Turntable ground

Not strange at all. EVERY turntable system is different based on gear. Last week I helped a customer who was having grounding/hum issues and it took 4 grounding cables to get the hum to completely disappear. Yes that is unusual, most require 1 - 2 cables depending if using an SUT or not.

At the end of the day it is all magic to me.  I can still remember my first Electrical Theory 101 professor trying mightily to teach us all the theory of magnetism.  At the end of the lecture he smiled, broke his chaulk in half, threw it in the air and said "It is all magic after all!  Class dismissed."  Grounding, magnetism, same same just accept that it works, except don't try too hard to understand it.  It will just screw with your head.  

I've had great successes in substantially reducing earth loop issues by using a wire from a stripped Telecoms Cable.

Using Wire of this type is extremely cheap, as an old redundant Ethernet Cable will be a satisfactory donor. Wrapping connections with a wire and creating a bridge between Input > Output has done the job to my satisfaction.

Typically, if a SUT is in the signal path. The SUT's - Input > Output and Phon' Input bridged with a cheap copper wire is a working solution on my ancillaries used to add gain to the generated and sent signal.