Debuzzing a Wheaton TriPlanar problem

Can you tell whether the cartridge body itself is vibrating so as to feed back into the tonearm wand? That is the only mechanism I can think of for this strange phenomenon. If you ignore the problem and play an LP, what happens? Is there added hum coming out of the speakers in addition to directly from the tonearm? Have you tried changing cartridges? If the insulation on the tonearm leads has a defect such that one of them is in bare metal contact with the tonearm wand, I still don't see how that would cause the phenomenon you report. The odds are vanishingly small that there are TWO defects, one on each lead such that there would be a voltage delivered to the tonearm wand (maybe). But strange things do happen.

Sometimes grounding everything to everything is a bad idea. Try removing some of those ground wires. But on the other hand, your report is clearly out of the ordinary; as you know, 99% of the time grounding problems manifest themselves on the amplified audio signal only, not in the form of causing vibration of an inert metal part.

Based on your responses to Dave and Ralph, I am now thinking that I got it wrong. Am I now correct in thinking that the tonearm per se is not necessarily vibrating but that the hum you hear (over the speakers, I presume) is ameliorated when you grasp the arm tube? If so, this makes much more sense, and I agree with Dave. But I will throw in another idea; the arm tube structure is grounded to the arm pivot (i.e., makes electrical contact with) the bearings only. I once had a maddening hum problem that was only cured when I took my tonearm to Herb Papier (the inventor and original manufacturer). Herb lived about 10 miles from my house. Herb took my arm, and before my eyes he tightened the bearings by a hair, and the problem was gone. That has to have been nearly 20 years ago, and I have had no recurrence of the problem. Problem is you need a Herb or a Tri to do it so as not to over-tighten the bearings.

Wow! Why so glum? Send it back to Tri, and he can tighten up the bearings to restore the proper ground connection, if that really is the issue, which I am beginning to believe it is. None of the strategies you mention could be expected to cure that problem. Just explain the symptom to him, and refer him to me if he does not get it. (We have met a few times; I was at Herb's house when Tri was there to learn how to build the tonearm. I last talked to him in person at RMAF last month.) The cost of shipping to and from Tri for you would probably be less than $25 round trip, if you use US Priority Mail. Chin up, old man! Hum due to bad, inadequate, or incorrect grounding is ALWAYS fix-able, and definitely does not indicate you have a defective sample. IOW, shit happens.