How to set SRA after determining true vertical?

Ohhhhhhhhhh, you guy's are making my head hurt. I knew I shoud have stayed awake in algebra class (I never even made it to geometry). I'll supply the beer if one of you will just come on over to my house and set my TT up!

Chris

Simple applied trigonometry. I just can't seem to think like an engineer any more after all these years of writing software.

Thanks again, Neil.

Dan, architecture (what I do to support my audio addiction) is all about geometry, so it comes quite naturally ;~))

As I have said before and nobody pays any attention. Probably becuase they think I'm wrong. Your record could care less about the cutting edge angle. What you want is maximum contact with stylus and grove. if you are lucky this will occurr when the headshell is parallell with the record surface.

When that happens you can then use the catridge angle as a tone control rocking it back and forth by raising or lowering the back of the tonearm. vtf can also change this angle. the more down force the more the cantilever will deflect. Stereo seperation is affected by antiskate and azimuth.what you want there is the the stylus riding in the direct center of the grove. easier for linear arms.

what's important then is the angle of the stylus not the angle of the cantilever. the stylus should be perpindicular to the rcord surface. If you took an xy graph and placed it on the record surface and placed the stylus at 0,0 or dead center and measured the angle in a 360 degree rotation you want 0 degree deviation all the way around.

Take a nail and dirve it into a board at a 90 degree angle about 1" from the end. You will see that the nail will be perpindicular to the surface. Now lift the end of the board 20 degrees. the nail is no longer at 90 degrees. you have two choices either bend the end of board 20 degrees or drive the nail in at 70 dgrees to compensate.

The cartridge and arm manufacturer do this for you as best they can. There are two variables they can't account for vtf and record thickeness. those two things must be accounted for by the end user. It might be easier if you chose the same cartrdge tonearm and turntable as the cartridge designer used.

Once you determinde the the arm is level by making sure the height of the arm is the same at the stylus, midlle and pivot hopefully the stylus is now perpindicular to the recocrd surface. You should be getting maximum contact with the stylus and grove as the cartridge manufacturer intended. My sme 4 provides a line through the middle of the arm for this purpose. You can then simply lower or raise the arm for different record thickness. Of course you should determine vtf before you finalize this process.