurate, and I doubt a laser record weight is much better, just more spectacular and easier to monitor from your listening chair.
halcro's avatar
halcro
2,664 posts
 
It's very accurate, and I doubt a laser record weight is much better, just more spectacular and easier to monitor from your listening chair.
Written by a man who has not understood what he has witnessed in the Timeline in action.
The Kab strobe (and I have one) is NOT.......and I repeat.....NOT accurate nor able enough to detect instantaneous stylus drag.
The Timeline is.
isochronism
2,893 posts
 
If the need be, I would use my trusty guitar tuner which consists of a simple @ tuning fork. "BINGGGgggggg..."
lewm
12,845 posts
 
Halcro, When you made your observation with the laser, did you then actually do the experiment of seeing whether you could observe the phenomenon of wandering speed with the Raven, using your KAB strobe and disc? And did the KAB fail to detect the problem? If so, I stand corrected. If not, how can you argue? In principle, the strobe and disc should be quite sensitive to changes in speed due to stylus drag. I am quite sure that the KAB would have picked up the speed variability I observed in my neighbor's home using his Timeline. But we did not do the experiment. Fortunately, he has cured the problem, so we cannot do the expt now.
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