Stylus Rake Angle

There is such a thing as "good enough" indeed!

As for no VTF change with VTA change, it is complicated. Springs do NOT do acheive this as they are linear force per displacement devices, and VTF varies as a trigonometric function. Therefore, the compensation system for changing VTF with VTA to make VTF constant would need act in proportion to a trig function. Too complicated, best to adjust center of gravity height for minimum change in VTF with a given VTA change, and if you make a big enough change in VTA to actually change VTF meaningfully then just adjust VTF.

All tonearm guys who say their perfect height of the pivot point, the height of the counterweight, the underslung nature of their counterweight, or their spring, are not very good at trig, calculus, and running the experiments or they would know that they are wrong and then confirm it with the tests.

Changing VTA at the headshell brings with it several other problems while trying to solve a problem that readjusting the counterweight would have solved anyway.

Lew, I haven't carefully studied the Arche headshell, so take this with however much salt as you want.

Since the Arche's pivot for VTA adjustment appears to be placed above the top of the cartridge rather than at the stylus tip, it seems to me that it will alter the overhang and effective length along with the VTA.

hth, jonathan carr

Thank you Kiddman. But my question is really an assertion or really an assumption that although the angles may not have to match, SRA still needs to be precise and exact irrespective of the stylus still making full contact with the groove within that 3 degree allowable tolerance. I'm suggesting that that 6 degree margin is actually far larger sonically than the math suggests. Where mathematically that exact point is, is anybody's guess and seems to me what this discussion is all about according to the op.

...and hence the need to find it on the fly.

Jonathan, Thank you for your response. I too have never beheld an Arche headshell in person, but from what I've read about it on other threads, you are correct. So, my concept of how that works is to rock the cartridge either forward (and downward from the horizontal plane with respect to the top surface of the cartridge body) or backward (and upward from the horizontal). True, this would very slightly alter overhang and effective length, in either case, because the stylus tip must move in an arc along with the cartridge. But since very tiny movements of this kind have a drastic effect on VTA and SRA, perhaps the effect on those other two parameters would be minimal, i.e., acceptable. I guess there's no free lunch.