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Digital Microscope advice SRA

I have my digital microscope (DM) installed on my laptop. I want to use it to aid me in my stylus rake angle SRA.Has anybody tried this before? I'm looking for any helpful ideas or aids from someone who has gone through this before.I understand that the TT platter should be taped or otherwise kept from moving. I'm thinking that some sort of white background to have as a contrast. I intend on using an old Album of no use as a platform to make sure of the correct height with the stylus resting on it.
I've already figured out how to get the angle degrees with the software. So am I forgetting anything?Just using it to inspect how clean it is. Is a P.I.T.Arse.  Any little movement and where did the stylus go? I have to readjust everything again.
BTW, I'm using FLUX hi fi stylus cleaner Which works beautifully I might add, 10 seconds and wow. spotless.
128x128joes44
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rauliruegas
13,093 posts
 
Dear @joes44: A few years a reviewer discovery the " black thread " with the use of a microscope to fix the rigth SRA ( I think MF. ).

Don't waist your time as he did and do, everytime he has a new cartridge, as several " audiophiles ".

During playback SRA/VTA is changing at almost each single groove in the LP due that the LP surface is not absolutely FLAT always exist micro and macro " waves ", additional the LPs comes with different tickness where always the SRA/VTA will be out of our original SRA/VTA set up.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.
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tcbrinkley's avatar
tcbrinkley
20 posts
 
Others can debate the value and effectiveness, but to specifically answer your question about using a digital microscope, here’s a 5 min video by Mike Fremer who I consider a premier expert https://youtu.be/otysEyET6yE

You might also enjoy and learn from his one hour siminar on all aspects of turntable setup, including info on the microscope/SRA adjustment
https://www.youtube.com/watch?v=eQDa7suJn64&feature=share

Happy listening 


tcbrinkley's avatar
tcbrinkley
20 posts
 
Also...
just for fun I measured a few regular and 180 gram records and saw an average  thickness difference of around .6 mm in a range from 1mm to .25 mm.
On a 9” arm .6mm height difference  equals a change of .15 degrees (.12 degrees on a 12 inch arm) or about one turn on a VPI VTA on the fly arm.
Fifteen one hundredths of a degree? I’m amazed that makes a difference.
atmasphere's avatar
atmasphere
11,841 posts
 
An additional bit that can mess with things is that the cutter head's rake angle isn't a certainty!


A cutter stylus lasts about 10 hours of cutting. It has to be heated for best noise floor; as it wears it gets noisier and the temperature has to be adjusted but eventually it simply has to be changed out.


To do that the cutter head is removed from the lathe and the stylus is replaced. Then the head has to be set up again- to get the stylus to the proper position, depth, etc. Once that looks right, then test recordings can be made. Its right when the groove is completely silent. And by 'silent' I mean so quiet that literally the playback electronics are the noise floor.

At no point is there a measurement of the rake angle. The engineer is setting up for *lowest noise* and not anything else. Each stylus is a bit different, so after replacing one the engineer might have to do a bit of head scratching to get it right again. So that whole 92 degree thing is an approximation; its not cast in concrete and every LP is slightly different on this account.


IMO (I own a Scully lathe with a Westerex cutting system) this is a thing that isn't worth your worry. About the only thing that the microscope might be good for is making sure that the stylus is indeed on the end of the cantilever in the first place and that its not at a weird angle and so on- that you **will** be able to set it up in your arm.
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