SME V arm: dynamic VTF or straight weight

Raul and Daniel,
Thank you very much for your comments and thoughtful advice. Raul, I did try loading the PC-1 with 100 ohms just like my old Sumiko Celebration, but something was missing. With the help of a friend, I went up to roughly 120, 140, 200, 249 and 452 and down to 75, 47, 22, and 10. As you may know the XOno has about 230 possible settings and has an active initial gain stage. I agree that the 22ohm setting seems low, but for me there is a good balance between bass definition and weight and good upper end extension without stridence. But more importantly, at 22ohm everything suddenly sounded right with air and presence. At 22 ohms, the "gestahlt" hit me and everything just sounded right.

Regarding tiny VTA adjustments: The biggest problem with the SME V design is the difficulty of adjusting height. Every time I try it, the arm column moves slightly out of vertical because the VTA screw is off center and I have to recheck azimuth. This is a big problem with the SME arm. So I tend to make very tiny VTA adjustments by altering VTF. And unless I bought the TriPlanar or Phantom, I would not consider changing VTA for each different LP thickness like some people do.

Regarding tiny VTA adjustments: The biggest problem with the SME V design is the difficulty of adjusting height. Every time I try it, the arm column moves slightly out of vertical because the VTA screw is off center and I have to recheck azimuth.

This is not the case with any of the (5) SME 312S tonearms I own or have set up. Wonder what the difference is?

Hi Albert,
That is interesting. When I loosen the set-screws at the base of the arm, I can tilt the cylindrical arm post slightly to the left or right. I had thought this was a way to adjust azimuth before tightening the screws again. Then a read a post by dougdeacon that this was not a good idea because the bearing would then not be level if the arm post were not vertical or plumb. That got me thinking that if the arm post is not truely vertical, or plumb, then all the rest of the geometry as the arm swings toward the LP center is not correct either. So now I check for level with a bubble level placed on the flat surface to the arm lock which I assume is perpendicular to the arm post. When it is level, I then retighten the setscrews. Is this slight play in the arm post not normal?

The issue with the VTA screw is that it is off-center from the pivot point so as it is turned clockwise to raise the arm, it exerts a force which tilts the arm slightly to the right as viewed from the front. I then tilt it back by pushing the bottom of the post to the right, moving the top back to the left and making it true vertical again. I thought all SME arms had this slight play at the base.

I now agree with all of those people who say that azimuth is not adjustable on the SME arms because the post has to remain truely vertical or plumb. Fortunately, my PC-1 cantilever is "perfectly" straight and centered in the vertical plane.

This thread is getting off the topic of dynamic vs. static VTF and becoming more about adjusting the SME V arm. Perhaps a topic for another thread. Sorry.

Peter,

The SME 312S has removable head shell, so the collet may be loosened and the head shell twisted to obtain proper azimuth. Once set I've loosened the post in the rear to change VTA and never experienced any "shift" in azimuth after raising or lowering the arm.

Hi Peterayer

>>> The biggest problem with the SME V design is the difficulty of adjusting height. Every time I try it, the arm column moves slightly out of vertical because the VTA screw is off centre and I have to recheck azimuth <<<

My solution:
Make some hardwood spacers (small oblong blocks) fit between armrest and clamping assembly, loosen the bolts press down on the pivot bearing-bridge. The arm will ALWAYS be level with the spacer block. I have made these according to VTA requirement. I started somewhere from 1/2" which fits for a Windfeld. If the PC-1 is by X taller this must be added.
You can achieve quite easily the small differences Raul is talking about --- AND HE IS RIGHT THERE --- a 0.3mm difference can just make that difference to be more pleasing.

Greetings,
Axel