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Turntable speed

Discussion in 'audio' started by koi, Dec 7, 2019.

  1. koi

    koi pfm Member

    How often do you check yours?
  2. chartz

    chartz pfm Member

    Beobloke likes this.
  3. Richard Lines

    Richard Lines pfm Member

    In my case I trust that a Linn Radikal set-up would be doing its thing and using say an iPhone based app to check it is several measures of accuracy down on what Linn are using.

    Having said that I was surprised to see that only one reference point is used by Linn.


  4. jimpey

    jimpey pfm Member

    Strange coincidence.....

    A couple of weeks ago I had a visitor whose ring tone was Hotel California so while having lunch I put the LP on. Before the title track reached the end he exclaimed that the TT was running fast.

    I have borrowed a digital photo tachometer (thanks to Hermit:)) to check it out and googled the matter extensively.

    Initial check showed a speed of 33.7. The TT is an Inspire Eclipse SE12. it utilises a pair of standard Rega belts on a motor pulley with 2 grooves and a plain machined stainless steel sub platter. I called Robert Isherwood at Inspire and he suggested experimenting with one belt on either pulley groove to check for disparity. This I did during PM Thursday.

    One belt ran faster than the other in either groove and the 'slower' belt ran slowest in the lower groove, but still 33.5. Thanks to Amazon Prime I was able to order a Rega white belt and have it delivered yesterday in the late afternoon.

    Result! the white belt in the lower groove fluctuates between 33.3 and 33.4 but mostly 33.3. If the tachometer had 2 or 3 decimal places perhaps it would be 33.333!

    Can I hear the difference? I doubt it.......... but will play a variety of LPs over the next few days to investigate.

    hermit likes this.
  5. Rockmeister

    Rockmeister pfm Member

    Every time i give the deck an overhaul, I stick the strobe disc on and fine tune the speed (an adjustor is provided on the power supply). After that, very rarely, but I know there are enough variations in mains supply, temperature and etc to sometimes set it off a tad, but I can't hear the difference so?
    I guess people have seen this?

    A stop watch and some maths. 3 mins for 100 rotations is accurate enough! Get counting!
    p147 and koi like this.
  6. davidsrsb

    davidsrsb pfm Member

    Many belt drives run a little fast, possibly sounding more exciting in a comparison
  7. hermit

    hermit pfm Member

    I have to say Jim I'm impressed that your visitor could detect such a minor speed error. That's a man who has no need for a digital tachometer or a strobe disc.
  8. 2ManyBoxes

    2ManyBoxes pfm Member

    Does the tacho have a stated accuracy? Also, can I borrow it next please?:D

    There are (free) phone apps for this but of course it means plonking your phone on the platter, which adds to the weight. Maybe not significant with a direct drive but another story with a belt drive I think.
  9. Tony L

    Tony L Administrator

    Mine (a TD-124) has a built-in strobe and easy adjustment. I have it set so the speed is bang on after it has warmed up for a while, but easy to check at any time.
  10. hermit

    hermit pfm Member

    Yes. Specs here. You could borrow it but by the time you've paid postage both ways you'd be better off buying one at less than a tenner.
  11. cobbers

    cobbers pfm Member

    Just stick a strobe on it.
    These mobile apps are just s--t.
    Once in a blue moon by strobe for me - not anal enough.
    Can you hear the difference?:confused:
  12. Mr Pig

    Mr Pig ^'- -'^

    Yes, I'm sure Linn use Samsungs to check their Radikals.
  13. kensalriser

    kensalriser Well-Known Member

    Normally maybe, but if you're listening to a piece of music multiple times every day it's possible you'd become so habituated you could pick up a tiny difference.
  14. kensalriser

    kensalriser Well-Known Member

    Normally maybe, but if you're listening to a piece of music multiple times every day it's possible you'd become so habituated you could pick up a tiny difference.
  15. Zombie

    Zombie pfm Member

    What speed difference is a different key?
  16. poco a poco

    poco a poco pfm Member

    One semitone equals about 5.9% speed change (base A440). Unless you have perfect pitch, thought to be less than 1 in 10,000 of the general population, you are unlikely to hear this amount of change if constant and not varying. Even musicians without perfect pitch have difficulty in telling standard pitch A440 Hz from Broque tuning A415 Hz.
  17. Mr Pig

    Mr Pig ^'- -'^

    I don't know. 'High' pitched Instruments, ie saxophones, made before the adoption of 440 as concert pitch can't be used with modern instruments and they aren't as far out.
  18. sq225917

    sq225917 situation engineer

    I'm not one for soundstage depth or stereo width, it just doesnt register with me. But pitch, or rather the slight sense of urgency that comes from playing too fast stands out a mile to me.
  19. Beobloke

    Beobloke pfm Member

  20. poco a poco

    poco a poco pfm Member

    I am not saying that if one instrument is tuned to a different pitch to the rest that it would not be noticed by trained musicians. I am assuming all the instruments are or have been tuned to the same pitch. In this case the modern standard convention of A440. With a constant turntable speed difference and assuming all the instruments are tuned and recorded correct (an over simplification for some music) then they would change pitch by the same amount.

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