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Stylus-Drag..Fact or Fiction?

Most audiophiles can't seem to believe that a tiny stylus tracking the record groove on a heavy platter could possibly 'slow-down' the rotating speed of a turntable.
I must admit that proving this 'visually' or scientifically has been somewhat difficult until Sutherland brought out the Timeline.
The Timeline sits over the spindle of the rotating disc and flashes a laser signal at precisely the correct timing for either 33.33rpm or 45rpm.
By projecting these 'flashes' onto a nearby wall (with a marker attached)....one can visualise in real-time, whether the platter is 'speed-perfect' (hitting the mark at every revolution), losing speed (moving to the left of the mark) or gaining speed (moving to the right of the mark).

RAVEN BELT-DRIVE TT vs TIMELINE 
Watch here how the laser hits the mark each revolution until the stylus hits the groove and it instantly starts losing speed (moving to the left).
You can track its movement once it leaves the wall by seeing it on the Copperhead Tonearm.
Watch how it then speeds up when the tonearms are removed one by one....and then again, loses speed as the arms are dropped.

RAVEN BELT-DRIVE TT vs TIMELINE
Watch here how the laser is 'spot-on' each revolution with a single stylus in the groove and then loses speed as each additional stylus is added.
Then observe how....with NO styli in the groove.....the speed increases with each revolution (laser moves to the right) until it 'hits' the mark and then continues moving to the right until it has passed the mark.

Here is the 35 year-old Direct Drive Victor TT-81 turntable (with Bi-Directional Servo Control) undergoing the same examination:-
VICTOR TT-81 DD TT vs TIMELINE 
128x128halcro
jtimothya
612 posts
 
Thanks for doing the experiments, making the videos and a very interesting report, Halcro.  I'm not familiar with the Timeline.  Does the horizontal spread of the laser on the wall indicate a frequency range of turntable speed?


halcro's avatar
halcro OP
2,664 posts
 
Glad you found it interesting @jtimothya....
The Timeline actually emits a tiny circular red laser flash but because it's revolving as it does it, the projection onto a nearby wall becomes an elongated dash.
The more obliquely and further away the wall is situated....determines the length of the dash.
Look at the dash when it's projected on the nearby Copperhead tonearm...🤗
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intactaudio
293 posts
 
the time constant of the timeline is so long in relation to the music it can only show general speed and your experiments seem to show that stylus drag does indeed slow the platter.  It is interesting that the TT-81 seems to correct for this "automatically" and seems to suggest that speed on other tables should be set with the stylus in the groove.  I think the more true tell as to how much of an issue this is would be to use a much higher sample rate to see how the music dynamically effects the speed.  As an aside, I have a 301 and a TT-81 and all i use the TT-81 for is as a test deck to measure cartridges since I much prefer the sound of the 301.


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