Need to purchase a separate ground cable - from my TT to my Phono Preamp

GOT IT 

Electrons have become very fashion conscious lately...conductors must be silver plated, have at least 6 Nines, clad in PTFE jackets, with gluten-free packaging.

In other words, standard 20 ga. hookup wire with or without spade lugs crimped on should get the hum out.

My TT has no separate ground wire and it is dead silent. 
even with a MC cart. 

YO MR. CRUSTYCOOT - I am going your route - Vegan Wire with a dash of hot sauce - Combined with a slather of pig fat so it doesn't get dried out. 

20 ga. with with spade lugs.

Thank you to all and to all a goodnight.....