Measure My Turntable Speed

It seems the old mentality of must spend lots of money in order to get good results has overcome logic again. Get real here. The powergrid line frequency is very tightly controlled to 60 Hz. Just google it and you can learn how accurate it is kept- to within 0.15 Hz. That is an error of just 0.25%. Probably less than the wow and flutter of many turntables.

Now go out and buy a cheap $100, give or take strobe light and tell me that it is accurate to within 0.25%? No way!

I laugh even more when I see someone looking at a digital readout and believe it to be accurate to the display's 2 decimal places.

OK, I have to speak up here as well. I pondered this same question a while back and found via the grape vine a great and cheap solution. I bought the Wally tools and tried the Cardas LP and frequency measuring via the test meter. My TT was running fast and I was trying to correct it via this approach. So, the problem was that the LP had a slight tendency to increase or decrease in the frequency tone due to a warp or LP pressing issue. So it was either right on or ever so slightly fast. I then contemplated buying into another method such as you. Then someone suggested buying a Digital Photo Laser Tachometer from Amazon. It worked great and cost $20, with an accuracy of +/- 0.05%. Plus you want you can play an LP for stylus drag while you measure. This is the only way to go!

"it worked great and cost $20, with an accuracy of +/- 0.05%. Plus you want you can play an LP for stylus drag while you measure. This is the only way to go!"

+/-0.05%? Unless it has a calibration sticker traceable back to the Bureau of Standards- no way. +/- 0.05% is the domain of very expensive laboratory grade equipment. A stobe-disc and fluorescent light is the most effective method. It leverages the Power Company's technology and accuracy- and it is dirt cheap. Plus, you can check the speed while playing a record.

Gerardff... how very interesting and simple.

Exceedingly dumb question (but I have to ask it anyway):

Does the accuracy of the measurement of a Digital Photo Laser Tachometer matter at to the placing of the reflective tape: whether the reflective tape is on the outer edge of the LP, toward the center, or somewhere in between?

Thanks & have an excellent new year's eve and new year.

:) listening,

Ed

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I made my own strobe for pocket change, when I was making 3$/hr as a kid.

Used an NE-2 / socket and diode. changes AC to half wave and pulses the neon bulb on/off. Perfect 60hz. I scavanged a cord/plug from something and used a plastic tube for a mount. No exposed AC and worked fine. My TT at the time had 'barcode' circling the spindle for 45/33rpm at 50 or 60hz.

90$ for a strobe? nutty.