Analog Magic Question

Most cartridges will exhibit at least some zenith error.  Parenthetically, for those who don't already know, zenith for us audiophiles refers to the angle that the stylus contact patches for left and right channel information, respectively, make with the groove wall.  Someone else quoted the industry tolerance for a +/-5 degree error, which is huge. Because of zenith error, any subsequent effort to "zero in" on the alignment of an overhung, pivoted tonearm is folly. You won't get the null points where you think they are, if indeed you get any null points at all on the playable surface of the LP. So, for me, once you've set overhang and VTA, the most important thing is to correct for the inherent zenith error built into the cartridge.  And yet, only Wally has marketed a tool to correct it, so far as I know, and I have heard that the tool is difficult to use and/or may require sending the cartridge to Wally.  But if you are finicky about alignment, you gotta face the music.

@ledoux1238 

You ask a fair question, what am I hearing?  How do I characterize the sound of distortion?  Or more specifically, when distortion is reduced, what is the result?  I am not good at describing sound.  My records sound clearer, more open.  An analogy might be drawn with photography.  It is like the difference between a well depicted image and one that is a little bit blurred.  I am still hearing that it is a Steinway backing Sarah Vaughan, but both are easier to hear.  Does that make sense?  The difference is not subtle I can tell you that.

Lewm,

Now you know of two and I can tell you from having used both, that for correcting zenith AnalogMagik is far easier to use.  The other parameter that by measurement contributes significantly is azimuth.  These two together, azimuth and zenith, contribute more distortion, and in consequence offer the greatest opportunity for improvement of all of the variables.

@lewm 

I have heard that the tool is difficult to use and/or may require sending the cartridge to Wally

The Wally zenith tool is easy to use IF you send the cart in for microscopy analysis which precisely measures zenith error as well as providing a custom shim to optimize SRA/VTA at the headshell, which is what I did.

Otherwise you are correcting by ear which I imagine isn't easy, hence Bill's comment that AnalogMagik is easier.

I have not used AnalogMagik so I am not advocating one method over the other.  

And further to that point I did not send my cartridge for microscopy analysis so my comparison is not fair either.  One other interesting observation is that using AnalogMagik I found SRA and VTA contribute comparatively little distortion.