vpi aries/jmw-10, grado hum

Grado's are notorious for their unshielded cartridges. Most commonly they react to the electronic field of the motor in a turntable which is commonly on the far side of the table from the arm. As the arm moves toward the center the hum becomes more and more apparent. The are some things that can be done to shield the motor but I'm not knowledgable about VPI. From your description of when the hum appears I would think the cartrige is too sensitive and you will, ultimately, have to replace it with a different brand.

Try grounding the turntable with the tonearm to your preamp.

Newbie is right. The Grado hum problems are well-documented.

I run a Grado Sonata on my Rega Planar 3. I was told that it would be hit or miss with each individual Grado as to whether there would be hum if used on Planar 3's. I have a tiny bit of hum as the cartridge gets near the end of the LP, but nothing so bad as to warrant a cartridge swap. Some people with Planar 3's report significant hum.

I am virtually positive that there is a "hum eliminator kit" for the Planar 3's that is made precisely for the purpose of addressing the Grado hum problem, but I do not know who makes it (or whether it is still available).

I also have a VPI Aries. I ran the Sontata on the Aries for awhile and never had hum. Given that the motor on the Aries is outboard and exposed, I don't know what could be done to shield the motor from the cartridge. There is a plastic motor cover that comes with the table which sits over the motor and plinth, but I do not know whether it would help (and it looks ridiculously out of place on what is otherwise a beautiful turntable).

Hope this helps.