Integrity Hi-Fi tru-glider tonearm

@lewm Great technical discussion with much details.  Thank you.

I don't think @drvinyl01 meant to imply that the arm does not have a pivot point.  What he said was, "There is no fixed pivot point."  What I think he refers to here is that because the TG mounts to a tower that is not attached directly to the TT in any manner, the pivot point, i.e., the location itself, is not fixed.  Thus the arm/tower can be placed at any location around TT with the correct distance set.  

I run a similar setup with two Schroeder arms - one, the Ref SQ that you mentioned above, and an LT - each on their own tower.  I position the Ref, distance and angle, to orient the arm at the two null points of the Schroeder protractor.  I position the LT based on its required distance from Pivot point to Spindle.  And then I rotate the LT's tower, around this distance point, for the stylus to lower just inside the outer edge of the LP right at the LT's notched "rest stop".  I check the PtoS distance again and tweak the tower distance as required. Having the freedom to position the arms around the TT and the motor tower, is mighty handy.   Because of this, I seriously considered the TG but I got good deals and excellent support with the two S arms.

John

As I read the latest posts here, I see there is much commonality between the Schroeder Ref SQ and the TG tonearms.

The Schroeder’s string attaches to the top of the tonearm’s structure. The string’s endpoint attaches directly under the arm tube through an "attached-to-the-tube" convex magnet. Another magnet below, which appears to be a flat surface, attaches to the lower end of the tonearm’s structure. So no, the Schroeder arm does not pivot around a string; it simply hangs from a string as does the TG.

The key adjustment is the gap between the magnets. Frank’s documentation suggests that a business card gap works well. I have experimented with this and found that the shortest gap possible provides for the greatest bass extension. I start with the magnets close so that I can barely get the smallest feeler gauge through the gap. I raise and then lower the arm over an LP, and observe that the arm’s lowering down to the LP. With the magnets tight, the arm slightly shifts along the horizontal axis on its way down. I make very small adjustments to the gap until lowering the arm results in a smooth, i.e., no sideway shifting, all the way down.

I will leave it to the mechanical/structural engineers to debate the benefits of the magnetic coupling below the Schroeder's arm tube and no coupling below the TG’s arm tube.

I could not attach a closeup picture of the Schroeder’s string/magnet view here so I added such a picture in my virtual system page.

John