Tri-Planar grounding question...

Dogpile, It is my understanding that it is common among shielded interconnects to connect the shield to the negative wire, which can cause a ground loop since the negative wire often does double duty as the ground.

If in the Triplanar, if the shield and the tonearm are connected to the ground wire which is in turn connected to a grounding post that is out of the signal path, then I don't think such an arrangement would contribute to a ground loop and would be superior to affixing the shield to the negative wire in the interconnect.

If the grounding post is connected to the negative wire somewhere in the circuit downstream, then such a configuration could contribute to a ground loop.

I think this is arguably an advantage of xlr interconnects in that the shield is never connected to the negative wire and the ground is altogether out of the circuit.

This is my beginner understanding of grounding topology. Perhaps Ralph or somebody with more grounding understanding will jump in here.
Jeff

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