2. analog
  3. 1379522903

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??
128x128stringreen
Ag insider logo xs@2x
drrsutliff
860 posts
 
I think they are all correct. The issue is the groove bearing edge or facet edges should be at 92 degrees, but if you have an additional facet on the back (towards the cartridge body) of the diamond you cannot use that back edge as your measured line with the microscope. Visualizing the facet edge contacting the grove can be difficult. It is usually the junction of two facets who form the line on the side of the diamond somewhere between the front and back of what you visualize on the microscope computer projection. If you used the easily visualized back edge of the additional facet and set it to 92 degrees, your actual contact line could be at many degrees above 92. I hope this helps some.
stringreen's avatar
stringreen OP
6,470 posts
 
Guessing is way too complicated with this cartridge on this installation. What I did today was LISTEN. The arm is a bit high, but not absurdly so which the microsope dictated. I just heard Mahler's 2nd symphony conducted by Bernstein on DG....E-Gads....I never heard anything so fine. Because the arm was raised, the VTF is now probably a bit too light, the Azimuth, is probably skewed....I'm too tired to futz with this arm. When Harry sends me the new weight he promised, I will fine tune the setup.
stevecham
3,340 posts
 
The whole point of this exercise is moot simply because no two pressings are going to be exactly the same thickness. Way too much attention is paid to this VTA/Rake issue IMO.

The answer is to set it by ear (as you have done?) to a ~180 gram pressing and be done with it. Some records will be thinner, increasing rake, and some will be thicker, decreasing rake.

Set it and, please, by all means, forget it!

Listen to some music!
More to discover