Lofgren A and Lofgren B

[ovlov854]

Can anyone tell me the difference between the above?

I am setting up an Audio Note V2 arm and a Denon 103 and find the supplied AN cardboard protractor less than helpfull.
I have found a site where one can put in parameters and it will print out a protractor but there are differences between Lofgren A and B

[Ammonite Audio]

Either Lofgren A or B represents a compromise regarding tracing errors and tracking distortion, and both are perfectly good and nobody should worry that one or other must be 'better'. Vinyl Engine sums up the differences:

Baerwald
Identical to Löfgren A, minimizes and equalizes distortion at the three weighted tracking error peaks resulting in moderate distortion between the inner and outer grooves

Löfgren B
Minimizes distortion between the inner and outer grooves resulting in the lowest average RMS distortion at the expense of slightly higher distortion close to the inner and outer grooves

So, if you are concerned about higher distortion at the end of an LP, then Löfgren A might be preferred, but there's nothing to stop you from trying both and using whichever sounds better to your ears.

[ovlov854]

Either Lofgren A or B represents a compromise regarding tracing errors and tracking distortion, and both are perfectly good and nobody should worry that one or other must be 'better'. Vinyl Engine sums up the differences:



So, if you are concerned about higher distortion at the end of an LP, then Löfgren A might be preferred, but there's nothing to stop you from trying both and using whichever sounds better to your ears.

Thank you Hugo

[Barry]

Unless you can change the offset angle, by 'slewing' the cartridge in the headshell, as well as adjusting the overhang, you are really obliged to follow the geometry for which the arm was designed. To that end you need to use the protractor that came with arm.

With Lofgren B, whilst the tracking distortion over most of the LP is reduced, it is significantly increased towards the end of side; exactly where the effect of other tracing errors increase ('pinch' distortion). To my knowledge there are very few arms that are designed to follow Lofgren B.

Give the geometric values for the Audio Note 3 V2 arm, the two null-radii can be calculated to be at 60.3mm and 114.2mm, which suggests the arm is designed to follow the Stevenson geometry, rather than either of the Lofgren geometries. This is quite usual for most Japanese tonearms.