Lyra Atlas experiences

If I may jump into this erudite group with a related question ...
My Lyra Atlas lives on a Basis Superarm 9 on a Basis Inspiration table, set up by the dealer, and it sounds superb.  But on rare occasions and only with a "hot" recording of piano, I'll hear breakup in the left channel.  Cartridge weight was set to Lyra's recommendation.  What's the most likely fix, do you think?  I don't want to start messing with the wrong parameters.  

Drastic....   After inspecting the stylus and declared it not bent......I would make positive that the turntable itself is level, I would make positive (using an electronic scale) that the vtf is exactly what the cartridge manufacturer recommends as optimum (not a range)... then I would absolutely make sure that azimuth is set correctly using the Fozgometer and its recommended lp using a brand new battery. If that doesn’t work, get back and we’ll go further.

Nandric....did you get up on the wrong side of the bed this morning or are you always mean spirited?

Stringreen - Thank you.  All this will be done.  Though I don't have a Fozgometer (my dealer does this by ear), I presume you feel that having the instrument is important so I'll get one.

Drastic - breakup in left channel - can you give some examples, I’d like to test this in my system also. I have heard that kind of thing before. Is it mainly on the inner part of the record? Can you check, it is associated with mistracking, inwards or outwards? In my system, I can’t recall my Lyras have mistracked much inwards, mainly outwards (groove is repeated). And the Atlas seldom mistracks anyway.

Stingreen - nice to hear about the arm - I have a VPI HW-19, upgraded over the years, although now I mainly use another player (Hanss T-30). I had a Souther / Clearaudio parallel arm for some years, but could never get it to work well with the VPI.

A little reality check today. I played my three versions of Credence Clearwater Revival: Heard it through the grapewine. If my cartridge is poorly adjusted, I will be confused which one sounds best. I wasn’t. Instead I could hear, not only, that all in all I prefer my latest (Acoustic sound RTI) version, next the Mofi version, and then the original - but I could hear the different plusses and minuses with each version. My gratitude to Lyra.

This experiment does not prove anything, except that it indicates that if the cartridge is fairly well aligned, other matters tend to take over - like the quality of the mastering and pressing. The guitar went from good to great, on the best recording.

Happy listening!