Like I’m sure many of you, I’ve become aware of “stylus rake angle” (SRA) as an improvement of the venerable measurement of VTA as promoted by Michael Fremer.
I’ve done some experimenting with it using the macro lens of my Olympus mirrorless camera and I must say I’m not overly impressed. Fremer recommends an optimal SRA of 92 degrees to mimic the angle of the record lathe while cutting. I find SRA to be frought with measurement error. You have to get the USB microspcope/camera exactly perpendicular to the cartridge which is a little tricky. Then you have to make sure that the scope/camera is perfectly level, which is a hassle. Third, your line of sight has to be exactly level with the tip of the stylus. Furthermore, it’s very hard to get styli with eccentric contact zones measured correctly. I have two carts and both have irregular stylus contact points in the Shibata stylus of the Ortufon 2M Black and contact line stylus of the Soundsmith Zephyr MIMC Star. Plus, the SRA changes as the record plays (increased friction flattens cantilever and SRA) so a static measurement isn’t a real world scenario, honestly. Now I just get the cart and tonearm level using a spirit level and then drop the tail of the cart a couple degrees and then use a couple tracks with a lot of treble to adjust by raising the tail until it sounds right. For reference I’ll check with digital files that are EQ’d closely to the vinyl. I find this method superior to trying to do this by means of SRA. Maybe I would benefit from a USB microscope to do this more accurately, but I don’t want to spend the $200 necessary to get a decent one. What are you guys experiences with this??