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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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lewm
13,266 posts
 
Smoffat, I think your sequence would work, except then the truly precise audiophile has to start over back at "VTF". In other words...
VTF
Overhang/Zenith
VTA/SRA
Antiskating
Azimuth
Damping
VTF
Overhang/Zenith
VTA/SRA
Antiskating
Azimuth
Damping
Etc.
smoffatt
205 posts
 
Thanks Lewn. You've confirmed my understanding of the adjustment sequence. Understood that once VTA/SRA have been adjusted, Overhang and VTF have been compromised and need to be re-visited.

I do have a USB microscope (Dino) that i have been using to assess my SRA angle. I had sent a few pictures to Wally Malewicz to get a feel on accuracy. The first one was not clear enough. The second picture, which i thought was right on 92 degrees was actually 94 as per Wally. The 3rd one which i also thought was right on 92 degrees was actually at 91 as per Wally. So you can make your own assumptions but unless you're a rocket scientist able to use a USB microscope properly, i suggest that you throw it out on the sidewalk and adjust (repeatedly i must admit) by ear as described by Doug and others in this thread until it's dialled in to your own ears.
Sly

peterayer
1,382 posts
 
Smoffatt, Here is my sequence, (SME V-12 arm) realizing that others may do it slightly differently. I tried the 92 degrees with USB scope and now just start with arm horizontal and adjust VTA for favorite LPs by listening. If lazy, I just pick a good, average VTA setting.

Start with arm horizontal and anti skate at zero
VTF
Overhang (with Mint protractor)
Zenith (Mint protractor)
anti-skate
Azimuth (not adjustable on my arm)
Damping (tried it, don't need it)

Listen

VTA 2nd round fine tuning by listening to representative LP
anti skate back to zero to
reset overhang for new VTA
reset zenith due to new overhang
reset anti skate by listening
decide if re adjusting VTA for each LP is right for you.

Ready to listen and enjoy the music
smoffatt
205 posts
 
Thanks Peterayer. I have a Mint LP for my Graham Phantom II. My cartridge is Ortofon A90.

I would also re-visit VTF the second time around.
I will find a good compromise/average for VTA/SRA and set it and forget it. I'm no longer using my Dino-Lite USB scope for viewing/setting VTA/SRA.
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