Stylus Drag : Fact or Fiction

[Daniel Quinn]

Just reading tinternet instead of working and the topic of this thread as just occurred to me .

I set my turntable speed with a laser tachometer to two decimal places .However to set it you don't play a record. I was happy until today When somebody mentioned a rega running 5% fast wouldn't matter if you take it to account stylus drag. Further reading suggests that it a real phenomena and effect speed by up to 5%.

If I take in to account sylus drag @ 5% then I would need to set the speed at 34.96 .

So what do people think of stylus drag , a factor that must be taken in to account or just further hifi unnecessary neurosis

[Dr Bunsen Honeydew]

Variables - tracking weight, stylus profile, TT drive system etc etc

Spray WD40 on the record before playing that will cure it

[Daniel Quinn]

yes I am aware of those variables .

I have however since I posted , come up with a in play way of measuring which I will do and report back .

I have a habit of listening to tracks not albums and so wet play is not a viable option

[Alfi]

I have seen the effect of it with my PL71 via the strobe markings and the same with an LP12 using a Lenco strobe disc placed on top of the record label. I used the excellent little Keystrobe as the light source and it's plain to see.

On the other hand a Techy SL120 mk1 seems unaffected by styles "drag".

Interestingly the PL71 seems to recover from the initial momentary slowing, but the LP12 remains just a tad slower ?


Alfi

[_D_S_J_R_]

The LP12's after the early batches could be set up with their very accurate electronic strobe (300Hz) to be perfect, but play the record and try to synchronise it with a CD (for example) and it would run slow, confirmed with the stylus 'playing' the strobe and then lifted off. I found a way of setting the deck ever-so-slightly fast and got the speed spot on and consistent when playing with a 1.7g tracking pickup such as Linn's own. Rega's do run fast, or used to, around 0.5% from memory. Not enough to bother about in normal use, but compared to an accurate synched source, it was easily audible and the Linn strobe magnified it somewhat as well. An ordinary card type of 50hz strobe plonked on the platter and viewed with a light bulb wouldn't show it as much and slowing under stylus load wasn't enough to be audible to most, although golden pitch-perfect ears may have noticed - I don't recall ever having complaints though.

Direct driven decks have a servo and it was really bad examples of these that could cause 'hunting' if the load became too great. I remember the Technics SL2000 being horrendous, with basically low torque to start with and a cartridge (Stanton 500 variant) tracking at 2g or so would cause visual (on the platter strobe) and *very* audible wow. Marginal ones using the OEM technics motor (from memory, MA ET500, JBE and some Trio/Kenwood models) could be provoked under duress, but this was in the days of high compliance 1g trackers, so not really an issue. The top Technics models and my old Dual 701 suffer no hunting or overshoot at all, and if slowed by hand, the speed returns to spot-on fairly quickly but not too fast. The PL71 is obviously fine despite not having 'Techie-high torque' and quartz-locking, as an SPU is absolutely fine in it pitch-wise. The infamous 'DJ' Techie is also fine and if anything offers too much torque for most use, something I think DC investigated if I read his Timestep site properly

I'd suggest most decks are pretty good for 99% of use. People who wish to use SPU's at 4g and similar, would definitely have an issue with rubber band drives though, unless it was similar to a NAS deck with VERY massy platter using inertia to absorb and fluctuation or stylus-drag

[Alfi]

The LP12's after the early batches could be set up with their very accurate electronic strobe (300Hz) to be perfect, but play the record and try to synchronise it with a CD (for example) and it would run slow, confirmed with the stylus 'playing' the strobe and then lifted off. I found a way of setting the deck ever-so-slightly fast and got the speed spot on and consistent when playing with a 1.7g tracking pickup such as Linn's own.

I use the 300hz disc Dave and do what you did - set it slightly fast so when playing a disc it's pretty much spot on.


Alfi.

[terrybooth]

Six posts in and no 'Fact or Friction'. Tut!

[Dr Bunsen Honeydew]

'Cos its both. Depending...........

[zebbo]

It's a fact. I always set my speed with a Keystrobe which sits over the label while playing a record. Lift the stylus from the groove and the speed increases slightly.
Stands to reason really, you have two solid objects in constant contact and motion that's going to cause friction and drag. If you've got a high torque, big motor drive I guess it is of very little significance but with a low torque drive it needs to be accounted for.

[Geoff.R.G]

The energy used to create the output from the cartridge comes from the motor so extracting energy will require an increase in torque. With a synchronous AC motor this will be seen as an increase in slip and thus greater current flow to restore the speed. However, the drag will be greater at the edge of the record and reduce as the arm moves towards the centre, drag being proportional to the square of the speed.

Whilst stylus drag undoubtedly exists most drive systems will be able to cope.