Graham, It sounds like you may be inquiring specifically about the Rega subplatter. If you are, the diameter varies slightly in samples that I have measured between 101mm and 101.2mm
Obviously the other pieces to the puzzle are the pulley diameter and motor RPM. Add the belt to the equation and you have a nice mathematical formula.
Following all of the calculations you must machine everything perfectly to deliver the final result, not a simple task and this is why there are so many turntables out there running at incorrect speed.
Obviously the other pieces to the puzzle are the pulley diameter and motor RPM. Add the belt to the equation and you have a nice mathematical formula.
Following all of the calculations you must machine everything perfectly to deliver the final result, not a simple task and this is why there are so many turntables out there running at incorrect speed.