DagwoodGum
Squirreling Dervish
exactly, Hubbards original testing of the emeter did not have cable shielding on the wires going from the cans to the emeter. Toroids prevent wires and cans and a human as acting like an antenna to pick up RF signals and higher. Hubbards testing is done in an uncontrolled environment.
CB radios, TV cable, all use coaxial cable shielding. The center terminal is the signal, and the shielding is the ground connection, some more expensive cables have an additional aluminum shield in the cable to prevent unwanted signals entering in to distort. There is also the matter of the dialectic used to separate the center terminal from the outside ground shielding.
The emeter and cans use only wires and no shielding, nor is there positive or negative. Just thinking out loud, the proper way to test the emeter would be to have a testing done in a closed environment, like a large box that has been magnetically shielded from any outside influence.
FYI, old instuments of high standards had their electronics in a box lined with copper, these are precision instruments.
Cable 101:
https://www.belden.com/docs/upload/Insulations-Jackets.pdf
What just hit home as a result of this dialog is the true meaning of Elron stateing that "50% of gains come from training".
During my training package I was constantly twinned up where I was holding the cans during all the auditor drills.
After day after day of this for months on end, I was soooo buzzed up with a persistant f/n and floating t/a that my grades were completed in the evenings after a modest succession of short sessions with a "natural clear" determination off some list, could just have been a green form though I don't remember.
It was during this time I became hypersensitized to electrical currents, that I caught a substantial buzz when I would look at high voltage electrical transformers, as wierd as that sounds.
This went on for years.