Turn table speed variation question

Thanks everyone for the input - I now have a very good understanding of possible causes - never thought about the off-centre hole - good one :-)

I had always thought it was due to the tape ,machine used in the recording process.

I can see how the pure pitch of a long note and the associated harmonics would contribute to the immediate identification of speed variations - to these ears anyway.

Thanks again for the input - very enlightening.

"Lew's right.
Any stringed instrument is particularly sensitive to minute speed deviations.
When I listen to acoustic guitar on my Victor TT-101 DD turntable with unequalled speed accuracy......an off-centre record hole will be mercilessly exposed. :-(" - Halcro

Not to digress too far, but since the thread is about speed accuracy, I do believe the word "unequaled" may be a contentious one. I doubt if the Victor is unequaled, however. What measure of accuracy is it?

How about "rarely equalled"?
But it was not I who made the claim re the Victor, altho I am sure it is excellent in respect of speed stability.

I do believe the word “unequalled” may be a contentious one.

Perhaps I should have elaborated….but this has been discussed in other Threads on turntable speed accuracy and I did not wish to complicate this one?
The JVC/Victor TT-101 has pretty good specs….
Wow and Flutter- within 0.02% WRMS
Speed deviation- 0.002%
Load characteristics- 0% (with a 120g total tracking force)
Drift- 0.0004%
But to me….printed specifications are meaningless when it comes to ‘actual’ performance in relation to speed accuracy and consistency?

Until recently…the concept of ‘stylus drag’ on the speed performance of a turntable…was treated with scepticism.
Then Ron Sutherland introduced the Timeline….a laser-flashing ‘puck’ which sits over the turntable spindle and has a time-base accuracy of 2 parts per million.
With this device installed………..it provided scientific evidence of the phenomenon of ‘stylus drag’ as the laser spot was seen to drift the moment the cartridge hit the record with most turntables….especially belt-drive ones.
The very best belt-drive turntables have reportedly been able to
maintain the stability of the laser dot of the Timeline…..when the speed has been adjusted with the cartridge already tracking the record. But then it is ‘out’ of adjustment when no record is being tracked?
I have not witnessed any visual evidence of these accomplishments…..they are merely empirical claims.
I have not seen nor heard of any claims regarding the speed accuracy of Idler or Rim Drive turntables using the Timeline under ‘stylus drag’ conditions.
I have tested the TT-101 under all conditions…..with and without ‘stylus drag’….and the laser dot of the Timeline does not deviate.
TT-101
This test has not been reproduced successfully with 3 arms and cartridges on and off…..with any other turntable to my knowledge?
Hence my statement?
If your turntable can match this performance…..please upload the evidence to YouTube and I will revise my statement to ‘equalled but not exceeded’……:-)

"I have not seen nor heard of any claims regarding the speed accuracy of Idler or Rim Drive turntables using the Timeline under ‘stylus drag’ conditions."

Well, now you have. :-D

A good number of people have seen the turntable do it, but I'll try get a YouTube video made shortly.