Tri-Planar grounding question...

Jeff, I think you got it right. The reason it is not a ground loop is that the only place the ground occurs is the shield of the cable. Without that connection to the arm, the arm would be floating and it would buzz like crazy!

This concept is common to nearly all tonearms BTW (including BSRs from the 1960s). Since the arm is a separate ground circuit from the cartridge wiring, it is also why tone arms are or can be a balanced source.

All you cats have been a great help - a very kind thanks : )

I have one more Tri-Planar connection question;

What is the black ground wire (within the cable) attached to on the rca end? Is it attached to the cables shielding or nothing at all?

Dogpile, my setup is balanced, but the wiring is identical up to the box in the cable. The Black wire is the shield up to the box and connects to the tone arm ground itself. After the box, the black wire breaks out to its own connection, and ties to the ground pin of the preamp at its input.

A while ago, I documented the conversion of a Tri-Planar from RCA termination to balanced XLR, for use with my Atma-Sphere MP-1 preamp.

The photos in this website might help you visualize the discussion above: http://www.galibierdesign.com/prd_triplanar_xlr_build.html.

Of particular interest, after this termination is complete, the braided shield you see will have electrical continuity from the tonearm's headshell, straight through to pin-1 on the XLR connectors.

Cheers,
Thom @ Galibier

Atmasphere. I see where the black ground wire exits the box and have opened the box as well to see wire configuration.

The black ground wires which starts from the tonearm pillar DO break up within the box but also continues along the two L/R signal cables as well.

I can't unscrew the rca plugs for a peek since they have been wrapped with heatshrink.