Turntable Speed

@lewm, I have "RPM" on my phone and it seems pretty accurate. The Cosmos I have coming (hopefully soon) has a digital rev counter which I will compare to the phone. I made a hockey puck sized one inch thick platform with a center hole. It is placed over the spindle creating a dead center platform for the phone. It is made out of alder and is sized to match the weight of a 180 gm record. The phone is centered over the spindle. The phone also gives you wow and flutter. When it starts increasing it is time for a new belt.

tgyeti. there is a strobe pattern on the bottom of your platter and you are seeing it through a prism. Older turntable drive systems could wander a little so having a built in strobe was handy. Some people also like being able to match pitch. Modern turntables tend to avoid strobes either because of the added expense or their advanced drive systems are always locked in to the exact speed. Some modern tables display the speed electronically by reading a magnet or light strip on the bottom of the platter. The most advanced systems read the platter then maintain exact speed regardless of the drag exerted on the platter.