TT speed

What? To be clear, I am questioning what seems to underlie Holmz’ thesis. Maybe I could understand if you (Holmz) were to define the "top"of the arc, just for starters. But I still cannot agree that pitch errors are caused by or related to the position of the stylus tip on the LP surface, again given a perfect recording on a turntable with perfect speed control. I would also ask Mijostyn to say what is meant by "translocation" of the stylus. I seem to be missing something.

Let’s say that the top of the arc is the outside edge of the LP, and the bottom is the spindle side.

• Assume that the platter would spin at exactly 33-1/3.
• When I put a protractor on it and start at the outside, and then move to the inside, I need to rotate the platter to get the stylus on the arc.
  • so the stylus goes backward and would end up behind the spindle
• However with a linear tracking air bearing arm, I do not have to rotate the platter at all, and it’s protractor is a straight line.
  • It runs straight towards the spindle
  • zero angular platter change.

If I play the LP with both the regular arm, and also with the air bearing linear tracker arm, where does that required rotation of the platter end up? The rotation needed to get stylus onto the protractor?

Those two arm styles are not the same in terms of angular platter change.

Assuming a perfect test record, you could playback a pure 1kHz tone from the beginning of the LP to the end. Any deviation would be the result of the turntable’s w&f, not any "translocation of the stylus."

That statement is not correct.

Holmz is correct - on a pivoted arm the stylus is advancing and retarding relative to tangent, therefore there must be a timing error, but it will be minuscule on rotation re adjacent grooves.

I had pitch problems with my VPI Hw-19, with a linear tracker (Clearaudio Triquarz) as well as a pivot arm (SME V). Now, with a Hanss T30, with a superior dual motor / 6 string system, I don't have them.

@cleeds the error would need to be less than the W&F “noise”, and my stab at the error would be about 0.11 Hz at 1 lHz.

So it is likely to be more of an intellectual oddity than a severe problem.

Mathematically though. I believe that a linear tracker and pivoting arm would produce very slightly differing pitches.