2. analog
  3. 151541-486

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
mikelavigne
2,200 posts
 
Mike, you need to get rid of both the Wave Kinetics and Saskia. Get yourself one of those Monaco 2.0 tables and put a Gabon Ebony Durand arm on it. The Gabon Ebony has seriously better timbre than the rosewood and has much lower stylus drag. And here I am stuck with this crappy Clearaudio Statement. But don’t worry. I just ordered a Basis Work of Art. I can put the Statement in my Summer home in the Catskills
i had a Monaco 1.0 with a Dynavector arm in my system for a year back 10 years ago. very ’meh’ to my ears and far prefer the NVS to that. haven’t read Mr. Gregory’s review of the 2.0, but as far as timbre i think the Saskia is quite the king of that. neither of my tt’s are going anywhere.

’if’ i was acquiring another tt, it would be a belt drive of some sort. i already have what i consider top echelon direct drive and idler examples.

sorry, but not up to speed on what a Gabon Ebony Durand might be? please point me in the right direction and i’ll get informed. i’ve owned 4 different Durand tonearms and also own his record weight. i’ve owned 3 separate wood arm wand Durand arms, and have a wood arm Durand Telos on my NVS now with a Miyajima Premium Be Mono cartridge on it. sweet sounding arm.

i guess i could ask Joel directly about the Gabon Ebony, he is a local friend of mine. he was here in my room two weeks ago tweaking my Durand Tosca tone arm and listening to the Saskia.
lewm
13,258 posts
 
Off-topic:  Hi, Mike!  Good to hear from you.
I have only one further comment: It is not valid to lump all servo speed correction mechanisms as if they were all the same.  Technics was dominant in the DD industry, and they espoused powerful iron core motors driving heavy platters (if we limit ourselves to the SP10 series) and very frequent speed correcting. But other manufacturers, e.g., Kenwood in the L07D, settled on using less powerful coreless motors, to minimize or eliminate cogging, and a comparatively laissez faire approach to servo correction, which means that corrections are fewer and less frequently made.  This to my ears resulted in the L07D sounding a tad more "musical" than an unmodified SP10 Mk3.  Applying the Krebs mods and now the chip made by JP Jones have made my Mk3 sound a lot better.  So, just to say that those designers of the 70s were well aware of trade-offs related to servo control.
In keeping with Mike's critique of the Monaco, I had wondered what became of that product given the initial ballyhoo.  One problem with it, in my mind anyway, might be its relatively low mass. When speed corrections are made, there is an equal and opposite force generated at the platter such that the chassis "wants" to turn in the opposite direction from the platter. I think you need mass to overcome that manifestation of Newton's 3rd Law.
atmasphere's avatar
atmasphere
11,931 posts
 
Pardon me, but can we let this cogging thing go with respect to synchronous motors? Because its totally not a thing. Synchronous motors (seen in idler drives and some belt drive machines) are locked to the line frequency and don't really have power surges or the like regardless of line voltage.


Idler drives can work just fine if the turntable is designed fairly well. This is why some older vintage designs have a following- Lenco and Thorens (TD124) in particular.

If you look at the best of the vintage 'tables that have a modern following you will see one thing that they all have in common- a robust drive. This is true of belt drive machines- like the Empires, and direct drive machines like the Technics SP10, in particular the SP-1 MkIII which has so much torque its suitable for LP mastering lathe use.
I will gladly accept minor speed variation versus my tonearm hopping across the record when someone walks into the room.
@mijostyn
This can be solved with a proper stand. I have a custom Sound Anchors stand but what really did the job was placing the stand on a set of bearings which relieve side to side pressures caused by foot falls. I lived in an older house and this was a very effective solution to that problem! Sorry for the Off Topic bit...

richardkrebs
422 posts
 
Halcro. Thanks for posting the videos. I have seen tests like this before and the thing which startles is how quickly the platter slows down. All due to the drag induced by a tiny diamond thrashing about in a plastic groove. Others have said that a high moment of  inertia platter will save the day. Don't know what the inertia figure for the Raven is but the platter itself does look substantial, so it is reasonable to assume that it isn't a feather weight. 
A  high inertia platter simply changes the time constant for a given motor torque. Sure, its deceleration rate will be slower but it will also take longer to recover. There doesn't seem to be any free lunch here.
Also agree totally with atmasphere. "a robust drive" is a common thread through most of the collectable vintage TTs  
richardkrebs
422 posts
 
Wouldn't setting the speed with the arm lowered be, at best, a compromise?
What record do you choose? Surely the stylus drag is modulation dependant, so if you choose to set the speed at a 'medium modulation' level record, the platter will run fast some of the time and slow some of the time. This, purely dependant on what is going on with the music. Add in the radius where you lowered the arm and it becomes a lottery. 
More to discover