Sorry, you will need to restate your question as I don"t have a clue what you are asking. Also, state the type of protractor, single point, arc etc.
TT speed
When I use a protractor to align the stylus I do the alignment at the inside, and then rotate the platter maybe 20 degree when I move the arm to the outside of the LP, or protractor.
On a linear tracking “arm” it would not need to rotate at all.
At 33-1/3, then 15 minutes would be about 500 rotations. And that 20 degrees would be a delay of 18th of a rotation.
So a 1 kHz tone would be about 0.11 Hz below 1000.
It is not much, but seems kind of interesting... maybe?
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Ditto to what testpilot said. I think you are saying that the two alignment points afforded by some types of protractors are typically separated by 20 degrees, using the arm wand and the pivot as the definers of the angle. But tone is about the constancy of turntable speed, not a factor much affected by alignment. The custom of checking alignment at two points is to improve the accuracy of the process vs just aligning to one point, which typically used to be the inner null point of a particular alignment algorithm. The classic Dennesen protractor used one alignment point, for example. Anyway, tone is speed. A 1000Hz tone recorded at the location of the inner null point will look different, if you could see it, from the same tone recorded at the outer one. So ideally the record cutting process accounts for the accuracy of the frequency, and then we need an ideal turntable with constant speed. Then you would hear 1000Hz at both locations on the surface of the LP. |
@testpilot It is a paper protector for a 9” arm which has 13mm of overhang. Maybe Baerwald? I don’t know for sure. @lewm I am saying that when aI go from the outside to the inside, I need to rotate the platter somewhat… maybe 20 degrees, but probably less.
So I am saying that the arm moves in a way that makes it advance or retard with respect to the platter spreed. I need to remove some rotation the platter more going from the inside to the outside. (Add rotation if going form outside to inside) The stylus is not moving linearly along a fixed line radially inwards. It is moving in an arc that is not perpendicular to the track’s direction. |
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