SRA change from 140g to 180g


Assuming there is 1mm difference in thickness betw 140g and 180g record and I started out with a 140g record with SRA at 90 degrees. When I put on a 180g record, SRA changed by 0.25 degree. (Provided I mantain the same VTF and using 9inch arm.

Is this correct? sin-1 (1mm/ (25.4mm*9))

I am amazed at how much I need to adjust VTA to maintain the same bubble reading on the Phantom 2.

I ultimately set by ear and ignore the bubble.
128x128glai
Glai, thanks for the comments-appreciate it. Mid last year you posted several times regarding the Spiral Groove Centroid arm. Did you ever try that or explore this option?
You r welcome. I have not tried the centroid but feel that it should be at least competitive with the graham. I am waiting to see how the SG2 perform first.