Tonearm recommendation

fleib: Finally! a more direct answer from you, good. I have no time now to give my point and I will give latter on.

Thank's.

R.

Fleib/Lewm

I calculated the effective length required to achieve a 21.5 degree offset with Lofgren A for the Dynavector arms. This would result in the cartridge being in line with the vertical bearings.

Using the formula
Effective Length = (r1+r2) / [ (sine(a)*[ 1 + ((r1+r2)squared / (r1*r2))] ]
where r1/r2 are the nulls & (a) is the offset angle.

Result is effective length of 254.97 and overhang of 16.158.
This is impossible with the Dynavector unless you extend the length of the arm or headshell.

This underpins that one really cannot judge an arm without at least trying the geometry that the original arm was designed for. Furthermore Rauls contention that he altered the mounting distance for Lofgren A to optimise the performance on his Dyanvector was probably wrong unless he modified the arm.  

My point was not about whatever is the "correct" geometry for a DV505/507, because I don't know what that is, except it's likely to be at least close to Stevenson.  My point was that twisting the cartridge/cantilever in the headshell such that the arc described by the cantilever is not in the same plane as that of the vertical bearing of the tonearm did in fact seem to produce unpleasant distortion (as opposed to "pleasant" distortion).  This is in agreement with Dover's line of thinking.  I heretofore kept this to myself, because this is a single observation of mine.  I was very interested to see that Dover and some others have arrived at the same conclusion.

In my case, I own a UNItractor, from Dertonearm.  He kindly supplied me with a template dedicated to the DV505.  That's what I now use to align my DV505, and it results in "correct" alignment of the arc of the cantilever vis a vis the arc of the vertical bearing.  Separately, I also have demonstrated to my own satisfaction that the DV505 comes close with standard Stevenson, using a Stevenson protractor I downloaded from VE for free.  But I don't now use that; I use the UNI for the DV505.  Dertonearm's design is complex and a bit cumbersome to use, but it is also ingenious and permits very accurate alignment because of the ancillary tools he provides.  However, I cannot quote distances in fractions of a mm; I'm just a slave to the UNI. Life is short.

Only the inner null is close to Stevenson. The outer null is exactly Loefgren B.