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Stylus Rake Angle

I am trying to set up my new VPI 3D arm as close to perfection as I can. On the Analog Planet, Michael Fremer gives one opinion, however, a different opinion was voiced by Harry at VPI, and Peter at Soundmith. I've been discussing this with them....Fremer says that SRA should be adjusted even if the back end of the arm is WAY high up as needed, whereas Harry, and Peter said to start with the arm in a horizontal position and move it slightly up and down to find the sweet spot. Peter said that my cartridge (Benz LPS) and some others have an additional facet in the diamond so bringing the arm up in back would be exaggerating the proper SRA. When I wrote back to Fremer, he answered with an insistance that he was correct. Does anyone want to add to the confusion??
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csontos
1,311 posts
 
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.
csontos
1,311 posts
 
...and hence the need to find it on the fly.
lewm
13,228 posts
 
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.
lewm
13,228 posts
 
I was trying to fix my post when I accidentally posted it. I obviously was referring to the front end of the cartridge body when I wrote that a "forward" tilt would move the cartridge body "downward". The rear end would move upward.
atmasphere's avatar
atmasphere
11,901 posts
 
I'm still wondering why, if slant angle varies not only from record to record but by the signal itself, by a cutter who's VTA is for all intents and purposes static, does cartridge VTA/SRA need to match VMA?

The SRA of the cutterhead does not vary with signal. It is a constant.
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