Rpm's and The Strobe

What do you think it means when the strobe indicates the speed is correct but, in actually counting the revolutions in one minute I came up with 30 more than once??? The music sounds fine I do not hear any pitch changes...
It means that it running at correct speed since the US is a 60 hertz country.
This is not an onboard strobe, and the motor is DC powered...
It means you need a Phoenix Eagle and Roadrunner. Eagle is a highly tuned power supply for tts, Roadrunner is a real time tachometer.  The two units coordinate to lock in rpms to within .005/minute. 
I have no affiliation with the company, I'm just a very happy customer. 

The Phoenix does not work with DC motors
So jsman, what is the strobe you're using?
It one those KAB strobes..
If the music sounds correct I would not waste my time worrying about it.
Relax and enjoy the music ;-)

jsman, if you're using the KAB strobe and disc and the battery is good, trust the strobe. It's a lot better at "counting" revolutions than humans will ever be. '-)



I agree but, when I count I only get 30 rpms shouldn't it be 33 rpms?
Hello jsman
If your count of only 30 rpm is accurate, then you're talking about a 10% speed  variation. That would be audible.
I too have the KAB, along with several other stobes and other devices to check speed ( Feickert ), and the KAB is just as accurate as any of them.
Do you have another stobe you can use to verify results.

If not, go to vinyl engine and download one of the stobe patterns and check two ways:
1). With your KAB light source
2). With a standard incandescant bulb.

This should at least tell you if the problem is the strobe or your method of counting.

Cheers,                        Crazy Bill
Hi Bill,
Well I figure it out this morning, I was using the splice on the belt to count (dumb a--) instead of putting tape on the platter. Now I am counting 33 rpms and it matches the strobe...
Glad you worked it out.

Cheers,                      Crazy Bill