Hello Smart Turntable People...I have just purchased a Pro-Ject RPM-5.1 that came with a 9cc Carbon Arm. Arm and cart was factory installed, but I purchased without cart - so I have to put one in (for now, a Pickering XSV-3000, and maybe a Shure V15 type IV later.)
A friend gave me his universal protractor, and for the life of me, I cannot set the cart stylus location to hit both null points (without moving the protractor) no mater where I slid the cart within integrated 9cc arm headshell. He indicates that Arm was not located in the unit properly at Pro-Ject, since the two null points have to align (without moving the protractor)...
Now I plotted the config on Vinylengine's program, and input the overhang (18mm) and the effective length (230mm) and from the plot, I do not see any way those two nulls would match without moving (swinging) the protractor, as they are on an arc, and two nulls are radially in line from spindle. Purple is stylus arc, while green is line where protractor locates the two null points. Only one null location obviously can be set. Seems to me the closest way to have both nulls hit (without movement) is with zero overhang (arc thru spindle)
What gives? Is my friend nuts, or is factory installed arm wrong, needing to be moved back?
A friend gave me his universal protractor, and for the life of me, I cannot set the cart stylus location to hit both null points (without moving the protractor) no mater where I slid the cart within integrated 9cc arm headshell. He indicates that Arm was not located in the unit properly at Pro-Ject, since the two null points have to align (without moving the protractor)...
Now I plotted the config on Vinylengine's program, and input the overhang (18mm) and the effective length (230mm) and from the plot, I do not see any way those two nulls would match without moving (swinging) the protractor, as they are on an arc, and two nulls are radially in line from spindle. Purple is stylus arc, while green is line where protractor locates the two null points. Only one null location obviously can be set. Seems to me the closest way to have both nulls hit (without movement) is with zero overhang (arc thru spindle)
What gives? Is my friend nuts, or is factory installed arm wrong, needing to be moved back?
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You have to move the typical 2-grid protractor or it can't work. Download my arc generator for something more reliable and easier to use. Conrad's Free Stuff (third item down)
Hi,
That form of protractor must be moved to be useful. Settle
on a inner null point, then see how the the outer null point
varies with cartridge position and twisting in the slots.
rgds, sreten.
That form of protractor must be moved to be useful. Settle
on a inner null point, then see how the the outer null point
varies with cartridge position and twisting in the slots.
rgds, sreten.
Kudos to you Mr. Hoffman. I have recommended your protractor for years on different forums. Its easy to use, and nails it every time.
Steen
OK, apparently I can rotate the protractor (as I already have - apparently misunderstood the directions), but I will try Mr. Hoffman's protractor next...Thanks!
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