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
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.
Yes Lew, I have done the experiment with the KAB strobe.
The problem is that stylus drag is instantaneous and not consistent so whilst the KAB may waver at times.......it quickly settles back to a constant speed thus depriving one of any quantification of the drag?
With the Timeline.......the stylus drag has a permanent effect thereby 'shifting' the laser line for all future revolutions.......and additional drag just keeps shifting some more so that you have a permanent view of the graphics of this phenomenon.


I think the Timeline amplifies the speed error visually because it shoots out the laser very far away from the spindle all the way to the nearby wall so it's like having a 6 foot diameter strobe disc! The KAB after all is only 10 inch wide and microscopic error will be hard to detect by eyeball. The KAB is good at detecting speed drift over a longer period of time and is much more accurate than some digital tachometer but the instantaneous error is very hard to detect visually, make worse if you have an eccentric spindle hole. I think the Timeline is a great tool and I want to get one eventually.

I think the lack of torque to plow through the stylus drag is what contributes to the lack of dynamic range and will give a kind of pleasing compression. I can live with a little bit of dynamic compression caused by stylus drag but I can't live with analog jitter caused by cogging in the motor. Unfortunately cogging and torque don't like to work with each other. In the mid-priced turntable arena, I found the lower torque DD tables with coreless motor and heavier platter to be more pleasing to my ears than some popular high torque models with complicated electronics. Just an observation....

The JVC TT-101 appears to be a phenomenal turntable according to Halcro. I really wish Lewm can try the Timeline on his Kenwood L-07D. :-)

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