Grado Sonata pops out of grooves during crescendos

Doug, the reason VPI suggests that owners add an additional .1 gram to the cartridge manufacturers specified tracking force is because VPI arms do not incorporate any anti-skating mechanism. If I understand their design philosophy, they feel that less harm is done by this slight increase than would be done by the forces applied in an anti-skating scheme. The Grado Sonata is one of two cartridges that VPI sells and sets up for owners at the factory, so they are very familiar with this one. Thanks for the suggestion regarding a possible resonance problem. I just found it very peculiar that this problem occurs only on one out of hundreds of lps. I'll double check tracking force again.

Photon,
Thanks for the explanation, understood. Of course that just makes the problem more mysterious. :-( Do you ever see the infamous "Grado wobble"? That might be related to the resonance idea.

Yup, I definitely have had intimate familiarity with the "wobble." Several lps with slight warps on the perimeter excite the cartridge suspension and the wobble dance starts. I'll look closely while playing the suspect record & see if there's a connection. Will.