Turntable speed checking tech, old or new?

[2wice]

Checking my speed with strobe markings differ from android rpm measurements.

Which to trust?

It's possible the Hz might be off on the supply side.

https://www.youtube.com/watch?v=TAyuTCaqPyI

 

[alternativeroute]

 

[2wice]

 

[croak]

 

[vintage]

 

[Family_Dog]