Direct drive vs belt vs rim vs idler arm

Also, it looks like to me that the app is reporting peak values, it is not averaging. I noticed that while looking at the handheld CD test results vs. resting the phone on a table. So like I was saying, one blip on the test record, like a high spot and the resulting values will increase.

As I do the tests with the 1350Hz Test Tone.....I can graphically see the frequency on the iPad App moving backwards and forwards equally about the 'mean' frequency.......so that the average mean frequency comes in very nicely on the Data......but the wow and flutter is high.
This is definitely caused by the off-centre hole on the 7"" test record.
I suspect Lespier does not use the Feikert 7" Test disc.....or if he does.......his is a 'good' one?
As you say Tony.......I think our turntables are testing the 'test' equipment?

Back to the Timeline for me :-)

I know what you are saying. Our simple measuring equipment has limitations. If you stare at this data too long and try to interpret something that is just not there, then you will start to see fairies dancing on the screen. I think the app is perfect for dialing in platter speed and it gives us some assurance that our turntables are holding speed an order of magnitude better than the capability of the records themselves. And because of that limitation built into the records, the app is limited on accuracy probably to the 0.03%-0.05% range. Keep in mind too, like I said before; the Timeline needs to run for several hours on your tt in order to get a reasonable data set for evaluation. One side of a record play, 600 rotations, is not enough data points. You need thousands of rotations to conclude anything in the 0.01% range or else you will be seeing those fairies dancing around.

Halcro
Do you have any theories other than eccentricity as to why the results with the Feickert are inconsistent?

Thanks

Halcro. Thanks ... will have another look at your results. I've read about the Dual eds motors and have long contemplated a DIY using one of these. I still have a couple of these so the next project will involve using one of these motors. I managed to pick up a cosmetically trashed Revox B790 with a broken arm so scavenged all the working bits. The motor looks to be based on the dual with an identical upper casting but the electronics are much more complex and use quartz locking. I replaced the thrust pad and changed all the capacitors on the boards and housed the power transformer in an outboard enclosure ... no other mods except for the platter. I picked up an acrylic Feickert platter with brass inserts on German eBay and decided to chance using it as it is MUCH heavier than the Revox one. Decided to use acrylic for the plinth as I had a Basis Vector and figured that tonearm had been voiced on acrylic. I have used it over 6 months now with no problems. I pulled it apart a couple of months ago and the bearing seems to be holding up so far. I'm very happy with how the tt sounds.