Measuring Turntable Platter Speed

there  are a few apps at Apple Store

I use the Clearaudio strobe disc. I think it is somewhat expensive, but you can use either side, one for standard household lights, or the other side with the optional Clearaudio strobe meter, which is definitely expensive. 
 

https://elusivedisc.com/clearaudio-stroboscopic-speed-test-record-strobe-disc-180g-lp/

Digital Speed Readout Turntable Platter Speed Tool - Any Table (turntableneedles.com)

Thanks guys/gals.

audioquest4life - If I read the literature correctly it measures average platter speed which doesn't address the small fluctuation problem I perceive. 

big_greg - Nice suggestion. I might try the platter, but he stroboscope is a quarter of the price of  a new P2. So I don't know. 

I was just trying to confirm what I am hearing is actually true. You never know, faulty hearing, big imagination?

Jim S

The Clearaudio has groove that tracks the cartridge and its drag on the record 

to give you a more accurate reading

A strobe device may miss what you're trying to identify. The other devices mentioned would be even less likely to catch it, in my opinion. Best would be a Phoenix Engineering Roadrunner but that's too costly for this use. Your ears are free.

Your trying to measure WOW. A strobe test will tell you speed only..

Blow all the dust and crap out of the motor first.

Remove the belt and spin the platter. If you see the platter come to an abrupt halt after a spin you found your problem. If not it’s the motor and it need to be lubed and cleaned.  Make sure the bushings are not wore out and the armature is making contact with the field coils or to much end play. It’s only one or the other. The motor or the spindle. If the spindle well is full of crap, clean it out service the shaft and change the oil. It should spin for 100 years when it’s clean AND burr free.

OH WOW, NO WOW... Boo Boo.

Just a guess though.. :-)

Wow is one of those things that seems clear but really must be specified in order to get it right. Wow factor, wow that sound, and wow you got it for what are all important. Can we even agree we all are going for wowza? 

Get the ap "RPM" on your phone. It measures platter speed and wow +flutter.

It will definitaly tell you if you have a problem. 

@lewm , The Roadrunner is excellent. You can see exactly what your turn table is doing as far as speed is concerned but, It will not give you a wow+flutter spec. It measures speed based on one entire revolution. You might see it if the wow + flutter is really bad.

KAB, the folks that cater to the Technics SL1200 crowd with parts and accessories sells a very nice strobe disc and lazer light. Amazing just how still my rebuilt Victor TT71 platter looks when using it. Anyway, disc and lazer is $109.00

https://www.kabusa.com/strobe.htm

The phone apps have plenty written about them, not super accurate but a good comparative tool. I use one as well, the RPM Speed and Wow app.

BillWojo

@stilljim Sorry, I think I just read the title of the thread and didn't read the entirety of your post.  I don't think the device I mentioned will help with that.  I'm not familiar with that table, but you say it's "older".  Ever changed the belt?

The P2's performance could possibly be significantly improved by replacing the plastic subplatter. But it's $220. Perhaps not worth it. 

https://groovetracer.com/subplatter_groovetracer.htm

That was my experience with a P5. The Asylum forum may have additional insight.

You might find info of a less expensive alternative.

IF you had the worst case of WOW (slow then fast then slow) the RPM might be affected. But it would have to be way off. No record today would cause it unless the the hole is punched off center. I haven't seen any or had any for a LONG time, unless it's on UTube. 

Motor, Spindle, Spindle Well, pullies and belt. There nothing else to cause it unless you actually have an electrical contact problem in the motor or powersupply etc.

I've seen it in fractile motors for rem drives TT.. Washing machine motors.

Russco/Sparta/QRK and the ity bitty Garrards.. :-)

Regards

I know exactly how the RR works, Mijo. If the phenomenon that the OP is sensing lasts for less than one full rotation of the platter, I doubt he’d hear it, and the other devices mentioned would be even less likely to detect it.

Anyway, the RR is too expensive for this investigation.  No harm in trying the cheaper alternatives, but the ears tell the story here.

I had a long-delayed second thought. The best course of action, IMO, would be to follow the procedures suggested by MC and oldhvy, and determine whether there is a change in the condition. There are also obvious things, like observing the platter in operation to determine whether it is rotating eccentrically or off axis, either of which would suggest a major problem with the bearing and/or spindle shaft.  I wouldn't be so obsessed with measuring what one can already hear to be a problem.

IF you don't have the feel you can use a stethoscope and listen for the noise on the spindle pocket. You'll hear if something is wrong.. If you know what your feeling for you can just use your hands. Just have to pay attention..

Regards

The short answer is . . no!

But that doesn’t mean you’re at the end of the road. While you can’t measure the fluctuation, you can probably fix it. New bearing, new bearing lubrication, repair of worn bearing, new belt, new motor. Somewhere in there is your answer. A belt driven TT is really a very simple thing. Is there support for this sort of thing at Rega? Is there a forum of Rega users where you might find good advice?

Sorry, but how will measuring help? Won't. All it will do is quantify and confirm what you already know. If the wow seems related to platter rotation that points towards the bearing. Which you would want to clean and lube anyway as that is the next logical thing after the belt, which you already did.

If when changing the belt you also cleaned it and everything it touches with alcohol, that eliminates the belt.

We are now down to the motor. Look closely, is it perfectly straight or bent at all? Listen close, is there any sound with the same pattern as the wow? Can you lube the motor at all? Use only the tiniest amount of oil if you can.

My guess is "slight, quick, pitch changes" could be the bearing. It is an older table and could be going dry. Inspect, clean, and lube. I like Liquid Moly 90wt gear oil but you could use anything and Origin Live is the creme de la creme. In any case do all the steps above. Really just smart ongoing tune-up/maintenance. Can't hurt.

All - thank you for taking the time to reply and make suggestions. I did go over the spindle bearing and it is clean and oiled. I can't here any noise from the motor itself. The "flutter" is noticable and consistant throughout the entire side of any album.

Funny that you can hear something so subtle that is so hard to measure. I have some measurable hearing loss (right in the frequencies of my wifes voice ;>) ) so I wanted to check it via instrumentation to make sure it wasn't my hearing or imagination.

Net - the TT is almost 30 years old. The motor might just be worn out. A new P2 is very reasonable so I guess it's time to update.

Again - many thanks !!! - Jim S.