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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
 
Hi @lewm.

... No matter how much I search on that last topic, I have never found a satisfactory treatise on the subject of coreless motors vis a vis cogging, but most talk about coreless motors as if they are free of it. ...

Here's a few links that may be of interest;  cannot say if they count as satisfactory. 

Comparison of Slotless and Slotted Motors. The article does discuss cogging.https://www.celeramotion.com/applimotion/support/technical-papers/slotless-vs-slotted-motors/

Brushless, slotless, and cogless (1999)
https://www.designnews.com/content/brushless-slotless-and-cogless/60538412940113

pickindoug
66 posts
 
Very interesting thread.  As I read through these responses, I have to wonder if the original recording mechanism, the record lathe that cuts the master from which the molds are made, is equally subject to modulation induced speed variations.  Plowing a new field, so to speak, would seem to take a bit more energy than playing an existing groove.  How does the record lathe overcome this?  And if it doesn’t, perhaps stylus drag speed variation in the playback system mirrors the speed variation in the recording process........
peterayer
1,382 posts
 
I started a thread years ago inviting people to upload videos of their turntables with the Timeline.  Lots of promises but no one took me up on the challenge.  Here is a link to that thread:

https://forum.audiogon.com/discussions/turntable-speed-accuracy/post?highlight=SME%2Band%2BSutherlan...

Here is a link to a video of my SME 30/12A with the Timeline:

https://www.youtube.com/watch?v=Clwc_c8sVn0

Look for the red laser dash on the edge of the LP cover.  It is not perfect, as you can clearly see the quality of the laser dash changes slightly indicating micro speed fluctuations, but it is pretty good.

I also made a video using my friend's Technics SP10 Mk3 with the Timeline:  https://www.youtube.com/watch?v=haqhT6khqZY

Great performance, but when we moved that table into my system and compared its sound to my SME 30/12A using the same arm and cartridge, the SME sounded much more natural and like real music.

The belt v. DD debate will go on for a long time.
rodman99999
6,206 posts
 
’Very interesting thread. As I read through these responses, I have to wonder if the original recording mechanism, the record lathe that cuts the master from which the molds are made, is equally subject to modulation induced speed variations. ’
@pickindoug- Phoenixengr addressed that exact issue, just four posts before yours.
ct0517's avatar
ct0517
2,041 posts
 
^^^^  up 2 posts

@peterayer 

Peter
your findings were very interesting (One table short of a Goldilocks adventure.) 

Your findings are supported by what Richard said.

richardkrebs
The level of granularity we use to measure TTs is simply too crude to show us what is going on in real time under dynamic conditions.

But we sure can hear it.

Still

IMO, based on my personal journey, "Stylus Drag" is not an Iceberg Scenario, where most of what is happening is below the surface; where this thread is focused.  The table and keeping speed. 

What is happening above the surface is just as, if not more important in regards to Stylus Drag, since I believe the type of cartridge and tonearm pickup used are worth ........hmmmmm..........let's call it 33.333 % each. 8^0

As we know playing vinyl properly requires good setup between the trio of parts.
Cheers Chris

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