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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
 
Google 'record groove modulation photo'
csontos
1,311 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? Does it not stand to reason that in the same way variations are produced, the same information will be retrieved? Albeit once external influences such as adverse lacquer/cutter interactions are compensated for via SRA adjustment? Once adjusted, will the play back stylus not follow the same behavior as the cutting stylus. Same VTA constant.
csontos
1,311 posts
 
When I adjust SRA to where it sounds correct, how close is it to (average?) VMA? It sure sounds like the entire frequency spectrum is correct, not just parts of it.
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rauliruegas
13,101 posts
 
Dear Kiddman: Great post/contribution. Thank's for that.

Regards and enjoy the music,
R.
ack's avatar
ack
115 posts
 
@peterayer: adjusting VTA/SRA affects tracking force and other parameters, so what you are hearing is probably a combination of all these parameters, and perhaps more of the tracking force than the very tiny SRA/VTA adjustment you affected (if you do the math for your 12" arm, you will probably see that the difference is less than 1/4 of a degree for a 1mm vertical movement of the arm at the pivot point - perhaps significant, but I somehow doubt it).
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