Stylus-Drag..Fact or Fiction?

^^^^  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

Peterayer, no big surprise. The 30/12 is an amazing turntable. It's degree of isolation is better than any turntable I am aware of. The V12 is IMHO SME's best tonearm. Have you checked your resonance frequency on a test record? The SME is the lightest 12" tonearm I am aware of. It's effective mass is only 12 gms. The Air Tight is almost as stiff as a Koetsu.
My guess is that adding some weight to the head shell might improve your bass a bit. I set mine up for between 8 to 10 Hz. 
Guys, chakster has a very valid point. Speed variation is just not a problem for modern turntables because we can't hear it. This is just a spec war. Same goes for lathes but they have to be a lot more powerful and stable because the cutting head causes way more drag and variation in drag than a stylus running in a groove. The big problem with both lathes and turntables is noise particularly rumble which is not only very audible but you can see it!  Just look at your woofers dancing around wasting amplifier power and Doppler distorting everything else the woofer is doing. All our preamps use to have rumble filters, just high pass filters 3 dB down at 30 Hz. As I have mentioned in previous posts it is not uncommon for a poorly maintained lathe to rumble. I have had several discs that were so annoying I sent them back. The ones I sent back were all 180 gm "Audiophile" pressings and all were Rykodisc. I have many records that rumble a bit but not so bad that I can't listen to them. I have never been bothered by speed variation and none of the audiophiles I know have complained about it. I think that probably only rapid speed changes would be audible but our heavy platters just can't change speed that fast

The 30/12 is an amazing turntable. It’s degree of isolation is better than any turntable I am aware of.

while the passive isolation for the 30/12 from all those rubber bands is relatively effective, it is limited. OTOH the overall build quality of the 30/12 results in top level sound, but the isolation component is relatively pedestrian. i think maybe Peter has his 30/12 on a passive air decoupling Vibra-plane platform to improve isolation. that is degrees better than the stock 30/12 isolation, but still passive.

for ultimate turntable isolation you need to observe how science does isolation. they use active shelves with piezo-electric sensors and actuators in 6 axis’s.

http://www.herzan.com/products/active-vibration-control/ts-series.html

as it comes stock for science this product is not fully ready for high fidelity purposes. it has a SMPS which broadcast’s noise into your signal path, plus it’s limited to effectiveness under 200hz so needs further modification to cover the whole FR. and as it cannot discern the source of resonance it attenuates, only tt’s with very low self resonance work well with it. but properly modified and applied to the right turntable it takes things where no passive isolation approach can follow.

I THINK that some of us are saying this:  Absolute accurate speed is not the issue.  I (and whoever) would agree that I am not able to discern the difference between 33.334 and 33.333.  In fact, I know for sure that I cannot tell 33.333 from a constant 33.5 or from 33.2, because I can do that experiment with the Phoenix Engineering Eagle and Roadrunner driving my Lenco motor.  What IS potentially audible are VARIATIONs in constant speed, drifting of speed during musical passages especially that feature piano and/or stringed instruments.  Whatever technology used in turntable design and build that eliminates or minimizes speed instability (DD, Belt-, or idler-drive) is fine with me.  It just so happens that for me the best vintage Japanese DDs and my Lenco do it at lowest cost or best bang for the buck.  Belt-drives at anywhere near the same cost have failed, speaking for myself.

Mijostyn, Those rumble filters may be useful if you hear rumble, but in all other cases, they are no free lunch.  The filter elements color the sound all the way up the scale, inevitably.  I also don't know where you are getting your LPs from, but I rarely encounter rumble that is problematic enough for me to want to engage a high pass (rumble) filter.  This is using two completely different audio systems in my home environment, driven alternately by 5 different turntables.  I'm not saying "never", but it's rare.

The most popular motor for the cutting lathes is a Technics SP02 direct drive motor which is quartz locked for speed accuracy and weighs ~110lbs with plenty of torque.

I doubt this statement. It implies that there are more lathes using the Technics motor (which is great) than those that don't. The simple fact is all lathes unless custom built are vintage machines. Mine is typical- its a Scully built about 1948 or so, equipped with a Westerex cutterhead and electronics from about 1970 (refurbished). The lathe portion didn't see much change over the decades until Scully ceased production altogether- the big change was how the cutter head was advanced across the LP (IOW, when variable groove spacing was introduced) not how the platter drive operates.

To that end, the platter is driven by a drive shaft operated by a transmission that has the gear ratios for its two speeds (33 and 45), which is in turn driven by a 1/8th horsepower synchronous motor running at 1800 rpm. The motor, if operated with no load (or external flywheel), takes over 30 seconds to spin down (nice bearings). That, coupled with an external flywheel and the various bits of rotating mass in the transmission as well as the actual ~17" platter, insure that the platter's motion is very constant. In a machine such as this, the proper function of the drive shaft and whether the platter bearings have been properly lubricated and warmed up (the manual calls for a 20 minute warmup time) has a much greater effect on the platter speed stability than any 'cogging' that might be present in the motor!

Scullys were one of the most popular lathes in the US for a long time, but there are other types such as the Neumann as well. Except for those that use the Technics drive motor, they all run along similar principles.


I've used the Timeline on the Scully; when we were finishing the refurbishment a few years ago I felt it a good idea to see how we were doing. Its pretty stable- but IMO isn't the last word in speed stability or accuracy. It can keep a strobe absolutely still and doesn't vary except when the cutter head touches down to do a cut (which runs about 60 grams of pressure on the stylus). Once touched down the strobe stays put. But the Timeline tells a different story- essentially that the lathe  runs ever so slightly slow. How much I've yet to determine since I've not set up the Timeline to present a calibrated assessment. But its clearly close enough that hearing a pitch variation is impossible.


IMO, the big issue of stylus drag affecting speed isn't pitch stability so much as it can induce oscillation of the arm over the stylus- in turn causing the tracking pressure on the groove wall to vary left to right and back. As that happens, it induces to my ear a slight 'shimmer' in the soundstage; when you have a 'table that has really locked-in speed, that shimmer is gone and the soundstage is like that which you hear in reel to reel tape.